View Full Version : sr20 compression test results

02-11-2008, 10:15 AM
So yeaaaaa out of sheer boredom at work i decided to do a compression test on my motor and this is what i came up with:
Engine is moderatly warm.


When i searched for compression test results i saw people coming up with 140psi numbers and new SR motors should be around 200psi...this blew me away, i didnt think that compression numbers were supposed to be that high. Should i pull the head and check her out?? This is a stock sr with stock boost, stock cams just the normal bolt ons, FMIC, Tubular mani, exhaust. Thanks guys

02-11-2008, 10:59 AM
What is your elevation?

Put a teaspoon of motor oil in a cylinder and test it. If the compression goes up its most likely your rings. If it doesn't go up then it could be a headgasket issue or valves seals etc etc.

02-11-2008, 11:35 AM
Elevation is about 500ft nothing that would effect that. The power hasn't felt weak or anything i just did this compression test out of randomness. The motor has never been refreshed to my knowledge, it should have stock pistons and such.

02-11-2008, 11:37 AM
warm your engine to normal operating temps and test it again. You should have more normal numbers. Also make sure you test with the throttle body open. You should be getting number around 150-155.

02-11-2008, 11:45 AM
Also,crank it enough until the gauge stabilizes the highest reading. I would also leak down your motor as well.

02-11-2008, 12:12 PM
my experience has been that EVEN numbers across the board like you have got - are good news.

i did a test on one of my VW 1.8t last year. with 2 different air devices. first run i was seeing 135-140s acrooss the board,

the 2nd run, 2 days later, i was seeing 180s across the board, different measuring device (probably better) and different day.

gotta be a warm motor, just be slow taking out the spark plugs, warm threads are tender.

02-11-2008, 12:25 PM
You have cams or stock? TB held open?

02-12-2008, 06:56 AM
throttle body open, yes i let it stabalize i let it crank over about 5 times and the gauge maxed out after about 3 cranks. When i did the test when the motor was hot it came out to 98-95psi numbers. Stock cams. I think im gonna do a leakdown sometime this week. thanks guys

03-26-2008, 10:37 AM
so wat were the leakdown results? I"m in the same process with my honda motor.

03-26-2008, 10:43 AM
Also,crank it enough until the gauge stabilizes the highest reading. I would also leak down your motor as well.

isnt it you need to crank the motor 3 times at most by FSM?

03-26-2008, 10:49 AM
You really shouldn't have to crank it more than 3-4 times

03-26-2008, 06:40 PM
4 times should be max. on my first sr, i got 150 in the first 3 and 155 in the last. on my current motor, i'm too scared to do a test. its running fine and i don't wanna start getting all paranoid