INTAKE MANIFOLD ( Modification / Design / Fabrication )

[gfrg88]

OMG!! and i though edlebrock had a big plenum, damn thats huge.... i want one

[A20A1]

The runner taper looks reversed... but it's not really a taper. It just looks like it does. The increase in wisual width near the flange is just because of the oval transition to the ports.

Also the plenum doesn't get smaller near the last runner, a lot of plenum shapes from F1 cars to the manifolds on the market today have some taper to the plenum shape towards the back.

Alright, after a long research it is common sense that the B series intake manifolds modded to fit the A20 motors are the best to use for Turbo application. Then comes the question of what kind of design should the intake manifold carry to utelize the maximum flow of pressure with minimal restriction. Larger and streamlined plenum with short runners are the best for the application despite the engine rpm since its forced induction. Instead of slapping on widley used or recommended intake manifolds, i would like to list pretty much all the good quality manifolds available off the shelf for good companison and pick out the best at hand. The following images/products are the manifolds i want to choose from and recommend it to people who are along the lines of turboing their car since the quality of these are superior and reliability is great. So here are the following.
BBK (around $120)

Edlebrock ViictorX ($220 to $350)


Venom ($500 to $600)


JG Engine Dynamics {Endyne} ($ unknown)


AIR Endyne ($400 - $500)

NOTE: The reason for the comparisons is purely based on performance on these manifolds and valid technical responses only. All the bullshit and offtopic posts will be deleted by a mod upon my request to keep this thread clean and specific.

PS: Price is not an issue so do not use it as a reason. If price was a reason for me, i wont be undertaking the turbo project and neither would have many who are under way. I have a pick in my mind with reasoning behind it based on my engineering. Aside from that, i would like to hear what people think would be good based on their experience either personally or thru their friends. Thanks fellas.

[A20A1]

Focuz B16/B18 Intake Manifold
It's polished like a mirror on the inside

Welds aren't very well done on the flange end

It's cheap, but it looks like it will do well!

Plenum is larger then the Edelbrock unit as well. =)

Please take that inside picture again but try and cover the flash or disable it... if it's too dark try and adjust the exposure time... just make sure you hold the camera steady.

[carotman]

DAMN!!!
I thought my Edelbrock manifold was big.... this is huge!

[A20A1]

Yeah, the Full Race looks like a f'ing Zepplin. =)

We should dub it the "Hindenburg"

[Accordtheory]

You cannot get the bbk for $120. that is complete bullshit. If you can, let me know where!
My only question about the full race is that the velocity stacks do not follow endyn's 1/2 radius formula. But we know how everyone '"rides full race's nut sack"...h-t..
but full race does engineer really exceptional shit though.

[A20A1]

I did this a while back but it was a fairly rough measurement, I guss I was off.

The smallest port inside the carb manifold measured 1.48 square inches... well 1.162392000001
The port where it meets the head it’s 1.76 square inches, well 1.656703125 actually.
hehe I think I did HxW instead of: pi ( r x r )


You're right I think the intake diameter of the port to the head is 1.5" you find both radii then add them to get the new diameter... or am I wrong?

it was 1.125' High and 1.875" wide oval port.

4802 Peak Torque RPM
Optimum Intake runner area 1.62 square inches (calculated)
Optimum Intake Length 17.49 inches long (from valve head to plenum).

I double checked it with this as well
http://www.bgsoflex.com/intakeln.html

I used 17 inches.

Looks like we have a winner, no?



http://www.team-integra.net/forum/di...PagePosition=1

Here is a snipt from JUN
http://www.junauto.co.jp/products/in.../index.html?en

Surge Tank / Plenum


Also some nice info here:
http://www.team-integra.net/forum/di...PagePosition=1

Also on page 4...

my reading continues.
.
.

Check out this computer design program.
http://www.ricardo.com/download/pdf/...nifold_opt.pdf

It's showing VW manifold.

Showing honda
Lean burn blah blah blah, yakety smackety.

http://www.ricardo.com/download/pdf/...honda_vtec.pdf

.








