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Old 05-11-2015, 10:21 AM   #1
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Default Pre-Boost Compression Numbers

1994, motor at 174k.

Compression numbers as follows.
Cyl#1 182
Cyl#2 150 (200 wet)
Cyl#3 175
Cyl#4 175

"Book" delta is 28psi, I'm at 32psi. Is this going to be detrimental if I put on a JR stupidcharger M45 with 8psi boost?

I know most will say to do a leakdown first. I'd like to move forward with boosting the motor, with the knowledge it will one day go. Anyone think that's an absolute no-no and im gonna blow within 1000 miles? I don't really think it's so bad I need a full rebuild, since I'm just playing with a fun, cheap car and not building a track monster.

Any thoughts?
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Old 05-11-2015, 10:38 AM   #2
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Do it anyway. Who cares. You wont make much power with a piece of crap m45 anyway. If it blows it blows.

Numbers jumping up when wet suggests it's the rings on #2. (though that's a huge jump, hope you didn't just pour a ton of oil in there)
Leakdown would confirm
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Old 05-11-2015, 10:45 AM   #3
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1 tbsp. oil, cranked twice w/out a gauge, then hooked it up and tested.
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Old 05-11-2015, 10:49 AM   #4
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This is why I didn't check compression before I turbo'd my high mileage motor, I knew I was going to do it either way. If this is your only car I wouldn't do it but if it's a fun car then boost away.
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Old 05-11-2015, 04:40 PM   #5
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Boost the socks off of it.
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