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Site
09-08-2002, 05:10 AM
I want to plan a blow-through boost setup for my 40 DCOEs (once the suckers are in - having the intake made now). From what I understand, DCOEs are sealed and can take moderate boost. I also have some pics of a "turbo hat" made for DCOEs (See Pic Below). Most who boost DCOEs do it with one 45mm carb, not twin 40s. I want to do it with twin 40s. I'm new with this, but I have time and $ to put toward it.

Things I wanna think through - supercharger or turbocharger? (Remember, the sidedrafts open toward the windshield.)
Fuel management - no Funstick, I don't want EFI :) .
Exhaust considerations - what size piping, etc.
Compression - new pistons, Wiseco, JE, etc.
Cam regrind specs.
Consider that I will want to put in nitrous (fogger-type).

You won't be wasting your time helping me think through this. This is something I plan to carry through with. Thanks!

Site
09-08-2002, 05:12 AM
Another pic of the turbo hat:

Site
09-08-2002, 05:13 AM
And another:

Sean
09-08-2002, 06:34 AM
i thnk youve got a long road ahead of you for sure. manageing the fuel is gonne be tough but spark it another issue. i got some help for that.

Site
09-08-2002, 06:44 AM
A long term process for this is okay for me. I'm in no rush, but I am determined to do it. In you opinion, is this do-able, funstick?

Sean
09-08-2002, 12:59 PM
yeah but yr gonnaneed to manage the spark

Site
09-09-2002, 05:59 AM
After some reading, seems like I'm gonna need to build a box around the carbs. This seems like best route to take. My carbs have plastic floats, so I'll either need to get brass floats or maybe fill mine with foam to keep them from being crushed.

As far as fuel enrichment goes, what do you think about fitting fuel injectors in the intake runners (like a direct port fogger system) that open up at boost? I'll need some kind of boost-sensing controller for the injectors. That way I can keep my carbs with normal jetting for off-track driving.

I guess I need to take back the "no EFI" comment I made earlier, maybe.

I've thought about a belt driven fuel pump, but I would have to jet the carbs for boost then and they will run way rich at low RPMs.

Site
09-09-2002, 07:22 AM
Here's a really nice pic of a single 45DCOE enclusure in a lotus (came stock like this!). I know it's for a single sidedraft, and I'm dealing with twin, but you get the idea.

http://www.fiveofus.com/dad/images/Intercol1.gif

Site
09-09-2002, 07:45 AM
Anyone know where I can get an adjustable FPR with an atmospheric (not boost) pressure reference? Possibility - I could plumb it into the carb enclosure, set the FPR to start at 3.5 psi, then it would adjust according to the pressure the carb views as "atmospheric", since they're enclosed. This and a slightly updgraded fuel pump theoretically could solve the fuel management issue.

Site
09-09-2002, 01:28 PM
Would something like this be sufficient to produce enough forced air to fill and boost an enclosure? Someone with turbo knowledge help me out here - would I need this whole setup?

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1856471906

Site
09-26-2002, 06:21 AM
Found this post way deep in an forum archive online. I emailed the originator of the post (it's from 1995) and my message got returned with fatal errors - oh well, at least I have his post.


A blow thru turbo installation is next to simple with mikuni/weber side drafts. An "air box" mating with both carb faces, allowing boost to barrels and fuel bowl vent is the start. Keeping air cleaners inside helps to reduce turbo turbulence. Apply your boost to this enclosure. Fuel supply must be enhanced to accomodate the boost however. You need a pump with sufficient volume, and pressure to match original requirement plus boost pressure. Use an adjustable fuel pressure regulator, with an atmospheric pressure reference vent that you can plumb into the air box, so fuel pressure will automatically be regulated to the set value, compensating for varying boost pressures. Holley offers such a regulator. (that is, if set for 3psi, pressure will be regulated to 3psi above boost pressure). Jet sizes for the carbs can stay the same, although slightly richer jetting can be easier on the turbo. The webers, I'm told can handle up to 20psi positive boost, without leakage around the throttle shaft, or gaskets. Im sure the mikuni's are capable of the same. They're a fine carb of almost identical design. I have a picture of a quad4 oldsmobile engine done this way, I'll try to find and scan it. It made 700 HP from 2.3L! Word is, the blow thru set up on sidedrafts offers excellent throttle response, since the throttles are a few inches from the valves. Beats the crap out of the stock EFI lag. I don't need time to drink a cup of coffee, between pressing the accelerator, and leaving at a green light...

