changing compression from 8:5:1 to 9:1

[AdamRPS13]

My S15 unopened SR went from stock cams 150ish-153psi to poncams 160ish-164psi
That confused me to ****

Hmm, my comp test results of 145 were before the head work, i'll re test it soon and see what it does!

[immy21]

I tested mine directly before and after the cams, so direct comparison, new poncams, new rockers and that's it.

[green_rs13]

thought I would update this with some feedback incase anyone wondered what the effects of just fitting higher comp over sized pistons was.

in the handful of times I actually drove this last year I found that it would over fuel then cough/splutter and foul the plugs if driven aggressively, seemed to be fairly ok if just cruising around with moderate acceleration/engine breaking.

I didn't have a wide band or any other logging equipment fitted at the time so am not sure what is actually going on.

putting miles on a none road legal car totally sucks.