Eric or Rich race fuel question....

[flattie]

I realize VP C12 is about as good as it gets for race fuel as far as premixing and two strokes are concerned. However my local fuel supplier only carries Sunoco race fuel. They keep Sunoco "standard" and can get Sunoco "supreme". My question is which one will be better for pure MX usage. According to the cross chart on Sunoco's website the "supreme" is comparitive to VP C12 , but it also says the it is best suited for engines that typically run 7-10,000 rpm. So that is somewhat confusing to me as to what it is intended for.

thanks brian

 

[Rich Rohrich]

The distillation curve on Sunoco Supreme is significantly different than the curve of VP C12.

The 10% and 50% temperatures on the Sunoco fuel's curve are really too high for your use. You'll have a difficult time generating enough heat in the intake to get this fuel to vaporize consistently.

Temps like this on the distillation curve make for poor throttle response and part throttle jetting difficulties.

C12 will be a lot easier to live with in my opinion.

 

[flattie]

Thankyou Rich

I have been trying to do my homework past couple days and from what i read this is what i was afraid you would say. Thanks for the answer i will just make the extra drive for the C12. Just needed some reassurance.

 

[hot125mod]

like rich said ya cant go wrong with C12, hey rich how is that MRX01? looks like its good stuff.that front end temp is awesome

 

[Rich Rohrich]

MRX01 might be too much of a good thing on a two-stroke. If you get too aggressive with the front end temps two-strokes can be prone to pre-ignition.

No free lunch.:)

 

[TRexRacing]

Hey Rich what's your opinion on the U4.2?

 

[flattie]

Ok the hunt for VP C12 in my area is not looking good short of driving hour and half one way.

Lemme throw another sunoco fuel type in here and see if there is something i'm missing. i noticed that it has a closer distillation curve to the C12

Mo2X which i'm assuming the M"o2"x means its oxygenated

Ron 115

Mon 109

IBP 92

10% 122

50% 208

90% 229

FBP 251

Oxygen, wt% 2.7%

or perhaps sugest an alternative to the c12 that i can live with....

thanks brian

 

[flattie]

Ok nevermind the the Mo2X.... only thing the local Sunoco dealer says he can get is Sunoco "standard" which makes no sense to me why he can get only one type and not another, but anyway.

Think i have stumbled onto a Phillips dealer who hopefully can get me some B32/TT111 from which i understand from many many pages of achived post on here is a very good alternative to VP C12.

 

[flattie]

(Feel like i'm talking to myself here... someone chime in)

Ok i can get 5 gallon cans of TT 111 from fuel company here in town.

Is this the best alternative to VP C12?

Strickly MX usage only 05 CR250 (two stroke, if anyone remembers what that is lol)

 

[hot125mod]

I have heard nothing but good stuff about the 4.2 used the old school U2 and it was unreal all I can say is jet for it watch the plug the 4.2 isnt nearly as pungent of an odor as the 2 but still a little stinky

 

[Rich Rohrich]

Think i have stumbled onto a Phillips dealer who hopefully can get me some B32/TT111 from which i understand from many many pages of achived post on here is a very good alternative to VP C12.

T111 would be a good choice. Better in my opinion than the others you have listed so far.

 

[flattie]

Ty Rich

 

[flattie]

Another question if you will humor me Rich,

read this and copied it from another post:

" the 10%, 90% and end point are very important. If your bike is jetted correctly for the fuel you are using, the lower the 10% number, the better throttle response. The closer the 90% number and end-point the more complete burn and less SPOOGE!"

Is this what makes C-12 such a good fuel?

Just for comparison:

sunoco std's(179) 10% is quite abit higher than C-12's (131)

Plus the difference between the 90% and the EP on sunoco (121) huge compared to the C-12 (5)

i have also charted on a graph the distallation curve of four different fuels. If your curious to see it i will email it to you. Just trying to picture in my head what makes one better than the other. Its easier for me to see it then read it.

 

[whenfoxforks-ruled]

And that is why I really liked firepower Flattie! It is all about throttle response. Dr. Dave recommended 537 and xamax, with the ether boost, incredible! Their anti freeze is pretty good also. Dave has some new stuff on his website, and a race fuel quiz. http://www.precisionautoresearch.com/RACING_CHEMISTRY/FirePower/FirePowerFuels.pdf

 

[flattie]

I havent see any specs on Firepower.... nor can i find a dealer. I know from reading Rich likes it. But i need some help locating some within reasonable driving distance.

 

[flattie]

Bump...

Anyone have the distillation specs for Dragon racing fuels? Their main focus seems to be MX fuels....???

 

[hot125mod]

I was on their website a while ago looks like good stuff but I have never had an opportunity to try any of it. They dont show any specs other than the octane numbers most of them are oxy fuels too. I would like to try some B35 but it seems to have become none existent in minnesota. The B35 and VPs MR2 seem to be alot alike. I'm kind of between a rock and a hard place since rich said the MRX01 might be too much of a good thing. Would it be alright in a stock motor 125 or is the front end temp just too low, if so how could I raise the light end. Theres enough octane though.

 

[hot125mod]

Rich whats API Gravity some fuels show it some don't?

 

[whenfoxforks-ruled]

It will cause the piston to melt hot125mod. Wikipedia knows everything, http://en.wikipedia.org/wiki/API_gravity

 

[hot125mod]

yeah i googled it

 

[hot125mod]

is it because it evaporates too fast?

 

[whenfoxforks-ruled]

2 strokes need piston cooling properties first. Then everyone mixes the fuels differently. The results? The whole idea is throttle response. You need an ether oxygenated fuel.

 

[Rich Rohrich]

Would it be alright in a stock motor 125 or is the front end temp just too low,

It's tough to say for sure, you might be OK, but I would suggest some controlled testing on a practice day to know for sure. If you run into the early stages of pre-ignition you'll see evidence of it as excess heat on the plug especially the ground strap. I'd suggest using a BRxES plug as they are usually easier to read when looking for heat related issues.

 

[hot125mod]

do we need to be worried about the initial boiling point?