1st Gen 100K+ Most liked posts in thread: Compression Test Results

A wet compression test is used to indicate if low cylinder pressures are caused by worn piston rings only. The test is done exactly the same as the “dry” test, however a small amount of engine oil (about 1-2 teaspoons) is added into the cylinder to create temporarily seal (to prevent possible blow-by). If compression rises significantly afterwords, then worn piston rings are the culprit.

 

question

while I am going to google it, what's a wet test? I have 125K on my R53 and had similar numbers and range, so pleased there. This may be a more general question-- I feel I am not getting the HP I once did. Several mods under the bonnet (CAI, 17% supercharger pulley, and air diverter for supercharger). Routine oil changes and filter cleaning, plugs and wires-- keep it in top running condition. Just wondering if valves and/or even rings needs work. Knowing this is all vague, any ideas? Thank you, and I will keep checking around this thread. C.I.

 

:cornut: This thread is 2 1/2 yrs old so you should probably PM k-huevo to be assured of getting an answer and/or drawing his attention back to this thread

Jason

 

Thank you, Jason. New to forums and will be mindful of post dates, Chris

 

You warmed up the motor prior to this test?

 

Nothing wrong with that compression - the important thing is that it's fairly even across the board and well within spec. #3 is a little low, but not horribly so.....could just be a tight valve that needs adjusting. (Or are those hydraulic in 2004?)

I say drive her another 100K and check it again!

 

You're down somewhat. Did you perform a wet test afterward? Between a wet test comparison and leak down test you'll know if it's time for headwork, rings or both.