AWESOME information and results, take a read.
Evolving Member
Joined: Jan 2006
Posts: 437
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From: akrun, ohio
DB will have to settle this then!
Yeah we did a similar test in June (results somewhere in the ECUflash forum). 3" true cold air (went into the fender where the sprayer res should be) was 482 @ 26 and on the edge on timing. Pulled it off, car made 495 with absolutely no changes to the tune. Next day spent a little more time on the car and was able to add 2 degrees in that the night before it would not take. Got the power up to 510.
I built him a 4" intake pipe that placed the filter in the corner of the engine bay right by the side panel cold air inlets. I believe I just used the standard 4" outlet K&N cone filter that is ~8" long and 6" diameter at the max. The intake pipe had like 30 degrees of total bend to make a smooth jog in the tube to get over to where it needed to be and was about 18" in total length.
The car had an SC61 and at 20 psi on 91 octane, it made 390 WHP with the intake on. He then took the intake off (no filter) and power dropped to 380 WHP. He just told me the results though, I have no idea how well he controlled engine temps and run conditions.
I also don't believe in adding bends to get into isolated area though, as often the bend will drop the pressure more then what the cooler air will make up for. I try to bring the isolated/insulated/cold air feed area as close to the turbo as possible using excessively large ducting (5"-6" aluminum flex duct works great) where ever possible and then keep the intake as straight and short as possible. It is not a "RAM Air" system though as I do not seal anything off. From what I've been able to find, sealing things off often causes aerodynamic issues that actual restrict flow at the system inlet at high speeds and you are better off just letting the excess air escape through to the path of least resistance.
3" MAF << 3" cold air << Open Turbo < 4" Cold Air ???
Last edited by 03whitegsr; Oct 20, 2009 at 02:41 PM.
I don't think it's the bends on the piping but the actual size. Someone should search and dig up AMS's similar test. They simply changed the pipe from 3" to 4" and the car gained like 20awhp. On a stock frame turbo the gains might be minimal but when you have huge 4" turbo inlets, a reducer with a smaller pipe and filter can defnitely restrict airflow
I've done this testing in the past. Had a customer a few years ago with an AEM equipped car, I finished tuning it, noticed the MAF still on the MAF pipe. Told the customer we should pull it off and do nothing else. I think that was on car making low 300's on the dyno, power went up 15 whp with no other change.
This car when we switched from the stock ECU to the AEM I ASSumed the stock maf was taken off. When I questioned that today my brother who runs service reminded me about Dan the car owner wanting to switch from the stock ECU to the AEM easily.
We also tested a 3" intake with a reducer at the 4" inlet to the turbo then swapping to a straight 4" inlet a few years ago on Pete H's car. I can't remember what it did then but I want to say that was worth about 15 whp too.
In the case of this car, before I made the first pull I expected the boost was going to go up, so I turned the boost control down a 1/2 turn. The boost was at 29.xx after that adjustment.
The AFR's really went lean the further the car was rev'd, clear sign it was making more power, I wasn't even watching the dyno screen and could tell watching the EMS screen the power was going to go way up.
This car when we switched from the stock ECU to the AEM I ASSumed the stock maf was taken off. When I questioned that today my brother who runs service reminded me about Dan the car owner wanting to switch from the stock ECU to the AEM easily.
We also tested a 3" intake with a reducer at the 4" inlet to the turbo then swapping to a straight 4" inlet a few years ago on Pete H's car. I can't remember what it did then but I want to say that was worth about 15 whp too.
In the case of this car, before I made the first pull I expected the boost was going to go up, so I turned the boost control down a 1/2 turn. The boost was at 29.xx after that adjustment.
The AFR's really went lean the further the car was rev'd, clear sign it was making more power, I wasn't even watching the dyno screen and could tell watching the EMS screen the power was going to go way up.
Awesome write up. Good info.
The COP did not make it on the car. Remember me talking about trying not to sell something that's not needed? The car runs perfectly and smooth as glass on the stock ignition, so I left it.