Race Gas ?'s

[NacNac250F]

"Mixing alcohol based pump fuels with ANYTHING in an attempt to make it BETTER is just a chemical circle jerk, and if you're that cheap or that ignorant you deserve the crummy performance and the insurmountable jetting problems that you will invariably be blessed with."

I read this here and made me think, if I mix the C-12 that I get with 93 octane pump fuel 50/50 it basically defeats the purpose of buying race gas? Because if doesnt do anything I'll have to plan on spending twice as much on the already expensive $10/gallon C-12.

And has anybody tried the Ultimate 2 race gas? How does it work?

 

[biglou]

Man, I've tried to wrap my brain around the race gas thing for years now. I was running straight B32 in my 05 YZ250 since new, and bclapham suggested I might get better throttle response out of a 50/50 mix with pump premium. I switched to Klotz 113 low-lead (closer, from a karting dealer instead of the crappy bike dealer close to me) and it seems to run just fine. On one hand, it is kinda like mixing Perrier with pool water, but on the other, it give a nice resistance to predetonation, smells nice, and runs great.

My next step is to try VP U4 in my smoker... I've got some jetting info on that and I'll post it as soon as I dig it out of a PM I got from SeniorKXrider.

 

[biglou]

Hey Mark-I've found a few sources for U4 in the KC area, and was wondering if you mix yours with pump or run it straight. Also, did you have to adjust jetting for it? I'm thinking I'd need to go richer, if it's anything like the Phillips B35.

I've got 10 gallons of Klotz 113 mixed 50/50 to burn off first though. Bclapham said to go 50/50 and expect more throttle response than straight unoxygenated fuel. We shall see at DW I guess!

Thanks

Lou

Lou, I used to mix 50/50 with pump premium but it seemed like it was real hard to get the jetting just right. Now I mix 50/50 with VP C-12. I get C-12 for about $5 a gallon and it gives a real consistant mix. Your 2 stroke should absolutely RIP on that fuel. Mine do.

As for jetting............to run straight C-12 I always lean the main 2 the needle 1 and the pilot 1. To run the oxy U-4 I always start with the main 2 larger than stock, needle 1 richer and pilot 1 richer so it hits close to stock on my bikes. If your YZ is prone to detonation(lot of the new bikes are) I would start a little to the rich side.

With premium pump at $3 a gallon I think the C-12 is well worth a couple more bucks so you get a good consistant mix.

Running an oxy fuel in your two strokes will give you a kick that you won't believe and make you wonder why you took so long to go that way

 

[Rich Rohrich]

" if I mix the C-12 that I get with 93 octane pump fuel 50/50 it basically defeats the purpose of buying race gas?

It really depends on why you are using race gas in the first place. What are you trying to accomplish by running the C-12?

 

[NacNac250F]

So people run VP Ultimate 4 in two strokes now? What about VP Ultimate 2?

Any other opinions on 50/50 C-12 with 93 octane pump fuel?

 

[NacNac250F]

It really depends on why you are using race gas in the first place. What are you trying to accomplish by running the C-12?

My bike is ported and has a pipe and was pinging badly so I starting using that mix. It pretty much got rid of the pinging, but after reading all this stuff about pump gas, race gas, and avgas, I just had to question it.

 

[Rich Rohrich]

If all you are trying to do is stop it from pinging and you know your jetting isn't the cause, then mixing 50/50 with C-12 is a good consistent way to accomplish that goal.

 

[NacNac250F]

That is what I am doing right now(mixing 50/50). I am just a little on the rich side with jetting, but should I expect any increase in throttle response with 50/50 or is that just something that you get running straight race gas? I think that the jetting could go a clip position leaner and probably a size lower on the main to be perfect, it is pretty responsive right now with but just haven't taken the time to do it perfectly yet since the bike is running fine the way it is.

 

[Rich Rohrich]

If it's jetted on the rich side now as a hedge against pinging then raising the octane with the 50/50 mix should allow you to lean it out and pick up some throttle response.

 

[Rich Rohrich]

Bclapham said to go 50/50 and expect more throttle response than straight unoxygenated fuel.

I wouldn't hold my breath. ;)

 

[NacNac250F]

If it's jetted on the rich side now as a hedge against pinging then raising the octane with the 50/50 mix should allow you to lean it out and pick up some throttle response.

Thanks Rich