egh22ahatch

Okay I have a jdm h22a compression is 10-6-1 stock block built head and going for a retune Friday just added meth kit new downpipe so I went over everything and did a compression check cold it was 210-210-240-240 then I checked it hot and it was 220-220-220-245 both times with fuel off and wot maybe faulty comp gauge or is it time for rebuild I'm suppose to get a retune this Friday but might hold off thanks for any input or suggestions

busa4

your compression is fine. no need for a rebuild. higher than normal compression can be caused by carbon build up in the combustion chamber. run some carbon clean through it. i use water. you can slowly add it to the intake via a vacuum line. add the water slowly to a point where the engine still runs. the water will evaporate and turn into steam. it cleans very well.

egh22ahatch

Okay sounds good but wouldn't my meth injection do the same thing thanks for the response just don't wanna louse anymoney on a tune if its only gonna last week after tune oh also I just did a leak down test and results were good only reason for the thread is my tunner said it sounded sketchy with one cylinder being higher he said it might throw the wideband off

busa4

no. meth is injected as a fine mist.

have you tried a different compression tester?

egh22ahatch

Yeah tried different tester and same results,, I was thinkin about tryin the sea foam but I just want to put it in that high cylinder can I just remove the spark plug and pour little bit down that cylinder to remove the carbone in just that cylinder id hate for the other 3 to go down

egh22ahatch

Update pulled motor apart 3 broken ringlands

busa4

pretty damn impressive compression numbers for having broken ring lands. glad you got it figured out but i would still try and fix the two cylinders with 240 psi compression. thats very high especially for boost. since your pistons are shot anyway pick up a set of forged low compression pistons.