If this guy's right, then I won't need to enclose the carbs. Instead, I'd be able to use a "turbo hat" type box as is pictured above.

I've also found this, which I think will help with the fuel management problem if it can be set to regulate fuel pressure at a low enough psi. I've emailed the company to ask:
http://www.magnumforceracing.com/magnaflow_fuelregulators.asp#MagnaFlow Racing Fuel Pressure Control Units or Regulators

Or this, since I'm not sure that the above regulator references boost:
http://216.242.145.16/products/product.phtml?p=20

Sean
09-26-2002, 03:36 PM
might a irecomend a fuel pump. any of the gm truck tbi pumps will fit in the stock hanger with soem trimming and they tend to run at a mzx of about 20 psi. with a good regulator this should pose no problem with a sufficient reutrn line.

Site
09-26-2002, 03:45 PM
Thanks for the info, funstick! One thing that I saw as a roadblock is the cost of the aftermarket performance electric fuel pumps for carb setups. Most are nearly $300! Again, your advice is invaluable - thanks!

Site
10-07-2002, 08:47 AM
Just got off the phone with Jeff from www.mazdaracing.com. He says they have single DCOE turbo setups using the above pictured "turbo hat" for Mazda racecars that run 25 psi boost. He told me that they "turbo-prep" the Webers using their own special methods and that turbo-prepped DCOEs can handle 30+ psi of boost. I'm presuming this turbo-prep might include high strength gaskets and other sealing techniques. He said if I sent in my whole sidedrafts/manifold setup they would custom machine me a single "turbo hat" that feeds both carbs.

I'm thinking that sending it off to them will be way expensive. A single turbo hat for one DCOE goes for $380 on their site - a custom job would surely be more than that.

The more I think through this, the more I believe that enclosing the carbs in an airtight box (keeping the pressure inside the carbs the same as the pressure outside) is the best option. I can't help but think that consistent boost pressure inside the DCOEs will mean frequent rebuilds and leak risks. I enjoy rebuilding carbs as much as the next guy, but this car will be a daily driver and will get lots of use. I'm not up for doing a "carb check" every time I pull into the garage!

I'm going to look into having the machine shop that did my manifold do an enclosure box for me. Or I may do some experimenting with other heat resistant, lightweight materials. It would be very tight to use some kind of clear, acrylic type material for the enclosure. Then I'd still be able to check out the carbs without removing stuff from the engine.

Update - I'm hoping to start the car up with the DCOEs installed tonight!

3rdGenFanatic
11-10-2002, 05:11 PM
Is turbo possible for the Weber 32/36?

Site
11-11-2002, 05:52 AM
I don't see why not - A20A1 has forced induction through a hood scoop on his 32/36. It probably adds 1-2 psi boost. If you want strong boost on the 32/36, I'll bet you'll have to enclose it in an airtight box.

3rdGenFanatic
11-12-2002, 05:34 PM
Thanks site :) How many PSI boost will I be safe with? Maybe around 5?

Site
11-12-2002, 07:01 PM
I've looked around for an answer to how much boost the Weber D series carb can take, and I'm finding nothing. Maybe it will be up to you to test it out! There's not a lot you could permanently damage by experimenting with it.

3rdGenFanatic
11-12-2002, 11:32 PM
Sounds fun.. I'll give you guys very thurough results.

Site
01-16-2003, 09:00 AM
This project is coming along well. I've got a lot of part #s and a lot of ideas, but not a lot of money to spend - LOL. Yet . . . but tax return time is soon :D

I'm approaching this from the perspective of setting up a small-displacement drag engine. There's some good resources out there (websites and catalogs) for this.

I think I have the fuel supply close to do-able. I want to use an Aeromotive Street Rod pump or A1000 fuel pump to flow the fuel. To regulate fuel pressure I'm choosing between an Aeromotive Carb Bypass regulator with boost ref or a MagnaFlow Fuel Control Unit with boost ref. Both companies carry a model with 2 port output so each carb will get a feed.

I'll have to put in either LXi fuel lines (so I get a return line) or custom something.

A big deal gets made about spark control. I'm not sure why, but I don't want to blow this off. I don't know what the problem is with throwing in a MSD Programmable Digital 7 (click to read up) (http://www.msdignition.com/2000_1.htm), but some people seem to think that spark control will be a much bigger deal than anything else in this project.

I'm totally open to ideas on ignition.

