Engine compression.
Newbie
Joined: Oct 2010
Posts: 66
Likes: 0
From: Buffalo,New York.
well first question is how many miles does ur motor have, does it have a bunch of timing thrown at it and how much boost is being run through it. depending on those numbers would reflect what the compression test roughly should be. i dont know how much psi they put down stock it mihgt be somewere around 180-200 psi. but mainly u want somewhat level number across all 4 cylinders
something like 162,167,165,160 would be fine/ u dont wanna see like 140,165,162,135 that means u have serious blowby issues/vavle sealing issues also.
something like 162,167,165,160 would be fine/ u dont wanna see like 140,165,162,135 that means u have serious blowby issues/vavle sealing issues also.
According to the service manual:
-Standard value is 163psi or 1128kPa
-Lower limit is 138psi or 951kPa
-No upper limit is given, but like the guy above stated, it depends on car mileage and may be as much as 200psi.
-The key is the difference between all 4 cylinders. No pressure value should deviate from another by more than 14psi or 98kPa.
*Note..compression testing should be done with the vehicle warmed up (coolant temp 80-95*C)
Hope this helps...I trust you can convert psi or kPa to atm
-Standard value is 163psi or 1128kPa
-Lower limit is 138psi or 951kPa
-No upper limit is given, but like the guy above stated, it depends on car mileage and may be as much as 200psi.
-The key is the difference between all 4 cylinders. No pressure value should deviate from another by more than 14psi or 98kPa.
*Note..compression testing should be done with the vehicle warmed up (coolant temp 80-95*C)
Hope this helps...I trust you can convert psi or kPa to atm
Evolving Member
Joined: Mar 2007
Posts: 357
Likes: 0
From: Camano Island, Wa
I had a Compression Test and a Leak Down Test, my results were Cylinder #1: 175PSI Leakdown 0%, Cylinder #2: 180PSI Leakdown 3%, Cylinder #3: 175PSI Leakdown 0%, Cylinder #4: 180PSI Leakdown 3%. The Leakdown test was a 3 hour test. This was on an Evo 8 motor but the 9 motor should be pretty much the same.
Evolving Member
Joined: Mar 2007
Posts: 357
Likes: 0
From: Camano Island, Wa
you cant really do a compression test with the plugs in as the tester goes into the spark plug hole. I would recommend a leak-down test if your going to get a compression test done, but thats my opinion.
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Well you have to remove the spark plugs to have access to the combustion chamber. Whoever you heard that from was probably referring to whether or not they left the other 3 plugs in while testing each cylinder. Sure, readings may be different compared to if all 4 are removed during the testing (seems unlikely though). I have always taken all plugs out and tested that way. There is a large range of acceptable compressions, so the value itself isn't as important as the consistency between cylinders. Mitsu manual says remove all plugs and then test each cylinder
Evolving Member
Joined: Mar 2007
Posts: 357
Likes: 0
From: Camano Island, Wa
Well you have to remove the spark plugs to have access to the combustion chamber. Whoever you heard that from was probably referring to whether or not they left the other 3 plugs in while testing each cylinder. Sure, readings may be different compared to if all 4 are removed during the testing (seems unlikely though). I have always taken all plugs out and tested that way. There is a large range of acceptable compressions, so the value itself isn't as important as the consistency between cylinders. Mitsu manual says remove all plugs and then test each cylinder
According to the service manual:
-Standard value is 163psi or 1128kPa
-Lower limit is 138psi or 951kPa
-No upper limit is given, but like the guy above stated, it depends on car mileage and may be as much as 200psi.
-The key is the difference between all 4 cylinders. No pressure value should deviate from another by more than 14psi or 98kPa.
*Note..compression testing should be done with the vehicle warmed up (coolant temp 80-95*C)
Hope this helps...I trust you can convert psi or kPa to atm
-Standard value is 163psi or 1128kPa
-Lower limit is 138psi or 951kPa
-No upper limit is given, but like the guy above stated, it depends on car mileage and may be as much as 200psi.
-The key is the difference between all 4 cylinders. No pressure value should deviate from another by more than 14psi or 98kPa.
*Note..compression testing should be done with the vehicle warmed up (coolant temp 80-95*C)
Hope this helps...I trust you can convert psi or kPa to atm
That is the info for the EVO 8, which is different then the EVO 9.
EVO 9 info:
Standard value: 1,000 kPa (145 psi)
Minimum limit: 637 kPa (92 psi)
Difference Limit: 98 kPa (14 psi)
According to the service manual:
-Standard value is 163psi or 1128kPa
-Lower limit is 138psi or 951kPa
-No upper limit is given, but like the guy above stated, it depends on car mileage and may be as much as 200psi.
-The key is the difference between all 4 cylinders. No pressure value should deviate from another by more than 14psi or 98kPa.
*Note..compression testing should be done with the vehicle warmed up (coolant temp 80-95*C)
Hope this helps...I trust you can convert psi or kPa to atm
-Standard value is 163psi or 1128kPa
-Lower limit is 138psi or 951kPa
-No upper limit is given, but like the guy above stated, it depends on car mileage and may be as much as 200psi.
-The key is the difference between all 4 cylinders. No pressure value should deviate from another by more than 14psi or 98kPa.
*Note..compression testing should be done with the vehicle warmed up (coolant temp 80-95*C)
Hope this helps...I trust you can convert psi or kPa to atm
Is it bad if you do a compression test when its cold?
