Compression test on built motor/All cylinders were right at 150psi.

[trmin8ter03]

So I finally got a round to doing a compression test. Built the motor last year using 18cc manley pistons, teksid block, felpro mls gaskets. All cylinders were right at 150psi. Is this normal for the lower compression pistons, thinking 8.1:1. Planning on going with a whipple 2.9 crusher really soon :rockon:. Thus the reason I went with 18cc pistons. I'm hoping I can run 20psi on 91 octane for a street tune and 25 psi for race.

 

[TVSCobra]

Yes.

Was there a battery charger on the car while doing the test? engine at operating temp? fuel system disabled? throttle wide open? Did you crank the engine until the max psi was made?

Just wanting to know the conditions the test was performed under.

Not questioning your testing methods, just wondering how the test was performed.

 

[nightsun]

My built motor was also right at 150psi on each cyl. I'm running cams but to answer your ? Yes it's normal.

 

[trmin8ter03]

Yes.

Was there a battery charger on the car while doing the test? engine at operating temp? fuel system disabled? throttle wide open? Did you crank the engine until the max psi was made?

Just wanting to know the conditions the test was performed under.

Not questioning your testing methods, just wondering how the test was performed.

Had my battery tender pluged in, it was at normal operating temp, throttle was held wide open and I cranked it till the needle stoped moving.
Did'nt disable the fuel system though. I know i was supposed to but dont know what fuse to pull.

 

[trmin8ter03]

My built motor was also right at 150psi on each cyl. I'm running cams but to answer your ? Yes it's normal.

Thanks, Im just worried that I may have a weak motor due to the lower compression. It was a nightmare to get my motor built and finished, I really dont want to do it anytime soon.

 

[Modular Racing]

Yes, these #'s are pretty average for a -18cc (rough stock compression depending on final bore size) - so no need to worry!

MMR
Modular Mustang Racing
1-877-MOD-POWR

 

[trmin8ter03]

Thanks guys for the responses, feel much better now. Also forgot to mention we went .20 over. So compression is even lower.

 

[trmin8ter03]

Also, thanks MMR for great customer service during my build and great parts.

 

[Modular Racing]

Our pleasure, thank you!