Honda Prelude Online banner
1 - 9 of 9 Posts

·
On the 2nd Prelude
Joined
·
2,736 Posts
numbers with a deviation between each cylinder of less than 10%, same as any other car in any other location.

Probably not what you wanted to hear, but it's the main thing you should be concerned with.
 

·
Premium Member
Joined
·
122 Posts
Discussion Starter · #4 ·
I did some math and a good estimate is 206 psi for the JDM h22a.

H23a1 compression ratio: 9.8:1
H23a1 nominal compression: 178psi (helm)

h22a1 compression ration: 10.0:1
h22a1 nominal compression: 185psi (helm)

h22a compression ratio: 10.6:1
h22a ESTIMATED nominal compression: 206psi (see below)

h22a1 has .2 higher compression then a h23a1 and should get 7psi higher compression test numbers according to the helm. The H22a has .6 higher compression than a h22a1. This is 3 times the difference between the h23a1 and the h22a1 so I'm guessing the compression test numbers should also have 3 times the difference of the h23a1 and h22a1. 7psi x 3 = 21psi 185psi + 21psi = 206psi. My compression test numbers were between 208 and 210 on all cylinders so i imagine my numbers are pretty close. Sorry my explanation kind of sucks but if anyone sees any error or happens to know what the JDM service manual says let me know.
 

·
Premium Member
Joined
·
122 Posts
Discussion Starter · #8 ·
That seems very high for a USDM considering the helm says it should be around 185 with max variation of 28psi. My numbers were 210 212 210 210 just now with all plugs out, ECU fuses pulled, and a pretty warm engine... had been driven awile when i parked in the garage but cooled off for about 10 minutes. Last time I did the test engine was much cooler and was only about 2psi lower per cylinder. How much does temperature affect the readings?
 

·
Premium Member
Joined
·
122 Posts
Discussion Starter · #9 ·
Just talked to one of the honda dealer technicians and he said that in this area the tests usally range from 150 to 170. I found the equation to calculate it based on bore/altitude/etc earlier so i'll have to get that again and just do the math.
 
1 - 9 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top