PhydeauX
01-16-2003, 09:05 AM
Wait untill they finish developing this, http://www.bgsoflex.com/mjl/mjl_edis.html
Unless sean comes up with a stand alone dis unit before that.

andy

2old_honda
01-17-2003, 11:34 AM
hey check this out- http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2400550129&category=6755

Site
01-17-2003, 11:39 AM
Behold the picture of a Toyota 22R blow-through turbo setup with Weber DCOE 45s!

LOL 2old, I think I posted this right after you posted the link above. That setup is amazing! I've never seen anything like it. It's beautiful :lol

I'm trying to find out where he got the airboxes that bolt onto the carbs.

2old_honda
01-17-2003, 12:15 PM
yeah, it really is beautiful! If only I had a toyota truck to put it on. lol

1989 DX R
01-22-2003, 08:06 PM
Old Celicas like the 1986 and previous had the 22R and RE motors if I'm not mistaken.

kraftaroni
01-22-2003, 08:42 PM
You can find those airboxes everywhere they sell webber or mikuni carbs. All the vw aircooled places have them in orange county you see the turbo hats on all the aircooled vw bug engined in the dunes. Try local dunebuggy stores with high performance parts I've seen them for 120$ for both bonnets. The first civic I saw break into the 13's had them on his car back in the late 80's/early 90's and ran a blow thru system.

Site
01-31-2003, 07:20 AM
From Härkölä Jukka, a guy that has a blow through setup with a Dellorto DHLA (very much like the Weber DCOE) on a Mini. I found him on the Yahoo blow-through turbo forum (http://autos.groups.yahoo.com/group/blowthruturbo) and I've been emailing with him. Check out his webpage: www.geocities.com/jharkola/1380turbo4.html


Most local "experts" have said that the trick is to use relatively small choke to get any kind of drivability. I started with 36 mm chokes, then 34 mm and finally 32 mm chokes. Note that the engine size in my Mini is 1380 cc and usually it uses either 36 mm or 38 mm chokes in n/a street engines and 38 mm or 40 mm in serious race engines.

With larger chokes the hig speed mixture could be made rich enough but the transition from idle jet to main jet was just a big hole. Anothe emulsion tube fixed the transition but then there was no fuel under boost... Going to smaller chokes did help the drivability enormously but did not cure it completely.

Now, the real trick was to locate a book called "Turbomania" by Bob Tomlinson. A guy called Dan Noble in San Diego USA hinted about the book that contains a load of info about turbo VWs. Located and bought. The trick here is to use a restriction at the carb mouth, like a stub stack but with a bore smaller than the carb bore. Judging by the jetting info supplied it seems that the size of the restriction is about the size of the choke or even less. So I turned a pair of inserts with 34 mm ID for my stub stacks and refitted the 34 mm chokes. Well you know the old wisdom: only change one thing at a time...

Now the engine works just as well with the 34 mm chokes + restrictions as with 32 mm chokes. It would probably be better with even smaller ID restrictions. By making the carb pressure sensitive it has made the jetting a bit easier. Still the jet sizes look a bit large compared to choke size but smaller simply will not work... Still the jetting is not perfect: there is a spot at about 2500 rpm where the engine hesitates: depending on the idle jet holder vs. emulsion tube combo it´s either rich or lean. But with WOT it runs very nice. I would like the engine to run smoothly from idle to max rev on 4th gear. Now it stumbles at about the said 2500 rpm. Actually no big deal once you know it is happening, simply go to 3rd gear and hit it.

I have experience only with Dellorto carbs but similar approach can possibly be adapted to DCOE range. Dellorto turbo carbs had seals on throttle shafts plus rubber 0-rings for idle screws. All drilling plugs had been sealed with lacquer. The gaskets were made of rubber.

A couple of years ago I did phone around about DCOE suitability and was informed that 151 and especially 152 type Webers were suitable for blow thru out of the box.

Sweet info!

Grant2k
01-31-2003, 04:00 PM
sorry to get off topic, but for a 32/36 this is a pretty good picture of what you would need to build. it's a pressurized box that encases the whole carb. it's on a V-8, and it's a supercharger, but you get the idea. i have this issue at home somewhere and if anybody wants i can scan it when i go home this weekend. i only have a yahoo email though so i don't really have a way to send it to anybody. i couldn't shrink it down enough to where it would be sendable through yahoo and still readable. sorry to interupt. ironic cover though.
http://www.the-direct-source.com/images/CC0802.JPG

Versanick
05-26-2003, 09:52 PM
I'm probably looking at a supercharger instead of a turbo... the custom header work and intercooler custom setup is going to cost a bundle. With a centrifugal (not root) supercharger, I could run the same type of blow-through setup. How would the timing work, though? On a carb'd a20, the timing is retarded quite a bit from the efi one... and on an efi setup, I'd advance the total timing 16-20 degrees (depending on a lot of things)... how would you know how to prevent detonation with this? Besides rods and seals and pistons and the usual... I mean as far as timing goes. Trial and error?

