low compression motor ??
04-20-2006, 08:16 PM
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low compression motor ?? I am trying to find out how much vacuum I should see on my motor. It is 8.5:1 compression. What are all of you guys seeing?
I know this seems like a bit of a loaded question, so I'll explain why I'm asking. I went to the track last week, and had 4 runs....all of them had serious issues. I had the car tuned up to about 9 psi, and the boost spiked a couple of times to 13 psi. I know the motor will take it, but it went lean on those spikes. About 13.5:1 afr!! So, I'm hoping I didn't bust anything. Thanks for any help.
I know this seems like a bit of a loaded question, so I'll explain why I'm asking. I went to the track last week, and had 4 runs....all of them had serious issues. I had the car tuned up to about 9 psi, and the boost spiked a couple of times to 13 psi. I know the motor will take it, but it went lean on those spikes. About 13.5:1 afr!! So, I'm hoping I didn't bust anything. Thanks for any help.
04-20-2006, 09:35 PM
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I see about 20-25 lbs of vacuum at idle. I only run 7 lbs of boost. I did hit 9 when my cats were collapsing, so I would look for an exhaust restriction.....
04-20-2006, 10:38 PM
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hmmm, before my trip to the track, I would see about 18-19 at idle. Now it looks like 16-17. Now, granted I haven't driven the car out of the garage since then. But after having some discussions with a buddy of mine, I'm wondering if I have a vacuum leak somewhere. During that trip to the track, one of the vacuum lines popped off completely. So, I have to check all of that stuff. The car is not running rough our anything. I'm just a little concerned, that's all.