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Old 12-29-2012, 02:31 PM   #1
larrycox3
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Default STi running rough after switching intake

i just switched from my aps 65mm cold air intake to a short ram intake. i reset my ecu and just drove it, now my car is running fine, but when im in 1st thru 3rd gears in low rpm and hit WOT it has a strong hesitation then just kicks in. no its not turbo lag lol its real rough at first...do i need to re tune? no accessport, its open source tuned. do you think the ecu just needs to get used to the short ram? my MAF is installed correctly and theres no leaks. thanks for your help!
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Old 12-29-2012, 02:41 PM   #2
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Different intakes, require different tunes. Your MAF scaling is probably way off, among other things.
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Old 12-29-2012, 02:42 PM   #3
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You need a proper retune. Resetting the ECU back to factory isn't going to accommodate for a short ram. Chances are your A/F ratios are harmful levels. I would suggest you put your APS intake back on and use the proper tune for it before you damage your motor.
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Old 12-29-2012, 03:02 PM   #4
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yeah i just ran it for a second with the MAF unplugged and it ran way smoother. so i will plug it back in and get a re tune. thanks a lot!
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Old 12-29-2012, 08:12 PM   #5
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Sounds like a leak or dirty MAF to me. Usually an aftermarket intake wont make it idle rough. The tune is (mostly) for the boost issues associated with a higher flowing intake.
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Old 12-30-2012, 12:23 AM   #6
larrycox3
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Quote:
Originally Posted by roadtrip1098
Sounds like a leak or dirty MAF to me. Usually an aftermarket intake wont make it idle rough. The tune is (mostly) for the boost issues associated with a higher flowing intake.
I think you might be right. I think I may have damage the maf sensor during the swap because the car ran great with out it plugged in.

Last edited by larrycox3; 12-30-2012 at 11:04 AM.
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Old 12-30-2012, 08:12 AM   #7
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waiting to read the next thread about.."well my car blew up"
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Old 12-30-2012, 11:05 AM   #8
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waiting to read the next thread about.."well my car blew up"
why is that? because i left my maf unplugged for less than 2 minutes?
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Old 12-30-2012, 11:10 AM   #9
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Quote:
Originally Posted by larrycox3 View Post

why is that? because i left my maf unplugged for less than 2 minutes?


This is why \vv/

Quote:
Originally Posted by JordenP View Post
Different intakes, require different tunes. Your MAF scaling is probably way off, among other things.
Quote:
Originally Posted by mattisnotreal617 View Post
You need a proper retune. Resetting the ECU back to factory isn't going to accommodate for a short ram. Chances are your A/F ratios are harmful levels. I would suggest you put your APS intake back on and use the proper tune for it before you damage your motor.
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Old 12-30-2012, 01:00 PM   #10
larrycox3
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Quote:
Originally Posted by RoadKillDMD View Post


This is why \vv/





thanks for your input, i really appreciate it. please, when you meet someone who has blown their motor by switching intakes, let me know. as far as the problem goes, it was a damaged MAF. i took one off my buddys wrecked car. my car is running fine now.
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Old 12-30-2012, 01:58 PM   #11
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you need a fresh Map to compensate the airflow
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Old 12-30-2012, 02:13 PM   #12
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you need a fresh Map to compensate the airflow
yeah goin in next monday. a local tuner said i will be just fine until then.
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Old 12-30-2012, 02:30 PM   #13
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just curious why the switch from probably one of the best intakes around to a sri??
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Old 12-30-2012, 03:10 PM   #14
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Quote:
Originally Posted by larrycox3 View Post

thanks for your input, i really appreciate it. please, when you meet someone who has blown their motor by switching intakes, let me know. as far as the problem goes, it was a damaged MAF. i took one off my buddys wrecked car. my car is running fine now.
Be that as it may, each intake needs to be retuned for the appropriate mapping and A/F ratios. Although your idling issues may have in fact been the MAF, it doesn't change the fact that you're not properly tuned for the intake. If you were switching from one CAI to another, I wouldn't be so concerned for you. Since you changed the intake properties all together by switching to a SRI, I would exercise extreme caution and avoid boosting. I understand your tuner said it would be okay, but time and again it has been proven that it's not. I'm not a professional tuner, so what do I know.
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Old 12-30-2012, 07:45 PM   #15
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Quote:
Originally Posted by scby rex
just curious why the switch from probably one of the best intakes around to a sri??
Because my CAI is a straw up here in rainy Washington. Going back to CAI during summer.
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Old 12-30-2012, 07:45 PM   #16
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Quote:
Originally Posted by Decipher

Be that as it may, each intake needs to be retuned for the appropriate mapping and A/F ratios. Although your idling issues may have in fact been the MAF, it doesn't change the fact that you're not properly tuned for the intake. If you were switching from one CAI to another, I wouldn't be so concerned for you. Since you changed the intake properties all together by switching to a SRI, I would exercise extreme caution and avoid boosting. I understand your tuner said it would be okay, but time and again it has been proven that it's not. I'm not a professional tuner, so what do I know.
Dude. I know.
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Old 12-30-2012, 09:43 PM   #17
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Quote:
Originally Posted by larrycox3 View Post
i just switched from my aps 65mm cold air intake to a short ram intake. i reset my ecu and just drove it, now my car is running fine, but when im in 1st thru 3rd gears in low rpm and hit WOT it has a strong hesitation then just kicks in. no its not turbo lag lol its real rough at first...do i need to re tune? no accessport, its open source tuned. do you think the ecu just needs to get used to the short ram? my MAF is installed correctly and theres no leaks. thanks for your help!

put the other intake back...do it now
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Old 12-30-2012, 09:48 PM   #18
Tripintaz
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Youze trollin
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Old 12-30-2012, 09:59 PM   #19
Decipher
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Quote:
Originally Posted by larrycox3 View Post

thanks for your input, i really appreciate it. please, when you meet someone who has blown their motor by switching intakes, let me know. as far as the problem goes, it was a damaged MAF. i took one off my buddys wrecked car. my car is running fine now.
Dude...if you know, then this makes no sense.^ There are plenty of documented cases of how different intakes create dangerous lean spots. Just trying to help man.
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Old 12-31-2012, 01:45 AM   #20
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you need a tune, cobb sri dosent require a tune.
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Old 12-31-2012, 01:49 AM   #21
larrycox3
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Quote:
Originally Posted by WaitTheresMore
you need a tune, cobb sri dosent require a tune.
It is a Cobb Sri.
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Old 12-31-2012, 03:13 AM   #22
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put the stock intake back on...
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Old 12-31-2012, 11:27 AM   #23
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The Cobb SRI is at the top of the list when it comes to how much MAF scaling INCREASE is needed at WOT to not go lean. Keep running it without the right MAF values and you are at risk of creating a new thread called, " I need help on building a shortblock."
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Old 12-31-2012, 10:54 PM   #24
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Quote:
Originally Posted by Tripintaz View Post
The Cobb SRI is at the top of the list when it comes to how much MAF scaling INCREASE is needed at WOT to not go lean. Keep running it without the right MAF values and you are at risk of creating a new thread called, " I need help on building a shortblock."
Explain!
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Old 12-31-2012, 10:55 PM   #25
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I never noticed my cobb Sri go lean even before my tune at WOT. Which was cobb stage 2, now I have a protune.
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