Has anyone installed regular pistons into a s/c 4.0l engine? This would boost the compression from 8.9:1 to 10.75:1. My stock XJR runs fine on 87 octane gas. If I did this modification to the extra s/c engine I have, would it make a lot more power and run ok on 93 octane?


I thought a saw a thread on here where someone put the supercharger onto a n/a 4.0l, but I searched and didn't find it.

 

If not ok with 93, then use race fuel or E85

 

The engine would probably run fine but the knock sensors would reduce power to keep the engine from destroying itself.

You will likely get more power by increasing boost than increasing compression.

bob gauff

 

Does anyone recall the thread where someone put the supercharger and intercoolers etc. on a N/A engine? The thread had pictures. I don't remember if it was and XJ8 or XK8.

 

I think that was a XK8. I remember reading about it a few years ago.