I'm real interested in running 45 DCOE's for this, and a blow-through supercharger... that'd be amazing. A turbo is just too much work (though I LOVE the whine, and the blowoff sound... ugh..)


hit back

A20A1
08-15-2004, 07:36 AM
bump... I hate having to search for this thread, anyways I'm adding you, SIte to the turbo thread under "in the works"

Civvy
09-17-2004, 05:49 PM
Sooo what happened? u got any further? I'm only used to keihen's and i should proly just shut up and listen and not ask questions but hell with it...help me understand something.
If hyperthetically we were to use the stock carb and it didn't leak.we just put a hat on the top.we made the secondary really rich and went back to being vacum controlled but from the boost guage pipe....so we get a normal running car using the primary then boost plus extra fuel on the secondary. Then those fuel vents can we not use rubber pipes and have them outside of the hat using no pressure? = thus not crushing floats etc.

A20A1
09-17-2004, 07:44 PM
only setup that won't crush the float is a draw thru...

the float bowl and the inlet to the barrels are all connected.... you'd have to make some pretty tight seals to ceep the float from seeing pressure... but you'd still need to up the pressure of the fuel... soo you'll probably end up breaking the float anyways or at least busting the O-rings on the float valve itself.

A20A1
09-19-2004, 04:42 PM
If you must know here was my plan to turbo a carb...

http://www.3geez.com/showpost.php?p=440731&postcount=5

taken from the FAQ

http://www.3geez.com/showthread.php?t=37169

:D

Civvy
09-20-2004, 05:16 PM
It doesn't mention the vacum problem u get when the butterfly has just closed and the turbo is still trying to boost and the weight of the fuel on the compressor fins.
I like the idea's that (hawaii.com) lude did running twin 40's. He ran 16psi boost thru that motor with most of the engine as stock and managed low 12's. I'm gonna run the B20 with 45's/total seals/forged pistons/p+p head/spun flywheel/crank and not to forget a better looking header than his! he,he
with the B20 i can have better valve timing using 2 adj pulleys as opposed to 1! ....11's? and should compensate for that issue they had having to go smaller in intake size...(mini)?

Seriously, we should bitch all these concerns out and that way it'll point us in the right direction with using carbs. I cant wait to hear what robs runs at!

eightyfivelude
09-20-2004, 05:55 PM
did anyone actually look at the hawaii guys setup? He is usinga blow through weber setup mated to a a20 fuel injected manifold. The injectors are there to add the extra fuel the engine needs while under boost. Ingenius seupt if you ask me

Matt

A20A1
09-20-2004, 06:39 PM
Civvy I read about those 2 very issues and added them in to the FAQ where I'm discussing the draw-thru setup.

I'm going to use the injector ports for water / alcohol injection... sure it's a pain to carry around an extra resivoir... but it's the only alternative since an intercooler isn't possible.
Plus I read that richening the mixture to prevent detonation isn't the best way and only works up to a point.

I also read that water injection will allow for less retard on the ignition.

2ndgenludedude1986
09-20-2004, 07:47 PM
eat your heart out. i have been studing this for about a week nowa nd came donw to that i will need a inline beefy fuel pump, and a beefy fuelpreasure regulater with 2 ports for each weber like you said. also the thing that is holding me back is the turbo exhaust manifold. i woudl need to build one. along with the piping adn the airbox. auctualyl this project is very doable for under 1200 bucks.

Ludi Mali
09-20-2004, 08:58 PM
i'd say a blow-through would work better or maybe be easier, i read somewhere that the webers can take a considerable amout of boost(for our cars) out of the box. or you can have weber rebuild them for use witha turbo up to over 20lbs i think.

A20A1
09-20-2004, 11:39 PM
Actually the draw thru will be easier since it requires less fuel management... but isn't the best for making the most power in a more efficient manner.

I'm going for a low boost though, just to know that what I'll be using works together ie: the water injection and turbo Charge pipe routing and efi manifold and long wrapped turbo header tubes.

Plus I'd need a turbo cam...

One thing I hate about all this is carrying the water resivoir... one reason why I'm still a big supporter of N/A

But the technical challenge of turbocharging is right up my alley.

