VPU4

[tstruyk]

Anyone run this on a carburated bike?  I have an 02R6 and am considering runnig it.  What are the HP gains, what kind of jetting issues can I espect?  I planned on getting my carbs sync'd, run dyno, add VPU4 rejet and re dyno and go from there...just looking for a heads up if anyone runs the same bike.  I'd hate to go through all that testing and tuning to see minimal gains.  any thoughts?

performance mods are Yosh carbon slip on, factory jet kit... thats it

thanks!!

Tim

[james-redsv]

As tested in Sportrider mag, VPU4 gives the best HP numbers for any other race fuel that they tested. Each bike is different, but some guys with R6s can get you in the ball park. I ran it last year in my carbed SS legal SV but this year Im doing some motor work and the compression will be too high to run U4, u4 is 89 octain and is better for SS motors.

[xseal]

I run it on a carberated 02 Kawi 600, much crisper throttle response.  Just ensure you jet it using the U4.  

[pnther15]

I race an '02 R6 and really like the U4, I can tell a pretty big difference.  I'm pretty sure it's 92 octane, not 89.  I don't know where you race, but Robb at Lithium Motorsports sells it for the GP/MW regions and he could tell you more about it.
Call him at 712-546-7747


This is what his website has it listed as:

U4 is used in stock and modified 4-stroke applications, as well as stock 2-strokes. Makes up to 6% more power than pump gas and any basic nonoxygenated racing fuel. Passes fuel rules for AMA amateur racing and is also perfect for club level racing, CCS, WERA and AFM. • Color: Clear • Motor Octane: 92 • Specific Gravity: .718 at 60° F

[tstruyk]

thanks for the heads up, once he's back from vegas I'll give him a call.  

[motomadness]

Tim, what's up?  I ran U4 in my R6.  Unfortunately, I never ran anything else, except at one track day.  I also have an Ivan's Jet Kit, which I think is the best.  The resulting power curve from that kit was amazingly smooth and just kept on rising.

I've got R6 carbs with the Ivan's kit for sale.

[tstruyk]

hey moto, thanks for the heads up!  I have got a pretty darn good tuner here, the work he did rejetting the factory kit was phenomenal!!  I think I'll just stick with what I have, dont want to be broke prior to the season starting!  If he cant work out the tuning I'll just run without it... but he's pretty strong.  With just the pipe and jet on my 02, no ram air he's got me tuned to 106-107... if the U4 can get me to 111-112 I'll be happy!  We'll see, as soon as Rob get back from vegas I'm gettin some ordered.

thanks for the thought though!!

tim

[rotoboge]

Yes, I run it in my SV and it gets great results...

[pmoravek]

Rotoboge (or anyone else for that matter)

Do you know what kind of jetting needs to be run in a 99-02 SV for Ultimate 4?

[rotoboge]

Rotoboge (or anyone else for that matter)

Do you know what kind of jetting needs to be run in a 99-02 SV for Ultimate 4?

Call AJ at AJ's Performance in Phoenix, AZ. He built the engine/bike and can give you the lowdown on the engine tuning: 623-587-7708. 8)

[gpstar1]

Has anyone had problems with this stuff? I ran it in my SV last year and it made the bike run awesome at the track, but i let the bike sit for a couple of days and the thing ran like total S&!T. I had the thing at the shop 3 times and everytime we would clean the carbs there was a lot of sediment clogging the jets. The same thing also happened to a guy i do track days with. He has a GSXR 600 and it caused his carbs to malfuntion, as a result he crashed pretty hard. For me i love the power gains you get out of U4, but i am sick of all the problems, i'm going back to C12. I have a 15 Gal. drum U4 i want to get rid of. I will most likely sell it at the first summit point race. I'll let it go for $75.

[Zac]

Has anyone had problems with this stuff? I ran it in my SV last year and it made the bike run awesome at the track, but i let the bike sit for a couple of days and the thing ran like total S&!T. I had the thing at the shop 3 times and everytime we would clean the carbs there was a lot of sediment clogging the jets. The same thing also happened to a guy i do track days with. He has a GSXR 600 and it caused his carbs to malfuntion, as a result he crashed pretty hard. For me i love the power gains you get out of U4, but i am sick of all the problems, i'm going back to C12. I have a 15 Gal. drum U4 i want to get rid of. I will most likely sell it at the first summit point race. I'll let it go for $75.

If you run U4, drain it out of the tank after the race weekend and run some pump gas (or other race gas) through to flush it out of the carbs (or just drain the carbs).  No big deal, a lot easier than cleaning the carbs all the time.  The light fractions evaporate very quick, leaving all the gummy stuff behind.  

I run U2 in my CR, and if I leave it in the tank my garage will stink the next day because it will difuse through the plastic tank.  In a week it will all evaporate out of the carb leaving only the premix oil in the bowl.

-z.