Quote:
The distance from the piston pin the the top of the piston is the compression height. That is different between the 790 and 865 to maintain the same compression ratio. That would be MUCH cheaper to change than changing the combustion chamber on the cylinder head, in the long run.
I have a question. What is a "safe" static compression ratio to run on crap fuel, like 87 octane? Also, would would the "recommended" minimum octane be for these new TTP pistons?
depending on where you live and what is available for fuel, this could be a big deal.
having run 12:1's for some time now. i would have to say that 97 octane for regular gas is the minimum for no knocking. I got to this number from playing around with Sunoco 115 octane from a near by track and blending it with lower octane gas. Fun but not a reliable fuel source.
a couple years ago I converted to run on 93 octane E10. that seems to burn slower run the best for pump gas.
05 speedmaster - 1100cc, 11:1 racing pistons, Carillo rods, thunderbike cams, ported and polished head, 2mm over intake and exhaust valves, Barnett kevlar clutch, scepter pipes, oversize manifolds, 45mm HSR's, TTP stage 4 firestarter
| 