A20A1
09-21-2004, 01:34 AM
I added even more info. take a look :D

http://www.3geez.com/showpost.php?p=440731&postcount=5

I'm a bit concerned about the oil issue...
I'm sure I can make a manifold more acceptable for a carrying the air fuel charge... the problem is at the turbine...

What drives me nuts is that the turbo is hot so the fuel would vaporize right and thus be less affected by the turbine then what most people are trying to suggest.

Lok
09-21-2004, 04:04 AM
http://up.edu/~midehara/index.htm

A20A1
09-21-2004, 04:22 AM
Yeah I live in Hawaii, :D

If I closed off the stock keihin manifold like the guy with the Nissan did... and had the turbo in the same spot in relation to the manifold it might end up being better to route the turbo pipe from the head, under the pan and back up top the turbo... that way I have the shortest possible connection between the turbo and the carb wet-flow manifold... I have a short version of the carb manifold but I'd still need to split the air/fuel mixture.

http://www.3geez.com/attachment.php?attachmentid=3634
http://www.3geez.com/attachment.php?attachmentid=3635

unc25
09-21-2004, 05:59 AM
I have alway sbeen confused about turbo and the carb. I dont understand why this ouwldnt work the same way as an efi Just add the manifold and and the turbo and run the piping like the carb was the TB.

You guys dont have to explain I was just saying..Showing my ignorance

Civvy
09-21-2004, 10:34 AM
well, oil is just a case of longer pipes usually but, i dont think an oil cooler is gona cool it to the extent that it gets thicker again! also, it would then be heavier - so theres one loss. that manifold sprung the a18 carbs 2 mind!!!? ...we could use them for their butterflys only? ...why is an intecooler out? dont 4get the scoobies!! they're directly above your setup. whats this turbo cam? ...thats crap! i'm more for thr su design mike as a drawthru..thoose are sooo easy to tune. Still concerned about heat on that setup tho...its bad enough on the common design. i know ure always up for a challenge but is low (hot) boost really worth all? I have alwys been fond of the N/A specialy the u.s. muscle sound, and i defo will NOT be getting a noisy dump valve. I'm in steady competition with a N/A drag driver so i've descided i cant go the same route to beat him ...thats not competition, and it gets boring to quick

NXRacer
09-21-2004, 02:20 PM
I have alway sbeen confused about turbo and the carb. I dont understand why this ouwldnt work the same way as an efi Just add the manifold and and the turbo and run the piping like the carb was the TB.

You guys dont have to explain I was just saying..Showing my ignorance

ther are a LOT of issues that come up with turbo's and carbs. Carbs work by vacuum and air pressure and that all changes 10fold when you hook up a turbo to a carb. Its been done a lot, but its significantly harder to rig up then with fuel injection.

2ndgenludedude1986
09-21-2004, 07:19 PM
http://up.edu/~midehara/index.htm

yea i ment to psot that link in my reply but forgot it!

A20A1
09-21-2004, 07:39 PM
Turbo cam, something with less overlap... and a delayed intake opening to combat reversion...
I need one because I have a wild N/A grind now that has way too mush overlap to run turbo.

Forget easy to tune.... SU carbs aren't sexy... or at least not the ones I've seen...
I want a 4bbl (Demon, hehehe) or something with a stack or fitler on top... I'd hate to build goofy carb hat or cover the carb up completely in a box... that just doesn't sit right with me.

Fuel would get caught up in the intercooler and seperate from the air... it's not a wet flow design and I haven't seen any wet flow intecoolers. I had stated that as the problem... in the FAQ.

I woudln't worry about the pumping losses of heavier oil if it ment the turbo was safer.

Sure gains will be minimal without water injection, but with water injection boost can be increased.

I'm trying to find an article written by TURBO TOM
they say he's done plenty of work with draw thru and other turbo setups and prefers draw thru.

A20A1
09-21-2004, 07:53 PM
Sweet!

http://www.bryanf.com/510/e3.htm

390 dbl pumper. :D

rotary :D

oldschool datsun :D

yellow and black :D

Civvy
09-22-2004, 06:37 AM
Since its a very much triall and error project i'm gona use cheap stock cams for now.
We used twin S.U's on a friends MG Mini turbo and the only tuning methods were simply Spring/jet/needle ...wasn't so hard!
As i said there'll be nothing goofy about my tophat it will have inertia in mind when its getting designed, unlike the many i've seen...so far!
With the oldskool drawthru method it has its several drawbacks i.e. poor economy/throttle response....and i'd hate that!!
The S.U's and maybe the prelude a18 carbs could be dual or 4's and wouldnt be too hard to fit the stock mani maybe??..i know we can get the linkages for quad su's from the old triumps and ?honda 800?? These along with the Webers are particulary good for both setups..in fact most if not any carbs could be used!!?
As for floats i've got a few idea's i could use thin piping from a hobby shop and have them each side of the float...this will prevent collapse. Fill them 'proportunatly' with spray foam. use solid plastic one's...hey, sometimes u can get away with stock floats under low boost!

