Compression ratio
Thanks RammerJammer75, I was planning on that as well.
When I said the tune up window gets tighter as the CR goes up, I mean to say that you have less room for tuning errors. Let’s take 3 different compression ratios. 10.5:1, 12.5:1 and 14.5:1 and look at them.
At 10.5:1 you may be able to be off two heat ranges on plugs on not kill it. At 12.5:1 you may get lucky if you are off a heat range, and at 14.5:1 you will do damage right quick if you are off a heat range.
Same thing with ignition timing. You can play around with total timing and the actual curve at 10.5:1, but as you go up in CR, that “window” you have to get the timing correct starts getting smaller, and by 14.5:1 two degrees can be the difference between big horsepower and big piles of broken parts.
And so it is with most tuning aspects as CR goes up. The higher the CR, the tighter your crap has to be wired together or the consequences can be expensive.
