Fuel

[muddy450r]

Just wondering what kind of fuel yall are running. I dont race, just ride real hard! I run 100 octane race fuel through my stock power plant. How high of an octane can be used? And is anything higher worth it?

[Sjorge450R]

running the 100 now isnt helping you. It could potentially be hurting you. Pump 93 is will be fine for a stock motor. Thats what I run, no problems at all.

[XCRacer236]

i dont understand the fascination with everyone running high octane gas on a stock motor, or mixing it.

[soyo]

save your money and run pump!!! no gains from high octane!!!

[BlaineKaiser450]

race gas has no gains on a dyno but there the quad is definatly more responsive with it. I would run 112 on 12.5:1 compression but its wayyy to much money for me

[loons]

You can still run straight pump 91 and above with 12.5-1. 13-1 requires about 105 octane depending on elevation. Race gas is a waste of money if you don't need it.

[BlaineKaiser450]

Originally posted by loons
You can still run straight pump 91 and above with 12.5-1. 13-1 requires about 105 octane depending on elevation. Race gas is a waste of money if you don't need it. i know. I was saying that i personally like to run it

[gcart2]

correct me if im wrong but doesn't it run cooler?

[muddy450r]

I ride with other trx45r's and mine runs stronger starts better and is way more responsive than the other guys. So it does make a difference. On a 40 degree morning morning it fires right up and is ready to ride. Everyone else is always still sitting with the chokes on waiting till thier R is warm and ready.

[chayes627]

i run 93 octane. works just fine. it has been in the 20'2 here the past week and mine starts with one kick and 10-15 seconds later i can turn the choke off. wasting your money in my opinion.

[440ex kid]

I find it hard to believe that you are noticing THAT much of a difference between stock motors. pump gas should work just as well if not better. it aint my money though.

[smo0oth1]

People don't realize exactly what the octane rating represents. It is a measurement of its sensitivity to ignite (catch fire).

Higher octane fuels have LESS energy than lower octanes. A stock bike that only needs 91 will NOT make any more power or run better with higher octanes. You are simply wasting money. Higher grade fuel (brand names) may make you bike run better since there are stricter guidelines in production and you actually receive what you pay for. There are different ways to measure octane and cheaper companies will sway the test results and actually sell you say 91 octane that is actually only 89. This is where you will see a difference buying there 93 because it is actually 91 that your bike requires making it perform as it should.

The only reason you need to run high ocatane is to curb detonation. Higher ocatane fuels burn SLOWER than lower octanes.

There is actually allot of science into how much advertised compression you can run on 93 octane. Cam profiles, engine temp and bore and stroke all play into this. In some cases you can actually run 13+ compression on 93 safely

[pro-rider46]

Originally posted by smo0oth1
People don't realize exactly what the octane rating represents. It is a measurement of its sensitivity to ignite (catch fire).

Higher octane fuels have LESS energy than lower octanes. A stock bike that only needs 91 will NOT make any more power or run better with higher octanes. You are simply wasting money. Higher grade fuel (brand names) may make you bike run better since there are stricter guidelines in production and you actually receive what you pay for. There are different ways to measure octane and cheaper companies will sway the test results and actually sell you say 91 octane that is actually only 89. This is where you will see a difference buying there 93 because it is actually 91 that your bike requires making it perform as it should.

The only reason you need to run high ocatane is to curb detonation. Higher ocatane fuels burn SLOWER than lower octanes.

There is actually allot of science into how much advertised compression you can run on 93 octane. Cam profiles, engine temp and bore and stroke all play into this. In some cases you can actually run 13+ compression on 93 safely

EXACTLY!

[Rancher2005]

Originally posted by smo0oth1
People don't realize exactly what the octane rating represents. It is a measurement of its sensitivity to ignite (catch fire).

