Fuel poll: race gas, pump gas, or combo?

[mcwilly]

Seen lots of threads where people suggest running different types of fuel. So what are you running?

Right now we're running 50/50 w/ VP C12 and 93 octane pump gas.

[greenmachine70]

trust me sooner or later the ethanol in pump gas will get you.
Google "phase separation in fuel"
If you are running a high compression motor, then you dont have a choice as pump gas will predetonate.

[mcwilly]

Originally posted by greenmachine70

Google "phase separation in fuel"


Interesting stuff

use 93 octane and race fuel 50/50 that will be your best option.

[Ride1Rob]

93 all the way... our motor doesn't require race fuel.

[greenmachine70]

Originally posted by greenmachine70
trust me sooner or later the ethanol in pump gas will get you.
Google "phase separation in fuel"
If you are running a high compression motor, then you dont have a choice as pump gas will predetonate.
I was assuming we were talking about 2STROKE racing motors.
Ethanol will separate the oil from the fuel after sitting for a period of time and you may be running straight alcohol for a minute until your fuel gets mixed. This will cause a lean seizure. I see it all the time in 2stroke motors in equipment I sell.
If your gonna run pump gas in a stock or lower compression motor, just be sure to shake the tank or can everytime before you ride or pour it in the quad.
Also the ethanol absorbs moisture into the fuel from simple humidity. As we here in Florida know, it is ALWAYS humid down here.....lol

[mcwilly]

Originally posted by greenmachine70
I was assuming we were talking about 2STROKE racing motors.


Yeah, I guess I should've specified....I was referring to 2-stroke

[Coley'sdad#8]

if you are going to run pump gas you can call around to your local stations and find out who has ethanol free fuel. Sunoco, Mobil, Phillips 66, the good ole stations will be the ones carrying it. It isn't but a few cents more either. We just run straight 110 because you cant have too much octane rating, better quality fuels burn faster more cleanly and completely which results in less flame time in the cylinder thus lower cyl and head temperatures.

[nastynotchback1]

NOTHING BUT VP-110 HERE

[fearlessfred]

Originally posted by Coley'sdad#8
if you are going to run pump gas you can call around to your local stations and find out who has ethanol free fuel. Sunoco, Mobil, Phillips 66, the good ole stations will be the ones carrying it. It isn't but a few cents more either. We just run straight 110 because you cant have too much octane rating, better quality fuels burn faster more cleanly and completely which results in less flame time in the cylinder thus lower cyl and head temperatures.
i would have to disagree with some of your comments
you can have to much octane (but will not hurt the motor only performance )
the higher the octane the slower the burn,if u slow it down to much,the flame front is chasing the piston down instead of meeting it at t.d.c. resulting in a power lose.race gas is good because it burns more evenly and usually has a lower specific gravity,whiich gives u better throttle responce. anymore octane than is needed to prevent pinging and detonation is a waste

[Coley'sdad#8]

the waste is my waste, I would rather run straight 110 than run around town finding non ethanol fuels and having to mix them and the mixing oil, I have too much to do already. The reason lower octane fuels run hotter is that they have loose atoms that "linger burn" and that causes higher cyl temps because of a longer burn time. this is just regular race fuels, If yall want we can get into oxygenated fuels:D

[fearlessfred]

Originally posted by Coley'sdad#8
the waste is my waste, I would rather run straight 110 than run around town finding non ethanol fuels and having to mix them and the mixing oil, I have too much to do already. The reason lower octane fuels run hotter is that they have loose atoms that "linger burn" and that causes higher cyl temps because of a longer burn time. this is just regular race fuels, If yall want we can get into oxygenated fuels:D i have no arguement against race gas ,or your reasons for using it. my disagreement was that u stated that u cant have to much octane, and that is not true. u also stated that race gas burns faster than pump gas, not true again. as far as loose atoms and all stuff goes, i will have to take your word for it,because i dont know. a lot of people think by using race gas that it is a power adder ,and that is not really true. if u took a stock 400ex and went from 93 pump to race gas would it make any measurable diff, in horsepower.race gas will allow a modded motor to make more ponys. please educate me if im wrong

[Ride1Rob]

I keep hearing 93 is hotter than race fuel. But if you go from 93 to race fuel (110) it leans the bike out doesn't it? In almost every engine that I've used race fuel in I've had to richen the main. Lean condition = more heat. Maybe one of you Gurus can educate me better on this.

[greenmachine70]

Oxygenated fuel or VP U4-2 will give instant horsepower, but it will blow your motor if not jetted fat.

