[synolimit]

what do u guys use??? ive done a few dyno runs and tuning with bazzaz then used the bazzaz self tuner. first time i ran i used U4, but with no bazzaz and cam timing stock after i did engine work i was down 5hp up top but up 11hp mid range. after i was told u4 was stopped being made about a year ago and any can would be expired. i then ran with u4.2. after long dynoing one day with Synoco 94 pump and U4.2 all the results were the same.

so i figured the $14 a gallon fuel was a waste since the gas station down the street gave me the same results! but after thinking and talking to a few people both thoughs fuels wont make my bike power because of the low compression and bazzaz has no ignition timing.

so question is i see ama running MR11, but anyone else use something that will get me power? do i scrape the bazzaz and A/F self tuner which is awsome cause i can self tune everyday at the track dude to temp differences and get the PC3 and ignition box?

 

[Sev]

The only reason to run race gas is if you've bumped compression way up. Otherwise all you're doing is carboning up your pistons and cylinders. Run normal gas so long as you're not suffering from detonation.

 

[Cobra]

....but it smells delicious!! I love riding behind people that run race fuel.

--David

 

[synolimit]

The only reason to run race gas is if you've bumped compression way up. Otherwise all you're doing is carboning up your pistons and cylinders. Run normal gas so long as you're not suffering from detonation.

well compression isnt way up! im mean stock is 13.2.1 im prob at about 14.1 now. but the race fuel isnt just for helpiing you not detonate, well the high octane fuel helps but not the oxygenated fuels. U4.2 is 102 while AMA uses MR11 which is only 90 and my pump is better than that. The oxygenated fuel makes power due to the fact the oxygen in it acts as a little nitrous boost allowing you to burn more hotter fuel. and ive never seen a race bike that runs race fuel carboning up pistons and cyclinders, its PURE fuel unlike shit we put in are cars with all the additives.

 

[runfromme]

The only reason to run race gas is if you've bumped compression way up. Otherwise all you're doing is carboning up your pistons and cylinders. Run normal gas so long as you're not suffering from detonation.

not true. U4.2 and MR9 are proven to increase HP with no changes to the internals or the mapping.

 

[meanstrk]

....but it smells delicious!! I love riding behind people that run race fuel.

--David

I hate running behind bikes that run it at the track when they don't need to. They leave so much unburned fuel fumes it gives me a headache.

 

[spooner427]

Wierd you would run the same numbers on U4.2 and pump but now for the questions.
Did you suck your tank dry before putting in the U4.2? U4.2 is something like 92 octane but %6 oxygenation. The oxygenation is where the power is made and when you mix it with any amount of pump fuel you lower the % and will lower the amount of power you actually make.
Did you get the U4.2 from a sealed container? If the container is not sealed during storage it will evaporate out the oxygenation from the fuel and become normal 92 octane and you will see no extra power.

MR9 and MR11 are just higher octane with a larger percentage of oxygenation so there is more power to be gained with tuning. Since the U4.2 is 92 octane there is no need for tuning to see some extra HP but with tuning could pick up a couple more.

The only reason to run race gas is if you've bumped compression way up. Otherwise all you're doing is carboning up your pistons and cylinders. Run normal gas so long as you're not suffering from detonation.

You are thinking about normal high octane racing fuel NOT oxygenated fuels like V4.2, MR9 and MR11.

I hate running behind bikes that run it at the track when they don't need to. They leave so much unburned fuel fumes it gives me a headache.

All bikes in theory will see a gain from U4.2 it isn't just high octane...... and it smells AWSOME!!! in raw form(straight from gas can) it is over welming and that is why they stopped U4 and started U4.2 and a few other reasons.

 

[synolimit]

not true. U4.2 and MR9 are proven to increase HP with no changes to the internals or the mapping.

thank you! but you say proven, what the hell is wrong with my bike at the moment running 114ph with 94 pump and U4 then U4.2 am i seeing no change and went to 2 different dynos?

 

[synolimit]

I hate running behind bikes that run it at the track when they don't need to. They leave so much unburned fuel fumes it gives me a headache.

i love it, lol i must say it puts a smile on my face when i get passed in practice by a faster guy whens hes using it, it smells so good, or i may just be getting high, thats y im smiling

 

[synolimit]

weird is right. ok i was at the dyno for about 3 hours. i did about 10-15 runs on pump 94 and the gas light was on when we had it all dialed in. filled the tank with U4.2 and did about 15 more. (FYI VP rates U4.2 at 102 octane) so no i didnt drain the tank but made sure it was almost empty with pump and did plenty of runs where the exhaust then smelled of nothing but race fuel. the can was brand new and only a few months old from the born on date.

now im not sure about the % of oxygenation but i no on VP's site lists the U4.2 at 102, MR9 at 87 and MR11 at 90 which is why AMA is not aloud to use U4.2 because its "so powerful"

 

[spooner427]

weird is right. ok i was at the dyno for about 3 hours. i did about 10-15 runs on pump 94 and the gas light was on when we had it all dialed in. filled the tank with U4.2 and did about 15 more. (FYI VP rates U4.2 at 102 octane) so no i didnt drain the tank but made sure it was almost empty with pump and did plenty of runs where the exhaust then smelled of nothing but race fuel. the can was brand new and only a few months old from the born on date.

now im not sure about the % of oxygenation but i no on VP's site lists the U4.2 at 102, MR9 at 87 and MR11 at 90 which is why AMA is not aloud to use U4.2 because its "so powerful"

Your right U4.2 is 102 and U4 was 93 oxygenated. I ran U4 last year but but stopped due to the cost and the slug it builds when it mixes with normal gas. I had never ran MR9 or MR11 but figured that they were higher octane to try and run cooler with more oxygenation. BUT if U4.2 didn't make more HP it wouldn't sell and when I ran U4 the guy at the track selling it said in order to get everything out of it I had to suck my tank dry. Reserve coming on still leaves fuel in there to lower octane and oxygenation levels. You will smell race fuel if you mix it 1 gallon to 3 of normal pump.

If you search there was a guy a while back that had his bike tuned for 92pump and 87pump and made more HP on 87 since the lower octane is more explosive. Your engine might run a bit hotter though.

 

[synolimit]

hmm well i think after i re-degree cams, and move my 11hp i gained mid range from the thinner head gasket up top, i put 15w50 synthetic oil in by mistake, i went back to 10w40 and ill try U4.2 one more time at the dyno and drain the tank. i was looking at my numbers last night and i was wrong i lost 3hp after head gasket not 5. but after bazzaz i went back up to 114. im hopin to move all 11hp up top but if not a good amount to get to about 120rwhp. O and the U4.2 did gain some hp .8 to be exact haha