Originally Posted by jr's3800
I run 87 Octane, I have never seen any KR on it... I have always figgured that these cars could use a bit more timming...
And aren't you the guy that used L27 pistons for a 9.1 to 1 compression rating?
And I know I am off topic, but what was the diffrence in the dish between the LN3 and L27 Pistons...
And how does the compression relate to timming advance?
Yeah, I am the guy. The vin L pistons I used measured 30 cc in the dish. The original pistons were 26cc, but were .050" shorter compression height. The new pistons are flush with the deck to about .002" above. The reason I mentioned compression was the flame front travels faster with higher pressure, somewhat offset by higher octane fuel.
Before I got with the program to increase performance, I would sometimes see 1-2 degrees of knock retard at the shift points running 87 octane and the engine stock, save for a cone intake filter. I think GM did a pretty good job optimizing the stock setup.
I saw the comment about getting to the point of too much timing, and that is possible. The conventional wisdom is to set the timing to get the best trap speed rather than the quickest e.t., it is safer. You really need to experiment with what works best with a particular combination once you start modifying. Most aftermarket chips do offer some improvement, but will usually be safe, rather than optimized for your particular combination. Ryan is a good guy to work with and I recommend him highly.