Here's what's up:

6000 km on new street ported motor w/ 3mm seals, new rotor housings and dowell pinned

Poor mans compression tester read 60psi in each rotor on a warm engine consistently

However gas pedal was not pressed when this was done, if this makes any difference.

Is cranking compression less than compression under load for this type of motor since the apex seals are not being forced against the housings?

 

Are they 1 piece seals? I had my last motor with 3mm 1piece ceramic
seals and when it got hot the compression was about 70-75 psi. It was hard to start is yors hard to start also? Ralph

 

Yeah mine is hard to start most of the time, especially when its hot. I am not sure if they are 1 piece seals or not, I will ask tommorrow.

I am putting it on the dyno in the morning, I'll see what king of numbers its putting down.

What happened to your last motor?
Erik

 

It does make a differance. Flooring the gas opens the butterflys to allow more air to enter the engine. Try retesting to show what the true numbers are.

 

yea, what T-von said. without the throttle open, its limiting the amount of air that goes into the motor. less air=less compression

 

wide open throttle plates allow the starter to crank the motor over at a higher rpm. your compression #s are quite variable relating to rpm. check out the graph of cranking rpm and compression readings in the shop manual.

howard coleman

 

I just had the car onthe dyno, I am dissappointd with the results. Check out my post in the single turbo section under (t-78 dyno w/ ported motor).

I am going to compression test the motor again today with the throttle open.

Thanks for the feedback