Gas Octane

[bansheelover]

right now i run just regular gas out of our farm tank, would i see a big difference switching to like premium/supreme like 91 or 93 octane?? im running stock cylinders and heads.

[ledofthezep]

I usually run 91 cause that's pretty much all we can get. I used to run 92 oct, but the station closed....I've never had any issues. If you up your compression a lot you'll need to run the higher octane, but if you're still stock you'll be fine with 91. I've got my head milled .030 & have 150lbs compression & still run 91 w/out any problems. Hope this helps...

[bansheelover]

ya it does, thanks

i was just wondering if i went from regular to premium if i would see a difference or not

Thanks

 

Matt

[2004LEBanshee]

If I am not mistaken I think that you are only supposed to run premium at least thats what the sticker next to the gas cap on my bike says. But if there like cars run the lowest you can with out preformance loss or knocking.

[bansheelover]

no i havent had any problems yet. I think this summer im gonna switch to premium and see if that gives me better combustion of the fuel, which i think it should. and maybe a lil more power.

Thanks

 

matt

[boonman]

If your engine doesn't ping on the current fuel you are using, I would stick with it. No need to be dumping extra money on octane that you don't need.

[sneeky]

i think the answer you are looking for is this

 

octane level makes a very minimal difference with regard to power output.

 

 

when compression is increased to create more power a hiugher octane fuel is required to limit detonation (firing too early and causing engine damage)

 

if standard 91 octane is not giving you detonation problems then you might as well just use it.

 

but if you want to satisfy your curiosity then fill her with the good stuff and try it

i did a dyno run with 92 octane(standard here) and then one straight after with 98 octane and there was a 1/2 horsepower difference, 1/2 hp less at low revs and 1/2 hp more from about 7000 up.

 

not realy worth the bother

 

i dont know what the fuel is like over there but the premium fuels come in 2 levels here standard 92 oct premium 95 octane and one higher which is 98 or 99 (each fuel company has there own name eg. shell optimax, bp ultimate, ampol vortex etc.

 

there is also the option of avgas (leaded aeroplane fuel 104 octane)

 

this can cause power losses at high revs due to slow combustion(in a stock engine)

but make i huge difference in a bombed engine with killer compression(according to a local mx bike repairman)

[teamriot]

Yamaha does recomand 91-93oct for there perforamance Quads. @ high rpm's were Banshees usual live you my and my not here minor detination (knocking).

 

All motors 2 or 4 stroke are all designed to run at a specfic oct. If you run to high of an oct the motor doesn't have the comprerssion, hot enough spark, or timing advanced enough to fire all of it and your running a little fat.

 

To low of oct will slowly kill the motor with pinging. Only in a pinch should you use a lower oct fuel at that dont run the motor at high RPM's very long just get to the closes station to get the proper fuel.

 

 

Always try to run what the manufacture suggest to have a happy long relationship with you motor and always run good oil.

[SICK BOY]

I was always told if you run more octane then what you need your just wasting your money.If your engine set up needs 93 mixed with race gas and you run strait

110 race gas you'll see no more power then you would with the mix.Is this right?

[Wallrat]

Yeah that's correct. You should use the minimum octane that you can get away with and still not have any pinging. Any higher octane and the only extra combustion you'll have is in your wallet.

[teamriot]

The bikes motor was not designed from the manufacture to run or need a higher octane fuel.

 

But if you modified it with cutting the head more than .035 or a cool head w/small chambers and a hotter ignition than in order to run that motor efficently you will need to run a mixture of race gas and 93 or all race gas 108.

 

Just running race gas will slow down the burn in the combustion camber and fatten the motor up slowing you down just to smell good and waste motor.

[Stuff]

Hey guys, I can actually use some of my college education towards this topic. I took a class on Internal Combustion Engines and switching to a higher octane will give you very little or no performance gains. Octane is the part of gasoline that resists ignition. When you increase compression on an engine you increase the pressure and temperature of the air-fuel mixture. If the temperature of an air-fuel mixture is raised high enough, the mixture can ignite without a spark plug. This is very bad for gas engines! Higher octane is used to prevent pre-ignition.

 

Gasolines with different octane ratings will produce about the same amout of heat during combustion. This means no big change in power output.

 

On the other hand, higher octane gas is more refined. Therefore, it will burn cleaner and of course......smells much better!!

 

I run 93 in my stock banshee and it smells way better than the cheap stuff.

[bansheelover]

Hey thanks a bunch guys

u really helped me out with this

i guess ill just save my money and stick with what works

thanks again

 

Matt