[Roger G.]

1993' Mitsubishi 3000GT TwinTurbo

1.0 bar boost
8.00:1
2997 ccm
twin intercooled
fuel injected
timing not known for sure

1.14 bar with WIS and same amount of knock

The problem on the V6 is knock. Some engines don't knock at all others start at 0.85 bars. We haven't really found out what the differences are. Fact is that at 1 bar the IDC is 100% due to the overrich mixture the engine needs. Leaning it out results in knock. Here in Switzerland we have 95 and 98 ROZ octane gas. This is somewhat similar to 91 and 93 or so octane. Not sure about this.

My car is equipped with a MAF replacement where the restrictive Mitsu MAS is removed. A fuel controller tweakes the airflow signal for the 720cc injectors (360cc is stock). Therefore the timing is probably too much advanced under full load causing the unwanted knocking.

WIS helped to lower down the high inbtake temperatures but I haven't been successful yet in knock control. In some other threads I will report my progress to this goal. Interestingly I saw huge knock on the AWD dyno but almost noe on the roads when testing. This tells me that the IC were not able to work properly on the poorly air cooled dyno.

Today the car has two 20g sized turbos and heavily ported (I call them overported) heads installed. Discharge temperature is lower due to the higher efficiency islands the compressor works on. With this I see beter intake temperatures and can concentrate WIS for knock control.