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View Full Version : Custom, Performance Carb Intake Manifolds ( 2bbl / 4bbl )



A20A1
08-28-2004, 03:10 AM
-Just for Reference-
For A 4BBL manifold you would want to increase the runner diameter. The stock diameter is too small.

I was reading up some and found that I could increase the CFM the engine pulls by 52 if I divide the cylinders into pairs.

Below 3,600 rpm the divided plenum manifold makes more HP and Torque
Above 3,600 rpm the open plenum makes more HP and Torque

A20 @ 100% VE is good for 224 CFM @ 6,500 RPM
22R @ 100% VE is good for 270 CFM @ 6,500 RPM

The vacuum secondary 390 CFM 4bbl conversion for the 22R uses a DUAL PORT MANIFOLD which is sort of what our stock manifold tried to do. I'm guessing that having the primaries and secondaries seperated up untill the runner meets the port helps a 270 CFM motor run a 551.5 CFM carb. It probably has a simmilar effect as a dual plane but without sacrificing the top end by having access to all 4 barrels.

The A20 would peak at 276 @ 6,500 with a DIVIDED PLENUM 4bbl manifold... but we just barely inch over the 390 CFM 4BBL's rating of 275.75. Because of this it's probably better to stick with the 390 since you'll have an easier time jetting it and it will be more responsive. If you plan to rev to 7,500 then you'll get about 310.25 CFM with the manifold, but you're still closer to the 390 4bbl than you are to the 500 4bbl.

Lets see if I'm doing this right

2bbl and 4bbl are rated differently for CFM

2bbl CFM = 4bbl CFM x 1.414
4bbl CFM = 2bbl CFM / 1.414

(I'm rounding to the nerest 0.05)
So the divided manifold would make the 4bbl into two 2bbl's

390 CFM 4bbl converted to 2bbl is 551.5 CFM but since it's split into two I divide by 2 right... so then I get two 275.75 CFM carbs which is just like having two 2bbl Keihins each feeding 2 cylinders.

500 CFM 4bbl converted to 2bbl is 707 CFM but since it's split into two I divide by 2 right... so then I get two 353.5 CFM carbs... which is just like having two 38 Webbers each feeding 2 cylinders.


http://www.3geez.com/forum/attachment.php?attachmentid=3485&stc=1
* This shows the vacuum port for the rear of the manifold in the center and also the brake booster port to the left of it. The 4bbl adapter is placed on top of the manifold.

http://www.3geez.com/forum/attachment.php?attachmentid=3486&stc=1
* This pic shows me messing up and installing the adapter in the wrong orientation. The center divider to divide the plenum is insterted but not really permanent.

http://www.3geez.com/forum/attachment.php?attachmentid=3487
* This pic shows the correct orientation.

http://www.3geez.com/forum/attachment.php?attachmentid=3882
* This pic shows the bolts securing the manifold... x2
5/16" shaft with 1/2" Head.


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http://www.3geez.com/forum/attachment.php?attachmentid=3483&stc=1
* This pic shows the DGV Weber adapter, notice that the center wall has a chunk taken out of it, otherwise the rest of the port was left untouched.
* This mod can be used with JAM ENGINEERING ADAPTER (http://www.jameng.com/products/index.phtml?section=12) to use 1 WEBER DCOE.

http://www.3geez.com/forum/attachment.php?attachmentid=3484&stc=1
* This pic shows the DGV adapter on the manifold ported to accept the 4bbl, notice that the center wall was shaved down, but so was most of the original manifold port as well. It's possible to remove the center wall entirely... and only widen the port enough to match the port on the DGV adapter plates.


POSSIBLE STOCK MANIFOLD MODIFICATIONS

1bbl X 1bbl Manifold ( BIKE CARBS )
http://www.3geez.com/forum/attachment.php?attachmentid=3879

2bbl X 2bbl Manifold ( 38/38 WEBER CARBS )
http://www.3geez.com/forum/attachment.php?attachmentid=3880
http://www.3geez.com/forum/attachment.php?attachmentid=3884
* The pic shows a 32/36... a 38 will be used instead and it will face the other way so that the fuel neck doesn't hit the valve cover... I used that orientation in the pic because I had an elongated throttle shaft.
* This mod can be used with JAM ENGINEERING ADAPTER (http://www.jameng.com/products/index.phtml?section=12) to use 2 WEBER DCOE's.


4bbl - 2bbl X 2bbl Divided Plenum Manifold ( DOMESTIC 4BBL CARBS )
http://www.3geez.com/forum/attachment.php?attachmentid=3881
* This mod can be used with JAM ENGINEERING ADAPTER (http://www.jameng.com/products/index.phtml?section=12) to use 2 WEBER DCOE's.

A20A1
08-28-2004, 03:11 AM
I hope to get pics from Phydeaux to complete his project.



I'm just toying around with an idea that I'm not sure will work yet but I'll throw it out here anyway. I remember a few people talking about making a performance manifold for the Weber DGV I got thinking and started looking into things. Making a new manifold wouldn't really be practical. It would be harder to make, i.e. cost more, then a DCOE manifold. The way I see it if people could afford the DCOE manifold why would they bother with a DGV. Basically what I'm doing is modifying the stock manifold to have a larger plenum and accept a Weber carb without an adapter. I making this with the DGS in mind but a DGV will be able to work on it with no problems. Basically I'm grinding out the plenum area. Not just the dividing walls but also the whole plenum area, removing the top and all reshaping it for max volume. Then I plan to weld a new top on the plenum ready to accept the DGV series carb. This manifold should give the car better breathing up top and be good on a stock or mild cam engine. I have no idea on pricing yet. Most likely it will be less then $200. I just started making the prototype and I'll have a better feel once that’s done. I'll probably also put a $50 core on it so those who buy one will send me their old manifold. Manifolds are such a pain in the ass to get off at the junkyard.

A few updates. I might consider making the manifold to fit a DCNF if the interest so arises. The DCNF is a 2 barrel down draft carb usually found on Italian V configured engines, Lambo, Ferrari, etc. The common bore sizes on e-bay are 40 or 42mm, though they came in 36, 40, 42, and 44mm versions. Used they don’t tend to cost any more then a DGV. The carbs are performance carbs and are fully tunable. The available choke sizes range from 23-38mm. The DGV uses a 26 and 27 mm choke, not changeable, and the DGS uses 2 27mm chokes, also not changeable. This could prove to be a rather potent setup.

It should clear the hood using a short stack. It’s no taller then a DGV, which is why I'm thinking about it instead of an IDF or IDA series carb. The bores are also closer spaced making it fit the plenum better. The way I am setting this up there will be no adapter plate so the carb will sit closer to the manifold to help with clearance issues as well. The only major concern I have is that the carb will be sitting sideways. The throttle shaft is supposed to sit parallel to the crankshaft on an inline engine; the DCNF will be sitting perpendicular. I've read that this can cause issues with uneven distribution of mixture to the cylinders, but I don't think it will be an issue here with the enlarged plenum. Though the only way to find out is going to be when I finish building it and test it out. I already have a manifold that I'm using as a prototype but thanks anyway.

The throttles sit sideways. When they are only partially open fuel only comes through the side that is tipped down. That puts it closer to the 1-2 half of the manifold then the 3-4 half. That could pose a problem with cylinders 3 and 4 getting a weaker mixture at partial throttle. I'm not sure how much of a problem this will be. As you can see in those pics the plenum is now cavernous compared to what it was before. I think that will cancel out some of the effects. I want to stick with the DCNF because of its tunability and compact size. Ideally I'd like to use an IDA but that’s not feasible. I saw a carb on e-bay labeled 40 DFO. It looks like a cross between a DCNF and a DGS. I can't find any info on it; it doesn't even make it into my Weber book. If its what I think it is then this carb would be perfect. The one on e-bay is in sad shape and way over priced so I'm not going to bother, besides its too rare. I'm going to give it a shot with the DCNF and see what happens. If it doesn’t work out then I'll settle for a 38/38 DGS. There's probably a chance that I'll make some for the DGV anyway just because I think I'll have a better chance of selling them.

My DCNF came today. I must say it fits the manifold like a glove. The outside dimensions are almost the same as a DGV carb. I have just a bit of work left to do before the prototype manifold is complete. Then its testing time.

The manifold still isn’t completed. I drilled one of the holes crooked when I was doing the studs. I've made a plug for it but I haven't got around to actually plugging and redrilling the hole. I'm going to wait until I can either get access to or just finally buy a drill press to finish it.

I'll assume it will give some sort of gain with a DGV. The whole reason I started this was to fit a DCNF carb to the car to offer a cheaper performance alternative that was some where in between a DGV and a DCOE conversion. I toyed around with making some studs for the DGV because theoretically it should give some gains in the upper rpm. I never ran the numbers to see if it was worth it though. It would also eliminate the need for an adapter plate, which can be the source for numerous vacuum leaks. The car would also sit about half and inch lower allowing you to run the taller air filter, which may or may not make a difference. I always ran a taller one, but then a gen2 doesn't have the clearance issues a gen3 does.

