s2kbtos

Sup guys , this thread would help people that are wondering what is the average compression that the s2k has. please post compression, miles, year of the car, and motor mods.




i will start:



Mods: Intake, test pipe, exhaust, fidanza flywheel, and stage two clutch.

Compression: 1#185 2#185 3#185 4#185

year and miles: 2002, 62,850.

CoralDoc

Note that there is variation between compression testing devices, and in the way the test is performed, so what's more important than the absolute numbers is the variation between cylinders. It's surprising that all of yours are exactly the same! When perforrming a compression test, the ignition system should be disabled, the throttle should be wide open, and the same number of compression cycles should be used for each cylinder. I use 7.

Here are my numbers for a 2003 @ ~ 25k miles, Mugen exhaust:
#1 = 202
#2 = 198
#3 = 197
#4 = 201

Spud2000

MY2002 @ 41k miles - after a seafoam treatment

#1 228psi
#2 228psi
#3 227psi
#4 230psi

LubedKoala

What is normal?

Mister Jew

those are very good close numbers. they have to be within a certain percentage of eachother.

Another great test to do is a leak down test which is a little more of a pain to do but, nothing to big.

CoralDoc

According to the Helm manual, an F20C (the engine found in an AP1; MY 2000-2003) has a nominal compression test reading of 228 psi (1,570 kPa or 16.0 kgf/cm2).

The minimum value is 135 psi (930 kPa or 9.5 kgf/cm2), with a maximum variation of 28 psi (200 kPa or 2.0 kgf/cm2) between any two cylinders.

Are these numbers different for the F22C in the AP2?

iam7head

yes and no, you will always see varible in the number since the not all the gauge reads the same, the condition of the battery, peak number vs fixed number of crank, sparkplug all out or just one, etc.

most of the people with higher number are doing the max reading, which they crank the motor until the gauge will not read higher anymore.

I always do a fixed number of crank, for example 9 cranks for EVERY cylinder.

i do it two and three times for each cylinder, added all three and / by the number of test to get the mean/average.

the number should be within 5-10 percent of each other, if not it could be a big ring, valve, etc. after a dry test, do a wet test on the problematic cylinder to see if it's a valve or ring problem

did a compression test last year around 100k, all the number came out to be 205-210 psi. i know my old gauge reads lower since i did a compression test on a 06 and it's 215-210ish on a 7 crank test.

jimknapp

Dunnot what spec is, but my stock F22C runs 260, 261, 261, 261. Might be because of the longer stroke and a slightly less radical camshaft than the F20C. Even with 14:1's in it my F20C never got these numbers.

mxt_77

Craftsman gauge, Ambient Temp 50F:
255
245
248
245

txs2knoah

so whats the normal spec range ?

i'm just seeing #'s being tossed around