Compression test results

[Newbie]

I finally had a chance to get the compression tested in my 13B S4 motor. The front rotor is 7.8 - 7.7 - 7.9 bar at 237 rpm. Rear rotor is 6.8 - 6.3 - 6.6 bar at 231 rpm.

So the rear is a little down on compression and the front is fine according to the technician. Any guestimates on how far down on power I am with this low comprerssion rear rotor? Is this terminal or can I run it awhile while putting together another motor?

Steve

[wlfpkrcn]

Personally, I would drive it till it dies. If you are still learning to drive and not racing for the win, I don't think the HP loss is going to affect your lap times to much. Just my pennies worth.

E

[lateapex911]

Agreed. It's not ideal, but it will run fine.

Last summer I "blew" a motor...I was running with the other RX7 guys just fine all around the track, and even got up to their doors on the first part of the straights...but they'd ease away down the straight. I was about a second or just over a second off my normal pace.

Compression results were fine in the front...high 6s across the board..but the rear was the ugly part...3.5 5.7 and 3.7 or so. When two numbers are low it indicates a blown apex seal. When one number is low, it's a side seal.

In your case, no single number is low, and they are pretty even, but a touch low across the board.

My free opinion is that its' going to be fine and you'll not be hindered by it. Make sure you treat it well by running good oil, an oil cooler and a good radiator, to keep the temps down, and you'll be fine.