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View Full Version : Cold Air Induction for ITBs



speedpenguin
11-21-2006, 09:32 AM
So I've been researching ITBs for my Acura and have run into an area that affects anyone who wants to or is currently running ITBs, and that is the buildup of hot air in the engine getting sucked into the intake. Obviously for the drag racers out there it's not as big of a deal, but for longer track and backroad bombing the loss of power would probably be annoying. I'm posting this here because whatever we discuss here would be equally beneficial to anyone running an A20A with ITBs (All 1 or 2 of you :) )

Anyway I am trying to come up with a way to route cold air into the velocity stacks. I could just fab a cold-air system from the wheel well, but it seems like that would restrict airflow too much to be really beneficial.

Here is what I have come up with so far:
An airbox/heatshield assembly built around the openings of the velocity stacks that sits flush with the bottom of the hood, essentially sealing the air in that area from the rest of the engine bay. Air would then come in vented through a hole cut in the top of the hood a la the evo-style hood. A carbon-fiber or similar aftermarket hood would have to be used for this application. Obviously in street driving filters will have to be installed in the velocity stacks, but they should be there anyway.

Here are some extremely shitty diagrams I drew in Appleworks 6.

http://img47.imageshack.us/img47/2716/1635qk0.th.jpg (http://img47.imageshack.us/my.php?image=1635qk0.jpg)
http://img47.imageshack.us/img47/9148/51gy3.th.jpg (http://img47.imageshack.us/my.php?image=51gy3.jpg)
http://img56.imageshack.us/img56/4206/1417ac7.th.jpg (http://img56.imageshack.us/my.php?image=1417ac7.jpg)

I think this setup is the most ideal for airflow and air temperature, but I am by no means an expert. The only problem is of course that when it rains you are essentially driving a car with a funnel running into the intake. So here is the main problem. How would one route air into the stacks in an efficient manner like this, but still keep water out?

Vanilla Sky
11-21-2006, 10:25 AM
cut into your cowl area (where your wipers are) and pull the air from in there. box everything up and have that one side open.

gp02a0083
11-21-2006, 10:35 AM
here is an idea , look up the airbox for the AE111 carolla i think its a 4AGE engine and came with ITB's its got a odd air box style to it, look that up and a possable way after that is running a large single pipe for the CAI or split it into 2

A20A1
11-21-2006, 11:16 AM
cut into your cowl area (where your wipers are) and pull the air from in there. box everything up and have that one side open.


Yup run straight back into the gutter behind the wind shiled wiper area. Just be sure you filter it or put a baffle and a screen to block water and crap that gets back there.

speedpenguin
11-21-2006, 11:18 AM
That gutter thing sounds good, but does anyone have a diagram or something of what the baffle would look like?

rjudgey
11-21-2006, 11:39 AM
Wouldn't just apply to ITB's but Weber DCOE's as well as Bike carbs too. with a effective hood scoop you could also get a ram air effect going on so that the faster you go the more air gets sqaushed into the intake

speedpenguin
11-21-2006, 12:05 PM
So is this essentially what you guys were talking about?

http://img144.imageshack.us/img144/1766/2796wg5.th.jpg (http://img144.imageshack.us/my.php?image=2796wg5.jpg)

Vanilla Sky
11-21-2006, 12:11 PM
remember that the cowl area is a high pressure area on these cars, while anywhere on the hood is low pressure. putting the intake in a high pressure location will give you what is called a "ram-air" intake, just as rjudgey pointed out.

MessyHonda
11-21-2006, 01:06 PM
just slap a turbo on that baby :thumbup:......on a serious note...how much is the set up going to cost you?

Vanilla Sky
11-21-2006, 01:31 PM
i've seen bike ITBs end up costing less than $1000 if most of the work was done by the owner.

MessyHonda
11-21-2006, 01:32 PM
i've seen bike ITBs end up costing less than $1000 if most of the work was done by the owner.

they only give you like 30 more hp right?

Legend_master
11-21-2006, 01:41 PM
Check out this all motor H27 setup

http://i14.photobucket.com/albums/a320/pocketrocketsracing/H27finalpics003.jpg

H-T h27 thread (http://www.honda-tech.com/zerothread?id=1376406)

speedpenguin
11-22-2006, 08:07 AM
I was just thinking of small filters in each of the stacks.

And as for the cowl/hoodscoop option, I'll do it if I have to, but I really don't want an ugly-ass lump of any kind sitting on my NA setup. I'm still trying to figure out the option Mike laid out, it seems cheaper and more subtle. I want a sleeper here.

Zufer
12-20-2006, 10:09 AM
with my quad carb setup i'm trying to figure out a filter system as well. My choice so car is running a hood scoop and either just run a screen over the carbs or making a box to hold a panel filter for the carbs. Haven't decided completely. Also with the cowl setup how would you box it off because the engine moves quite a bit when under load?

nzBA1lude
11-20-2007, 02:56 PM
a subaru wrx letterbox scoop would look good and still be able to keep your car looking reltivaly sleeper if you wanted

speedpenguin
11-20-2007, 06:57 PM
Well it's an old thread, but not a bad idea at all.

mushroom_toy
11-27-2007, 09:56 PM
You could try cutting up an old exhaust manifold or something that was a sorta straight through design and run a single pipe fro the front of the car, or from a collector on the cowl, sorta like a cai or cai/ram air setup. Heres two ideas i had...yes I know they are crappy drawings. lol:cheers:

http://img.photobucket.com/albums/v28/JubeiMunchCurry/Craigslist/Poop.jpg
This is the air coming from front of car design.

http://img.photobucket.com/albums/v28/JubeiMunchCurry/Craigslist/Poop2.jpg
Coming from cowl area.