I'm not sure if I'm even going to test this setup on my car anyway. I know it will be a step down from what I have now, but I might like a comparison as to how close it comes. I already have a tester lined up to run it on a stock motor when ever I get it done so don't even ask ;-b.

Andy

train
10-05-2004, 06:00 PM
i'm not very knowledgable of carbs, but this reminds me of an H22 or B18C intake manifold, with dual runners for each cylinder. (except they have butterfliy valves, and you don't.) many people that want to keep the stock H22 or B18C intake manifold remove the butterflies and do a nice p&p job. some go as far as to remove the wall separating the runners, making one very large runner for each cylinder, rather than having two. this reveals a lot more power than dual runners for those manifolds.

it sounds like a cool project tho. if your math is correct, it looks like it would outflow pretty much any carb on the market for this engine. be sure to portmatch this bad boy to the head! i'd like to see dyno results comparing your carb/manifold and other aftermarket carbs. cool idea.

train
10-05-2004, 09:59 PM
i say you def put that on the dyno after all this is done. i'd really like to see your design outflow a reputable carb company's design. then post those dyno numbers up! if you can't afford a few runs, ask around the site for some donations. its not something i would do since i don't seem to be very well liked on this site at the moment, but you seem like an upstanding 3geez resident. i'm sure most people wouldn't mind throwing in a few dollars here and there in the name of research and development. i'd throw a few bucks your way.

A20A1
11-22-2004, 11:31 PM
I found a #7455 450 HOLLEY ECONOMASTER QUADRAJET CARB on e-bay... I'm hoping to get some money soon but it may not be in time for the auction... :(
I'd need a bigger pump too.

It should be about 318 CFM for each side of the manifold with the divided plenum.

STAHLE (http://stores.ebay.com/Stahle-Performance-Inc)

http://ftl.realbig.com/pipermail/detomaso/2002-October/018416.html

390 4160 (http://store.summitracing.com/default.asp?target=partdetail.asp&part=HLY%2D0%2D8007&N=120+400178+300737)
450 CFM (http://store.summitracing.com/default.asp?target=partdetail.asp&part=HLY%2D0%2D9776&N=110&view=4095)
.
.
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Oldblueaccord
12-04-2004, 12:29 AM
Has anybody looked into the Holly 2300 2 barrel carb. Its a great carb comes in 350 and 500 cfm versions. There real popular with circle teack racer and drag racers that require a 2 barrel carb. They take all the standard holley parts. Usually about $200 from Summit or a reman for $150 there selling now.
I have had great luck with them on all kinds of v-8 cars that need a new carb.

The Quadrajet is a good 4 barrel carb it has very small primaries then the big sucker back barrels. The backs are vacuum operated. There real popular on Chevy's cars and trucks any junkyard should have a bunch. There harder to tune and there arent many parts for them as far as jets a rods.

wp

Mike's89AccordLX
12-04-2004, 02:25 AM
I need to find that other spare intake manifold I had laying somewhere.... Mike I think I caught the bug for this ;) What kind of fuel pump would you need for a quadrajet? Or one of those 2 barrel holleys? I was arranging to buy a carter fuel pump for my weber carb but I wont buy it if I wouldnt be able to use it with a bigger carb.

So basically Mike you got one of those 4 barrel carb adapters from a parts store and you just started fitting it and cutting to match the intake right? I'm definately going to need some bigger performance parts since I will be staying carbed :) Keeping the dream alive!

-Mike

Mike's89AccordLX
12-04-2004, 03:04 AM
Couldn't you buy one of those 2 to 4 barrel adapters? I was thinking about this and I know hoodline would be a problem but that's more reason to have and ram air hood cowl with and big ass air cleaner :)

I have a machine shop at my school at my disposal and will basically do almost everything for free. I could have them make the plates to go from our stock manifold to a 4 barrel adapter. Would this be ok or would that be too restrictive? I know having less adapters is best but sh*t if we had a 500+ cfm 4 barrel I highly doubt we would notice any lost performance and it would be a heck of a lot easier than trying to just fit a 4 barrel adapter to the stock manifold. I'm real serious about this Mike so let get this thread rollin! I would prefer a 4 barrel with electric choke and for a manual trans. I've seen a ton of good deals on ebay they just need to be rebuilt and I've rebuilt many carbs already so thats no biggie. What brand should we stick to or doesnt it matter?

-Mike

Mike's89AccordLX
12-04-2004, 03:15 AM
My god the possibilities :crying:


http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7937830422&category=33551

That would sure fix the hood clearance problem :) But probably get my a$$ kicked by the muscle car guys in town :(

Vanilla Sky
12-04-2004, 04:19 AM
mikelx... you have machine shop access... can you weld a manifold? for DCOEs...

Mike's89AccordLX
12-04-2004, 07:07 AM
I've only welded once so I don't think I will be welding any manifolds :) Now if my dad broke down and finally gets a welder again he could definately do it. He's been welding for like 35 years so he's pretty good. And he can do aluminum too. He used to weld aluminum truck tool boxes out in Oregon at Highway Products.

But if you're wanting me to get some flanges made I could probably do that if you give me the exact dimensions you need.

Mike's89AccordLX
12-04-2004, 07:35 AM
I should have brought this up before but I thought I read somewhere at school if you have too big of a carb for the engine the engine won't perform well. I think it had like the size of the motor and then had what cfm would be ok to use for a carb. The carbs I have been looking at getting are anywhere from 600 cfm to 800 cfm. What carb sizes and brands are you guys looking at getting?



edit: I found my spare intake manifold :) So I'm going to go out and buy a quad carb adapter kit. And start the measuring process. I would like to figure out a way to make some sort of adapter plate to fit onto the stock manifold to fit a quadrajet carb. This way it can give other carbed accord members a better chance at having a big carb. I know it probably wouldn't flow the best but it would still be better than stock and the weber 32/36 that I have now.

Vanilla Sky
12-04-2004, 07:53 AM
i'm using 40DCOE 136's... i've got the DCOE flange, CNC in aluminum... and it's not a big deal for me to finish cutting down a head side flange... i am having trouble finding the proper piping, though... i don't plan on supporting it with anything from the bottom, so it needs to be pretty hefty...

i think the cabs they are wanting to use are in the upper range of being good matches... some of the carbs that have been brought up are way too much for a 2 litre motor, unless they go with forced induction... that's why my choice is in the DCOE carb... tunability... too much fuel? whoopdee doo... change the jets, chokes, and/or venturies and you have a carb that behaves totally different...

that's my $.02

Mike's89AccordLX
12-04-2004, 08:57 AM
I bought a 4 to 2 barrel adapter b/c I couldnt find a 2 to 4 barrel adapter. I flipped it upside down and you can better visualize what I want to have my schools machine shop to make.

http://www.3geez.com/forum/attachment.php?attachmentid=3868
I plan to buy the carb I will use and then bring both the carb and intake manifold to the machine shop and see what they can do.


The only bad thing I see about doing the adapter plate from 2 to 4 barrel is the bolts that hold the adapter to the intake manifold would be exposed to the intake air and fuel. It might be easier to do that 2 barrel holley. I'm still not certain that those huge carbs will even be any good for our cars.

Mike's89AccordLX
12-04-2004, 09:14 AM
Here's a link I found about carb sizes. I must have been right when I remembered something in school about carbs are good if they're too big.

http://realbig.com/detomaso/1999-04/800.html


I think I did the math right I could have messed up who knows. But for our motors I think 462.9 cfm is optimal +/- 10% So it is possible for us to have a 500 cfm carb... What do you guys think about that?


edit: This looks like a pretty decent carb.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7937989699&category=33550

And this one too.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7922528559&category=33550&sspagename=WD1V

I think maybe our cars would rock if we added a little demon to them ;)
This guys has a ton of demon carbs and he live in my state. I'm going to try and call him and maybe he could help us out on what carb would be ideal for our applications. Here's a 500 cfm demon. And oh so pretty :)

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=7936363619&category=33550


Not too bad for $300


I would be a whole lot easier to adapt that 2 barrel 500 cfm road demon carb than a 4 barrel carb. 125 cfm per cylinder sounds pretty amazing to me. I have heard great things about demon carbs I just forgot about them until I ran across one on ebay. I could easily have an adapter plate made to fit out stock manifolds to these demon 2 barrel carbs. Demon has a 375cfm carb too. But I think the 500 cfm one would be nice and not too much overkill. I'm going to talk with the seller and see what he thinks about the cfm and maybe he can match something better who knows.... Basically I would just need to bring 2 gaskets to the machine shop at school and tell them how thick I want the plate and that I want to have that coolant passage blocked off on the intake manifold. Anyone that has a weber either knows that or found out the hard way ;) Yeah I was one of them... I shot coolant about 10 feet of the muffler. It was pretty funny seeing the green spray but man did that smell and freak us out.

