I did a compression test last night on my car using the newer twistedrotor.com unit. I let the car warm up to about 130-140 deg, removed trailing plug, and ran the front rotor...68-70psi avg. i did the same at the rear rotor and got the exact same reading. I then did the same routine using the leading, expecting maybe a different readout...nope..same result on both rotors.

I thought maybe the battery was faulty, so i dropped a new one in the tester, ran test again and got the same reading.

with compression that low the car should be stubborn to start, if it will even start. The car fires right up with no issues or hesitation even after sitting for days at a time, and it spools up just as it always has.

anyone else have an issues similar with these testers? I'm gonna meet up with a friend today and do a test on his car to see if i get a different reading.

any thoughts welcomed.

 

Are you at altitude? Was the cranking RPM 250? You need to adjust the readings for altitude and cranking RPM. This online calculator will do that for you: Foxed.ca - Rotary Compression Calculator

 

thanks for the link. i plugged in the numbers and basically got an avg compression of around 100. this makes me feel better!! spoke to other people and due to larger clearance of apexes, it may be the cause for the tad bit lower numbers.

 

Just to add to this discussion, if you didn't disable the fuel pump, the extra gas can cause low readings also.

 

Fuel pump switch was off when doing test.

 

Was the throttle wide open while cranking?

 

Used a 2x4 wedged on seat holding pedal down. Ghetto but functional.