ChaseR
11-27-2007, 10:01 PM
What about direct exhaust injection???

http://i238.photobucket.com/albums/ff119/williamsnc/motivate_retard.jpg

prob a much better idea.

ChaseR
11-27-2007, 10:29 PM
not tha your idea is retarded, Your drawing reminded Me of that pic! lol

ghettogeddy
11-27-2007, 10:32 PM
remember that the cowl area is a high pressure area on these cars, while anywhere on the hood is low pressure. putting the intake in a high pressure location will give you what is called a "ram-air" intake, just as rjudgey pointed out.

that would be a good thing right

2drSE-i
11-27-2007, 10:52 PM
Most filter boxes for ITBs kill me. It wouldn't breathe as well as opened-up due to them putting one filter on one side in a plenum configuration.

Personally I'd go for a cowl or hoodscoop with a large surface area K&N panel filter, or dual CAI tubes (one on each side.)



i have actually been working on this problem for my car (future plans only, but i have a really good gameplan already.)


my idea was to build a filtration box that covers the ITB's, with two sealable panels. One attaches to the hood scoop, one facing the firewall. That way if it rains, just seal the hood scoop up. Good weather = seal the firewall one up.

MessyHonda
11-27-2007, 11:32 PM
why not turbo?

speedpenguin
11-28-2007, 07:20 AM
not tha your idea is retarded, Your drawing reminded Me of that pic! lol

It's cool, that pic made me laugh.

And no turbo, thanks. I know it's not too hard to build a reliable setup, but it's still less reliable than NA. There's just more parts to break.

Zufer
11-28-2007, 10:05 AM
http://photos-c.ak.facebook.com/photos-ak-sf2p/v74/123/38/29300111/n29300111_30602510_5850.jpg
This is the setup i built. It gets some cold air down by the axle. If it was desired it could be routed to to the fender or something quite easily.

2drSE-i
11-28-2007, 10:09 AM
This is the setup i built. It gets some cold air down by the axle. If it was desired it could be routed to to the fender or something quite easily.

doesnt look pretty but it sure as hell gets the job done. It almost disguises the ITB's, but i bet you still get that incredible sound huh?

Zufer
11-28-2007, 10:11 AM
ya its quite loud. Its actually a lot prettier in real life. And also it was all done by myself with a Lincoln MIG Spool Gun. So if someone were to have a setup professionally welded, or welded by someone who is actually decent with aluminum welding it would be a lot better. Oh and including the carbs i think the whole project has cost me less than 100 dollars.

2drSE-i
11-28-2007, 11:49 AM
very nice. FI ITBs sound amazing

AccordEpicenter
11-28-2007, 01:42 PM
usually ITBs dont run that well unless they are tuned pretty good, usually with obd1 or a standalone... I like your project zufer, how does it run? I thought of itbs on an A20 but i ditched the idea because i doubt i could make any real power na...

2drSE-i
11-28-2007, 02:07 PM
usually ITBs dont run that well unless they are tuned pretty good, usually with obd1 or a standalone... I like your project zufer, how does it run? I thought of itbs on an A20 but i ditched the idea because i doubt i could make any real power na...

not as much as boosted for sure. I can't wait to get my project underway.

Zufer
11-28-2007, 10:37 PM
Well mine are carbs. At the moment they run like shit. But on the first manifold i built i had it tuned great. It ran awesome, and pulled harder than any other NA accord i've been in. Ask Boba, Justin86 they both rode in it.

cygnus x-1
11-29-2007, 10:49 AM
Well mine are carbs. At the moment they run like shit. But on the first manifold i built i had it tuned great. It ran awesome, and pulled harder than any other NA accord i've been in. Ask Boba, Justin86 they both rode in it.

Do you have pictures of the first manifold?

C|

Zufer
11-29-2007, 10:53 AM
http://photos-c.ak.facebook.com/photos-ak-sctm/v173/123/38/29300111/n29300111_30814898_8973.jpg
http://photos-d.ak.facebook.com/photos-ak-sctm/v173/123/38/29300111/n29300111_30814899_9339.jpg

there ya go.

AccordB20A
11-29-2007, 11:59 AM
Looks good. im sure it got the job done even tho it looks like i made it :)

ChaseR
11-29-2007, 08:27 PM
IM very curious, that's and awesome custom job but did you really get any gains from it?

cygnus x-1
11-29-2007, 09:54 PM
http://photos-c.ak.facebook.com/photos-ak-sctm/v173/123/38/29300111/n29300111_30814898_8973.jpg
http://photos-d.ak.facebook.com/photos-ak-sctm/v173/123/38/29300111/n29300111_30814899_9339.jpg

there ya go.