Higher octane fuels have LESS energy than lower octanes. A stock bike that only needs 91 will NOT make any more power or run better with higher octanes. You are simply wasting money. Higher grade fuel (brand names) may make you bike run better since there are stricter guidelines in production and you actually receive what you pay for. There are different ways to measure octane and cheaper companies will sway the test results and actually sell you say 91 octane that is actually only 89. This is where you will see a difference buying there 93 because it is actually 91 that your bike requires making it perform as it should.

The only reason you need to run high ocatane is to curb detonation. Higher ocatane fuels burn SLOWER than lower octanes.

There is actually allot of science into how much advertised compression you can run on 93 octane. Cam profiles, engine temp and bore and stroke all play into this. In some cases you can actually run 13+ compression on 93 safely

essentially, you run higher octane in high comp. so that there are not two flame fronts (combustion from compression and combustion from spark which sounds like pinging) As smooth said, high octane is more resistant to burning (requires more energy). If you don't have the compression required and are running a high octane, it will only make it more difficult for your engine to burn the fuel.

[GIXXER1KR]

Exactly if u dont need it dont burn it.Send me your wasted cash and ill buy my overpriced VP to run in my fully built race motor.I miss the $2 a gallon pump gas:eek2:

[mattonln]

that, and racing fuel is leaded, creates more buildup on your carb, internals and exhaust. and as stated above, you can actually LOSE power using higher octane fuel because it is a lower energy (takes longer to ignite) fuel than standard unleaded fuel.

[TJ Bradley]

Originally posted by smo0oth1
People don't realize exactly what the octane rating represents. It is a measurement of its sensitivity to ignite (catch fire).

Higher octane fuels have LESS energy than lower octanes. A stock bike that only needs 91 will NOT make any more power or run better with higher octanes. You are simply wasting money. Higher grade fuel (brand names) may make you bike run better since there are stricter guidelines in production and you actually receive what you pay for. There are different ways to measure octane and cheaper companies will sway the test results and actually sell you say 91 octane that is actually only 89. This is where you will see a difference buying there 93 because it is actually 91 that your bike requires making it perform as it should.

The only reason you need to run high ocatane is to curb detonation. Higher ocatane fuels burn SLOWER than lower octanes.

There is actually allot of science into how much advertised compression you can run on 93 octane. Cam profiles, engine temp and bore and stroke all play into this. In some cases you can actually run 13+ compression on 93 safely

So if your running a more aggresive cam it changes things also.? Like If you have a fully built head, bigger valve train and such and a aftermarket cam but still run a stock compression piston does it change anything even tho the compression is stock?

Just a stupid question i was curious about

[maddmatt02]

if you have a fully built head, like port work, oversize valves, and a wild cam and you keep your stock piston, youre compression is going to be even lower than before. its called dynamic compression and it takes a lot more things into consideration than when a piston manufacturer advertises the static cr.

[TJ Bradley]

O ok, i def didn't know that. Im running The HRC cam which isn't Wild by any means, But i took my JE 13.5:1 out when gas went to the sky so i could afford to ride. So by the low Comp. my motor is running now is all the Work i have done not helping me? And i should put my high comp piston back in?

[maddmatt02]

well, the way I understand it is that generally higher cr benefits the low end more than the top end, well it benefits both but it you have a lot of valve overlap, which moves the power to the top of the rpm range, then bumping the cr could help get some low end back. I am not very educated on this but ive read alot and tried to learn a thing or two.

but with your stock cr, making modifications to the head wont hurt you at all, it will still be an increase in HP. somewhere. maybe you lose a bit down low but have a bunch more on top, so you gear accordingly so that you ride in the higher R's more often. and the 13.5 will definately be an improvement, just depends on how much you wanna pay for gas.

I was reading on a 450 forum that when they were fully building there engines, the difference between a pump gas setup and a race gas setup really only differed around 2-3 peak HP, not sure about the rest of the curve. but for me, that doesnt sound worth it to spend 8 bucks a gallon when premium pump gas is only 1.89 right now. if they got gas mileage like a stock 250ex does, then sure, but those built 450's can drink it pretty fast. especially if you ride WOT all the damn time like I do...