So I want to know what you guys think about the 2 barrel 500 cfm demon? I think if we bored out our blocks and got some larger pistons we could get a bigger carb but with stock bottom ends and modfied top ends and other things 500cfm is plenty big.

-Mike

A20A1
12-04-2004, 09:16 PM
------------------------------------------

That link isn't the best one for info... try "grapeape racing"
Our Engine CID is : 119
Our max rpm for now can be : 7,000
I would set your max rpm to where other parts on your motor like the header and cam can help out.
If you stick it at 8,000 and have a cam for 6,000 and have a header for 6,500 then you're selling yourself short.

VE is volumetric efficiency which is never at 100% in most N/A street cars but it is just used. Thats why most carb makers usually say go one carb size smaller then what you get when doing the calculations to account for loss of VE. You'll be much happier with a properly sized carb because it will be more responsive for the entire rpm range instead of having a bigger carb that is sluggish down low and only having some high rpm benifit. 104% was with ram air... usually only in forced induction motors does the VE go above 100%.


I put the A20's CFM up top already.



I was reading up some and found that I could increase the CFM the engine pulls by 52 if I divide the cylinders into pairs.
Below 3,600 rpm the divided plenum manifold makes more HP and Torque
Above 3,600 rpm the open plenum makes more HP and Torque

A20 @ 100% VE is good for 224 CFM @ 6,500 RPM
22R @ 100% VE is good for 270 CFM @ 6,500 RPM
*I used the 22R because there is a 500 CFM 4bbl conversion for it.)

Lets see if I'm doing this right
2bbl and 4bbl are rated differently for CFM

2bbl CFM = 4bbl CFM x 1.414
4bbl CFM = 2bbl CFM / 1.414

So the divided manifold would make the 4bbl into two 2bbl's
500 CFM 4bbl converted to 2bbl is 707 CFM but since it's split into two I divide by 2 right... so then I get 353.5 & 353.5 CFM carbs... which is just like having two 38 Webbers each feeding 2 cylinders.
390 CFM 4bbl converted to 2bbl is 551.46 CFM but since it's split into two I divide by 2 right... so then I get 275.73 & 275.73 CFM carbs which is just like having two 2bbl Keihins each feeding 2 cylinders.

Mike's89AccordLX
12-04-2004, 10:11 PM
So basically it would better to get the smaller road demon carb 350 cfm. I'll have to check I can't remember what the weber 32/36 cfm is. Thanks for fixing up the info. I wasn't sure that info was 100% thanks for clearing it all up for us.

Mike's89AccordLX
12-04-2004, 10:19 PM
I can't remember what the cfm is of the 32/36 but I read online that the weber 38 has 370 cfm. So I think I'm going to find me a cheap 38 and rebuild it.

-Mike

A20A1
12-04-2004, 10:31 PM
Here's a link I found about carb sizes. I must have been right when I remembered something in school about carbs are good if they're too big.

http://realbig.com/detomaso/1999-04/800.html

I think I did the math right I could have messed up who knows. But for our motors I think 462.9 cfm is optimal +/- 10% So it is possible for us to have a 500 cfm carb... What do you guys think about that?
-Mike


Mike, I think what the original person ment by 10% is -
090% to 100%
instead of
100% to 110%

CFM info I posted for the weber... I did some searching and found different CFM ratings for the same carbs... but they were all in about the same area... I then did an average CFM rating based on the info.

http://www.3geez.com/showthread.php?t=19464
.
I honestly don't believe the 38 is more the 370 cfm... yet there was one place that rated it at 400 so I added that in.

.
.


So basically it would better to get the smaller road demon carb 350 cfm. I'll have to check I can't remember what the weber 32/36 cfm is. Thanks for fixing up the info. I wasn't sure that info was 100% thanks for clearing it all up for us.


I miss read his explination for 104%... I thought he said short ram... instead of ram air.
I was like WTF...
I edited my remark.
Anyways it still isn't the most informative site.

I just notticed something about the manifold adapter you posted... I made the same mistake the first time I installed mine... you actually need to turn the adapter 90 degrees.
If you install a 4bbl the way it is now then the secondaries will be closed to one half of the manifold and the primaries will be on the other. It wouldn't make too much of a difference if we had a big plenum and the carb sitting on a spacer, but that isn't the case.

Still it is a nice looking adapter. I'm sure it will be useful.
I would use some stainless bolts with a hex key insert head (like the ones for the weber adapter plate) instead of studs and nuts... and use a locking washer.
With a machine shop it should be easy to tap and drill new bolt holes... I think shepherd had to fill in areas with the alumaloy to get his adapter to work.

Mike's89AccordLX
12-04-2004, 11:26 PM
I'm just going to take the adapter back and get a weber 38. Seems that it would easier adaptable and useful for my car.

A20A1
12-05-2004, 03:38 AM
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=7939353337&category=33550

Yeah the 38 will be easier to adapt... the 350 demon is a sweet carb though. And certainly more up to date the the 38. They are both around the same price.


Here are some fuel components if anyone was looking to run a bigger carb. http://www.edelbrock.com/automotive/fuelpumps.html

Oldblueaccord
12-05-2004, 04:23 AM
A little bigger is not going to hurt you. I know what those books say but thats really old tech. If your motor only takes 250 cfm then a 300 cfm carb isnt gonna cram any more air down it.Holley makes a 390 4 barrel carb its kinda pricey.

Demon makes a pretty good carb there have been some problems with them you need to look into that. There tech sucks. If you do get a Demon get the idle-eze carbs.. They had some major problems with getting the idle correct and came out with this new design. Thats why you see so many on E-bag every ones dumping the old design.

The VE on our cars could go over %100 in some areas RPM wise dont be surprised .Honda was no fool he new how to make power. There some scanvaging effects etc. that come into play.

wp

A20A1
12-05-2004, 09:34 PM
NEW PICS OF THE MANIFOLD PROGRESS UP SOON... gimmie a minuet

scroll to the top or go to the first page to see the updated pics.

HondaBoy
12-05-2004, 09:47 PM
so you are still keeping somewhat busy on the custom manifold? thats really interesting what your doing. guess you really need to know what your doing to attempt anything to this degree. guess you should be called the carb master of 3geez.

Mike's89AccordLX
12-05-2004, 09:49 PM
I think I said it best 2 years ago when I called him the Carb God of 3geez. I can only hope to know what he does about the carbs. I'm graduating in Auto mechanics this coming year and I still don't know as much as Mike about carbs. But that isn't too big on the list for mechanics to know nowadays :(

-Mike

HondaBoy
12-05-2004, 10:03 PM
yes, but it should be. many of the things from carbs still apply to fuel injection. as way of routing your intake to its best ability i guess. anyway, i dont think carbs will ever die out. not soon anyway. ah, you have your good and bad points on either carb or fi. so its all prefurence i guess. i dunno, its fun to tinker with carbs. you can only go so far with fi. fi doesnt take as much skill now days, but then i does, ya know. dont know what i'll do if i do the B20 swap, then i'll have to do the fi thing. that's kinda what i'm getting my money together to do instead of fixing up the A20. ah, i dont know, probley not too soon though.

A20A1
12-05-2004, 10:11 PM
I was so worried the shaft wasn't going to be drilled straight... I used the base of the keihin and clamped it to the adapter... then drilled thru a smaller hole in the keihin to act as a pilot and drilled straight on thru the base and the adapter...

Starting the next hole will be tricky since it's lower then the one I drilled so there will be less surface for the gasket to seal with.

Mike's89AccordLX
12-05-2004, 10:16 PM
Mike when you you put it all together get a tube of this sealant called Hylamar. It's a blue colored sealant and I used that on every gasket surface when I put my custom intake manifold on with the car and to the head. It will make sure there won't be any leaks and the stuff is an anarobic sealant so it never drys or gets solid so it will keep it sealed up.

-Mike

A20A1
12-05-2004, 11:16 PM
Right now it seems like I'll have to fill in the bolt holes after I get the manifold peiced together... there just isn't enough meat left around the edges.

I was thinking I could put down some quick steel to act as a mold then lay over alumaloy. This will cover the big gaps on the left and right side of the manifold as well as help form a new plenum that will help direct fuel around the sharp bend... as it is right now the primaries are placed closer to the valve cover... which means fuel will have to travel back towards the firewall then make the turn towards the cylinders. I want to fill in some areas so that fuel will ramp down from the primary barrel because of a taper I will add in the plenum... and the fuel will end up colser to where the secondary barrel is... this will mean the fuel will have to make less of a turn. I need my special engraving bit to help roughen up the smooth surface of the alumaloy some... then run over a some sand paper to get rid of the sharp burrs.

