Super Jet WHAT Octane!?

What octane to run!?

  • 91 Octane (Premium Pump Local)

    Votes: 4 21.1%
  • 92 Octane

    Votes: 0 0.0%
  • 93 Octane

    Votes: 9 47.4%
  • 94 Octane

    Votes: 1 5.3%
  • 95 Octane

    Votes: 2 10.5%
  • 96 Octane

    Votes: 0 0.0%
  • 97 Octane

    Votes: 0 0.0%
  • 98 Octane

    Votes: 0 0.0%
  • 99 Octane

    Votes: 0 0.0%
  • 100 Octane

    Votes: 3 15.8%

  • Total voters
    19
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
 
Last edited:

tor*p*do

Squarenose FTW
Site Supporter
Location
NW NC
Probably get by with 91 running 35s. What is your compression?
And make sure it is ethanol free!
 

OCD Solutions

Original, Clean and Dependable Solutions
Site Supporter
Vendor Account
Location
Rentz, GA
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

Squarenose FTW
Site Supporter
Location
NW NC
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

Buy a Superjet
Location
California
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.
 
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.
 
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
 
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

Formerly Motoman25
Location
Long Island
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

James
Site Supporter
Location
Long Island
@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.
 
@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
 
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