The "CAI" is NOT a "performance" modification.

seijirou - Yeah I agree, that is why I think the powerpipes do better as well because usually the "modder" will add it after some more engine breathing mods like atleast an intake and heads/cam.

You do need a form of velocity to get the power. The engine (as stated before) acts like a vaccum pump...you need some incoming air with speed (velocity).
 
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http://www.fordmuscle.com/archives/2002/03/coldair/

If the question is does colder intake air produce more HP than warmer intake air - the answer is unequivocal - yes. Approximately 1/2-1% more HP for every 10F drop in intake air temp. That's why our cars feel faster when it's nice/crisp/cold outside. That's why they intercool boosted cars.

If the question is will the typical CAI sold for Stangs increase HP over the stock box/silencer/filter -- the answer is in most cases yes. However, the gain is because of the removal of the silencer and the restrictive paper filter. If you remove the silencer and put a k&n flat panel filter in - there's no gain by going to an aftermarket CAI on stock or mildly modded 5.0's. Why not? Because the stock box IS a CAI - it pulls it's intake air from the fenderwell. There comes a point where the HP/air flow levels of a modded motor will be more than the stock box/flex elbow can handle - at that point moving to something less restrictive will help. But the box is probably not the issue - the rubber elbow is.

Careful trying to mimic things on the chassis dyno - all runs I've seen are made with the hood up, so "underhood" temps are different on the chassis dyno than under normal running conditions. This benefits engines/runs where an uneducated owner has hung a K&N conical where it injests much hotter underhood air into the intake - when the hood is closed.
 
Wow...I can't believe I just read all 7 pages of this thread.

Here's my imput and testing results. I do not have dyno sheets to prove the power just decreases in ET...which was and still is more important to me.

When I was on my quest for STOCK MOTOR NA 12's I tried a few different set-ups. I started with a custom Ram Air set-up that I made using a K&N 12" cone filter, the car responded with a crisper throttle and slightly more mph at the track. This was over a stock set-up minus the siliencer, and a K&N filter. So the addition of the ram air did do something...

I then upgraded to a 75mm Bullet Pro-M sall very minimal if any gains over the stock set-up...still a stock motor.

I was able to get into the 12's (12.89) with the stock air meter, but was never able to go faster with the 75mm on the combo.

I built a new combo shooting for NA 11's, started off with the above ram air setup using a 24# inj and the same 75mm Bullet. It ran well but I wanted to try different things, I upgraded to a 76mm C&L and air tube and the same ram air set-up and it ran good but I had some a/f ratios issues as it was lean up top. I was rewarded with a few more mph (2) and a quicker ET. I tried to make my own power pipe however the C&L needed to stay in the stock location, it could not read in the inner fender. I noticed the car would run better with the K&N air filter off the car, so I put the stock air box back on my car, mated to my custom ram air set-up and the car was faster in all the 330, 1/8, 1/4 etc. I was shocked to say the least... I then swapped in a K&N panel filter and to my surprise the car slowed down, swapped back to a cheap paper filter and it went right back.

I then tried different TB, swapped the 65mm out for a 75mm and went 2mph faster and a few tenths on back to back testing at the track, similar 60ft's, air temp, car temp, etc... so the larger 75mm TB on my 8.8:1 NA 302 was worth some power (I shifted at 6600rpm), datalogged it all on my Speedbrain as well. I also upgraded to a 30# inj since I was pretty lean with the 24# according to all the dataogging I was doing.

I ran the 76mm C&L air tube, 76mm C&L meter,m 30# inj and the stock airbox, and the 75mmTB and was running 12.0's at 112-112.8mph. I swapped to a 80mm Pro-M and was rewarded with my first 11.98 @ 113mph, eventually got a best off 11.96 @ 113.6mph.

The car was a little smoother with the Pro-M and I was happy as the drivabilty seemed better over the C&L so the 80mm Pro-M was worth the upgrade. I then decided I wanted a AFM power pipe, and I was getting the HV version 4" pipe. I put that on the car and with no other changes the car went 11.80 @ 116.7mph, and the car made more power across the entire rpm band based on my dyno calculater in my Speedbrain. (I found it was only off 2hp from my Dynojet readings). The car was smoother, pulled harder and seemed to run better in the heat then in the past. I was using on of the AFM open ended filters and still had the inlet of my custom ram air hooked up at the fog light hole.

I took the car apart at the point to build my new adventure, NMRA Drag Radial car.


Was the AFM pipe worth 20hp on my set-up...no but it did increase power and showed that I did have some restrictions with the other set-up's, that were straighter. I feel most of it was due to the larger ID piping and my motor was able to take advantage of the air.

We have done some other testing and have seen a straighter airpath with a longer tube make a few more HP on the dyno, still larger I.D tubing though, alum.

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What I'd add is 1) ram air is different than cold air - you do get some HP by actually creating a bit greater than atmospheric pressure - the 'ram' part of a ram air; 2) Rick's motor is clearly making quite a bit more HP than stock. At some point you can overwhelm the stock components' ability to flow enough air - then larger than stock pieces will help.

But for the majority of modded Stangs out there in the 300-350 crank HP range - you won't see significant improvement over the stock box/no silencer/low restriction filter.

Now - I'd change it just because to me it LOOKS much better to have that big ceramic coated (if you do it right) pipe headed over to the fender.

Rick - do you have/were you data logging - a/f ratio for the maf changes? Without that it's impossible to know if your mph gains were due to reduced inlet flow restrictions, or better control of a/f closer to stoich.
 
Michael Yount said:
What I'd add is 1) ram air is different than cold air - you do get some HP by actually creating a bit greater than atmospheric pressure - the 'ram' part of a ram air; 2) Rick's motor is clearly making quite a bit more HP than stock. At some point you can overwhelm the stock components' ability to flow enough air - then larger than stock pieces will help.

But for the majority of modded Stangs out there in the 300-350 crank HP range - you won't see significant improvement over the stock box/no silencer/low restriction filter.

Now - I'd change it just because to me it LOOKS much better to have that big ceramic coated (if you do it right) pipe headed over to the fender.

Rick - do you have/were you data logging - a/f ratio for the maf changes? Without that it's impossible to know if your mph gains were due to reduced inlet flow restrictions, or better control of a/f closer to stoich.

Yes I had hundreds of datalogging files, the a/f ratio between the 2 meters were near identical since I could tell it what I wanted it to be. I had all the airlfow readings as well, timing, fuel, etc... I founf so much power reading the files and learning how to tune and how certain things effected others, datalogging is one of the most important tools you can have.
 
Michael Yount said:
Thanks for adding that Rick - your example shows how important and difficult it is to carefully measure to assure you know how incremental changes are truly impacting the results.

You would be amazed what .5-1 degree of timing will do in the right rpm range. We seen 1 degree of timing make or break 40hp on a blower car ;)
 
Another line for the fast and furious freaks who think a CAI will give them that amount of power. Heck, add everything my MOD's say from their ad's and I must have over 1000HP easy...lol, but for some reason I dynoed at 390 RWHP
 
Killer50stang said:
Another line for the fast and furious freaks who think a CAI will give them that amount of power. Heck, add everything my MOD's say from their ad's and I must have over 1000HP easy...lol, but for some reason I dynoed at 390 RWHP

You didn't install the stickers correctly!
 
No way i'm reading 8 pages, so forgive my lazyness.

On a mildly modified car (no heads, cam or intake) a Cold air intake does no more than a K&N filter in the air box.