I was messing with the calculator.
- Peak TQ @ 5500 RPM with a 1.76 Square Inch Runner you want 112.90 CID
- Peak TQ @ 5500 RPM with a 1.84 Square Inch Runner you want 118.03 CID
- Peak TQ @ 5500 RPM with a 1.86 Suare Inch Runner you want 119.31 CID

Our 119 is actually between 1.85 / 118.67 CID and 1.86 / 119.31 CID
But I consider our 119 CID measure to be arounded figure anyways.

If you go back up top and type in 1.86 and 119 CID you get 5,514.35 Peak Torque RPM
Then if you use those values for the next calculator to get 15.23" Intake Runner Lenght.

15.23" - 2.55" = 12.68"
The stock Carb manifold is about that long.

Why are those measurements So far off from dyno proven manifolds? Look at the AIR, Full Race, BBK, Victor X, RevHard, etc, etc. All Much shorter runners than 20 something inches..more like under 6

Maybe it has to do with plenum volume... something that is not included in these calculations.

Maybe plenum volume or valve diameter has an effect on V ?

Same as collector shape diamter has its effects on pressure waves in a header, I'd have to refesh my exhaust tunning to explain further.

All we need to do now is figure out how to make V = 400 so that L = 8.12 .



So is V an effect of plenum volume or valve diamter(s)... or both?

What is the stock peak TQ and HP RPM for both EFI and Carb?

I agree, but it would be nice to have some means of throwing out some of those variables to get us closer to our goal. At the very least find out what plenum volume does... since changing that isn't as easy as adjusting runner length.
If we can plug in the know plenum volume and valve diameter and see where / how V is effected then we'll be that much closer.

I kinda want to use the other formulas you posted in that link to figure out the intake runner diameter for both the primary and secondary barrel, using the fixed length of the stock accord 2bbl manifold.
I want a dual plane/port, not just a divied plenum one, like an offenhauser manifold where the primaries get smaller diameter runners of their own and the secondary gets it's own larger runner. It should be good in getting a vacuum secondary 4bbl to run, especially down low.

I'm not sure if the acid I have at school works with aluminum but I can use the flat biting technique to add textrue to aluminum pipe if I use any at all.

primary runners for peak tq @ 3,600 RPM

Optimum Intake Length 23.33

Secondary Runners for Peak TQ @ 6,800 RPM

Optimum Intake Length 12.35

I measured the runners a few times, it came out to 10" from the flange tot he plenum.

10.00 + 02.55 = 12.55

I'm not sure how I'd add on an extra 11 inches to the primary runners without introducing a few more bends. I could try extending the plenum towards the firewall in a /\ fashion. then at the norrowest point add the new runners out towards the strut towers... then gently loop around back towards the "Y" where it will feed the two runners from the top of the "Y" joint.

Since the secondary runners are already close to 12" I'll leave those alone.

here you can see where they split the primary and the secondary.

[Accordtheory]

I just read some of that stuff on the mototune site, and that's pretty interesting about reducing port size and actually making more power.. (I already know that it takes cylinder press to seat the rings..but that's good info too)
I have some questions about the port size reduction though..Why only the end of the port near the valve, and can't you still make more power by taking advantage of a larger port with the cam timing/setup? In other words, close the intake valve a little earlier to compensate for the reduced intake inertial charging, and still keep the better initial volumetric efficiency? I know people are making up to 300whp on n/a b18/b20s, and they sure as hell don't have stock or smaller than stock ports..and they do use flowbenches too..and so does endyn..

I jock endyn 4 life. There is an endyn sticker on my car

[Accordtheory]

yakety smackety indeed. Let me just go plug some numbers into that vectis program real quick, and then come out with the new hotness.

[Versanick]

On the subject of intake manifolds, (no one needs respond, but I wanted to post so that I knew what thread I wanted to post on later with it),

I just bought my b18a/b18b/b20d/b20z (I forget what others it fits)...
so that solves whether the b18a and b18b have the same manifold. In case it hadn't already been figured out. My good friend Mike is welding in his classes in college and is going to be in charge of everything the Tig needs to do, and the drilling of everything. We may or may not opt to use a ford 65mm tb, or find a good way to bore out the stock TB a little bit..

