Anyone run race fuel in their bike?

3439 Views 42 Replies 9 Participants Last post by 2FURYUS, Feb 18, 2005

GSXR1000DJ

Discussion Starter · Feb 15, 2005

I know Gas Man will have a lot to say about this one. I have used it before a few times and didn't really see a big difference.

Does anyone use it on the strip or on the track on track days?? Or just on the street?

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· #6 · Feb 16, 2005 (Edited)

Race gas is a waste of money unless ....

A) You have a motor with increased compression over stock. This will require race gas because you need the higher octane so as not to detonate the hell out of your motor. Or if you're trying to find no-mans land on ignition timing advance - octane will help here, depending on how far you go.

or ...

B) You're buying oxygenated race gas and are mapped/jetted for it. You can buy race gas with anywhere from 2.5% to 10% oxygen in it. On the dyno, you remap/jet for this - more fuel (richer map/jetting) + more air (in the fuel) = more power. Of course, oxy race gas *starts* at about $10 a gallon (and goes up from there).

If you have a stock street bike, you can actually lose HP running race gas as the higher octane and burn characteristics (mainly the speed) are not right for the motor. If you run oxy fuel without remapping, you can be way too lean and burn up your pistons. Also, most race gas is leaded - if your bike has a cat converter on it, you will burn it up.

Put in what your manual tells you to!

- Brian Roach
- SpeedWerks.com

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· #8 · Feb 16, 2005

GSXR750DJ said:
Thanks for the info Brian. :cheers:

Trust me ... I *wish* I could run pump gas in my TZ250 GP bike. It's a '96 motor which has leaded heads and ignition, and on top of that the current setup has compression where I need at least 105 octane. As a powermist dealer, I'm paying $7 a gallon for T111 race gas .... :sob:

- Roach

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· #21 · Feb 17, 2005 (Edited)

2FURYUS said:
Are you guys getting 100 octane at a gas station? I don't know of anywhere in Southern Cali you can get over 91 octane.

Sunoco out here on the east coast sells 100 octane unleaded at stations near race tracks and drag strips. It's actually really convenient and cheaper (compared to specialty race gas) if you've got a motor with a decked head or thin gaskets and just need a bit more octane. We always take an empty 10 or 20 gal drum with us if we're going to a track that has one nearby - we use it in the shop for dyno tuning race motors.

But again ... putting it in a stock motor ... does nothing. If you want to burn $20 bills, I'd be happy to take them off your hands instead

- Brian Roach
- SpeedWerks.com

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· #22 · Feb 17, 2005

bulldog said:
so gas man i should get the cheap gas???? or the primium gas?????? (button 1 2 or 3)

The SV only has a 11.5 to 1 compression ratio stock. I don't have a manual in front of me, but I would guess it recommends 89 octane (though it could be 87 ... it's close).

- Brian Roach
- SpeedWerks.com

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· #25 · Feb 17, 2005

GsxrJack said:
i think your talking about avgas (sp) at the airport, and i beleive it has a lot more additives in it than regular gas station pump gas or even leaded race gas...i would stay away from it even if your bike needs 100+ octane gas.....

AV gas is 100LL - 100 octane "light lead" ... used for small prop planes.

- Roach

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· #27 · Feb 17, 2005

GsxrJack said:
i always thought it had different additives in it than pump gas for cars...things to prevent it from freezing at altitude etc...gas will gum up at -40f or so..(we test jeta and JP5 at those temps and have to be carefull) and i was also told that avgas could harm seals etc on a car engine, though this is going back a few years or so....

course it all could have been bullcrap, to prevent us from using it in our cars too :wink:

That ... I don't know. The only reason I know it's 100LL is because in '99 we went to CMP (Carolina Motorsports Park) when it first opened ... and they didn't have their fuel pumps up and running yet. Silly us ... didn't bring any race gas. After finding nothing else, I drove to the little airport in Kershaw, SC and bought 15 gals of AVgas for us to use for the weekend ... worked like a champ

At the time I was running a FZR400 superbike and a TZ125 GP bike ... both needed the octane. And actually, a lot of 125GP bikes used to be tuned for AVgas due to the availability of it and lower cost (vs. real race gas).

One thing about racing ... you end up in the most bizarre situations on a regular basis

- Roach

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· #33 · Feb 17, 2005

2FURYUS said:
Brian, you say you used it with no negative effects?

Didn't seem to be a problem. Like I said - 125GP used to be tuned on AV gas in the '80s and early '90s ... and while they're two-strokes, they still have seals and everything else (just no valves). My 400 didn't seem to mind at all, and lived a long life well beyond '99.

Condisering a Cesna engine is still an engine ... I can't see why it would be any different. Of course, I know *nothing* about aircraft, or their motors ... so this may just be ignorance on my part. I don't believe small prop craft that would use AV gas are pressurized or fly high enough that fuel freezing would be a problem? Gasoline tends to have a fairly low freeze point anyway (provided there's no water in it).

- Roach

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