compression & detenation

[weiner]

have a big bore and at 2700 feet was told to mix 50/50 race yet the compression is not high only 135psi i thought any over 140 you started to worry about race fuel

 

[Modman]

have a big bore and at 2700 feet was told to mix 50/50 race yet the compression is not high only 135psi i thought any over 140 you started to worry about race fuel

Maybe check your squish and determine the correct compression ratio. You will need to CC the domes as well. This is the proper way to do it. Compression gauges just aren't accurate enough IMO. Good indicator, but if you are running an 1150 big bore, I would not cheap out on the fuel when running down low, motor is worth too much to risk it IMO.

Talk to the guys at Mountain Magic, they have built a couple 1150's and will probably know what the compression should be.

I do know at anything above 185 PSI you need to run 100% methanol.....and band your motor. :d

 

[DRD]

Port timing, squish etc. Can all have an affect. Cranking compression is just part of the picture.