Civvy
12-06-2004, 03:05 AM
Nice work mike! Wonder if i should try that RX7 carb on my B20 afterall! Anybody know if the ignition is controlled by PGM-Fi?? I want to try disconnecting the injectors and installing the carb and mani. but, will the ignition still work??

A20A1
12-07-2004, 01:12 AM
can you use a B18 distributor and ECU? or just Distributor... the accord DOHC carbed B18... I think...

Oldblueaccord
12-07-2004, 05:46 AM
If you get something you can use I can make you up a better spacer. Aluminium is easy machinng. I think I have one of those spacers in the shop it looks fimiliar.

Not to push but if your making 8 -10" of vacuum you want a very adjustable carb like a Holley. I really think that model 2300 is a great carb plus it takes all the special Holley stuff they make and 2 barrels are simpler carbs then 4 barrels.

You might want to modify the mechanical advance in your distributor. Most of the time you want more advance sooner just off idle. Domestic cars you can fool with the springs and weld up the slots on the plate inside the distrbutor to get the advance in sooner with out having to bump up the static timing so far it wont start hot. It really helps give you alot more vacuum which means a better carb signal which means a better running carb.

wp

A20A1
12-07-2004, 12:49 PM
I have a stock cam so if it runs like poop I'll swap out my race cam.

A20A1
12-07-2004, 08:08 PM
Look at the first post, I added more pics.

doug
12-12-2004, 07:32 PM
i'm using 40DCOE 136's... i've got the DCOE flange, CNC in aluminum... and it's not a big deal for me to finish cutting down a head side flange... i am having trouble finding the proper piping, though... i don't plan on supporting it with anything from the bottom, so it needs to be pretty hefty...

i think the cabs they are wanting to use are in the upper range of being good matches... some of the carbs that have been brought up are way too much for a 2 litre motor, unless they go with forced induction... that's why my choice is in the DCOE carb... tunability... too much fuel? whoopdee doo... change the jets, chokes, and/or venturies and you have a carb that behaves totally different...

that's my $.02
vanilla, don't know if you have heard of these guys but check out the wbsite, andy mentioned them I think for one of his projects, if not andy then another member that was planning to do a manifold, I think they used 2" tube with 3/8
thickness but not sure. the site gives you alot of good choices. good luck. doug\\

http://www.onlinemetals.com/

A20A1
12-16-2004, 03:37 PM
I think I'll stick with that vacuum secondary Quadrajet... I was reading up on manifolds and carbs and what not and although they didn't specify progressive vs synchonous, it was said that having a vacuum secondary overcomes some issure when having one cylinder fed by 2 barrels... I assume thats why they convert DGV carbs to vacuum secondary when preping them for turbo.
Now 1 cylinder per 2 barrels isn't completely true in my case cause there are 2 cylinders paired with 2 barrels... but still... I have my doubts at how effective the lower rpms will be.

----------

I went to borders and almost bought the three books I listed in the Turbo FAQ.
Maximum boost was the best of the three but a bit biased concersing carb/turbo althought it made some good points.
What I got from it was that the major problem concerning draw thru was heat... heat is needed to keep from icing and heat isn't taken away bacause there is no intercooler. Pull thru the problem is with Fuel and pressure, how to enrich the mixture and how to pressurise the carb and fuel and keep a safe relation between the two.
the end performance result with the pull thru is how well you manage heat without detonation
the end performance result with the blow thru is how wll you manage fuel without detonation
Both fall short to EFI in that they have restrictions in the form of the carb venturies and may have gaps in the fuel curve that lose power. Also added problems like fuel slosh. Still carb turbo is nastalgic and seemingly worth the effort... but I'm going N/A at the moment.

BOOKS ON TURBOCHARGING
Supercharging, Turbocharging and Nitrous Oxide Performance
By: Earl Davis, Diane Davis
http://www.3geez.com/attachment.php?attachmentid=3471&stc=1

Maximum Boost: Designing, Testing, and Installing Turbocharger Systems
By: Corky Bell
http://www.3geez.com/attachment.php?attachmentid=3469&stc=1

Turbochargers
By: Hugh MacInnes
http://www.3geez.com/attachment.php?attachmentid=3470&stc=1
I was also looking into TBI 4BBL injection for turbo apps. I don't think I'd go port injection cause I might as well do a B-series DCOE injection manifold swap. :P

carotman
12-16-2004, 05:15 PM
Civvy, the Euro B20A Has a vacuum advance ignition even if it is EFI (which is pure crap I think)

You can use a carb setup with that kind of distributor. However since it already has the EFI setup, I wouls stick with that.

rjudgey
12-21-2004, 03:46 AM
Nice work and research!! thumbs up!!

Just a thought but i presume you are doing all this just to be different from all of us who have DCOE's?
If so fully understand i'm working on a new project that uses a DCOE manifold but has seperate adapters that fit DCOE flange that actually pairs up two bike carbs then i can fit 4 bike carbs onto any twin DCOE inlet manifold, this has one of a few advantages that are better than DCOE's, angle is not as critical, bike carbs are also bigger 38-42mm maybe bigger on something really nasty, internals of bike carbs are a lot less complicated then DCOE's or other carbs so they flow more fuel and air and apparantly they produce much smoother low end power. Found a company in the U.K that had been making up manifolds and using Bike carbs on race cars for the last ten years!! Also may be easier to Turbo as well but not sure on that 100%
What do you think!! P.S if anyone copies me i'll send my ninjas round to sort you out ;0)
check out my cardomain site last page has pics of my new head and custom made inlet manifold,made it extra short as every other manifold i've seen has really long runners thought it would be interesting to see what effect it would have, normally most engine people would say i would loose torque and gain more Bhp be interesting to see if this rule of thumb is correct, my other manifold is really long and i also have long trumpets on as well!! so short manifold and short trumpets next!! Also it's a EURO ET1 2G accord head which i think is one of the best Honda designed early heads almost as nice as the D15 heads just wish we had the same exhaust port layout looks so much neater having them paired up not too mention being better for thermal heat retention and for making manifolds up!!
http://www.cardomain.com/memberpage/281725/8
In the process of building this one up at the mo!! It's based on a ET block thats been recently re-bored to 82.75mm, rods are stress relieved and polished, oil holes moddified, lighter piston pins, sealed power pistons, hastings oversize rings to fill up the extra 0.5mm gap in bore size, crank balanced, polished and oil holes chamfered, flywheel will be CM ally integra job, with AP pressure plate and ACT 6 puck disk, ACL bearings all round by far the best engine bearings in the world!! But still need to get my arse into gear and get my car to a new exhaust specialist i found other side of London who makes exhausts for Touring cars he can make me up a 4-2-1 with extra long primaries as well as big bore size, running straight into 2.5" system my current system which has 2.25" bore size but the cast manifold is still be using although heavily flowed and ported, but the custom downpipe i had made the numb nut cheaped out on me and only used 2" main pipe and joint then it goes 2.25" so i'm 100% sure it's bottlenecking as before it used to put so much back pressure on the older system that it would break off the silencers of the main pipes, and it's just done the same to the new stainless steel system on at the moment!! So i think it's time for a bigger setup again!! I'll put the 2"-2.25" system on my B20 and see if that makes it run any better!!

Civvy
01-05-2005, 07:35 AM
They're different, i had to ditch my EX exhaust and it was new.
Cant remember if the centre pipe didnt reach the downpipe or visa vrsa, the manifold and downpipe are impessive for stock spec.

my86dx4dr
01-09-2005, 06:30 AM
ok we have 2 differnt mike's that talk about a carburator like a nerd with a pentium 5 computer...


its all good

rjudgey
01-15-2005, 01:09 PM
well someones got to!! If only i could get my Pentium 4 2.4 ghz running at 4ghz with a FSB of 1066mhz with dual DDR 4500 ram then i'd be a happier bunny ;0) but i suppose 3.2ghz aint bad using a big heatsink and fan!!

A20A1
01-15-2005, 01:31 PM
Say what? :lol:

Cant Stop
05-20-2005, 01:56 PM
i sent a pm today, however have you finished this project?, has anyone else continued on?

i am currently working on a mod to use the kei hin dual carb setup should be done end of june.

lostforawhile
06-21-2005, 04:38 PM
if you want a dual webber try pierce manifolds 18008743728 last time i checked thay made a dual webber set up and manifold for our cars it was like 1500 bucks but they make one

A20A1
11-13-2005, 11:43 AM
I though it was for the A18, which had different ports then the A20.

Also there are B16 B18C5 manifolds but they don't take into account the 15* tilt that our motor sits at, so if we used their manifold we'd have carbs pointing up into the hood and they wont run right.

