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Discussion Starter #1
I already asked this question in the MK3 section, but I thought I might try here too. I recently dynoed my MK3 supra (7M-GTE) at 505rwhp sae at 25psi. This is with the SP59GT (61mm) turbo with an HKS manifold and HKS wastegate. I was dissappointed with the numbers, and thought I could make that power at much lower boost.

I later ran a compression check and got these compression numbers:

1. 170
2. 165
3. 168
4. 132
5. 157
6. 175

I know my head doesn't flow like a 2JZ, but do you think the low compression numbers in #4 and #5 cylinders cost me a lot of power? Comparing my car to other MK3's with similar mods, it looks like I'm making about 50rwhp less than I should be.
 

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i have seen many 2j's with compression like that and the continualy run 10's...for years

dont worry the 7m will let you know when it needs a rebuild...she will talk to you through the rod bearings....or she will get pissed off and blow a headgasket....as long as you dont have either keep beating her

I would put some meth injection on it and push some more boost and timming and have 600rwhp on pump gass

david
 

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Discussion Starter #5
Thanks for the input. Yeah the engine runs fine; I have a metal headgasket and I keep the oil level proper so theres no rod bearing problems. And the car does not smoke. I really don't care if the engine is going to blow-up, I just want more power. I'm looking for people who have had experience with low compression engines, and trying to figure out if this is really why my power is so low. The engines going to be eventually rebuilt anyway.
 

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Clifton said:
I run a 3mm HG and my compression is the high 130's, low 140's. I did 533 rwhp/571 tq at 28 psi.
we arn't talking strickly compression

one cyl is ~20% lower then the rest and the other is ~10% lower then the rest..

so say you have 140 in 4 then 1 has 126 then 1 has 112..
 
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