Which one, U4 or Mr12???

[Okcboi]

I have a head/cam package with raised compression. I've been using U4 and have turned some good numbers using it but I'm wondering if MR12 would be a better race fuel to use next year?!?!

What do you guys think and why?

[jojos750]

I posted up on this before and was told by every reply run mr12

[Ridehard]

As long as the compression is too high you can run Mr12.

[Trak Starr]

I've heard from a number of people that MR12 doesn't perform well in the heat. Not sure how true this is

[onemoregsxrguy]

If I'm not mistaken you can leave u4 in but you have to drain mr12 out.

[beanedisel]

If u have high compression and in heat or humidity u r better off with mrx01


04handclutch zx10 Bankjob

[Franklin]

I love Q16. works great all around

[03gixxer1k]

Mr12 would be better on motor with out spray makes good hp , switched to mrxo1 cause i run motor/nitrous and u4.4 i have a friend that is e it and he leaves it in the bike and havnt had any problems not like the old version of u4

[dragracer08]

i still wish we had the old u4 though it was a great fuel for the price

[kyrond]

Get mr12

[Born2Ride]

MR12 is the best fuel for all motor,but only if you have stock/low compression because it is fairly low octane. If you have "high" compression you may want to look into a different fuel,but it really just depends how high of compression. Q16 makes good power on motor and on nitrous.

[Okcboi]

Just went to VP Racing Fuel Website and I looked at Q16, MR12, and MRX01. Looks like I would have to increase fuel flow if I use Q16 but it seems like it is a consistent fuel and it is 116 octane. MR12 has a octane of 87, does have 5% increase in power over M9 and 6% increase in power over MRX01. MRX01 gives a 6% increase in power over pump gas and has a octane of 98. U4.4 also has a 6% increase over pump gas and has a higher octane than MRX01 which is 103. Im mentioning octane levels because I need a higher octane level due to increased compression. I have to run a mix of 50/50 blend of pump/race gas if I plan on street riding (expensive so I don't do much street riding). But I like the way U4.4 works for me. From the increase in mph and lower ET and with MR12 havin' a lower octane level I'm thinking of staying with U4.4.

[Born2Ride]

Just went to VP Racing Fuel Website and I looked at Q16, MR12, and MRX01. Looks like I would have to increase fuel flow if I use Q16 but it seems like it is a consistent fuel and it is 116 octane. MR12 has a octane of 87, does have 5% increase in power over M9 and 6% increase in power over MRX01. MRX01 gives a 6% increase in power over pump gas and has a octane of 98. U4.4 also has a 6% increase over pump gas and has a higher octane than MRX01 which is 103. Im mentioning octane levels because I need a higher octane level due to increased compression. I have to run a mix of 50/50 blend of pump/race gas if I plan on street riding (expensive so I don't do much street riding). But I like the way U4.4 works for me. From the increase in mph and lower ET and with MR12 havin' a lower octane level I'm thinking of staying with U4.4.

You wouldnt have to increase fuel flow with Q16,maybe just richen up your tune when using it(add fuel). Q16 gives you the octance you want,plus it is oxygenated like MR12 so you will gain power using it. But everybody has their own opinions!

[andyb]

Remember that VP is listing MON, not AKI, when they're listing their octane... AKI is what you'd find on a gas pump, so the numbers VP gives will act as if they're quite a lot higher compared to the pump gas you're more familiar with.

[gazx10]

you're good with mr12 with comp. 13.5 or a little higher, you will have to custom throttle position tune for this fuel to see the real benefits it produces, my bike loves it with thin hg, .015 deck, i show 8 hp increase at 7k, increases 8-12 hp thru upper midrange, levels out at 8 up top. throttle response and torque are vastly improved.