Need Some Help! Car Low on Power

dml145 · 11-12-2009, 10:57 PM

So I have an 08 STi with some performance issues. The car is currently Stage 2 with the following mods:

- Invidia Catless downpipe
- MXP Catback
- TOMEI equal length header
- Protuned with Cobb AP

With the above mods and according to my tuner I should be seeing roughly 30 hp more then what I am putting down. We compared my torque and hp curves with other cars with almost identical mods and I'm low on power through out the entire RPM range.

One thing that I did notice is that my boost comes on late, however I have no problems building full boost. I checked the turbo for shaft play and there is some present, I would thing if this was the issue then I would not be able to get full boost, please correct me if I am wrong. Is it even possible for shaft play to decrease performance while still showing full boost?

I've checked the compression twice after the tune and I'm seeing roughly 130 psi on all pistons, so I guess a cracked ringland is not the problem.

Right now I am all out of ideas I need some help in trying to figure out what possibly could be the problem. It gets me mad knowing that I spent all this money on the car and the mods and now its not performing like it should

I should also mention that I spent probably an entire day looking for vacuum leaks with no success. Thanks for the help.

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DHRDAN · 11-12-2009, 11:32 PM

1. You say "low on power"..... so how much power are you making?
2. Boost leak maybe, but what does your boost gauge say?

dml145 · 11-13-2009, 09:27 AM

1- The car dynoed at 270 whp, it should be closer to 300 whp on that dyno and with my mods
2- My boost gauge is indicating about 20.5 psi, but like I said full boost comes on late

thanks for the help

11-12-2009, 10:57 PM	#1
dml145 Scooby Newbie Member#: 105995 Join Date: Jan 2006 Location: CT Vehicle: 2008 STi	Need Some Help! Car Low on Power So I have an 08 STi with some performance issues. The car is currently Stage 2 with the following mods: - Invidia Catless downpipe - MXP Catback - TOMEI equal length header - Protuned with Cobb AP With the above mods and according to my tuner I should be seeing roughly 30 hp more then what I am putting down. We compared my torque and hp curves with other cars with almost identical mods and I'm low on power through out the entire RPM range. One thing that I did notice is that my boost comes on late, however I have no problems building full boost. I checked the turbo for shaft play and there is some present, I would thing if this was the issue then I would not be able to get full boost, please correct me if I am wrong. Is it even possible for shaft play to decrease performance while still showing full boost? I've checked the compression twice after the tune and I'm seeing roughly 130 psi on all pistons, so I guess a cracked ringland is not the problem. Right now I am all out of ideas I need some help in trying to figure out what possibly could be the problem. It gets me mad knowing that I spent all this money on the car and the mods and now its not performing like it should I should also mention that I spent probably an entire day looking for vacuum leaks with no success. Thanks for the help. * Registered users of the site do not see these ads.

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11-12-2009, 11:32 PM	#2
DHRDAN Scooby Specialist Member#: 204358 Join Date: Feb 2009 Chapter/Region: SCIC Location: Santa Paula, CA. Vehicle: 01 2.5RS W/ EJ257 99 2.5RS Black	1. You say "low on power"..... so how much power are you making? 2. Boost leak maybe, but what does your boost gauge say?

11-13-2009, 09:27 AM	#3
dml145 Scooby Newbie Member#: 105995 Join Date: Jan 2006 Location: CT Vehicle: 2008 STi	1- The car dynoed at 270 whp, it should be closer to 300 whp on that dyno and with my mods 2- My boost gauge is indicating about 20.5 psi, but like I said full boost comes on late thanks for the help