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View Full Version : Which intake manifold is the best upgrade for a turbo A20?



Accordtheory
10-21-2003, 11:22 AM
I want something better than the 86/87 piece, and also better than the 2 stage 88/89 piece. Here's what I know: Longer runners= lower resonant frequency, shorter runners=higher resonant frequency, and runner length being the same, a larger plenum lowers the resonant frequency, while of course a smaller pleneum raises the resonant frequency. When I say "resonant frequency", I mean the frequency of the pulses of air traveling back and forth through the runners. The resonant frequency directly affects the volumetric efficiency of the engine at that rpm. (Have you ever built a tuned ported sub box? The exact same principles apply, and you can see how this works with any box building program on your computer) With a turbo engine, however, things get different, because now the air in the manifold is compressed, at a higher density, and just like a stiffer spring, vibrates at a higher frequency. This is why turbo engines make more power with a larger plenum, because the larger plenum gets the resonant frequency back down into the engine's operating rpm range. So, what manifold has a nice large plenum and long straight runners, and is compatible with the A20? Actually, first ,what manifolds fit on the A20? I have heard that the bolt pattern is identical for the top bolts with the B16 manifold...? What are the differences between the B series manifolds? All I know is that the runners are WAY too short on the type R maifold. Is the GSR manifold a 2 stage? If so, fuck that. When I put my modified 2 stage 88/89 manifold on my car, it slowed it down...So far, the best looking manifold to me is the Skunk2 LS integra manifold, big plenum and long straight runners. I know that the manifold I want is not going to be intended for a high revving engine, like the type R, because the runners will be too short. How about the CRV B20 manifold? If any of you guys know anything about this, let me know, I'm taking my turbo A20 to the next level.

k-roy
10-21-2003, 11:38 AM
Edelbrock makes a intake for the B series that can be modified to fit the A20. I have seen one on a turbo 3g somewhere on this board. Do a search.
http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=111030&prmenbr=361

bobafett
10-21-2003, 12:40 PM
sean tuned his turbo ECM for the 86-87 Style, which he claims flows better than 88-89.

beyond that, i think justin used the jg edelbrock b18 manifold on his car. :)

k-roy
10-21-2003, 01:07 PM
Talk to 88turboaccord he used the edelbrock manifold,
http://www.3geez.com/showthread.php?s=&threadid=24875

crwa
10-21-2003, 03:52 PM
Dude, if you want more power do a motor swap with a B series and you can get anything and everything for it...

NXRacer
10-21-2003, 03:54 PM
Originally posted by crwa
Dude, if you want more power do a motor swap with a B series and you can get anything and everything for it...

innocence is bliss ain't it? :D

2old_honda
10-21-2003, 05:41 PM
b16 AIR manifold moded to fit the a20. Made 40hp more than the JG manifold, and it offers a better powerband.
http://www.honda-tech.com/zerothread?id=652605

crwa
10-21-2003, 06:43 PM
NXracer, don't even start... I know turbo accords using a20's can become 10 second cars, but if you want yo be able to bolt parts right onto a turbo'd motor, a b series would be easier then having to modify parts to properly fit an a20...

It just depends on how much work you want to do, but i know a20's stock can handle a good amount of boost, more then a stock B motor...

Accordtheory
10-21-2003, 07:23 PM
Yeah, Too old Honda, I'll be right on that... a $1400 manifold for an A20... can you guys stick to USEful info please...

Sean
10-21-2003, 07:29 PM
the best match for what your looking for would be a b18 ls manifold. i know the problem you were having with the split port intake manfiold on the 88-89 cars. the problem is the baldes start to flip over and it block the port. taking out the blade divider seem to really help on my car. a large plenum will help if your really revving the car. also those resonant FQ's typically just dont occur till veyr high RPM on a tubo engine. thats my 2 cents the b18 ls integra manfiold would be the easiest choice.

k-roy
10-21-2003, 07:29 PM
A $1400 manifold, that is crazy. I thought the Edelbrock was pricy at around $400. Its not worth a grand for an extra 23.6hp. You can do so many more mods for $1000 that will make more power. You can do a full exaughst and an ignition system for that price.

1988starter
10-21-2003, 07:39 PM
Originally posted by crwa
Dude, if you want more power do a motor swap with a B series and you can get anything and everything for it...

Except a nice a20 bullet proof block

2old_honda
10-21-2003, 08:00 PM
Originally posted by Accordtheory
Yeah, Too old Honda, I'll be right on that... a $1400 manifold for an A20... can you guys stick to USEful info please...

you asked for the best and didnt say anything about price.