Cant Stop
11-13-2005, 03:39 PM
i guess i just need to wack a intake like the pic at the beginning of this post and weld the lude mounting plate to it(carb side that is)

accord upset
08-05-2006, 07:09 AM
cfm recommendation & cid to liter translator
http://www.carburetion.com/calc.asp
check this out guys is does it seem like they calculate the cfm a lil bit low for our engines or is it just me. i mean how many of us have a 10000 rpm full race motors that would give us the sugessted cfm for the 32/36 webber(rated at 300cfm??) or worse the cfm for the 38/38 weber. i dono im just asking what u guys think. i found this stuff while looking for an adapter plate for my new 38/38 :-( uh oh still dono if it'll work i hopes so

MessyHonda
08-05-2006, 07:37 AM
yeah i have an automatic so my redline is according to my trany...it always shifts at 5800RPM so i need 169CFM....all i have is the K&N filter that should supply that already

87AccordLXsdn
08-05-2006, 11:03 AM
My car is still running like shit and I need some help. Does anyone have some specs of what all the vacuum lines should be pullin in?

A20A1
08-05-2006, 11:27 AM
The 38 will work.
I would say you could run twice the CFM that that calculator puts out on a single plenum manifold, so about 400 CFM

It's not just CFM but how much vacuum the carburetor sees at Wide Open Throttle.
As long as there is enough restriction in the carburetor to create a pressure drop, the carburetor will work, and you'll get the added bonus of the extra air flow.

You divide the cylinders and remove the plenum and the vacuum to the carb is even stronger which is why I think 45 DCOE's are able to work. Each barrel is about 220 CFM. That’s like having a single 880 CFM carb feeding all 4 cylinders. But when you have a single 880 CFM carb feeding all 4 cylinders not all cylinders fire at once... so the lower the rpm you have the less demand there is and the less pressure drop is going to be created.

A single 45 DCOE or even a single 50 DCOE will work on our car flowing 400 + CFM, greater then a 38 weber, but the performance from something like that will be determined by how and if you divide the cylinders into pairs.

When I was considering 4bbls

390 CFM 4bbl converted to 2bbl flow rating is 551.5 CFM

500 CFM 4bbl converted to 2bbl flow rating is 707.0 CFM
...go back to what I said about the 880 CFM...
The 500 CFM 4bbl is still below 880 CFM so it should still work at WOT in the higher RPMs. But below that you might have some trouble.

The 390 CFM 4bbl @ 551.5 CFM is closer to 400 CFM and would run better in the low range then the 500 4bbl and once you reach WOT the carb can still put out.

Also consider that 4bbls are not flowing the full CFM all at once. They use primaries and secondaries... so that the primaries see most of the engine demand when the demand is low and as the demand increases the secondaries open up.

As a side note small primaries are good for gas milage but not that good for performance... really you want a primary that is large and the secondaries to be the same size or larger.

That’s why SU variable venturies are nice. They maintain a pressure drop but open to increase air flow when the demand is there.

A20A1
08-05-2006, 11:40 AM
Most manifold vacuum lines pull about 24" hg. @ idle

Do you have a vacuum gauge?

Not all vacuum lines will have vacuum all the time... it will depend on the valve or solenoid they are connected to... and also if they are connected to throttle port vacuum, venturi vacuum, or manifold vacuum.

87AccordLXsdn
08-05-2006, 11:48 AM
ok cool thanks man...also this may be a stupid thing to do...but how hard do you think it will be to go from weber back to stock. because i think that my carb is pretty fucked right now and i can just go grab out a keihn for like 5 bucks.

A20A1
08-05-2006, 11:55 AM
By your post I thought you had a stock carb. :)

Whats wrong with the weber? have you tried replacing the gaskets... I found out later that too thick of a gasket can cause the plates and even the carburetor to warp causing vaccum leaks.


Also check the float level settings... there are plenty of diagrams online to adjust the float level... there are two adjustments... one is the maximum and the other is minimum amount of travel in the float.

Make sure that the float valve (the part that screws into the roof of the carb) is actually still screwed into the carb. They sometimes will work their way loose and begin to choke the fuel flow by putting pressure on the float needle.

accord upset
08-06-2006, 06:30 PM
ok thanks a20a1 sorry if i was annoying u with pms im just trying to put my stuff to gether as quick as i can(gota get back to work so i can spend more money) and u have alot of knowledge that i dont.

A20A1
08-06-2006, 07:29 PM
www.carbs.net sells the adapter plate, so does www.redlineweber.com

it's $50 for the plates.

http://www.3geez.com/forum/showthread.php?t=38161

2oodoor
08-07-2006, 10:32 AM
ok cool thanks man...also this may be a stupid thing to do...but how hard do you think it will be to go from weber back to stock. because i think that my carb is pretty fucked right now and i can just go grab out a keihn for like 5 bucks.
Believe me brother you do not want to go back. Once you go weber you go forever.
That five bucks will turn into fifty into a hunnerd ...and so on

A20A1
08-07-2006, 11:11 AM
Also check that the jets are all secure...


I went back to a keihin... but I had made some major adjustments to it.

I can't wait to try out the 4bbl.

2oodoor
08-09-2006, 11:37 AM
A20A1 are you going to use the four barrel intake you made?
That is one nice piece of work. I thought maybe you sold it, by some thread I was reading a while back.
I wonder what you would use, rochester quadrajet? Like those myself
street demon, thermoquad, ..... that wierd motorcraft 4bbl they put on an AMX.Javlin??

A20A1
08-09-2006, 12:49 PM
the predator :D

hehe


no not really.

the 390 holey is okay for cfm but I don't like it... and the edelbrock 500 might not be what I want either though.

The rochester has tiny primaries and fat secondaries. This design isn't as good for performance, I need something where the primaries and secondaries are close to the same size but the cfm needs to be low. 500 would be the max I would go. I kinda wished that demon would put out a 350 cfm or 400 cfm carb. The smallest I found was the road demon jr. with 500.

here is the carb throttle style I want. :)

http://www.mustangandfords.com/techarticles/38381/photo_22.html

it's an Autolite 4100 ... 480 cfm with the 1.08 venturi

It uses annular boosters so:

...an annular booster creates a stronger fuel signal, generally requiring smaller jet sizes. There are exceptions to this rule, but adding annular-discharge boosters requires smaller main jets and larger high-speed air bleeds...

2oodoor
08-10-2006, 04:11 AM
Yes I dont think the rochester would work for that app, metering rods would be hard to deal with on a four banger, trying to sych with the power band rpm.
That is funny I was kind of joking about the motorcraft (autolite) four barrel, but I think that is the one you say you like. There are not a whole lot of those around. I rebuilt one several years ago for a guy, it was on about a 74 Javelin 401 motor OEM.

A20A1
08-16-2006, 02:49 PM
If the annular booster is good then it should help even a small engine run a large carb once jetted right. Again you could set up the secondary to run on venturi vaccum or something instead of being a manual. I would have needed a vaccum secondary because I was automatic.

2oodoor
08-17-2006, 04:58 AM
the rochester four barrel has stationary boosters intergral to the casting, it would take some intricate biomedical type tooling to muck with those and a box full of cores. Actually the rochester 2 jet two barrel offers a booster that is more likely to tinker with , those are not really too bad a carburatorfor racing, well kept secret for dirt track I suppose. There is a good roch. book at books a million I got one.
I do know a few tricks with the q jet, probably changing the spring below the step piston would get a 2.0 to get a good drink when slippping the clutch. Come to think, it may be worth lookng into a 2 jet for a replacement performance carb for stock LX , it would have to be modified for sure. I saw mention of a motorcraft 2bbl in the forum but it never really got interesting, the holley weber pinto carb would have been betta.
the autolite still looks interesting if you can get some cores, I just wanna see yours set up and running with a 4bll, that is the ulitmate illness, right up there with big block airboats, and that turbo vw bug on pinks with the holley 750 sticking up outta the eng. compartment...

A20A1
08-25-2006, 10:13 PM
http://store.summitracing.com/partdetail.asp?autofilter=1&part=PHP%2D15001&view=16383&N=700+4294821996+0

wow I might want to look into a holley and the percy metering block. :)





I used the exhaust flow calculator and applied it to our intake manifold runner where is narrows to 1.5". If we take the 1.5" and we times it by 115, we get about 172 CFM, if the most our motor demands is 190 at 6,500 rpm... then the intake manifold is a restriction, however it will help the low end by having that added velocity.

2oodoor
09-10-2006, 01:08 PM
that is great idea.I see that on your car...taransula dude.....but really these carb gurus still around need to be figuring this stuff out so they can have advantage over those nitrious runners who dont know what the heck they are doing by counting on a large, too large percentage of secondary and heck primary too being much counting on bottle. then when it comes when times that the bottle malfunckeds , they have no motor to run , its a joke. agree?

A20A1
02-18-2007, 12:06 AM
Hey Shepherd79 what was the alumaloy like soldering stick you found that was better than alumaloy?

I need to finish the dividing wall in my manifold, that way I keep power in the low end by having a smaller plenum on each side, dividing the carb, and keeping the runners the small diameter that they are.