That's interesting. By looking at those I would expect them to not be that great because the runners get larger toward the head. Ideally with ITBs you want the inlets to bell out with the runners getting progressively smaller as they approach the head. This way the air charge velocity increases progressively as it nears the head. Maximum velocity at the valve means optimal cylinder filling. The runners are fairly long though so that will keep the power band lower, which is good for our low revving A20s.

C|

Zufer
11-30-2007, 09:53 AM
All the gains are from the butt dyno, although i have to say that over the weber it really smoothed out the power band.
The runner length has become much shorter and from what i can tell that has helped a bit more with top end, which was you could feel drop off even with the 282 cam. With the new shorter runners it seems to be more even through the revs.
It also made it drive a lot different, and made large throttle inputs respond much better.

As far as the runner diameter, yes its probably not optimal, neither is an A20. but the runners are just setup to match the carbs on one end and the head on the other.... Not much else was taken into consideration. This is not a million dollar race engine. Close enough is good.

And it probably looks like you built id XX because i built it. The newest manifold actually looks a lot better.

speedpenguin
11-30-2007, 10:01 AM
http://photos-c.ak.facebook.com/photos-ak-sf2p/v74/123/38/29300111/n29300111_30602510_5850.jpg
This is the setup i built. It gets some cold air down by the axle. If it was desired it could be routed to to the fender or something quite easily.

That setup might actually work. I was thinking about something similar.

Too bad the intake side is in the back on these engines instead of in the front like the K series. That'd be so much easier.

mushroom_toy
11-30-2007, 11:09 AM
You see the crappy drawing i did? I say get the air from the cowl area.

cygnus x-1
11-30-2007, 11:36 AM
All the gains are from the butt dyno, although i have to say that over the weber it really smoothed out the power band.
The runner length has become much shorter and from what i can tell that has helped a bit more with top end, which was you could feel drop off even with the 282 cam. With the new shorter runners it seems to be more even through the revs.
It also made it drive a lot different, and made large throttle inputs respond much better.


Even more interesting. Which Weber? 32/36 or DCOE type? A 282 cam is pretty aggressive and you won't get much out of it until 3500RPM. It would also need lots more flow which you won't get from a 32/36. DCOE 45s would scream though. But what you are seeing is how straight runner individual TB/carb setups are more picky about tuning and having all the components matched.



As far as the runner diameter, yes its probably not optimal, neither is an A20. but the runners are just setup to match the carbs on one end and the head on the other.... Not much else was taken into consideration. This is not a million dollar race engine. Close enough is good.

And it probably looks like you built id XX because i built it. The newest manifold actually looks a lot better.


I can understand close enough. Experimentation is fun even if you don't get the expected or desired results. You still have something unique and that's cool no matter what.

I rather like the A20 though. It just needs a better flowing head.

C|

Zufer
11-30-2007, 01:17 PM
ya I have no desire to get rid of the A20. thats why i have gone through this whole process.

The carbs i'm running are mikuni 34mm. They would be like running weber 45, with 34mm venturies i believe. I switched from a really well tuned 32/36, it was tuned on a wideband and did quite well. And you are definitely right about the cam.. I has no low end power at all. But it does rip hard in the high end.

oh and you nailed it with the experimentation thing. I know its not optimal, but i've spent less than 150 dollars on everthing involved.

oscwrestler
04-12-2008, 08:31 AM
i made a soerta ram air on my car.. i didn't spend more than 3 bucks on it. haha use vaccuum tubing to run down into your grille. there is even a plug in the wheel well to make it work! be sure that the tubing you use is big though. i did mine big and now my car sounds great even with stock exaust.

markmdz89hatch
05-05-2008, 05:26 AM
well since osc brought this back, I've got to ask...

Zufer: How's the flatslides working out now after another 6 mo of driving? I've been debating bailing on my 45DCOE's in place of 4 45 or 48 flatslides. So much easier to tune then the DCOE's.

Anyway, as for the airbox/hood scoop, has anyone actually moved forward with this? I had a few ideas I was mulling around for a while, but still have yet to go through with it.

Does anyone know where all of the high and low pressure zones are on the front of these cars? I never saw a 3G of any body style done in a wind tunnel / smoke test to see exactly how the air flows off the front end. That would be the most important part for me to take into consideration when choosing where to put it. Anyone?

2oodoor
05-16-2008, 07:52 AM
^^^ seems like someone could simulate that on the computer. (pressure zones)
I know of a few members here that could pull that off.

I don't think they get a lot of flow under the car-I am only saying that because I drive the interstate a lot and neither of my cars pitches too bad with cross winds and truck drafts. On the other hand, the Civic I had (94 DX) did catch a lot of wind under the front, the cars are built similar just the Civic was considerably lighter in front with a D series 200 lb motor.

b20a86lude
06-17-2008, 06:30 PM
is that carbed or fuel injected

Zufer
06-22-2008, 09:25 PM
Heres a video of my car running... and yo can see the new CAI
http://youtube.com/watch?v=cUjgaccsM5M&feature=user