dumb question on max compression ratio
 

Good evening Pelican

What is the highest CR on a single plug with pump gas?


Thank you


David

It Depends...
 

Fuel octane ratings vary. here in kalifoania, 92 is about it and that is with alcohol. We cannot buy "pure" gas unless we swear a blood oath, in writing, that such criminal fuel will NEVER be used on the highway.

did someone get bought off on that one???

To a lesser extent, it depends on the cam duration, overlap and the ability of the engine to go over 100% volumetric efficiency, (dynamic compression).

Still pissed off,
chris

10:1

10.5:1 with carbs and, most importantly, S + cams. The overlap reduces the dynamic compression. Single plug.
In MI, you may be able to get away with milder cams. My euro 3.0 has SC equivalent cams stock and 9.8:1 stock, pump gas, single plug.

I'm still on the fence weather I want carbs or ITB. I have absolutely no idea about what Cams I want other than I have no intention on racing so nothing too aggressive.

Thanks

David

Well tuned carbs vs well tuned ITB / EFI:

https://www.youtube.com/watch?v=aj-Z33MO2Gk

Quite interesting.