I really want this manifold to look nice, with black textured BBQ like paint and brass barbed vacuum fittings and colored brake fluid lines converted to vacuum hard lines for PCV, Distributor, and Brake Booster Vacuum.

At least I can finish it all up and sell this manifold and hopefully the header too, I don't think I can find another 3G and do the 4bbl conversion any time soon.

shepherd79
02-18-2007, 04:55 AM
i got it from this webpage.
https://weldingsupply.securesites.com/cgi-bin/browsecatalogs.pl?SIGNOUT
the stuff called WELCO 52. if you do a search for it, it is the first thing that comes up on that page.

make sure you get your hands on this http://www.bernzomatic.com/bernzomatic/consumer/jhtml/detail.jhtml?prodId=BernzoProd100044
or at least mapp torch, it burns hotter than propane.

this product is easy to work with.
just make sure you clean the area very good, ruff it up, and heat it up.

A20A1
02-19-2007, 01:09 PM
Thank you . :)


awe I searched but it says it's for galvanized steel? Was that what you used it for or did I search wrong?

EDIT: nevermind I found it :)


So I can use straight mapp? I'd like not to mix gas if all possible.

A20A1
02-19-2007, 02:32 PM
Yay, I ordered the 1/4" sticks :) time to rock and roll. I got two orders... i hope it's enough.

$27.10


I was going to buy their aluminum cleaner but figured I could find something locally.

Maybe I'll make a totally custom manifold as well with my other intake flange, or weld 4 keihin base plates together to make a progressive 8-BARREL M-ITB setup.

well I bit the bullet, I'm getting the Rochester Quadrajet
ROCHESTER QUADRAJET
Looks like I can play with it and get it to work.

nice article on the Q-Jet
http://www.carcraft.com/howto/57178/

Might think I'm crazy because it's a 750-800 cfm carb.

Numbers are aproximate

Primary 226 CFM

Primary + Secondary 1060 CFM

divided carb

Primary 112 CFM

Primary + Secondary 530 CFM



:(


I could actually run the carb with just the secondaries and it'll be enough CFM , 418 CFM to each side

I should be able to get it to work with the jets and passages set right and the vacuum secondary set right.

Just need me a tunning book... and a 3G :)


Really I just got it cause my manifold has been so lonely.
http://www.3geez.com/forum/attachment.php?attachmentid=3881

shepherd79
02-20-2007, 06:11 AM
it is not that hard to find another 3G on the island, is it?
i am not sure how much money you want to spend.
just look here
http://honolulu.craigslist.org/oah/car/281571046.html
http://honolulu.craigslist.org/oah/car/281517917.html
http://honolulu.craigslist.org/oah/car/281255851.html
http://honolulu.craigslist.org/oah/car/281251511.html


autotrader.com has some car also.

A20A1
02-20-2007, 11:56 AM
Actualy there is one outside my house that is abandoned... it has a broken upper ball joint for the rear knuckle and slashed up tires... and tickets on the windshield. I wanted to save it. It even had a muffler, but that worried me cause I dunno how they treated it.
5 hours to go on the ebay auction for the carb.
I was looking at the base gasket for the Q-Jet, I'll have to shave my universal manifold flange even more to fit the throttle plates.
.
.
27 minuets to go. :( I'm getting worried, another Q-Jet that i was watching was just bid on. I swear the same guy is buying all the cheap carbs... what a.....
Woohoo! I won
I broke out the manifold just to get a picture of things. This is going to be neato. :)

Here is the link if you want to see it... I may need to scrap my 4bbl adapter and put on a q-jet one because it looks like the throttle plates will hit outside the mounting area.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=160085298528

What about this mod for the Gasket? I might have to build support under the gasket though just to be sure the gasket wont tear and reopen the area I'm trying to reduce.

Anyways it should cut the effective area of the throttle to about %60 of it's maximum.

This is in case the vacuum secondary doesn't work out on it's own.

http://i23.photobucket.com/albums/b351/Wendy_girl/q-jet-gasket_mod.png

Then there are the mods to turbo a Q-Jet
http://www.wallaceracing.com/TFProjectUpdate1b.html


Might get this book as well :)

http://www.amazon.com/exec/obidos/ASIN/1932494189/wallaceracing

.
.
.

A20A1
02-20-2007, 03:41 PM
Interesting experience...

http://www.bob2000.com/carb.htm
Scroll down to the first paragraph under "BASIC THEORY"

He also confirms for me that with vacuum secondaries, big carbs could be made to open just right for the engine so size isn't that much of an issue.
.
.
.

A20A1
02-24-2007, 03:07 PM
All you carb guys can appreciate just how big theses secondaries are

I just love the person who designed the Q-Jet... just as crazy as I am. :)



Dual throttle bodies anyone?

http://i23.photobucket.com/albums/b351/Wendy_girl/The_gates_of_Helll.jpg

shepherd79
02-24-2007, 05:51 PM
good lord that is huge.
i hope you can tune that SOB.

A20A1
02-24-2007, 05:59 PM
lol, those two secondary barrels combined could swallow our entire keihin. :)


I got another picture that compares the secondary on the keihin to the primary on the Q-Jet. :)

The opening up top is the same as on bottom which is the throttle port size on the secondary.
http://i23.photobucket.com/albums/b351/Wendy_girl/k759.jpg

A20A1
02-24-2007, 06:07 PM
I will see how big the chokes and venturies are when I get the carb... then I'll get a better idea about what to do.

A20A1
02-25-2007, 08:12 PM
A bit off on the placement of the flange but oh well.

The flange is divided down the center so at least that is okay.



http://i23.photobucket.com/albums/b351/Wendy_girl/6668.jpg
http://i23.photobucket.com/albums/b351/Wendy_girl/6667.jpg

A20A1
03-03-2007, 03:44 PM
So scared... this secondary is not like what I'm used to... we shall see how things work out.


See something missing ?

their seems to be more to the secondaries than just the venturies... which I don't see.... seems i have a lot to learn.

I removed the upper secondary plates and the linkages and diaphragm that control them... I don't think it's sipmly a choke....

http://i23.photobucket.com/albums/b351/Wendy_girl/rq001.jpg

shepherd79
03-03-2007, 03:48 PM
well primary looks like they have venturies, but secondary looks like was designed for air flow and fuel dump.
what jets are you going to run?
did you get a car?

A20A1
03-03-2007, 04:03 PM
no car yet...

this carb is going to need some work... the fuel and vacuum ports come out of the carb casting... some look like they have been hit. like the carb was dropped on them. I'll see what I can do.

This is such a neat carb though... really worth playing around with.

it's not a vacuum secondary like I thought, not like the keihin or other carbs, but it still seems like the fuel metering is somehow dependant on a vacuum valve.

So as long as it's still load sensitive I'm okay.

A20A1
03-03-2007, 04:09 PM
It's heavier than a camshaft... well I think so at least.

2oodoor
03-03-2007, 04:37 PM
well primary looks like they have venturies, but secondary looks like was designed for air flow and fuel dump.
what jets are you going to run?
did you get a car?
that sounds like a fair statement, secondaries on Qjet do get some metering/atomization with the M rods connected to the butterflies, according to depth of the plunge. You can borrow different rods/rod seat or jet if you will, from other Qjets to increase or decrease how much fuel by how much throttle. There is also an adjustment on the primarie M rods on the "stepper piston" , you can take out a blocking plate ( most people dont ever do that) so you can adjust the amount of movement the Stepper gets. You can put a tiny hole in the plate and use a very tiny small screw as a 'handle'

A20A1
03-03-2007, 05:12 PM
See shep... the choke like plates covering the secondaries... which I had already removed in the first pic... open and as they open there long rods come out of the jets... much like how a needle valve works... there are bobbing rods for the primary and secondary... easy to remove and swap out the secondary ones... the primary ones need the top hat removed... I pushed on the accelerator pump and got a face full of dust... cough cough.

http://i23.photobucket.com/albums/b351/Wendy_girl/rq004.jpg
http://i23.photobucket.com/albums/b351/Wendy_girl/rq003.jpg
http://i23.photobucket.com/albums/b351/Wendy_girl/rq002.jpg

A20A1
03-03-2007, 05:17 PM
http://i23.photobucket.com/albums/b351/Wendy_girl/rq006.jpg
http://i23.photobucket.com/albums/b351/Wendy_girl/rq005.jpg

A20A1
03-03-2007, 05:26 PM
http://i23.photobucket.com/albums/b351/Wendy_girl/rq007.jpg

busted fuel inlet

http://i23.photobucket.com/albums/b351/Wendy_girl/rq008.jpg

A20A1
03-03-2007, 05:51 PM
I noticed a problem... I need a new adapter plate for my manifold... it appears that the area between and behind the primaries pick up vacuum, but right now they are on the outside of the wall of the 1" carb spacer that I'm using to mount the carb.

