I did a compression test because my HP numbers were low with a vmp tvs and a 4lb lower. It produce 563 rwhp 560 tq with about 15* timing. My tuner tried to raise the.timing but he said the car didn't respond good. I'm seeing around 20 lbs of boost on 93 octane which I know I should be over 600 easy. My tuner was puzzled so was I. Here are the numbers this was dry test with the engine warm. Passenger side 125 120 115 110 drivers side 110 100 105 120. I'm doing the test again on Saturday and I will drop some oil in the cylinders to see what I get. I know I should be somewhere in the range of 160-180 psi. Should I be concerned? The car has 39000 miles and it drives great and pulls like a train. Thanx in advance
Compression test results!
- Thread starter maxx0ne
- Start date
Its not so much about the number, but the spread of all the numbers on that bank. For example, On one gauge you may read max 120, now with another gauge, same car same senario the other gauge may read 170. It really depends on the gauge. Your over 10% difference on the pass. side and 20% on the driver side. I would be more concerned with the difference your showing from cylinder to cylinder. I would add some oil to the cylinders and re-do the test. Im going to guess your numbers are going to come up a bit. I think you have a ring/cylinder issue. Goodluck either way though bud!
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I see what you mean I'm doing the test again Saturday. Would ring/cylinder issue be enough to effect HP?
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Yes it will effect your hp.. Are you getting any smoking out of the exhaust? It really could be anything. Im assuming your numbers will go up when you add oil to the low cylinders and re-do the compression test. After that your next step is a leakdown test and a boroscope. If your driveside was lets say, 105, 100, 105, 100 and Pass. side was 130, 135, 130,130. Then you could be looking at a timing issue, but since yours are on both banks and not equal I really think its in the cylinder / piston area. Was your car tuned before?
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I haven't seen any smoke coming from the exhaust. The car was tuned before when I had my posi eaton blower.
did you do the test with the throttle body open?
Yes they did
Just did my compression test again drivers side 150 150 120 with oil (150) passenger side 155 150 155 150. I don't know if the shop didn't do the test right the first time but my results were different. Just an update.
Ole #7 again.:nonono:
Shop got a bore-o-scope? pull the plugs and look at the tops of the pistons for detonation evidence.
Lmao who the hell cares bout those compression numbers now lol
I'd look into it anyhow man good luck with it :beer:
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do a leakdown test and see what those results are
As of now I'm just going to do a leakdown and boroscope it. Hopefully its not serious. Thanx
Thanx Rick
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