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What race fuel?

CIE

CIE

New member
Joined
Aug 20, 2008
Location
Danville, CA
Moto(s)
'08 GSX-R 600, '75 RD 350, '01 CR250r
Name
Evan
Hey guys....

I've got a '02 GSX-R that was built to Super Sport specs. What race fuel should I be running. I'm not so much looking for specific brands as I am octane, leaded or unleaded. Bike obviously has no cat, no 02 sensor.

I'm currently running 110 leaded because I've got it around for a race car and the previous owner recomended it, but I'm not sure what is right for a bike in this state of tune. I'd like to run my bike on the dyno and re-tune the power commander, but would like to figure out what fuel I should be running first.

Thanks.
 
The guy that did my tune showed negligible performance gains between race and super unleaded. This is with no internal engine work.

I would think only bumped up compression would warrant the high octane race fuel, but I'm no motor builder :D
 
but I'm not sure what is right for a bike in this state of tune.
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You didn't state its state of tune. Milled head or thin head gasket for higher compression?

If you don't have a high-compression engine the only reason to run race fuel may be to enjoy its extra oxygen content. Some race fuels are oxygenated; some aren't. The ones that are cost more money.

Grocery-getters like gixxers generally make less power with high-octane leaded race fuel like the 110 you are using. It burns too slowly.
 
Hmmm, I ask because I was told to run race fuel only by the previous owner who was told by the owner before him who had the bike built by Arclight. The motor has been apart, but I'm not sure what you are or aren't allowed to do inside. I bought the bike as a track bike and had little intent to race it so I wasn't too concerned what class it would run. As far as I know it ran AMA when it was new, then AFM supersport. If the internals were semi-stock in terms of the bottom end then the only reason I could see to run race gas would be because of advanced ignition timing or a slightly thinner head gasket. Neither of which would warrant 110 octane, or leaded. When I bought the bike I'm pretty sure it had leaded fuel in it because of the white around the tail pipe and the smell of the fuel.

I guess I'm really just asking what the guys in super sport run in their bikes. Aren't there some engine mods allowed? (degree'd cam's, thinner headgaskets, reworked ports). Or am I just wrong?

Trust me.... If I can run regular old premium through it without a problem I would be completely happy....
 
You might get away with 97-100 octane which is a lot cheaper and can even be bought at a few service stations.Or less.
 
hmmm.... as far as I know, it was raced in formula USA, too. Not sure if engine rules are more lenient there.

So far the only real answer I think I can get is that the engine needs to be torn down to find out what's inside.

The last owner asked Chuck from Arclight a few questions to which he wasn't very forthcoming. I've been trying to find his contact info, but have come up empty. Anyone have a link to a website?
 
afm199 said:
You might get away with 97-100 octane which is a lot cheaper and can even be bought at a few service stations.Or less.
Click to expand...

Ernie is right, there are a few 76 gas stations up here(Sacramento) who sell the stuff.


It would be of major benefit to find out what has been done to your motor internally as mentioned before in the previous posts. Compression, ect..if you can get dyno time then bring 3 jugs of fuel with you...when you get it tuned with a PC.
 
The more I look into it, the more I'm realizing I need to get this bike on the dyno ASAP. Right now the fuel I'm running is ERC 110k. It's the same stuff we get from Morgan's machine shop and run in all the hot rod cars and race cars. ERC's website isn't too specific, but does mention that it's oxygenated. Tim Morgan has told me that the fuel can be blended with pump gas and he recomended running a top end oil like Marvel Mystery oil or a bit of two stroke oil to give it some lubricating properties.

The biggest concern I have isn't the horsepower the bike is making (since it's only a track day bike for now), but rather if the oxygenated fuel is making it run lean or not.

From what I'm reading 110 octane is likely overkill unless the bike has 12.5-13:1 compression (which I doubt, but who knows, right??). My bet with the motor is more along the lines of a thinner head gasket, cams and reworked ports. Even that may be an over estimation. Unfortunately I'm not going to be able to get it on the dyno before I go to the track this weekend. So far I've run 1 day on the bike with the 110k without any problems. That said, the stuff is super expensive (around $12/gallon). I'm thinking about blending it with 92 octane pump gas to get +/- 100 octane.

Am I being stupid here or would any one care to speculate whether this is a good idea or not. I'd love to stay with the ERC once I tune the motor because it's easy for me to get, but I'd love to tune it for a blend of ERC and pump gas.

Thoughts?

Thanks guys.... I know I'm asking noob questions, but when it comes to this stuff I'm a total noob. I'm learning as I go here. I probably should have bought a bike with a more documented history, but ........ I'm pretty attached to this ride and I know I can get it squared away relatively easily.
 
Blend that stuff, I'll bet you a beer you make more power.
 
I'll take that bet.... We both win either way right. I win, you buy me a beer. You win, I buy you a beer. Either way we're drinking. Ha, ha, ha :teeth

I guess if I blend it and burn up the motor I'll get the chance to take it apart and find out what's inside.
 
CIE said:
I'll take that bet.... We both win either way right. I win, you buy me a beer. You win, I buy you a beer. Either way we're drinking. Ha, ha, ha :teeth

I guess if I blend it and burn up the motor I'll get the chance to take it apart and find out what's inside.
Click to expand...

I think the chances of you burning the motor up are slim to none. you can slowly mix in the blended fuel with what you have in the tank...see how it runs, mix in a bit more, run it again until all the 100% 110 is completely gone and you are running 100% 92/110 blend. Just listen to it when you are running it, if you hear pinging, knocks...back out of the throttle and jump out of your session and go back to what you were using before.
 
I started out my built motor on 100 and have blended my way to 96 without any detonation or problems. More to go.
 
schweet.... I mixed up some 110/92 blend last night. I filled the tank the rest of the way with the blend. So the first tank should be 106-ish. The subsequent tanks should be 102-ish. If it works well this weekend I'll blend it down a bit further. I'm definitely cool with spending less than $12/gallon. $6 sounds like a bargain.
 
I had an '02 Arclight 600, and was told it was mapped for U4, but would run fine on pump (supreme). I ran it on pump and never had any problems with it.
 
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