Other copression vs race fuel

[jetpilot808]

At what compression should you be running more than pump gas?
Example: ADA has their 760 yamaha domes listed at 40cc domes for 91 octane , anything above you should have higher octane.
I see lot of people running 180-200 psi compression, are you all running high octane?
The last question, what happens when you run high compression and low octane, details anyone?

 

[Matt_E]

There is no magic line, it depends on the motor setup and even the pump. Ignition curve, squish, motor loading, bore size, and how you ride influence it.
A race boat that's WFO all the time would probably run race gas at 175 psi with a drypipe.
A surf boat might get away with pump gas over 200 psi.
Very lose rule of thumb, over 180psi you need something more than pump gas.

If you run lower octane gas than what the motor needs, there will be pre-ignition or detonation happening, especially at higher RPM's. This will destroy the pistons.

 

[jetpilot808]

Ahhh...makes more sense, thanks for the input.
Matt you need to change your avatar picture it's freeking me out!