Factory low-compression 4.0L v8: 8.23:1

[davran]

All,

The factory RAVE manual states that there is a low compression option for the 4.0 v8 -- but not 4.6 -- of 8.23:1 instead of the "high" 9.35:1. Does anyone know how this is achieved? Heads? Pistons? Happy thoughts?

Everything diesel seems to be $10K+, which I don't have at this point. If I need to do heads anyway on my '01 D2, I'd like to know what the low-compressio option is.

Thanks,

[rezdiver]

if there is such a beast, have you looked into what effects will be to the computer, sensors, cat converters, etc. on a D2.. also will a lower compression get better milage with the use of low octane.

[davran]

According to the rave manual for the D2 this was an option for it, so I have to assume it didn't effect the ecu.

[swamijake]

That's a dangerous assumption. The computer for the low compression option could easily have a different tune with more advance on the spark curve. Any reason you would want a low compression 4.0? The regular compression version is not exactly a race engine or a torque monster. Unless you plan on consistently running low quality fuel?