Civvy
09-22-2004, 07:21 AM
What about using the f.i. flange on the modded stock mani if your gona use an f.i booster, it'd also give u ports for injectors! and in the best place.

Looks like thats what the Hawaii Lude did too!

I've got to add at this point... The fastest road car in the U.K. is indeed an MG Maestro 2.0L Turbo! The car is now F.I. but, originally was using the push-through method via a single S.U. carb! and was then still the fastest hot hatch in the country! 0 - 60mph in less than 60secs! and also note this car is a 4door hatch

Civvy
09-22-2004, 06:09 PM
Just a thought on the ignition side...as a cheap ass mod, maybe this would work but, it would annoy the r+r tuner!..if it worked!! If i could reverse the role of the vacume advance diapragm and have it push instead of pull...taking it apart and somehow putting the spring under the valve causing it to result push rather than pull! and using the boost guage line to push the diapragm and retard the timing under boost!! Also, then i could control the amount of retard by having an inline tap..which could then have a additional under hood pressure guage to show how much pressure is coming thru the tap, if ness'ry!! What do u think could it work? maybe i'm overthinking this and my worlds too ideal!!?

A20A1
09-22-2004, 06:25 PM
No you're not over thinking... I was looking at a simmilar design.

2 possible spring placements ( in or out )... all you'd have to do is rig up the supports to hold the diaphram and mess with the spring tension.

The spring wont rest on internal moving parts nor interfere with them... this simply shows you the general location of the spring within the distributor if one will fit.

I can wled up a longer support rod... I've had to modify diaphragms before to work between hitatchi and Tec distributors.

http://www.3geez.com/attachment.php?attachmentid=3674

Civvy
09-22-2004, 06:37 PM
uve sussed it man! but if we used the inline air tap to adjust the pushing airflow to the diaphragm, it would save us worrying about spring tension?? what d'ya think?

A20A1
09-22-2004, 06:40 PM
I was thinking if the shaft is long enough you can add on a Drill Stop that they use on drill bits as a way to make fine adjustments to the chosen spring rate... it's a lot easier then adding say a few washers... plus it can act as a stopper if the diaphragm used is one that has more travel then you actually need.

A20A1
09-22-2004, 06:42 PM
air tap or do you mean restirctor? I dunno if you can give me an example that will be good. :D

Civvy
09-22-2004, 06:50 PM
I like it! What about a knock sensor(as a/if ncc'ry safeguard?) do u know how they're wired? if we could install one and have a light/l.e.d come on ...maybe under the bonnet for tune up? ..The only thing i'm not sure about is when is it going to need that specific particular degree of timing...if u know what i mean? ...i.e. if boost opens the diaphragm fully to the max retarded position will it be too far to early or for that rpm? kind of thing? ...thats what made me think of the knock sensor. i know it wont fix it, but mite alarm us of danger!

Ludi Mali
09-22-2004, 07:00 PM
you 2 is the craziest peoples. Actually this makes a lot of sense if you could have some kind of variable restrictor for more manageable control.

Civvy
09-22-2004, 07:01 PM
Yes, a restrictor. Like a fuel tap! u can adjust the flow.

2ndgenludedude1986
09-22-2004, 07:19 PM
ok you lost me, i was justing thinking aobut throing a turbo on the motor with custom piping and calling it a day!

Civvy
09-22-2004, 07:58 PM
been doing some more thinking. Hopefully, what will happen is as boost increases, this will cause (via fine adjustment using the air tap/spring tension) more pressure to the diahragm thus, retarding the ignition according to boost pressure = plan worked!
Problem. what if we havent got enough boost pressure to feed the diaphram?
Answer. we can plum in another pipe using a larger diameter.
Conlsn. If the original plan worked with the first pipe using the air tap to adjust pressure on the diaphram/timing. We can learn from the amount of flow needed to make a excact size pipe to flow the correct pressure to the diaphram. ...Making the job look pro!
I guess the knock sensor isn't that important but, it would tell us if we were too advanced and then perhaps give us a starting point to setting the timing from...maybe usefull!! O.K. i'm on a fine line of confusing my own shit! i'm going to bed! I guess since uve all logged off now i'm talking to my self anyways!?? ....Hello?

