[cheekychimp]

Hi,
I am about to start completely rebuilding a 1990 Mitsubishi Galant VR-4. It will be an extremely serious rebuild limited most likely only by funding, and addressing all aspects of the car from power through transmission and suspension etc.

Now for the purposes of this forum I want to concentrate on the engine. The VR-4 is powered by the now famous 4G63 2.0L DOHC turbocharged engine. The current plan is for a complete rebore and rebuild making this a 2.4 litre, 9:0:1 compression and mating it to a Forced Performance FP3065 turbo.

All my current research and the extremely helpful advice I have been given from people on similar forums suggests that 1.5 bar or 22-23psi is about the limit I can expect on this engine before detonation begins to raise it's ugly head.

The vehicle will be daily driven in Hong Kong where ambient air temperatures and humidity are very high for most of the year.

I am sure that 1.5 bar is going to be more than adequate given this set up and I am not looking to increase boost so much as increase efficiency and reduce the likelihood of detonation/increase reliability at what looks like the threshold of this rather high compression for a forced induction engine.

RIGHT ... TO THE QUESTION:

I have spent hours looking at water injection/water alcohol injection, propane injection, air intakes that are chilled with CO2, NOS, NOS chillers on a FMIC, water to air intercoolers where the water is chilled by a/c refrigerant.

All these systems work ... but are limiteby one factor or another. However having witnessed the effects of a combined air to air and water to air intercooler that reduced charge air to temperatures below ambient, I am now considering using some of these systems in conjunction with each other.

What I am really interested to hear from the experts is, if you are already reducing intake charge temperatures by using a cryogenic air intake, NOS or propane injection would this make WI redundant?

And, if not, would any of these systems be better suited for use together? I have already read some of the tuning issues inherent with using WI and NOS due to ignition timing, would similar issues exist with say propane or alcohol/water or pure alcohol injection.

These are complicated questions and I realise there are many factors that will affect results. What I am trying to avoid is a tuning nightmare caused by different systems creating different a/f ratios and just as importantly buying something that is not cheap only to find it is redundant if used in conjunction with another device.

A prime example here might be a water to air intercooler setup that fails to reduce the intake charge as significantly as using WI or propane injection in conjunction with a good quality FMIC.

Gentlemen if you got this far I appreciate your patience ... now please, any advice !!!

Paul.