So I had my car running pretty well with the stock turbo on a 2.3 litre until the stock turbo busted an oil seal and started pumping oil into my IC and engine

Now I've got a 35r and I can't get my knock sums to be as clean as they were on the stock turbo.

And another weird thing is that with the bigger turbo my load levels are closer to being accurate than with the stocker. Example - now I'm in the 260 load column at 20 psi where before I would have been in the 280.

So anyway I wanted to see if anyone on a stroker can post some evoscan logs or is willing to compare roms with me.

Thanks-

 

I have no experience of bigger engines or turbos on the Evo, but do on other cars, and have a general understanding, especially of tuning MAF based ECUs to run big power so I'll offer my 2c...

You may need a lot less timing on a big turbo because of the higher charge density which usually more than offsets the drop in EGBP since you end up running higher boost. Your knock sums are calibrated for stock engine and loads, so they may not apply to forged pistons or much higher engine outputs, especially if motor mounts and clutches are changed etc.

Changes to the inlet which are inevitable on a bigger turbo are likely to make the MAF read differently, so airflow or load readings are not comparable between setups.

Higher VE at higher revs at sensible boost on the 35R will keep the load readings closer to the boost level all other things being equal (which of course they are not as above).

 

Hmm I guess with my twin disk clutch, stiffer front motor mount and forged internals the stock ECU's knock filters probably aren't accurate? But I could still get low knock with the smaller turbo with everything else in the setup being the same.

Maybe my IC isn't doing a good enough job with the increased airflow? Then again my charge temps are pretty good.

I guess I could make some det cans and check for audible knock to see if what the ECU is picking up is real knock.