Vortex ROK GP - fuel requirements


(Jason Bedford) #1

Hi there -

New to the ROK, and want to ensure that I am running the right fuel so I don’t damage the motor.

At my track (in Canada), they run Sunoco Race Fuel - Standard 100 octaine leaded fuel. I guess this keeps things consistent amongst the racers. In the US, I beleive the ROK class uses Sunoco Race Fuel - Supreme - which I beleive is 112 octaine leaded fuel. Not sure if there are any other differences.

If I am just doing some training / lapping sessions, do I need to run the race fuel, or can I use pump gas? In Canada I can get Ultra94 - which is 94 octaine unleaded pump fuel. If I mix this to the correct ratio, will this hurt the motor? The track indicated it would cause detonation and damage the motor.

I have read to stay away from any fuel containing ethanol to avoid drying out the seals and to do away with the water/moisture content.

Does anyone have any opinion about pump vs race fuel for fun lapping sessions? The last thing I want to do it damage the motor during practice sessions.

Thanks for your opinions.


(James McMahon) #2

The actual octane of the pump fuel would be OK. The 110 race fuel is more octane than it needs, but it won’t hurt it and it gives everyone a bit of a buffer against detonation.

Two considerations for running race fuel.

  1. Internals of two stoke engine love, love, love lead.
  2. Consistency between batches: That’s actually the biggest difference between pump fuel and “race” fuel. Many race fuels are a lower octane than some pump offferings.

To answer your question, I suspect pump fuel would be “OK” for practice, keep things on the conservative side of course.


(Spencer Uzri) #3

Buy ethanol free branded gas, if available. Water binds to ethanol, so a trick to separate it from fuel is to add some water into a container of gas, & the water-bound component, being heavier than free gas, will sink to the bottom of the container.

Easiest way to do this would be to use a gas container with a drain tube, & preferrably with a petcock valve. Add in some water to the fuel in the container, then set it inverted for a day. The water will bind the ETOH & will be sitting below the free gas. While keeping the can inverted, carefully drain away the offending ethanol. A translucent container will makes it easier to see where to stop draining.


(Jason Bedford) #4

Thanks - ethanol free for sure, but I think I will purchase the race fuel for now while I am still learning things to give me some additional piece of mind.

I appreciate the feedback!