Cost was $168 shipped (from eBay). I did NOT opt for the AEBS because of all of the extra work involved, but actually more importantly because every AEBS I've ever seen has had some of the POOREST casting I've ever been in the presence of. I don't think you'll find too many people who will argue with that.

The BLOX is clearly a (VERY ported) integra type R style manifold copy. The difference between it and my a20/b20 manifold is ridiculous. The a20 manifold literally takes a 90 degree bend (as we all know) and its runners don't NEARLY match the size of the runners on this BLOX.

http://www.acsu.buffalo.edu/~pkopalek/blox/

That's what she looks like inside and out. Mikey is constructing a vacuum box that will tap off of the end of the plenum of that BLOX, and have the 19 vacuum ports (random estimate, I haven't figured out how many are needed yet really) required to be attached to the a20 manifold, for proper pj0 ECU operation.

I'll post a new thread about this once the project gets moving better. It doesn't look like too much will be involved. This manifold, also to note, seems to be pretty much exactly as large as my (GUDE ported) head ports. This will offer me a massive improvement over the old manifold. The a20 manifold looks like it's throwing a hot dog down a hallway there. Some minor port matching (by grinding the inside edges of the BLOX) will be done to try to smooth airflow.

Also, to note with what manifold is "best" here, guys, let's keep in mind a few things. An amazing ITB setup isn't going to completely 'blow away' a good setup with an Edelbrock (all things else well tuned and similarly configured, obviously) or other good IM. For that matter, an n/a setup with a skunk2 (or similar mani) isn't going to be that much less powerful than the same n/a setup with the AIR research manifold. You have to think about whether that $650 price difference between the high end manifold and the BLOX is justifiable, or if that money is better saved and spent later on a turbo kit or a bottom end rebuild or some tuning/dyno time with a professional..

IMO, $800 for a manifold is a COMPLETE waste of money to anyone on this board that I know. Unless you're spending $50,000 on your track car, and you need to make that extra 14hp at 9200rpm to pass that built BMW around turn #3, manifolds like this BLOX are for us.

I'm not telling anyone not to get whatever they want, and (can?) afford, but I'm telling you that I don't know anyone who, (considering everything involved, and the fact that money can be much better spent elsewhere) would reccomend spending as much as we could on some of those high-end manifolds. If the manifold is the last thing you need to do to your car and you already have retarded money into it, go ahead and get your ITB's. They're cool. But they're not going to make you blow the doors off of that kid with the Cobb tuned WRX. Maybe the BLOX and some nitrous would get you closer, though.

sweet work with the SC research too, fellas. I've always wanted to go carb on my b20a (two dual 45mm DCOE's, I've looked at)... but the carb manifold has always been the problem. I'd considered having one made, but I'm so deep into EFI at this point, I'd have to sell my whole EFI/ecu setup to afford the conversion.

thanks for reading. hope you like those pictures.

[b8er]

EDIT:

I want to know what the v stands for... if the value is wrong so is my calculations

well i found out what it means...."V = Pressure wave speed (approx 1250-400 ft/s)" so i guess the 1300 you had asumed was close but not quite right
what is the stock intake runner diameter?
also i ran the calculaions for a 252 cam and, second set of waves , 6000rpm and a intake diamater of 1.5, i ended up with an ECD of 498 and runner length of 26.22, the firewall is definatly gonna have to come out for me, aha, but what im wondering is if the optium runner length is like for a race application. and would you be cutting youself short if you, well cut it short, aha. what im getting at is that there doesnt seem to be 2 feet of room from the head to the firewall and would it serious cut power or 'restrict' power if you did follow the calculations?
EDIT: ( warning these are the best measurments i could take ) just took some measurments for a head i have lieing around. the stock intake manifold runner measures : width: 1.844
hight: 1.000
so im not quite sure what diamter that makes the stock intake runner but at least we got the measuments
and from the backside of the valve inside the head to the intake mani side of the head the runner length is 2.588
so that means in stead of my optimum runner length being 26.22 it only has to be 23.632 because the runner length starts from inside the head.

