compression test on cammed Evo
#1
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compression test on cammed Evo
Hey so i have searched around and i found alot of results on what the compression should be and it looks like it should be around 140 for an EVO 9 please correct me if im wrong.
I also heard that cammed cars will show lower compression then a stock car is this true?
i heard that a cammed evo should be around the low 100s
also do the numbers matter that much or is it just to make sure all the cylinders are similar.
Let me know
Thanks
I also heard that cammed cars will show lower compression then a stock car is this true?
i heard that a cammed evo should be around the low 100s
also do the numbers matter that much or is it just to make sure all the cylinders are similar.
Let me know
Thanks
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140 sounds about right for Evo 9 due to the MIVEC. Evo 8s have higher compression than Evo 9s do.
I wouldn't be TOO concerned about the reading, but rather the variance between the cylinders (no more than 10-15 variance)
I wouldn't be TOO concerned about the reading, but rather the variance between the cylinders (no more than 10-15 variance)
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is 110 bad? or is that normal for a cammed EVO?
Also i was thinking higher elevation = thinner air
does that mean at high elevation you can run more boost then you could at sea level because the air is less dense?
Also i was thinking higher elevation = thinner air
does that mean at high elevation you can run more boost then you could at sea level because the air is less dense?
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This may be an uninformed question, but why would a cam affect compression. Aren't the valves closed during compression? Don't cams only affect the degree of which a valve would open? I know in rotors with a very aggresive port sometimes the exhaust port would remain open almost always but I did not think this was the case with piston motors.
#13
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1) Should be around 140
2) Cams should not change compression because the valves are closed when doing a compression check
3) They should all be relatively the same. They should all be around 140. If one is lower than it shows premature wear in that cylinder. If it is lower in all the cylinders than it shows wear in all cylinders. They should all be 140.
4) If you have a lower compression do a wet compression check. This is squirting some oil in the cylinder. If the compression increases then drops after a while you have a worn piston rings. The oil will sit inbetween the cylinder wall and the piston wall and when the oil gets past the compression will then lower again.
Good luck. Hope this helps.
2) Cams should not change compression because the valves are closed when doing a compression check
3) They should all be relatively the same. They should all be around 140. If one is lower than it shows premature wear in that cylinder. If it is lower in all the cylinders than it shows wear in all cylinders. They should all be 140.
4) If you have a lower compression do a wet compression check. This is squirting some oil in the cylinder. If the compression increases then drops after a while you have a worn piston rings. The oil will sit inbetween the cylinder wall and the piston wall and when the oil gets past the compression will then lower again.
Good luck. Hope this helps.