A20A1
03-04-2007, 02:33 PM
I just went to measure my intake manifold, not the most accurate
it has two 58.42mm bores and two 35.56mm bores
what ever am I to do?

2oodoor
03-07-2007, 04:46 AM
I would not use that carb anyway, it is too old. Those carbs have lots and lots of tiny channels where that corrosion and hardened sediment would likely never get good and clean. You would have to soak it for weeks and even then it is questionable all of it would clear out. Also the casting can loose it's , I dont know what word it is I am looking for, say lubriscity? :) The metal looses its original oils and binders in other words. I am sure there is a more scientific way to convey that description.
Also on the base plate, some of those you can swap throttle plate. example cadillac throttle plate is not same as sb chevy, but you can use the higher cfm caddy carb by swapping. There are hundreds of RH4bbl apps and part numbers, year models etc. you have to match them up carefully. There are several different casting configs, example, fuel inlet positions and type. The picture you show has hose connection fuel inlet, I have not seen one like that too often, most are screw in with built in filter and flange nut connection.

cygnus x-1
03-07-2007, 04:16 PM
Also the casting can loose it's , I dont know what word it is I am looking for, say lubriscity? :) The metal looses its original oils and binders in other words. I am sure there is a more scientific way to convey that description.


Eh? Oils and binders? Your talking about how the surface gets kinda chalky and pitted? That's corrosion. I think if you were to take a file or sandpaper to the surface you would find that the metal underneath the corrosion is just fine.

But yeah, I noticed the corrosion on that thing. Looks like it's been exposed to the elements for awhile.

And man that carb is HUGE for a 4-cyl. I'll be totally amazed if it doesn't immediately kill the engine when the secondaries open.

C|

A20A1
03-07-2007, 10:36 PM
I don't think it will stall with the proper tuning.

Hey roo... the secondaries are supposed to open right? I mean there is a mechanical link... the only thing stopping the air is the second set of butterflies above the throttle plates. The one that has the little spring tension rich/lean bit and the vaccum diphragm to control the opening.

the carb is so damn tall. :)

2oodoor
03-08-2007, 07:02 AM
I told you guys there had to be a better way to describe what I was talking about, yea that thing looks weathered. If an orifice had corrosion on it , in it, that would cause problems.

Those plates above the secondary throttle plates are called air valves. When the primary throttle is open about 35 degrees the secondary throttle starts to open but no air flows through until the vacuum is strong enough to pull the secondary air valves open. The air valves will stay open until the primary can handle the air required by the engine. The opening rate is also controled by a damping diaphragm and connecting rod so bogging does not occur. Opening of the sec. air valve lifts the tapered metering rods attached, and pulls additional fuel thru the jets, the reduced tapering rods meter the amount from various positions as they pass thru the jets.

A good start may be to find a Q jet off of the smallest displacement motor they come on. such as 2.8, 3.8 v6. or possibly a Pontiac 301 or chevy 262 V8.

shepherd79
03-08-2007, 07:12 AM
Mike, i know you love the idea of a big carb, but i think that one is a little rusty.
see if you can find this one http://www.carburetorfactory.com/expvw26.html
it looks like it has equal barrels.
i am sure it will still give you a kick in your pants.

2oodoor
03-08-2007, 09:35 AM
4GC will be a tough one to get, they stopped making them in 1967. The Qjet was supposed to be the new and improved verision.
I was wrong about the Pontiac 301 and Chvy 262, they used what was called a dualjet, a QJet minus secondary. I forgot about those, yes Im looking at my Rochester book:) I do think that I have seen a Qjet on a 2.8 v6 in an s-10, I know Ive worked on them on a 4.3 s-10 and 3.8 buick motors.
Don't be intimidated by the size of those air valves, it only looks like a monster. Consider though your choice of 4bbl, do you really need dual bowls, four idle air jets? Q jet may just be one of the more adaptable choices, there are dozens and dozens of internal setups to make the carbs fit application. :D

cygnus x-1
03-08-2007, 10:51 AM
Hey, I used to have that Rochester book back when I was driving an '86 Cutlass. It had a computer controlled version of the Q-jet. The primary mixture needles were connected to a solenoid that would open and close depending on what the oxygen sensor thought the mixture needed to be. It was quite a piece of engineering. I remember rebuilding it once. There were so many little pieces and parts it was amazing.
Eventually I got rid of the car and started driving an import ('89 Nissan, fantastic car). So I sold the book figuring that I would never see another carb again. What was I thinking? :lol:

I'll admit it would be cool as hell to see a Q-jet on a 4-cyl.

C|

2oodoor
03-08-2007, 12:44 PM
Hey, I used to have that Rochester book back when I was driving an '86 Cutlass. It had a computer controlled version of the Q-jet. The primary mixture needles were connected to a solenoid that would open and close depending on what the oxygen sensor thought the mixture needed to be. It was quite a piece of engineering. I remember rebuilding it once. There were so many little pieces and parts it was amazing.
Eventually I got rid of the car and started driving an import ('89 Nissan, fantastic car). So I sold the book figuring that I would never see another carb again. What was I thinking? :lol:
I'll admit it would be cool as hell to see a Q-jet on a 4-cyl.
C|
yeah it is an excellant book. I have rebuilt several different apps of Qjet, but I had to pull out the book again to refresh on some things.
I am a little curious how this will work though, Hondas have short strokes and these carbs need gobs of vacuum to maintain.. this is interesting.
I know the secondaries on the 4gc are smaller looking compared to Qjet, but I think the Qjet needs that size as an engineered factor because of the upper air valve, not necessarily that it is all that more cfm.
I think maybe if you can use the four barrel, the secondaries will not be able to stay in long...on the same point, you dont hang around 8K rpm long anyway.
EDIT: also A20A1 if your looking for another core, that carb was also used a lot in marine apps., v6 inboards for example.

A20A1
03-08-2007, 11:47 PM
Well thats the point... have the carb that can open the secondaries if it needs to as much as it needs to.

But it was a big shock to lift the Air Valves open for the first time and see a very large fuel tube instead of the boosters. :)

A20A1
05-03-2007, 01:14 PM
http://www.popularhotrodding.com/tech/0511phr_carburetor_boosters_tech/

I'm so happy it hurts :)

dat
05-06-2007, 10:48 PM
nice carb lookin there.....

A20A1
09-04-2007, 01:52 PM
dear lord, this is a beauty
http://www.popularhotrodding.com/tech/0703phr_four_barrel_inline_carb/photo_03.html
















had to go looking for a broken link
http://www.popularhotrodding.com/tech/0511phr_carburetor_boosters_tech/index.html

DDRaptor
09-05-2007, 05:39 AM
Holy Progressive Carbs, Batman. That's a mean beast too bad it would flow way to much for our small engine.

cygnus x-1
09-05-2007, 10:39 AM
Holy Progressive Carbs, Batman. That's a mean beast too bad it would flow way to much for our small engine.

Well, not necessarily. The article says 500-1000 CFM depending on the venturis. For a fully worked over A20 (ported head, cam, header, high compression) 500 CFM wouldn't be out of line. Side draft carbs are still better though since the head ports are on the side. That way the air flow doesn't make any bends before head.

C|

A20A1
09-05-2007, 01:37 PM
Yup thats what I like about their carbs they offer venturi sleeves, possibly even different boosters but I didn't see that.

2oodoor
09-05-2007, 02:08 PM
I couldnt get the info link to open up but I think i wet my pants
that is one mean mixer

crucial
11-11-2007, 11:57 AM
What kind of secondary type sould i get. Vacuum, air valve, mechanicall etc.

Was looking at this one.
http://store.summitracing.com/partdetail.asp?autofilter=1&part=EDL%2D9913&N=700+4294925239+4294839063+4294919007+4294891681+ 4294902726+115&autoview=sku

2oodoor
11-11-2007, 12:09 PM
What kind of secondary type sould i get. Vacuum, air valve, mechanicall etc.

what kind of carb,what engine mods, etc... ?

lostforawhile
11-11-2007, 12:21 PM
Hey, I used to have that Rochester book back when I was driving an '86 Cutlass. It had a computer controlled version of the Q-jet. The primary mixture needles were connected to a solenoid that would open and close depending on what the oxygen sensor thought the mixture needed to be. It was quite a piece of engineering. I remember rebuilding it once. There were so many little pieces and parts it was amazing.
Eventually I got rid of the car and started driving an import ('89 Nissan, fantastic car). So I sold the book figuring that I would never see another carb again. What was I thinking? :lol:

I'll admit it would be cool as hell to see a Q-jet on a 4-cyl.

C|the rochester rebuild book? i have it around here somewhere.

