Just did a compression test... have some questions.
05-07-2007, 08:37 PM
#11
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RE: Just did a compression test... have some questions.
Changed the rear gearing from the first intial tune?Does the car FEEL like its lost40 plus RWHP? compression looks pretty good......did you do this cranking with the throttle open?
05-07-2007, 08:40 PM
#12
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RE: Just did a compression test... have some questions.
ORIGINAL: 8banger
Changed the rear gearing from the first intial tune?Does the car FEEL like its lost40 plus RWHP? compression looks pretty good......did you do this cranking with the throttle open?
Changed the rear gearing from the first intial tune?Does the car FEEL like its lost40 plus RWHP? compression looks pretty good......did you do this cranking with the throttle open?
05-07-2007, 08:42 PM
#13
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RE: Just did a compression test... have some questions.
ORIGINAL: stoes
where did you do your compression test, and how much was it? i want to know what mine is since im now supercharged
where did you do your compression test, and how much was it? i want to know what mine is since im now supercharged
I did the test, the numbers are in the first post for each cylinder. The numbers don't change because you're supercharged, unless you break something which I thought I did.
05-07-2007, 08:45 PM
#14
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RE: Just did a compression test... have some questions.
ORIGINAL: czwalga00gt
These were dry... I didnt do wet numbers. Honestly... I think the numbers are pretty damn good all things considered. I just dont know what the problem is.
ORIGINAL: cliffyk
The factory spec (dry, teardown limit) is for the lowest cylinder to be no more than 25% less than the highest--your highest was 165 so the teardown spec would be 125 or so. I am assuming these were dry figures, were wet numbers run too?[/align][/align]In any event I'd do it again in 3-4k miles and see what the wear rate is, if any--there may not be...[/align]
The factory spec (dry, teardown limit) is for the lowest cylinder to be no more than 25% less than the highest--your highest was 165 so the teardown spec would be 125 or so. I am assuming these were dry figures, were wet numbers run too?[/align][/align]In any event I'd do it again in 3-4k miles and see what the wear rate is, if any--there may not be...[/align]
These were dry... I didnt do wet numbers. Honestly... I think the numbers are pretty damn good all things considered. I just dont know what the problem is.
05-07-2007, 08:50 PM
#15
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RE: Just did a compression test... have some questions.
Oh, did you do a baseline before adding the s/c? [/align][/align]They always tell you to do that but when I /sc'd my '90 Miata at 235k miles I decided I didn't want to know--55k later it was still going strong. I baselined my '92 at 111k before the s/c and 75k later they were all withing 5% of the original numbers. Accelerated wear from FI is mostly about bottom end unless you don't keep the oil clean, or tune properly--they call it detonation because it is...[/align]
05-07-2007, 09:09 PM
#16
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RE: Just did a compression test... have some questions.
ORIGINAL: cliffyk
[/align][/align]Without wet numbers it's a guessing game; it could be a sticking valve on the low cylinder, or rings worn more than the others--all in all though I'm with you--not anywhere near time to freak out yet, do it again in a while and get some wet numbers...[/align]
ORIGINAL: czwalga00gt
These were dry... I didnt do wet numbers. Honestly... I think the numbers are pretty damn good all things considered. I just dont know what the problem is.
ORIGINAL: cliffyk
The factory spec (dry, teardown limit) is for the lowest cylinder to be no more than 25% less than the highest--your highest was 165 so the teardown spec would be 125 or so. I am assuming these were dry figures, were wet numbers run too?[/align][/align]In any event I'd do it again in 3-4k miles and see what the wear rate is, if any--there may not be...[/align]
The factory spec (dry, teardown limit) is for the lowest cylinder to be no more than 25% less than the highest--your highest was 165 so the teardown spec would be 125 or so. I am assuming these were dry figures, were wet numbers run too?[/align][/align]In any event I'd do it again in 3-4k miles and see what the wear rate is, if any--there may not be...[/align]
These were dry... I didnt do wet numbers. Honestly... I think the numbers are pretty damn good all things considered. I just dont know what the problem is.
How exactly do you do a wet test? I think its the rings that are going, so I guess the dry test wouldnt tell if the rings are going?
05-07-2007, 11:24 PM
#17
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RE: Just did a compression test... have some questions.
Put a tablespoon or so of oil in each cylinder before you test it, the surplus of oil (as compared to normal operation) will seal the rings for the 4 or 5 compression strokes needed to get a reading of "what it would be like if the rings/piston weren't blowing by"--if the compression stays the same then you've got a valve problem (sticking, burned seat/valve [though I don't think your numbers aren't low enough]). If the compression goes up significantly (let's say your 155 cylinder hit 165 to 170) then its rings...[/align][/align]Still not time to freak though, check it again after a couple/three thousand miles and see if it's stable or worsening.[/align]
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