polarismaster

I just picked up a GRP tuned .28 (promo pack) and was wondering which restrictor(came with the 6mm install) and how many head shims should I install? I will be running 30% nitrotane.
Thanx

Jaz240

iTrader: (52)

What size is the shim that's in it now? Most engines come shimmed for 20-25%, so if that's the case with yours you should try 1 1mm shim.

strngdze

iTrader: (16)

They come stock with (1) .3mm aluminum and (1) .1mm copper already installed. I installed one more .1mm copper shim for a total of .5mm to run 30%. I believe Drake had said on another forum that he runs them stock, which would be .4mm with 30%.
Running 20% or 25% you should be fine with the stock set up (.4mm).
I bought the promo kit before they started putting in extra restrictors. I run the stock which is 8mm I believe. Runtime doesn't seem to be an issue with this .28
Hope this helps.

polarismaster

Thanks for the help. I installed one extra copper shim and put the 7mm restrictor in. Will start break in tonight.