A20A1
12-20-2007, 04:17 PM
Well I bought another 4bbl
this time it's an old holley 4bbl for $10

I doubt this will be any easier to work with than the quadrajet but it gives me some options.


http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&_trkparms=tab%3DWatching&viewitem=&item=110205761864&_trksid=p3907.m32#ebayphotohosting

looks like crap but I think it can be rebuilt. :)
and it's a steal for $10 but I still need to pay for it... I'm missing funds today so I hope I can pay for it tomorrow after I deposit my check and wont get bothered by the seller.

A20A1
01-03-2008, 05:26 PM
450cfm

LIST# 4548-S
MODEL# 4160 or 4160 HP (unsure on this)

Holley 4bbl

Vacuum secondary

I think it's perfect. :D

I'll try and get pics of it on the manifold later.


from the mounting base for the stock carb to the top of the carb with no air cleaner on it is about 6.5" - 7.0" tall
Air cleaners themselves are usually 2" - 3" tall

the air cleaner does mount about 2" down from the highest point so even at 3" it will only sit 1" above the carb.



I'm looking at either getting a Renew kit or Trick kit to rebuild the carb

TRICK KIT: HLY-37-933
RENEW KIT: HLY-37-119

also a quick fuel adjustable secondary diaphragm
http://store.summitracing.com/partdetail.asp?part=QFT%2D63%2D1&view=16383&N=700+400990

A20A1
01-04-2008, 08:15 PM
So far I've figured out it's side hung float... unfortunately I don't think there is an application for the billet aluminum throttle baseplate. I looked at all the list #'s for the proform and quick fuel and neither lists My number but do list other numbers for the rest of the 4160 models

anyone know why this is? or if I can use a billet throttle plate even if it doesn't say it will work with my list but works with my model?

2oodoor
01-05-2008, 04:31 AM
could be a date of production thing?

I recommend a power valve guard for that thing though, the first time it spits back there goes the new valve.

Good to see the project back :)

A20A1
01-05-2008, 01:31 PM
yeah thats what the billet aluminum throttle base plate was for, it has the power valve protection built in and will probably seal and open/close smoother then the one I have now.

A20A1
01-31-2008, 01:36 PM
The Q-JET
http://i23.photobucket.com/albums/b351/Wendy_girl/rq001.jpg

The HOLLEY 4160
http://i23.photobucket.com/albums/b351/Wendy_girl/media1.jpg
http://i23.photobucket.com/albums/b351/Wendy_girl/media3.jpg



I got a cell phone and I'm learning how to use one... damn this things are difficult especially trying to type text, it keeps trying to spell words for me.


the q-jet really suits the manifold, not really because it's throttle plates are too large for the adapter plate beneath them, but because it looks more at home on the manifold.

A20A1
02-07-2008, 07:46 PM
alrighty I'm getting used to the new tapping set I just bought. I want my threads to be metric so I got a metric set :D damn thing keeps slipping. I need to find some pliers or something to help me tighten the chuck/ :(

2oodoor
02-09-2008, 05:44 PM
I agree the q-jet does look good on that thing, but the holley will probably be more tune-able in detail.
Proform has a billet Thr plate but it is pricey
I saw one somewhere recenty that was like a governer plate (billet) for bracket cars to keep from opening the throttle too much EDIT nilch on that, it was Dendenbear Products, DED TS6, throttle stop plate.. wierd looking critter.
I usually use the small vise grips and concentrate on keeping it streight up on the work. The chucks are a PITA for small stuff.

TWOLOUDNPROUD
02-09-2008, 06:00 PM
There Go's the gas mileage:cheers:

A20A1
02-09-2008, 08:16 PM
There Go's the gas mileage:cheers:

True, but it'll depend more on how I treat the gas pedal. I don't need to use all 4 barrels all the time.

2oodoor
03-28-2008, 10:44 AM
Any thoughts on the holley 2300 series 2 bbl, using a percy's metering block?
Those are available in 500 and 350 cfm versions.
A new set up like that can be had for less money than a 38/38.

2oodoor
08-22-2008, 07:35 AM
I am working on this custom manifold and I have come to a point that I am not sure I should take out the entire plenum divider. It seems to hold some structural support for the carb flange. Any recommendations?
Cygnus-x1 did you remove the whole thing, I dont want to remove the carb on the one I got from you.
I am going to be welding a plate on top of the flange so I am not too worried about how much I cut out of the opening, not too much more than it is now in this picture. I am still trimming off tabs I will not need, and there is still the middle part. I really want to loose some of that but without disturbing structural integrity. It would be easier to acces the middle lower intake nuts if I had just a little more room there. I am going to use the three vaccuum taps on the top and close off all of them in the back, just keeping the coolant holes in the back.
http://i162.photobucket.com/albums/t280/roodoo2/1219418826.jpg

cygnus x-1
08-23-2008, 07:01 PM
I removed that divider entirely. There should be plenty of material left for structural integrity.


http://bluegreenlabs.com/Prelude/Engine-build/IntakePlenumAdapter.jpg


C|

A20A1
08-25-2008, 09:15 PM
don't forget to weld that small coolant hole shut. I'm glad you're welding on the flange, it will solve a lot of problems.

Weber users should weld too. Considering how many adapter plates there are, it just increases the chance for a vacuum leak.



I don't think it's structural, it probably just needed to extend deep enough into the runner to be worth the while of having a divider there.

2ndGenGuy
08-25-2008, 10:26 PM
While we're showing off our manifolds: :D

http://i66.photobucket.com/albums/h256/jgturk/1g/DSC01388.jpg

The 1g had a huge, oval-shaped port for the bigger barrel. Took a long time to port that beyotch out... I don't even know how Cygnus got in there with the dremel and cut the whole divider out... I got as much as my dremel would allow... I do notice a nice puddle of fuel in the plenum under the primary when I pull the carb off though. I'm guessing it's not got enough velocity by the time it gets down there or something and it sticks. Prolly should have gotten rid of the whole thing, or divided the whole thing off.

If you could build the divider wall up and match it to the bottom of the carb, do you suppose you'd get some better results? Even with a DGS?

2oodoor
08-26-2008, 06:26 AM
That looks good 2ndGenGuy, that is how I did my first one for the DFEV 2 years ago. I just took a notch out of the wall and opened it up some and port matched the plates.
Cygnus used a roto-zip, like a dremels big brother. lol

You mention a puddle, that is something that I have been wondering about. Everytime I park my DX the one with the A20 and "temporarily" using Cygnus's manifold and 38/38... I get a strong gas smell, no obvious leaks anywhere. I wonder if it is puddling a little there. Also it spins real fast with out cranking up after it sits from a half hour to 9 hours, like it is flooded. Overnight it doesnt seem to do it.

cygnus x-1
08-26-2008, 11:13 AM
While we're showing off our manifolds: :D

The 1g had a huge, oval-shaped port for the bigger barrel. Took a long time to port that beyotch out... I don't even know how Cygnus got in there with the dremel and cut the whole divider out... I got as much as my dremel would allow...

I used a Rotozip with a flex attachment, so it's easier to get into tight spaces. I was always annoyed with the low power and cheapish construction of the newer Dremel tools so I decided to try the Rotozip. Oddly enough it uses the same flex attachment as the regular Dremels, just with a larger clamp to fit the Rotozip. It's a little more expensive but well worth it I think.
But even then, it was still a pain in the ass and took forever.






I do notice a nice puddle of fuel in the plenum under the primary when I pull the carb off though. I'm guessing it's not got enough velocity by the time it gets down there or something and it sticks. Prolly should have gotten rid of the whole thing, or divided the whole thing off.

If you could build the divider wall up and match it to the bottom of the carb, do you suppose you'd get some better results? Even with a DGS?

Oooh, now that's interesting. Because of the fairly large volume under there I could definitely see it being a place for fuel to puddle, especially at low RPMs. That's the downside to big plenums. I bet this is caused by the extra thickness of the adapter plates and how the primary can now feed into the secondary passage. With a 32/36 you might be better off to actually extend the divider almost up to the base of the carb to keep the passages more separated. With a 38/38 you can't really do that because the passages are just shaped wrong. What I would really like to see with a 38/38 is a manifold modified to fit the carb without the extra plates. I'm thinking that would generate some more turbulence in the plenum to reduce puddling. And it would eliminate the potential for vacuum leaks with the plates. AND, if you're doing this on a Prelude it might actually lower the carb enough to be able to close the hood without having to cut a hole or bash a big lump into it. AAARRRGGGHHH! Why didn't I think of that at the time!


C|

2oodoor
08-26-2008, 11:40 AM
How about for the 38 as well, making a plenum "booster".. ie welding a half diamond shaped piece of aluminum plate in the bottom. A cross shaped, cone to discourage puddling and give more surface without being restrictive. :rolleyes:

cygnus x-1
08-26-2008, 07:29 PM
How about for the 38 as well, making a plenum "booster".. ie welding a half diamond shaped piece of aluminum plate in the bottom. A cross shaped, cone to discourage puddling and give more surface without being restrictive. :rolleyes:

Yeah, I was thinking of that too. Could work.

C|