Your wasting your money at $5 a gallon and it wont run any better. Your ds is made to run on 91 octane. All your doing by adding a higher octane is makeing the fuel harder to burn and ignite when compressed.Thats why high compression engiens need high octane gas, if you ran low octane it would ignite premature and diesl and run like crap , raise the flash point of the gas and it wont ignite till the full piston dwell at t.d.c. When these companys like Rotax, Honda, Yamaha, or any other major Builder build and test these engines they arnt dumb.They tell you what works best. IF a 105 octane worked best there would be a sticker on it that says so. Just my 2 cents on the matter.

 

HEY DAZ i don't know where you get your fuel but last time i filled at the airport
it was no where near 5 dollars a gallon? and dose anyone happen to know what the octane reading is on nitro metanol 12% nitro and metanol ?

PS I only run 10-1 comp and nitro metanol could you explain why my bike is a little faster than the average ds?????? [img]i/expressions/face-icon-small-confused.gif[/img]

 

AZsand if you are ever in the neighborhood look me up. I never mentioned anything about alky so back up and re-read. I happen to agree with you not only do you get better combustion but the engine temps are cooler
with alcohol. I do not know octane of alcohol but I can tell you it increases octane rating in gasoline,on the new oxygenated fuels we add alcohol to the gas at the truck rack but 93 comes out of the blender at about 89 and that is a pretty good bump for 9% ethanol.
Lead will not harm a engines with hardened seats but unleaded will damage the seats of pre unleaded engines
I don't know much about nitro-methane it really raises cylinder PSI during combustion and I have been told that pure nitro will hardly burn at atmospheric pressure? it does make those glo-motors spin up some big HP and RPM for micro cubic inch.
I guess I have addresed the issues enough. lets try to be adults about it.
Scott Angleton
618 St. Rose
Godfrey Il. 62035
I just read back through, your the one who said he ran JP-4
(not a snowballs chance in Arizona) now I am sorry I took the time to reply.

 

<< Your wasting your money at $5 a gallon and it wont run any better. Your ds is made to run on 91 octane. All your doing by adding a higher octane is makeing the fuel harder to burn and ignite when compressed.Thats why high compression engiens need high octane gas, if you ran low octane it would ignite premature and diesl and run like crap , raise the flash point of the gas and it wont ignite till the full piston dwell at t.d.c. When these companys like Rotax, Honda, Yamaha, or any other major Builder build and test these engines they arnt dumb.They tell you what works best. IF a 105 octane worked best there would be a sticker on it that says so. Just my 2 cents on the matter. >>



Octane in gasoline itself does NOT make the fuel harder to burn or ignite. It is a numeric rating to its resistance to detonation. By running higher octane you simply make your engine less prone to preignition/detonation. It isn't accomplished through slower,faster,colder,or hotter burn. You can save money by running the lowest octane rating that your engine will allow you to run without detonation.

The cheapest way to raise octane is to mix touelene or xyetelene with gasoline.

 

slower burn rate is resistance to auto-ignition. higher octane fuel in low octane engines will run hotter. there is no reason to run high octane in low compresion just a waste of money as stated before.
What does zytelene do is it just another ene in the chemical chain, we don't use it in our pump gas unless its similar to benzene raff (high octane refromate)
A guy I work with out of Indy used to pull garden tractors and he told me about propyl either or propyl butalene something like that I can't remember what the exact name is. Do you know what he's talking about?
Oh well I pay 4 bones a gal for 110 at the pump for my stage 2 no mixing

 

Actually:

&quot;The antiknock ability is related to the &quot;autoignition temperature&quot; of the
hydrocarbons. Antiknock ability is _not_ substantially related to:-
1. The energy content of fuel, this should be obvious, as oxygenates have
lower energy contents, but high octanes.
2. The flame speed of the conventionally ignited mixture, this should be
evident from the similarities of the two reference hydrocarbons.
Although flame speed does play a minor part, there are many other factors
that are far more important. ( such as compression ratio, stoichiometry,
combustion chamber shape, chemical structure of the fuel, presence of
antiknock additives, number and position of spark plugs, turbulence etc.)
Flame speed does not correlate with octane&quot;

Once again. Flame speed does not correlate with octane. This was an excerpt taken from here:
More than you ever wanted to know about gasoline

 

In the strictest term you are correct octain is not an energy rating just a resitans to pre ignition. The thing is physics takes over and it just so happens that a gasoline with a higher octain rating burns cooler slower and has less energy.

 

I think the physics are more than plainly stated in the above link. This is nothing new. Many chemical engineers have stated the same thing in previous documents. These are the same engineers that develop petroleum products for the big companies like BP and Mobil. I think their credentials speak for themselves.

 

Wow, thanks for the link &quot;pretty cool&quot; I have been around motorsports for 25 years and have worked for Shell for 13 years where I work directly with the motor lab and gasoline blenders. I have always been interested in what is actually happening in fuels and picked up what I know through
years of asking a lot of questions and witnessing the affects in cars and bikes.
thanks again, Scott

 

Sorry to ask this again, but I don't feel like my question was really addressed.

What are the pros and cons of using leaded vs. unleaded race fuels?

I am asking this in regards to a 12:1 compression single cylinder, todays atv's (not a motor built specifically to run on leaded).

I have heard different thoughts on this question (leaded vs. unleaded) and it seems like a few of you know a thing or two about fuels, so I would like to hear your views.

Thanks!