Ludi Mali
09-22-2004, 07:59 PM
yeah, but if there was some way to automatically adjust it based on rpm's, you could tune the amount of retard at a given point.

Civvy
09-22-2004, 08:18 PM
I cannot believe uve kept up!!!
That would happen automatically! ..i think?

As stock, the vacume advance diaphram must operate in accordance to vacume pressure from the manifold (which i think? increases with rpm and load) to advance the timing for full power. More manifold vac = More adv. timing ..Definatly not sure about that one as vacum guages say poor when u got ure foot down?

So as we've now reversed that, i guess the Turbo will be generating full boost at higher rpm and load, and also because the throttle is opening further as the driver is compensating/feeling the load? ...full boost = max retarded timing

but, ive just had a thought! The engine can be reved up to high rpms without the use of the boost = meaning the ignition would not retard!!! but....it dosent need to retard then BECAUSE theres no boost to cause damage!

I'm working on a DIY ignition (c tech forum) which is Crank fired...maybe the answer? but its distributorless! up to now i havent seen how/if it can be retarded mechanically/at all, It mite be clever and be able to retard electronically. like our dizzy's! ...Think its time for more research!

Ludi Mali
09-22-2004, 08:50 PM
one other thing i was thinking of for fuel enrichment, instead of putting an injector in the manifold. What if you put it in the uppipe somewhere. like right before the carb, almost in a position where you'd put water/methanol injection. Might be easier to fab it there.

Civvy
09-22-2004, 09:24 PM
or u could use the needle drop type carb (i.e, S.U.). There's no change over point and u wouldn't need extra fuel systems, just correct jetting. The MG Maestro i mentioned earlier was also a 2.0L 16v so it gives us a good base to work from!

A20A1
09-23-2004, 12:19 AM
well a knock sensor could open the restrictor and then that would overcome the srping more and increase boost retard... problem is finding an electric restrictor valve...

Would it need to bleed the excess boost back into the intake I'd guess thru a one way valve? I may be thinking of it wrong...



*****

I wanted to know the effects of running something simmilar to a wastegate off of vacuum, like a secondary one that would operate off of vacuum created when the throttle is closed... So you can dump as much gas as you could to prevent the trubo from building up vacuum and sucking up oil... even to go as to say have the pipe from that wastegate exit into the down pipe in a way that would slow the turbo turbine...

I'm only saying this as a measure to save the turbo... and this will only be activated with high vacuum... normal cruizing should not open the valve.

I'd just rather not rely soley on the carbon seal...


I was reading and I found out that I need a larger wastegate when going for low psi levles.

A20A1
09-23-2004, 12:25 AM
Oh shizzle... what about a vacuum operated exhaust brake? Would that slow the turbo down without killing it... I just want to decrease the occurance of a high vaccum situation.

Have the brake come on and add resistance to the turbo... slowing it down but bleeding pressure thru some smaller exhaust port... this in turn would slow the turbo down and relieve lessen the vacuum pressure?

I wish we could just bleed the damn vacuum but that would be like opening up the throttle again but without any fuel to go with it.

I have 3 spicy chicken Taco Bell burritos in my lap waiting to be munched on... brb

A20A1
09-23-2004, 12:28 AM
Methanol isn't as easy to come by as alcohol... :beer:


BTW I was reading "HOT VW's" Magazine and saw a few dune buggies with carbs and turbo... one was blow thru and one was draw thru... both had DCOEs I believe. I wish they'd offer up more in depth info.

maka_RTH
09-23-2004, 12:36 AM
I have 3 spicy chicken Taco Bell burritos in my lap waiting to be munched on... brb
dude, why'd you say that? i just got a huge freaking craving for taco bell now, and it's 2:30 in the morning here! i need to go to bed, lol. anyways, you guys are crazy. if you're not too worried about budget, you could just always go with an aftermarket igntion that would automatically control everything. like retarding the timing and whatnot. possibly get the 4g dist. if you need to. otherwise, sounds like you guys are coming up with some awesome stuff. can't wait to see the finished setup. i suppose in a way we're going against the flow. turboed carbs for you guys, and N/A FI for me. lol, good luck! :rockon:

A20A1
09-23-2004, 01:10 AM
Well I'm not going turbo just yet... just getting the ideas on the table. Basicly though I want to be able to use existing parts and mods and run the setup with as little electronic controlls as possible to reduce the cost, but also have it duplicatable for others to make simmilar modifications.

