Race Fuel - Worth It?

Nick1994

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Messages
12,875
Location
Phoenix, AZ
Wondering if race fuel makes much of a difference in ATVs and others. I have a 2005 Honda Rancher 350cc so it is certainly not a race machine. Might be taking it to the dunes next Spring and wondering if I should use racing fuel (~110 octane or so) for a little extra power. Or maybe just use some octane booster?
 
Messages
808
Location
NJ, USA
Race fuel won't give you any extra power unless your machine has high enough compression to require it. I'd guess your Rancher won't require it. Manual calls for 86 octane minimum if what I'm seeing is right.

Ethanol free fuel is certainly beneficial to machine like that where it might sit for periods of time between rides though.
 
Messages
1,031
Location
Arizona
Put whatever octane the engine calls for in it. It it a low compression torque motor so additional octane just dilutes the fuel more. What will help is a jet kit. there may be a few but Dynojet has been making them a long time. You will get smoother throttle and a bump in torque which is definite help in the sand. https://www.dynojet.com/jet-kit-for-2000-2006-honda-rancher-350-trx350--stage-1-q108/
Factory carb is very lean. Fattening up the mix with a kit really works well and engine runs a bit cooler as a bonus.
 
Messages
1,633
Location
South Carolina
Not all race fuels are created equal. Your ATV may act a little sluggish with Sunoco 260 GT but may be very responsive and make more power with Sunoco EXO2, despite EXO2 having a higher octane. It's a matter of the makeup of the fuel. Being a naturally aspirated engine, it'll like a more volatile fuel with a lower distillation curve / boiling point and lower specific gravity. Octane is but one small fraction of the equation.

All of that said... you could probably put the cheapest E10 87 AKI pump fuel in that thing, beat the snot out of it, and it would be none the wiser. I wouldn't worry about it. On the point above, it'll like the E10 more than E-free as far as response and power is concerned because of ethanol's low BP and high heat of vaporization.
 
Messages
15,363
Location
NE,Ohio
Go ahead and look over that list again.

Unless I want 110 octane or drive 100+ miles 1 way, we don’t have E0

edit so I checked the 2 phoenix places sell in 5gal cans for about 10$ gallon ouch.
and mesa too. well that sucks.

not sure why they are even on the list. Just because I can buy VP fuel at walmart it shouldnt be on pure gas website.

I'd probably skip 110 octane it is usually leaded.. and those engines arent high performance.
 
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Messages
896
Location
Colorado, USA
Higher octane fuel slows down the burn rate of the fuel. If the engine doesn't call for higher octane, typically your actually not going to make as much power running it versus the octane the engine calls for. We are talking a small amount but I think if you read around, you'll find that to be the case.
 
Messages
1,633
Location
South Carolina
Higher octane fuel slows down the burn rate of the fuel. If the engine doesn't call for higher octane, typically your actually not going to make as much power running it versus the octane the engine calls for. We are talking a small amount but I think if you read around, you'll find that to be the case.

That's false. The octane (itself) has nothing to do with burn rate. As a good example, Sunoco SR18 (118 octane) has a faster burn rate than 93 octane pump fuel.

Higher octane simply means a longer timeframe before auto-ignition of the end gas occurs which is not related to the flame speed.
 
Messages
10,318
Location
Jupiter, Florida
I love the 96 octane VP-C9 and run it in all sorts of toys and lawn equp. It's available locally at a pump too. I also recently tried the Sunoco Optima AND 260 GTX (non ethanol) 95 and 98 octane respectively.

In the end, the C9 seems like the best choice.

Claims that "race fuel" won't make more power are untrue, if only slightly. It's clear that everything I own prefers VP-C9 over ethanol free pump fuel. I get higher RPM in my blowers, slightly higher top speed on my Polaris ATV and better overall throttle response in everything. We even use C9 in the Stemme S-10 motorglider, which has a turbocharged 4 cylinder 115HP engine. The Glider absolutely LOVES the C9.

A quality fuel is well formulated and will provide consistent results. There really is a reason so many of us insist on quality fuels.
 
Messages
1,633
Location
South Carolina
I love the 96 octane VP-C9 and run it in all sorts of toys and lawn equp. It's available locally at a pump too. I also recently tried the Sunoco Optima AND 260 GTX (non ethanol) 95 and 98 octane respectively.

In the end, the C9 seems like the best choice.

Claims that "race fuel" won't make more power are untrue, if only slightly. It's clear that everything I own prefers VP-C9 over ethanol free pump fuel. I get higher RPM in my blowers, slightly higher top speed on my Polaris ATV and better overall throttle response in everything. We even use C9 in the Stemme S-10 motorglider, which has a turbocharged 4 cylinder 115HP engine. The Glider absolutely LOVES the C9.

A quality fuel is well formulated and will provide consistent results. There really is a reason so many of us insist on quality fuels.

VP C9 has a few great things going for it. For one, the difference between the RON and MON numbers is very small indicating it is a stable fuel in a wide range of conditions. The 90% distillation point is ~100*F lower than pump fuel with a higher 10% point so it evaporates quickly and easily in the cylinder, not in the port. The lower SpG compared to pump fuel (.722 vs ~.745) indicates more light aromatics and a faster burn rate.

The reason the 914F (glider) engine likes it so much is probably the higher initial boiling point. That means less vaporization in the intake tract allowing for more air flow and thus better efficiency.
 
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