i had a compression and leak down test done to my evo 9. here are the results

compression

cyl 1 - 112
cyl 2 - 110
cyl 3 - 112
cyl 4 - 122

leak down

cyl 1 - 54%
cyl 2 - 64%
cyl 3 - 48%
cyl 4 - 39%

shop owner and his machinist said since compression is good, not to worry too much about the leak down results. they couldn't tell me if and where air was leaking out of. not without further testing. i have trusted this shop for quite a while now, but maybe they did the leak down test wrong.

car has 55xxx miles, pulls strong, and feels just fine. oil consumption is very minimal, there is no excessive smoke coming out of the exhaust.

what do you make of these results?

 

i would not call any of that good compression.

 

they called it good. min is 90 max is 145. i would have liked higher numbers, but at least they don't fluctuate that much.

 

Were both tests done when the engine was completely cooled?

 

if not completely cooled then close to it. the car was sitting for at least a half hour before they pulled it in the garage.

 

Take car to someone else..... FAST!!!!

 

So why did you bring it in for a compression test? That might shead some light into this issue.

 

If you have good compression and bad leak down its most likely leaking valves. Do you know how many times they cranked over the motor to measure compression? Some people crank it until the gauge stops reading and others 3-6 times.

 

to see in what condition the engine is before i try to get another 100 hp out of it. the engine seems to run fine.

idk how many times they cranked the engine.

 

Why did they test the compression with the engine cooled? Every how to on the web says to do this while the engine is warmed up so the rings seal the best and give you the best results?

 

The compression test also has to be done with the throttle down.

 

This is false

 

This is false ^^^^


Those are some low compression numbers, I just pulled out my pistons where the top compression rings on all 4 pistons were cracked in like 10 pieces and literally fell out and the compression test (no oil) right before I pulled it apart was 160psi so thats with only the lower compression rings sealing and has lower compression pistons and bigger cams which I'm sure bled off some compression lowering the static compression too. That is cranking till it stopped, all plugs out, and battery charger on the battery to keep the amps up since I have a mini battery. Leak down shouldnt be in the 50% or that high either way. I have no faith in shops, I would at leasstt have it rechecked by someone else.

I've seen shops lie and make up compression numbers (to get work = money) and you don't know the quality of there gauge and if they did it correctly. Go somewhere else for a second opinion or just do the compression test yourself, get a $40 gauge and pull the plugs and you can do it in less than 30 mins, or have someone on here help out

 

Average compression for Evo9 is 120-140 , Bigger cams generally have an negative impact on compression.
Its nice to see each cylinder within about 10% of each other.

Your numbers arent low at all, especially since you tested cold, Compression tests are supposed to be done with the block warm, Going from cold to warm usually is a 5-10PSI difference.

The guy posting above me did his test on an evo8 which usually average between 145-160, His numbers are high considering his issues and his 'big' cams but then again he has a built block, And i believe yours is stock.

To give you faith i Comp. test my car all the time evo9 stock block S1 cams and usually get 116-124 its been there for the past three years and most recently has made 527WHP on the stock block, Im saying you shouldnt have anything to worry about sice you have no other issues, (coolant, oil, power, drivability) The biggest pressure drop in our cars usually is the valves\seals, if the problem is that bothersome to you check there first.

 

Compression and leak down tests were done to my car last weekend. Car sat outside at 30*F for 30 minutes before it was taken inside the shop. Temperature inside the shop was 45*F LOL!

Compression:

1 - 135
2 - 135
3 - 135
4 - 140

Leak down:

1- 7.5 %
2 - 5.0 %
3 - 5.0 %
4 - 5.0 %

Car is Evo IX with 21,4XX miles. Stock. If your cams are stock, I would say your compression is low. Your leak down results are alarming, too.