Super Jet WHAT Octane!?

[Parsonsjb88]

I seem to be getting very mixed suggestions on what octane to run in my Superjet. Please vote and help me decide!

Here's my setup:
- 735cc Ported 61x cylinder, ported 62T case
- Speedwerx High Comp Head with 35 cc Domes (the domes have a pretty wide squish band ~17mm and my squish is set to 0.04" at the cylinder wall to 0.045" at the end of the band)
- 195psi compression
- MSD Enhancer set to max RPM limit
- Factory B-Pipe (ported and polished inside)
- TNT Waterbox
- Dual 44 carbs
- V force reeds
- Lightweight flywheel and couplers

 

[Roseand]

93.

 

[tor*p*do]

Probably get by with 91 running 35s. What is your compression?
And make sure it is ethanol free!

 

[Parsonsjb88]

Probably get by with 91 running 35s. What is your compression?
And make sure it is ethanol free!

Sorry I forgot to write that in. 195psi both cylinders.

 

[OCD Solutions]

I voted 91 (premium pump gas) but around here the pumps say 93. I have the same setup as you in one of my skis and it runs on pump gas.

 

[tor*p*do]

At 195 psi, I would stick to 93, maybe even rich it up with a dab of race fuel.
rule of thumb is 185 psi = 93 octane

 

[Quinc]

For blipping around doing freestyle 91 is fine. If you are holding it wide open and racing I would run 91/100ll 60/40 mix.

 

[Parsonsjb88]

Thanks for all the responses guys. Think I'm gonna aim for 93 octane. I like being on the safe side especially considering I'll have noob friends riding it that may ride it WOT for who knows how long lol.

 

[Lumpy]

Not long. They'll fall over right after they stand up.

 

[codyadams209]

What does everyone recommend for my setup in my hurricane, 760 with blowsion head just checked it 180psi each cylinder, b pipe, msd enhancer, light flywheel

 

[Quinc]

What does everyone recommend for my setup in my hurricane, 760 with blowsion head just checked it 180psi each cylinder, b pipe, msd enhancer, light flywheel

Even with WOT runs 91 will be enough.

 

[codyadams209]

Even with WOT runs 91 will be enough.

Ok thank you for the quick response

 

[Quinc]

Ok thank you for the quick response

Us Cali folk have to stick together!

 

[SXIPro]

I'm at 205 and run 93 all day long.

 

[All stock 701]

I'm at 205 and run 93 all day long.

I hope mostly low RPMs

 

[SXIPro]

I hope mostly low RPMs

I'm grabbing the throttle the whole time but for short bursts. I only go WOT for 45 seconds tops.

 

[Vortex]

I run 100 with some lead added at 210 psi and I do a lot of holding wide open. Actual octane is around 105

93 should be OK at least than 200 psi. Mix in race gas for hard riding days

 

[BruceSki]

All you scaredy cats. 33cc domes on stock porting 82mm bore 61x cylinder. Wide open all over the place for long periods of time.

If you jet it right and quench the heat at high rpm, 93 octane works just fine.

 

[eastcoastjumper]

@BruceSki some people don't know how to make an engine run like some of us do.

Just because you have 93 doesn't mean you will never seize a piston. Gotta have it jetted spot on and have the heat under control. It ain't all about octane.

 

[Vortex]

@BruceSki some people don't know how to make an engine run like some of us do.

Just because you have 93 doesn't mean you will never seize a piston. Gotta have it jetted spot on and have the heat under control. It ain't all about octane.

Yeah I'm still running single cooling on a ported case and cyl so I give it the good chit