Help me diagnose my problem
Posted: Thu Aug 25, 2011 1:41 pmI'm going to copy pasta from my thread in the OEM section, and add in some FI relevant stuff.
Had the night off work, so I decided to take the slowara out to the track to see how the new injen intake would improve things. Result? Power cut, mid-15s, almost a full second slower than with the stock intake. I noticed that it would lose power in first and sometimes second gear, then abruptly get it back. Is the knock sensor cutting fuel and timing since the intake makes the blower significantly louder, despite the boost level remaining at the stock level? The CEL has not come on, coolant temp level has been normal. The oddest thing, is the car pulls like a freight train in first and second gear on the street, with no sign of power loss, even on the onramp immediately after leaving the track last night.
I scanned the car with an OBDII scanner and there are no codes stored. Would it be possible for the knock sensor to pull timing this much, without failing and/or throwing a code? After the heat soak I experience at the track a few weeks ago (was much different in nature than this particular night) I brought a large bag of ice to cool down the intake pipe and supercharger in between runs, and even the hood was not at hot as it was the previous time I ran at the track with the stock intake.
Is it true that the whine of the supercharger can fool the rear knock sensor into pulling timing? The boost is stock as far as I know, but the supercharger is MUCH louder with the Injen intake on; it seems like the additional "growl" an engine makes at WOT after an aftermarket intake is installed, has been transmitted to the blower whine, my friend noticed a huge difference in the noise level of the supercharger at WOT.
About the pulley...is it true that these cars came with either a 3 lb or 4 lb pulley?
GregTRD mentioned the boost being limited/prevented in first gear, but why would that happen at the track, and nowhere else? First gear boost was perfectly fine the first time at the track, as the 205/50/15 tires were all but overwhelmed through first gear. Would installing the intake, even though I've installed several intakes over the years, bring about a possible issue?
Had the night off work, so I decided to take the slowara out to the track to see how the new injen intake would improve things. Result? Power cut, mid-15s, almost a full second slower than with the stock intake. I noticed that it would lose power in first and sometimes second gear, then abruptly get it back. Is the knock sensor cutting fuel and timing since the intake makes the blower significantly louder, despite the boost level remaining at the stock level? The CEL has not come on, coolant temp level has been normal. The oddest thing, is the car pulls like a freight train in first and second gear on the street, with no sign of power loss, even on the onramp immediately after leaving the track last night.
I scanned the car with an OBDII scanner and there are no codes stored. Would it be possible for the knock sensor to pull timing this much, without failing and/or throwing a code? After the heat soak I experience at the track a few weeks ago (was much different in nature than this particular night) I brought a large bag of ice to cool down the intake pipe and supercharger in between runs, and even the hood was not at hot as it was the previous time I ran at the track with the stock intake.
Is it true that the whine of the supercharger can fool the rear knock sensor into pulling timing? The boost is stock as far as I know, but the supercharger is MUCH louder with the Injen intake on; it seems like the additional "growl" an engine makes at WOT after an aftermarket intake is installed, has been transmitted to the blower whine, my friend noticed a huge difference in the noise level of the supercharger at WOT.
About the pulley...is it true that these cars came with either a 3 lb or 4 lb pulley?
GregTRD mentioned the boost being limited/prevented in first gear, but why would that happen at the track, and nowhere else? First gear boost was perfectly fine the first time at the track, as the 205/50/15 tires were all but overwhelmed through first gear. Would installing the intake, even though I've installed several intakes over the years, bring about a possible issue?
Even with all of my searching this forum, I never came across anything that mentioned doing that mod before anything; I always just assumed it was a necessary part of getting ready to raise boost. 