LOL your sig says blown engine, I almost thought you were turbo but then I remembered the hole in the block thread.


Here is my thread on HT A20's Turbo Question to the HT Guru's (http://www.honda-tech.com/zerothread?id=1000332)

It will be interesting to see what kind of replies I get if any.


urr, is it a surge valve or isn't it... I hope that will limit the high vacuum or is the surge valve another name for blow-off valve.

Ludi Mali
09-24-2004, 03:05 PM
i think surge valve is another name for blow-off valve, lets the extra pressure escape.
I was watching trucks today and they were upgrading the turbo on a what i think was a ford diesel. and it had this little vacuum actuated actuator that held the wastegate closed longer for more power. There has to be something you can do with that so it will work opposite.

Civvy
09-28-2004, 10:15 AM
Going back to carbs, i was planning on using twin 45's but i've been heard rumours 40's might be better because of choke size! Was wondering if i could fit chokes similar to the 40's into my 45's?

A20A1
09-29-2004, 02:51 PM
http://www.mooreparts.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=WEBVEN

Civvy
09-29-2004, 03:23 PM
Thats for IDF's? I'll be using DCOE's! guess i was asking if u'd heard/read of this in practice?

A20A1
09-29-2004, 03:48 PM
OOp's I didn't read what they were for... sorry.

What do you think about my EGR idea in the other thread?

Civvy
09-30-2004, 09:52 AM
I think I hope it works!
The draw-thru route is getting a little too complicated for me tbh!
I'll chip in my help as oftern as i can. but, i've never had any experience wit that setup!
It all sounds good tho i have to say, just copy from the oldskool finds out there!!
Good luck.

Civvy
10-16-2004, 08:18 PM
We'll its been a while. I've been talking to me dah 2nite and he reckons there's no reason for us titewads to not be able to run our timing at 12degrres retard and get away wit low boost such as upto 6=7psi. He said were over concerning and the car would just simply feel slugish with boost off.
He's put me off the MSD anyhow by saying that we could suffer from mild detonation and not hear or feel it! therefore the manual/custom setting is a bad idea! he said there's someone else called j and s??? that makes a similar thing which uses a knock sensor and controls the timing automaticaly.
Also, i know i have but, when running boost u have to remember to disconnect the pcv system! the pcv valve works wit vacuum from the mani. and when we add boost pressure to the mani it closes the valve and shuts off the pcv circuit. ...and at the worst time i assume, being under boost is when blow by the rings is amplified espescialy on our oler engines!

Have a question. I've noticed nobody uses ITB's on a turbo setup! ...soo are we going wrong using twin webers??? I read somewhere about a mini running boost and he had to restrict the airflow to the carb (single dcoe) to get more bhp!???
If soo...this is getting cheaper and cheaper ha/ha!! :rofl:

A20A1
10-17-2004, 11:50 AM
maybe it helped the carb work better with the added restriction...

Still I think it's better to go ITB's for a blow thru since carbs were ment to see vacuum.

Civvy
10-17-2004, 03:52 PM
No, i meant people with F.I. are using stock style single tb not ITB's?

A20A1
12-15-2004, 01:18 AM
More interesting sites
http://www.american-pi.com/corvair/html/turbo.html

http://www.dune-buggy.com/turbo/carbureted.htm

http://www.american-pi.com/safeguard/safeguard2.html

http://www.american-pi.com/corvair/html/DCOE_detail.html

.
.
.

A20A1
12-15-2004, 01:19 AM
http://www.jandssafeguard.com/

touring 1
01-06-2007, 02:23 PM
This isn't a forced induction note, but you are looking at DEOE's, and I wondered , Has anybody thought of what this guy's doing on his old Beemer 2002 tii? I was fascinated by his thoughtfulness, and geekiness in taking this on as FIRST time project! He's using individual throttle bodies which mimic the DCOEW carb, but with modern fuel control. thought you might be interested, as I was.
http://www.bmw2002faq.com/component/option,com_forum/Itemid,57/page,viewtopic/p,319629

I think I saw a Civic drag racer with "gasser" looking stacks thru the hood on one of those street tuner shows.

89T
02-11-2012, 07:43 PM
I am bumping every old turbo thread. Is it running or gone.

hondalude86
05-05-2013, 07:54 PM
I'm curious too, with the mosselman turbo manifolds in the mail for many, I'm wondering If you will see some more blow through builds