> For those of you who have or have had warmed over TR6/GT6 (although I
> suspect this question applies to 4 cyl engines as well) what compression
> ratio did you did you choose and why?
I aimed for 10.5:1, but made a mistake and wound up somewhere past 11:1 on my
street TR3A. I had to run octane improver containing MMT (the other stuff
didn't work even at ridiculous concentrations), and premium gas, but it ran
great. I'd still be running that way if the head hadn't developed other
problems.
But next time around, I'll only aim for 10:1, and hopefully get it right.
Higher compression doesn't hurt drivability or cooling at all; it actually
increases the motor's efficiency. The only hassle is the fuel issue. Took me a
lot of experimentation to find an octane improver that worked well for me, and
then they took it off the market.
Likely it would have done better though, if I had followed the instructions in
the Comp Prep manual about removing all the sharp edges in the combustion
chamber. I'll do that next time, too.
Randall
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