compression test results
12-20-02, 08:59 PM
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compression test results
The Mazda dealership did a compression test on my '90 non-turbo today and they said the readings varied from 7.8 to 8.1. Am I right in assuming they did this in kg/cm2? Also, if my conversions to lbs/in2 are correct, that would put it at ~ 110-115 lbs/in2....is this good?
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12-21-02, 09:54 AM
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Originally posted by Roy James
accually, i thought 120 was perfect.... **** if 115 is perfect, then i guess my old motor that had 120/120 was a freak motor.
accually, i thought 120 was perfect.... **** if 115 is perfect, then i guess my old motor that had 120/120 was a freak motor.
dual90s: looks like you've got a strong car
12-21-02, 07:43 PM
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Originally posted by Erik
i'm a freak too, lol...when i got mine tested BOTH rotors were over 125psi! hehe
dual90s: looks like you've got a strong car
i'm a freak too, lol...when i got mine tested BOTH rotors were over 125psi! hehe
dual90s: looks like you've got a strong car
12-21-02, 08:37 PM
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Originally posted by Mr. Eccentric
Maybe you're engine is really just so close to carbon lock that your reading is great!
Maybe you're engine is really just so close to carbon lock that your reading is great!
it was tested 2 years ago...still daily driven today and strong as ever...
12-16-03, 10:05 PM
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Just had a car checked today. Following figures are front rotor (3 specs) and then rear rotor. Help deciphering them appreciated!
Front rotor: 7.7 8.0 7.7
Rear rotor: 9.4 8.6 8.8
(when multiplied by 14 equals
Front rotor:107.8 112 107.8
Rear rotor: 131.6 120.4 123.2
on an engine with about 20k miles on it. Whaddya think, especially in the discrepancy between the front and rear rotor? Make any difference?
Thanks,
Tom Reynolds
Hereford, AZ
Front rotor: 7.7 8.0 7.7
Rear rotor: 9.4 8.6 8.8
(when multiplied by 14 equals
Front rotor:107.8 112 107.8
Rear rotor: 131.6 120.4 123.2
on an engine with about 20k miles on it. Whaddya think, especially in the discrepancy between the front and rear rotor? Make any difference?
Thanks,
Tom Reynolds
Hereford, AZ
12-16-03, 11:34 PM
#14
Anything over 100 is decent...over 110 is pretty damn good, over 120 is like new. Most rebuilds are *lucky* to exceed 115psi. Only a new housing, new seal motor will exceed 115psi. 125psi is basically brand new with less than 10k miles. After 50k miles compression starts dropping rapidly, and by 100k compression can be down near 90.
BTW< a 10-15psi differential between front and rear is normal, though not desireable. More than that and you start to worry...too much of a discrepancy will cause uneven idling and poor mileage.
BTW< a 10-15psi differential between front and rear is normal, though not desireable. More than that and you start to worry...too much of a discrepancy will cause uneven idling and poor mileage.
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