Accordtheory
10-21-2003, 09:54 PM
You guys aren't down with the skunk2 LS integra manifold? Are the bolt patterns between the different B series manifolds different?

Sean
10-21-2003, 10:01 PM
as far as i know the b16 b18 bolt patterns are the same. im pretty sure the ls and vtec heads use the same bolt pattern.goto the dealer and lay out some intake manifold gaskets to find out for sure.

Justin86
10-22-2003, 05:46 PM
Well as the more of this talk goes on the less I want to do a C1 swap. As for that $1400 intake, that sounds like something I would buy, nothing but the best in search of more hp then anybody else. :)

modu03
10-24-2003, 01:07 AM
uhh... this may seem like a stupid question, but uh... b16,b18,b20... what cars do these come off of???

Justin86
10-24-2003, 09:10 AM
B16a off the VTEC Civics and another but can't remember. B18 came off the integra and the B20 off the CRX.

Cyric_accord
10-26-2003, 07:53 PM
Originally posted by Justin86
B16a off the VTEC Civics and another but can't remember. B18 came off the integra and the B20 off the CRX.
also depends upon which engine series it is too... I mean, a JDM B20a and B20z are both b20s but are stuck in diff cars :D

2old_honda
10-26-2003, 08:00 PM
the b20 has a really weird intake manifold design that wouldnt be the best choice for the accord (it sticks up so far that you would probably have to cut a hole in the hood to get it to fit)

Justin86
10-26-2003, 09:17 PM
Originally posted by 2old_honda
the b20 has a really weird intake manifold design that wouldnt be the best choice for the accord (it sticks up so far that you would probably have to cut a hole in the hood to get it to fit)
Another good reason for a hood scoop.

2old_honda
10-27-2003, 11:47 AM
Originally posted by Justin86
Another good reason for a hood scoop.

naw, here is a pic.
there are actually two different manifolds one from the b20b and the other from the b20z
b20b- from the USDM crv
http://hybrid2.honda-perf.org/tech/b20/pics/b20b1s.jpg
http://hybrid2.honda-perf.org/tech/b20/pics/b20b2s.jpg
compared to a b18 manifold
http://hybrid2.honda-perf.org/tech/b20/pics/crvvslss.jpg

b20z
http://hybrid2.honda-perf.org/tech/b20/pics/b20z2s.jpg

Justin86
10-27-2003, 01:23 PM
Yea it would be better to go with the B16a for power and it fits under the hood. What is up with that crazy ass cover on that intake.

2old_honda
10-27-2003, 01:36 PM
It's an air chamber that is said to increase midrange torque. The idea is that the "resonator" chamber works like long runners and a larger plenum when the pressure waves travel back up the intake from the ports.

Justin86
10-27-2003, 03:41 PM
Oh..... ok.

k-roy
10-27-2003, 05:19 PM
How about one of theese.
http://www.twminduction.com/ThrottleBody/ThrottleBody.imgs/2000series-Z432.jpg
Strait airflow, individual throttle bodies, nuff said.
http://www.twminduction.com/ThrottleBody/ThrottleBody-FR.html

Justin86
10-27-2003, 09:11 PM
Well for the all motor set up that shit is gold. No really it is worth more then its weight in gold. $1500 for all 6.2lbs of it.

DarknessRS
10-28-2003, 02:09 AM
Originally posted by modu03
uhh... this may seem like a stupid question, but uh... b16,b18,b20... what cars do these come off of???
B16s typically come from Civics (CRXs and Del Sol also)
B18s come in Integras
B20 VTEC from CRVs

2old_honda
10-28-2003, 10:55 AM
Originally posted by DarknessRS
B16s typically come from Civics (CRXs and Del Sol also)
B18s come in Integras
B20 VTEC from CRVs

b16 is from the 6th gen civic SI and the del sol VTEC model. It also came in a variety of civic models in japan.

B18a/b is from integra LS models (no VTEC)

B17 is from 2nd gen integra GSR (VTEC)

b18c1 is from 3rd gen integra GSR (VTEC)

b18c5 is from the 3rd gen integra type r (VTEC)

b20b from the usdm CR-V (no VTEC)

b20z is from the JDM CR-V and there were some other cars that it came in in japan that we dont get here (no VTEC)

Johnny O
10-30-2003, 06:33 PM
A B18 a/b will fit with a little porting and drilling two holes,I will try it out this weeken.Our gaskets with a little trimming.

Justin86
11-02-2003, 03:48 PM
Damn every corner of this has been explained twice so far and still more questions come up. :wtf: