.....Fuel Help....

hi everyone,

i know that there is a lot of topics on race fuel, but .....

basically I've been have given 40 gallons of 104 octane race fuel. I need to know if its perfectly safe to run in my 2013 kxf250. no engine mods except a high comp piston. ive been told that over a short period of time it will blow a hole in the top of my piston !!! ( obviously i don't want that to happen. ) is it safe to run mixed or would i be better of selling it to someone who really needs it. if its safe to run then i will run it mixed with pump gas but i dont want to have to rebuild my motor every month.

cheers guys.

hi everyone, i know that there is a lot of topics on race fuel, but ..... basically I've been have given 40 gallons of 104 octane race fuel. I need to know if its perfectly safe to run in my 2013 kxf250. no engine mods except a high comp piston. ive been told that over a short period of time it will blow a hole in the top of my piston !!! ( obviously i don't want that to happen. ) is it safe to run mixed or would i be better of selling it to someone who really needs it. if its safe to run then i will run it mixed with pump gas but i dont want to have to rebuild my motor every month. cheers guys.

 

I think you'd be fine running it. Race gas requires higher compression for all octane to be used, which is why most dirtbike engines don't truly "go faster" from race gas alone. My 125 seems to like it, doesn't make it any faster, but the throttle response is a lot better especially off the bottom which helps. The only thing you have to worry about (heres where you don't quote  me I could be wrong) is that it can combust to early. Its called pre-something I believe. If you were seriously worried about that though, just cut it with the highest octane pump gas you have and you should be just fine. If you really want to get rid of it, ship it over to my house!

hi everyone, i know that there is a lot of topics on race fuel, but ..... basically I've been have given 40 gallons of 104 octane race fuel. I need to know if its perfectly safe to run in my 2013 kxf250. no engine mods except a high comp piston. ive been told that over a short period of time it will blow a hole in the top of my piston !!! ( obviously i don't want that to happen. ) is it safe to run mixed or would i be better of selling it to someone who really needs it. if its safe to run then i will run it mixed with pump gas but i dont want to have to rebuild my motor every month. cheers guys.

 

I have no answers, I ride a smoker in the woods with 93 octane fuel.. but if you ever come to Texas, share the wealth of them 40 gallons!!

Is it oyxegenated? If so, you'll need to remap for it. If not, you can run it but realize you will loose power. All this (and more) has been covered in all the 100's of similar fuel threads.

 

And no, it will not hole your piston,. You bike just may run real poorly.

Is it oyxegenated? If so, you'll need to remap for it. If not, you can run it but realize you will loose power. All this (and more) has been covered in all the 100's of similar fuel threads.

 

And no, it will not hole your piston,. You bike just may run real poorly.

William - Do you think it would be a good idea to have a FUEL sticky?  It could be a good place to dispel some urban myths and mis-conceptions as well as inform. 

How will 104 on a high comp run poorly? High comp high octane ......or detonated

William - Do you think it would be a good idea to have a FUEL sticky?  It could be a good place to dispel some urban myths and mis-conceptions as well as inform. 

Yes but... no one reads the stickies! Just like no one really searches. Everyone thinks their situation is completely unique. The fuel 'issue' comes up every week or so. The 'I let my bike sit for six months and now it will not idle' is a daily occurence.

 

I mege five or six threads near identical every day. I move ten to twenty that are posted in the wrong areas. Times six or so years and 365 days.

 

What can you do. :rolleyes:

Yes but... no one reads the stickies! Just like no one really searches. Everyone thinks their situation is completely unique. The fuel 'issue' comes up every week or so. The 'I let my bike sit for six months and now it will not idle' is a daily occurence.

 

I mege five or six threads near identical every day. I move ten to twenty that are posted in the wrong areas. Times six or so years and 365 days.

 

What can you do. :rolleyes:

At least you make good money for all that work.

At least you make good money for all that work.

ROFL... yeah...  I am rolling in it.. or at least, rolling in something green and sticky!

40 gallons?  id try and sell some if i was you.  

I think you'd be fine running it. Race gas requires higher compression for all octane to be used, which is why most dirtbike engines don't truly "go faster" from race gas alone. My 125 seems to like it, doesn't make it any faster, but the throttle response is a lot better especially off the bottom which helps. The only thing you have to worry about (heres where you don't quote me I could be wrong) is that it can combust to early. Its called pre-something I believe. If you were seriously worried about that though, just cut it with the highest octane pump gas you have and you should be just fine. If you really want to get rid of it, ship it over to my house!

Pre Detonation. But that shouldn't be a problem if he has a high comp piston.

Either cut it down with pump gas or remap.

Yes you should sell....to me.

Some really wrong answers.....as usual here. Race fuel will NOT cause pre ignition. It will not harm the motor. It will not slow the bike down. You do not have to re-map it. You can cut it 50/50 with pump gas for an octane rating of around 97/98. After you add the first tank of fuel to the bike, fire he bike up, and let it run for a couple of minutes. That way the bike will climatize itself to the new fuel. Use that fuel up, and have fun with it!

