Just checked my compression and here are the results.

#1: 150
#2: 145
#3: 135
#4: 145

Does this indicate a healthy motor or a motor on it's way out?

 

DID you use a digital tool or a analog? Was the engine still warm? Did you hold the throttle fully open during each revolution?

 

sorry i should've elaborated a bit more.

i used an analog tool and the engine was warm. the throttle was full when i cranked it over to get the readings.

car is a 05 Evo MR with 77k miles.

 

With MY analog tester on my evo8, when it was stock motor, it would blow 180 +- 10psi and by buddies evo8mr would blow 170-180psi and another buddies blew 165-175 on his 05 evo8 with a different tester. Take it for what its worth.

 

mine was from an analog which came out with mid 170's. 03' with 42K.

 

absolute compression numbers are only part of the story, you should be more concerned with variations between cylinders.

you have a variation of 10% between your lowest and highest cylinder, which is the max variation that is still considered ok. i would keep an eye on it and start doing compression tests whenever you do an oil change

 

^ yep

if i were you i would be looking into it as well. Could be alot of things over time injectors dont spray what they should carbon buildup and so on. Tune is a factor. If your on stock ecu you will be fine wuth theses numbers if the ecu see's anything out of the norm it will go into safe mode. my # 4 piston was down to 75 for almost a year didnt notice it untill we put the AEM in the car. Before that i knew there was a problem as i would lose tp other evos with less mods. After the aem was in a week later pop as it wouldnt go into safe mode.

 

Depends on if those #s haven't changed since the car was new.

My compression has had an 9 psi (5%) difference since day 1 60K miles ago