so this box is a bad idea? theres alot of back and forth going on.

Yeah, sorry about that... cold air box = good idea.

My advice was predicated on the idea that intake temp was still the primary concern- i.e., it's easier to maintain a lower DeltaT intake variation by lowing the engine bay ambient than by trying to insulate.
Since the average CAI makes no pretense of actually pressurizing the charge that seemed outside the scope of the discussion.

Trying ot get enough pressure from a CAI to actually be worth speaking about will be pretty difficult. Trying to find a location for a scoop of some sort would be one problem, then building the scoop to allow the airflow to velocitize and smoothly enter the intake tubing would be another issue.

Personally, wrapping CAI piping or box with ceramic insulation would be easier to me. I suppose to lower the engine bay temps would be to cut / add vents in the hood.


Evil Aviator, I wouldn't say homemade CAI fail at getting pressure since most of them, including mine, are not designed to get pressure. They are designed to duct outside air into the engine. Now if you were desinging a CAI for pressure and you got nothing, then I would say it failed.

Certainly wrapping insulation is easier and I'd like to see what effect it might have.
I have no way of measuring intake temps but I'd guess the difference would be very small.

Venting the hood would not only be at least as effective lowing the intake temps but also have the added benefit of lowering the coolant temps, assuming that the venting was designed to extract rad air outflow.
Hence my "more bang for the buck" statement.

If you buy the stuff with the reflective foil and ceramic insulation, depending on how fast the air is moving in the intake piping, im sure there would be a pretty good difference. My intake piping gets pretty damn hot at times.

I would personally like to see a vent system that actually did substaintially lower the engine bay temps and coolant temps. Getting the hoods with the whole center as vents, probubly would be the only venting system that would be worth talking about.

I'm sure it does but that's the whole point of the link I sent Micah...it's basically irrelevant.
In Micah's link look at page 5.
The temp difference in that test between plain sheetmetal and 1" thick insulated material was 4°F...over a 100 FOOT duct length.

Now, given the duct's poor heat transfer capability, the high airflow volume AND the short duct length what do you think the difference might be...a fraction of a degree?

By all means, go ahead and wrap your ducts...it certainly can't hurt but I'd be skeptical of any claims that it helps much.

You make a good point. 4 degrees, even if that was per foot, would make almost no noticable difference in power.

Well that's exactly the problem. Everybody is so gung ho about lowering temperatures that they completely miss the point that pressure also has an effect on density. I am not talking about ram air, but rather what you guys would call a "restriction".

See above.

4degF = about 1/2% hp difference

I know pressure effects density and also know that restriction can lower it. I do agree that some so called CAI I have seen seem to be just as restrictive if not more then the stock intake system. On that note I do agree with you.

First of all, saying ALL CAIs or AAIs are restrictive in your terms is incorrect. Yes ANY intake will have some restriction but the point that you seem to be trying to make is that they are usless because they are so "restrictive". This is one reason why I used 3.5" ID piping insteaf of 2.5" or smaller like most people do.

Like I said, nothing very noticable.

.

Forget all that aluminum garbage, some of those ceramic tiles of the space shuttle would be perfect. YaY

You mean the ones that fall off and need replacing every flight?
Yeah, those would be perfect.

I'm sorry a little off topic. But it's so much fun to watch you guys all but rip each other's limbs off, but still be so polite it qualifies as nice.

yea they do blow off, kinda reminds me of somethin. O yeah, apex seals.

I can prove that you did in fact design yours for pressure, and this also follows my main point that people are so wrapped up in "cold" air that they totally forget about pressure.

Given that: The stock intake system already ducts outside air into the engine.
Your goal was: Duct outside air into the engine? That doesn't make any sense because it did that to start with.

Therefore, your actual goal was: Design a new intake system that ducts in the EXACT same temperature air as before, but with less pressure loss.

So, using your own reasoning, if you designed a CAI for colder temperature, and you got the exact same temperature as before, what have you hopefully gained?.... That's right, pressure.

Therefore, I say back to you, if you designed the CAI for pressure, and you got nothing, then I would say it failed. The dyno will prove this, because if the temperature remains constant, there will be absolutely no power gain if there is no gain in pressure.

headlight vent FTW

I see what you are talking about now. I even mentioned the "positive pressure" helping in my old thread. For some reason I was still thinking "ram air".

Yes, but the air box is more restrictive then what I could have. Im sure my filter isn't helping and if I replace that with a K&N im sure it would flow better then the stock box. Anyways, my stock box was out of there when I first got the car 6 years ago, just starting out, following friends and what they said to do, later I learned, and when I had the time, years later, I built what I built.

I do 100% agree.

Now removing the stock air box and building a CAI that is lower in restriction, is already a pressure increase, but thats the issue, I suppose you could say, everyone is building their CAI for increase in pressure because restriction lowers it and thats what people try to minimize is the restriction. Although, like you have said in the past, some CAI are so convoluded, they may not have gained anything at all.

Yes, that's exactly my point. Ironic, isn't it? :)


Now there is also the issue of momentum, but I won't go into that. ;)

Ya sorry, I didn't think of it till now after remembering what I read about a couple months ago. Kinda clicked, felt stupid after.:uhh:

Oh come on now, lets :) I first asked if you were talking about velocity but thats only 1 product of momentum.

so lets talk :)