need help with an 06 Grand Prix
08-16-2010, 06:55 PM
#1
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need help with an 06 Grand Prix The knowledge on this forum is better than anywhere else it seems. Mine isnt an ls4, but a sc'd 3.8. Ive lost 70hp and over 100 lbs of tq in 6 months and everything is running perfectly. Where should I go to troubleshoot? The GP forums arent helpng. Does anyone here know these cars?
08-16-2010, 07:31 PM
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I havent changed anything since Feb. Sounds wierd but I actually started noticing the loss when I had a new set of tires put on it. I just thought they were gripping really well and when they broke in my acceleration would come back. It seemed wierd but it was a huge loss all at once. My gf had wal mart do it as a suprise while I was at work. Is there anything down there they might have screwed up?
08-16-2010, 07:40 PM
#5
What forums have you posted on?
Where are you from?
What mods have you done?
What maintenance have you done?
What is your mileage?
How do you know you lost those numbers in hp and tq?
Thanks,
John
Where are you from?
What mods have you done?
What maintenance have you done?
What is your mileage?
How do you know you lost those numbers in hp and tq?
Thanks,
John
08-16-2010, 08:08 PM
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k...mods: Magnaflow cat (less than 18months old), 3" catback, res delete, overkill pcm, front plog, cai. hp, tq numbers according to Aeroforce guage went from 315/538 to 248/411. Idk how accurate these are but its a distinct pwr loss in driving it. I went from a serious traction issue to not even being able to turn the tires from a stop in less than 6 months. The car has 84k miles on it and is in pristine condition. Just picked it up from the dealership today after a tranny flush and a topend and tb cleaning. Running up to 13lbs boost w no kr. Dealer had it for 2 days and said eerything checked out perfect. No codes, nothing. Throttle position is reading 99% and engine load hits 90% every once in a while, it hovering around about 85%. Im stuck...o, and Im in TX
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08-16-2010, 08:40 PM
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your running 13 psi boost. that means your running about a 3.0 pulley. what plugs are you running? stockers? what supporting mods do you have to run 13 psi of boost?
08-16-2010, 08:53 PM
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see now theres the kicker...I gained over a lb of boost since my problems started. Im running a stock pulley. Ive have a 3.6 in my console it hits 13 for a second at wot before it shifts, yet I have no kr, like 0.0 none. The only time I see any kr is in 4th at hwy speeds under very light throttle, which from what I understand is pretty normal. Im not putting the pulley on till I figure out wtf is going on. But as for supporting pulley mods Ive done exhaust, pcm, cai, 180tstat, and ngk tr6 plugs. See...its kinda a mystery here. Im not new to the hot rod game, but am new to the forced induction scene.
08-16-2010, 09:03 PM
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on this subject...can anyone tell me where the hell the hp and tq reading are coming from that the Aeroforce guage is displaying?? Or does it just guess? Its not an acceleration thing cuz it reads at an idle in park.
08-16-2010, 09:04 PM
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you should not be seeing more than 5-6 psi max with a stock 3.8 pulley. have you tried grandprixforums.net? when did you get the pcm? i would not do the 3.6 pulley not a big difference in boost maybe 2 psi with the mods you just listed you can run a 3.4 with no kr. the 3.4 should be about 10 psi which will be safe.
08-16-2010, 09:06 PM
#16
You lost all that power because the outside temps have increased from 6 months ago. Hot air doesn't compress as much as cold air so the motor is getting less fuel and air mixture. Plus you really can't count on a gauge to give you an accurate reading of hp & torque, you need a dyno to check power output. An intercooler will give you more power and help stop KR because it cools down the incoming air.
08-16-2010, 09:16 PM
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the guage is reading engine torque from the pcm. the pcm monitors it thru the transmission peramaters, uses it for toque management on some cars. the guage is just taking the data that is already there, applying a mathmatical formula and supplying the hp numbers. you can verify the guage by having your buddy at the dlr hook up a tech2 and go for a drive. monitor engine torque in the transmission scan tool data list, it's like the 20th or something down on the list, it can show in both Nm and ld ft.
Last edited by Cliffy; 08-16-2010 at 09:22 PM.
