Originally Posted by Ventmaster
I didn't realize you were running a plenum spacer (and IM insulator too, correct?).
I'll be interested in the results of your next tank of gas as well.
Have you already done a "with&without" comparison on the IM insulator?
I've been holding off on re-installing my Ice-o-lator and would love to see some hard data on that...
I had both on when I made my best pass of 13.4 @ 106.9 but I still had 4 degrees of knock retard. I'm going to see if the plenum spacer increases or decreases the knock retard now when I get the new tank of gas.
For the IM spacer, I have it RTV'd to the cylinder head, can't really take it off. I know I don't have any boost leaks though from that area. I feel like it makes a difference when its climbing to boost range, the IM spacer best gains were at 3000, right when the boost starts building up for the supercharger. Up top where the supercharger is strong it didn't do anything.
My knock retard before this tank of gas would get worse as the boost built up, from 1 to 2 to 4 degrees at redline. If the plenum spacer isn't causing the knock retard, I'm going to go to Denso ITV24 plugs, 2 steps colder than the stock plugs. Currently I'm running Denso ITV22 plugs, 1 step colder. Both the ITV22 and ITV24 are gapped @ 0.032" stock, so no modification required.