Hi, I just bought a WDK ROK with a 62T/701 that the previous owner says has stock internals. It has an ADA head on it (owner could not specify what size domes), when I went to buy it we did a compression test and it had 180 psi on a MAC tools compression gauge. I asked the owner if it would run on 93 octane and he said yes but when I picked it up he said he filled it with a 50/50 blend of 110 and 93. So now I'm wondering if I should run 93 or is there a way to tell what fuel to run without knowing the compression ratio?
When do you need Race gas?
- Thread starter WS6HUMMER
- Start date
You can't even tell if you do know the compression ratio, because it depends on the ignition timing and the pipe and the tuning and even how your ride it.
Still, a 62t that shows 180psi on a good compression gauge, assuming it has a reasonable ignition curve and is reasonably well tuned and isn't held wide open for long periods of time would generally be considered fine on pump premium.
Still, a 62t that shows 180psi on a good compression gauge, assuming it has a reasonable ignition curve and is reasonably well tuned and isn't held wide open for long periods of time would generally be considered fine on pump premium.
Thank you, it has stock super jet electronics, is there away to alter the spark advance?
- Location
- Wichita ks
Msd enhancer.
I would swap that stator and flywheel to a 760 style and run zeeltronics.
Thank you for the suggestion.
You want to verify timing and compression, this will give much insight on your octane requirement. A 701 can get by with its stock 21 degrees of max timing and around 170 PSI cranking pressure on super unleaded. You can still burn a piston on long full throttle runs if the carb is tuned a little hot or if the tank gets low and air gets into the fuel line. A short hull that never gets more than a few seconds of full throttle can run more compression and spark advance. A programable ignition can get better response along with cooler high RPM temps since the OEM CDI curve is flat after idle.
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
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