[fearlessfred]

Originally posted by greenmachine70
Oxygenated fuel or VP U4-2 will give instant horsepower, but it will blow your motor if not jetted fat. how much on what size atv . do u have any links to the site were u found this this info.i have looked on the net for this info. but mostly all i found was sites that did the dynos were people that allso sold vp. they have claims of up to 6 pecent gains,but i did not see any thing close to that.like u stated all the dynos needed an increase in jetting. so u dont just pour it in and have instant horse power

[LT80]

I'm certainly with Fred. Compression (mostly) dictates octane.
Too much is too much and too little is too little.
Coley'sdad, it's not about you wasting money, it's about you not having the maximum HP comming from your motor from having too much octane.

[fearlessfred]

i wish i would i would have worded it like u did lt80. i always make statements in away that offends the other persons, and its not meant to

[dblacks]

Originally posted by LT80
I'm certainly with Fred. Compression (mostly) dictates octane.
Too much is too much and too little is too little.
Coley'sdad, it's not about you wasting money, it's about you not having the maximum HP comming from your motor from having too much octane.


agreed, talk to any good engine builder.

it is what has been done to the engine not what size it is or more octane is safer or makes more hp.

For Example: a 50 lim it is usually hurting power in it to put race fuel in it usualy even mixed 50/50

[fearlessfred]

for anyone reading this thread,that is interested in getting the most performance out of whatever combination of parts they have,u should not look at fuel as a one size fits all,because it is not.
two important things about octane.it is used to prevent PINGING, which is when the flame front reachs the piston before tdc, and then theres DETONATION. which is worse than pinging,and that is caused from excessive heat and preasure.detonation is when the fuel is ignited from more than one sourse.hot spots or extreme preasure can cause the fuel to ignite on its own. when the two flame fronts collide that is detonation. to cure detonation a colder heat range of spark plug is one of the first things i do and is recommended by the spark plug manufacture ( when combustion temps have been by increased by raising compression or any other mod that caused higher comb. temps) a plug reading and proper jetting shoud be done when going to colder plug. i then select the fuel by the fuel by trial and error ,starting on the safe side of a high octane and working my to lower octanes of. course an engine builder or person with experiance can elimanate the trial and error part. to be on the bubble when it comes to tuning it takes effort,and if u are not willing to make the effort,by all means buy the highest octane and the most expensive fuel u can find and be safe

[LT80]

Originally posted by fearlessfred
i wish i would i would have worded it like u did lt80. i always make statements in away that offends the other persons, and its not meant to

Me too Fred, I just got lucky this time..:)

[greenmachine70]

Originally posted by fearlessfred
for anyone reading this thread,that is interested in getting the most performance out of whatever combination of parts they have,u should not look at fuel as a one size fits all,because it is not.
two important things about octane.it is used to prevent PINGING, which is when the flame front reachs the piston before tdc, and then theres DETONATION. which is worse than pinging,and that is caused from excessive heat and preasure.detonation is when the fuel is ignited from more than one sourse.hot spots or extreme preasure can cause the fuel to ignite on its own. when the two flame fronts collide that is detonation. to cure detonation a colder heat range of spark plug is one of the first things i do and is recommended by the spark plug manufacture ( when combustion temps have been by increased by raising compression or any other mod that caused higher comb. temps) a plug reading and proper jetting shoud be done when going to colder plug. i then select the fuel by the fuel by trial and error ,starting on the safe side of a high octane and working my to lower octanes of. course an engine builder or person with experiance can elimanate the trial and error part. to be on the bubble when it comes to tuning it takes effort,and if u are not willing to make the effort,by all means buy the highest octane and the most expensive fuel u can find and be safe

Thank You for posting, that is some good info.

[fearlessfred]

Originally posted by greenmachine70
Thank You for posting, that is some good info.
u are welcome, and im still interested in the vp u4 2 info.theres a lot of extra work involved in using those fuels and are u using it

[greenmachine70]

tried it but with the humidity and difference between day moto 1 and after dark moto 2 here in Florida, it is too much work. But I can tell you when you get it dialed in just right, it is noticeable.
Goin back to 110.

[fearlessfred]

Originally posted by greenmachine70
tried it but with the humidity and difference between day moto 1 and after dark moto 2 here in Florida, it is too much work. But I can tell you when you get it dialed in just right, it is noticeable.
Goin back to 110.
thanks ,and i know what u mean ,i lived in homestead for a year 90 percent humidity and 100 percent bugs

[Ryko racing]

4.2 has been discontinued, they replaced it with u 4.4 supposedly due to humidity altering the 4.2 .

i would like to know if anyone has tried 4.4 and how much different the jetting was. ( my guess is it would run richer than 4.2)