Yea, I am wondering why the higher octane fuel would slow the bike down or take power away? I agree that with a lower compression piston, it might not be necessary to run high octane fuel.

My experience of running 100 octane fuel was the improved throttle response and slightly less of a tendency to bog down at lower RPMs.

The theory of the octane thing is this, or so I've been told. The lower octane rating gas does NOT burn as fast as a higher octane rated gas. But burning a "slower burning fuel" increases power per say. As the piston is tdc and fires, the burn rate is slower and burns longer through the power stroke. Higher octane burns at a faster rate than lower octane. Higher octane would need to be used in higher comp motors due to the compression. I believe higher octane fuel is less dense than lower octane. It also burns cooler. It also has a more complete burn.

Look at water/meth injection kits for race car setups. Obviously water doesn't burn. Why would you inject water into the cylinder? Cooler, more compression. You can't compress water per volume so it increases the cylinder pressure. That also creates heat as does lower octane fuel.

Talking to a race fuel guy a few years back, usually he preferred his own mix over vp or cam 2. It was a mix of fuels and alcohol but these guys were running big motor dragsters. I don't think they were running nitromethane, but don't remember. I always run the high octane when available.

I've got a turbo sled. With the remap and tune, the race company REQUIRED high octane gas. Eg.... Another guy with a similair setup ran on the highest boost setting for his map and melted down the center cylinder. Why? Because he couldn't get the higher octane gas where they were riding and melted down on a 5 mi frozen lake blast.

Fuel is dependent on what build and what you are riding.

There used to be a guy JETFUEL on here that is pretty knowledgeable with fuel. Maybe he'll school us all once again

Anyone know for fact any different?This is a common argument at the pump.

I always looked at fuel like explosives. A really fast burning explosive is good for shattering rock and cutting and such. A slower burning explosive is for heaving and moving material. More of a working explosive.

The theory of the octane thing is this, or so I've been told. The lower octane rating gas does NOT burn as fast as a higher octane rated gas. But burning a "slower burning fuel" increases power per say. As the piston is tdc and fires, the burn rate is slower and burns longer through the power stroke. Higher octane burns at a faster rate than lower octane. Higher octane would need to be used in higher comp motors due to the compression. I believe higher octane fuel is less dense than lower octane. It also burns cooler. It also has a more complete burn.

Look at water/meth injection kits for race car setups. Obviously water doesn't burn. Why would you inject water into the cylinder? Cooler, more compression. You can't compress water per volume so it increases the cylinder pressure. That also creates heat as does lower octane fuel.

Talking to a race fuel guy a few years back, usually he preferred his own mix over vp or cam 2. It was a mix of fuels and alcohol but these guys were running big motor dragsters. I don't think they were running nitromethane, but don't remember. I always run the high octane when available.

I've got a turbo sled. With the remap and tune, the race company REQUIRED high octane gas. Eg.... Another guy with a similair setup ran on the highest boost setting for his map and melted down the center cylinder. Why? Because he couldn't get the higher octane gas where they were riding and melted down on a 5 mi frozen lake blast.

Fuel is dependent on what build and what you are riding.

There used to be a guy JETFUEL on here that is pretty knowledgeable with fuel. Maybe he'll school us all once again

Anyone know for fact any different?This is a common argument at the pump.

I always looked at fuel like explosives. A really fast burning explosive is good for shattering rock and cutting and such. A slower burning explosive is for heaving and moving material. More of a working explosive.

You have it backwards. Lower octane burns faster. Higher octane is used in high compression motors to slow the flame front across the piston to resist detonation/pre ignition. Yes, higher octane runs cooler and using it when not required does lower HP slightly. Using it when not needed is wasting your money though it will give peace of mind when quality of the fuel is unknown. Heat makes HP but theres a fine line between making HP and burning a hole through the piston. Octane is just a scale to resist detonation/pre ignition, nothing more. As far as the water injection. Injecting a mist of water into the combustion chamber will help suppress detonation, allowing higher compression, more spark advance, or both to be used without damaging the engine. This is used for the most part on forced injection motors to lower temps from the water vapor absorbing some of the heat to be expelled through the exhaust port. Race fuels can be expensive. You can raise octane by blending acetone(103),xylene(116.5) or toluene(114) at the proper levels. I've blended fuels for drag racing car and sleds for over 25 years. I wont' post the mixing rates because every application is different but a little searching will yield the rates that fit your needs. Warning, you will not past the fuel tech in sanctioned racing if they test.

Edited by Rotax

I use to do a 50/50 mix of race gas and Super Unleaded at 32:1. Note though I have an FMF Gold Series Fatty with a Shorty Silencer and this was FMF's recommendation to get the best performance out of their pipe set up.

 

I would say you could do a 50/50 mix at 32:1 mix and give it a try. You need more oil due to higher octane to protect piston ring and ensure there is enough oil getting to crank bearings.

 

I don't run this anymore due to nobody carries race gas anywhere near by me. I now just run Super Unleaded with Motul 800 at a 40:1 mix ratio. I got better performance when I was at 50/50 and 32:1 thou.

Edited by TheDank

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