Need some expert advice please!
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Joined: Dec 2010
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Need some expert advice please!
Ok on my 2001 c5 a4 it had a small type cone k&n filter my buddy i race with had a larger type K&N cone he gave to me, after installing it i noticed right away better throttle response but now when just cruising at like 40-50 mph seems it has a slight buck or miss to it as long as u are givin it gas its fine but at steady speeds it starts, put old filter back on an it went away! so what in the heck is that about its just a cone filter, looked bad a$$ ...wish it would have not done that any suggestions or any 1 ever heard of that?? an yes i have screen in mass air
Le Mans Master
Joined: Aug 2005
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From: CA.
St. Jude Donor '13-'14-'15
Whenever you make changes to the incoming air stream--The ECM has to re-learn the fuel trims to accomodate the more incoming air signal---
This is done via your fuel trims----It takes apprx 50 miles of normal driving to let the trims "learn out " A CAI or just a better filter (cone) can make your fuel as much as 15% off (lean) and the ECM is tring to fix it by adding that % to your PT fuel--but it takes awhile
Put it back on and give it some time to learn out--Thus is a common thing and happens on EVERY car---
An extremly modded intake air tract like a bigger intake manifold-different Throttle body-aftermarket air bridge will take longer to learn out---however the ECM can only learn out the trims IF they are below about +22 or -22%--Then a tune will be needed to correct--If that is needed you'll get lean or rich codes to advise you--
This is done via your fuel trims----It takes apprx 50 miles of normal driving to let the trims "learn out " A CAI or just a better filter (cone) can make your fuel as much as 15% off (lean) and the ECM is tring to fix it by adding that % to your PT fuel--but it takes awhile
Put it back on and give it some time to learn out--Thus is a common thing and happens on EVERY car---
An extremly modded intake air tract like a bigger intake manifold-different Throttle body-aftermarket air bridge will take longer to learn out---however the ECM can only learn out the trims IF they are below about +22 or -22%--Then a tune will be needed to correct--If that is needed you'll get lean or rich codes to advise you--
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Team Owner
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From: small town in S.E Pa. PA
St. Jude Donor '03-'04
Its a shame our beautifully designed C5 has fallen into such inept hands.
Bill aka Et
Melting Slicks
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From: las vegas nv.
I know what you mean-lots of smart a$$ on here----Anyway i had the same problem you have--this is what I did--I installed a set of front fender curb finders and a 25 ft. whip antenna--NO more surge-
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HA thanks tblu92 u seem to be the only one with a brain on this topic, greatly appreciate it.....i not trying the filter for performance it was free an looked better so thought i would give it a shot, i run low 11s with nitrous not that big a deal was just curious bout why the larger filter caused a slight miss thanks again will try it .....
Tech Contributor
Joined: Jan 2007
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From: Dyer, IN
You're an engineer? Cool. I have questions, based on your advice posted. Do you remove the air filter from the cars you drive? If so, have you experienced any downside? Have you every dyno'd your engine, running with and without an air filter, to see what gains are realized?
You mentioned turbulence. The distance from the air filter to the throttle body, is really not that long. That being said, is it possible to achieve laminar flow in such a short distance?
You mentioned turbulence. The distance from the air filter to the throttle body, is really not that long. That being said, is it possible to achieve laminar flow in such a short distance?
Drifting
Joined: May 2010
Posts: 1,482
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From: Pearland, TX
You're an engineer? Cool. I have questions, based on your advice posted. Do you remove the air filter from the cars you drive? If so, have you experienced any downside? Have you every dyno'd your engine, running with and without an air filter, to see what gains are realized?
You mentioned turbulence. The distance from the air filter to the throttle body, is really not that long. That being said, is it possible to achieve laminar flow in such a short distance?
You mentioned turbulence. The distance from the air filter to the throttle body, is really not that long. That being said, is it possible to achieve laminar flow in such a short distance?
Banned Scam/Spammer
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From: Oklahoma City
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16-'17,'19,'22
This will fix it
http://www.c5forum.com/diy/idlerelearn.php
Give it a little time to adjust like mentioned
http://www.c5forum.com/diy/idlerelearn.php
Give it a little time to adjust like mentioned
Le Mans Master
Joined: Aug 2005
Posts: 5,375
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From: CA.
St. Jude Donor '13-'14-'15
One more thing----I see some one mentioned turbulence---
On a bolt on modded car like yours--
Turbulence affects the way the air enters your MAF-- and how the MAF takes readings --
More or less is not that important as "the same as stock" is.
So it's important to try and keep the MAF in the SAME place as it was when stock--If it came with the honeycomb screen--LEAVE IT IN--
Common thing is to over oil K&N type filters--That will foul your MAF and require cleaning--Detected by--- surging bucking--dying-
On highly modded engines-- ( heads/cam/headers/turbo/SC--)Turbulence can become an issue--On those applications it is wise to decrease it as much as you can---But correcting the AFR via a tune is absolutely required
On a bolt on modded car like yours--
Turbulence affects the way the air enters your MAF-- and how the MAF takes readings --
More or less is not that important as "the same as stock" is.
So it's important to try and keep the MAF in the SAME place as it was when stock--If it came with the honeycomb screen--LEAVE IT IN--
Common thing is to over oil K&N type filters--That will foul your MAF and require cleaning--Detected by--- surging bucking--dying-
On highly modded engines-- ( heads/cam/headers/turbo/SC--)Turbulence can become an issue--On those applications it is wise to decrease it as much as you can---But correcting the AFR via a tune is absolutely required