i ran the equation again using V=1200 instean of 1300 and ended up with L=24.15 then i minused the 2.588 from above and ending up with 21.56, which saves me 2. 07 inches, a guess saving a few inches will help but i kinda wish it was more.
i also found another website with more equations
: http://www.wallaceracing.com/runnertorquecalc.php

[Accordtheory]

Why are those measurements So far off from dyno proven manifolds? Look at the AIR, Full Race, BBK, Victor X, RevHard, etc, etc. All Much shorter runners than 20 something inches..more like under 6

[b8er]

Why are those measurements So far off from dyno proven manifolds? Look at the AIR, Full Race, BBK, Victor X, RevHard, etc, etc. All Much shorter runners than 20 something inches..more like under 6

i think what it might be is that we didnt know what V was for, it could be anywhere from 1250 to 400.

when i ran it with V=1200 i ended up with 21.56 inches but when i changed V to 400 i ended up with L=7.55 minus the 2.55 from inside the head, would mean the optimun intake runner length only has to be 5 inches making it very possible. but that will only work if our pressure wave speed (V) is equall to 400ft/s

[b8er]

If you go back up top and type in 1.86 and 119 CID you get 5,514.35 Peak Torque RPM

so i re-ran the equation like L=((498x0.25x400x2)/(5500x2)-0.93 where 498 is the ECD for a 252 cam, 400 is the V and 5500 taken form A20's calculations for peak Torque and 0.93 as half the diamater of 1.86 also taken from A20's calulations.

the end result, L= 8.12 but then minus the 2.55 from inside the head and we get a 5.57 inches for my application, seems possible

[b8er]

So is V an effect of plenum volume or vavle diamter(s)... or both?

good question

im thinking the V is kinda depented on valve size, vacume pulse and how much vacum there is, plus intake runner diameter, prety much alot of things that are all questionable depending on each personal setup, what do you guys think

well i can knock the plenum one out for me cause im gonna be running itb's so i dont really need to knwo the plenum size but i will be looking to help fellow members on the board

[rjudgey]

my new inlet manifold is 6 inches long and then you have the length of the carbs and trumpets on top, great thing with Webers or ITB's you can get trumpets of varying size to increase or decrease length.

[2dsei]

if i cut the center out it should make the manifold more like the b-series with out the lower end torque loss of the b-series and a lot more air cutting out everything in the middle of the lines has anyone tried this not sure about the vacuum

[B16KILLA]

someone has done that I dont think you will see in increase since your ditching the secondaries, those allow you low end torque. If it's the secondaries that are bothering you just install an rpm activated switch so that they open at an lower rpm.

[snoopyloopy]

yeah, so nothing to do with any real major modding of the im but actually about disconnecting all those coolant lines from it. what would that do? because i'm tired of one of those things getting a hole in it and then i have to contort my arm in the dark to get it off and put on a new one. so if i remove them, can i just cap them off and run the two hoses that feed and drain it into each other and be fine?

[gfrg88]

talk to cke about this.....

[snoopyloopy]

nice. i like the sound of that. do you have an pix of how it looks? and what lines are getting bypassed? and does it have any adverse or enhancing affect on performance?

nice nice, very nice. i'm just tired of changing those damn hoses after it starts splitting and getting my arm into impossible positions. so as long as there are no adverse side effects, i'm happy. any performance gained is a plus.

[NitroNeonRT]

I would like to see the pics also!

Also anyone ever thought about pumping cold water in the manifold and tb?

[AccordEpicenter]

bypassing coolant lines def does help. Other than that i suggest getting a used LS or B16 intake manifold and get it to fit, dont waste your time on the 88-89 im

[A20A1]

I think you will lose low end... with runners that large it will move your power up higher in the rpm range...

Also the intake pulses will be effected... this supposedly has an effect on runner lenght. More taper in the runners appears to make the runners act like shorter untapered runners.

Detail are outlined in this thread, just read the previous posts.

[89T]

here is some good info that i found.
http://snow.prohosting.com/~johngift/intakefab.html
http://sdsefi.com/techinta.htm