race fuel

[gixster]

 If I have my bike mapped for pump gas will it lean out on u4 or mr9?Bike is a 07 zx6r.
  thanks chris

[JBraun]

It will lean out, but not to the point it's dangerous. My U4 map is pretty similar to my pump gas map. You can pretty much dump it in and go.

Be careful switching between fuels though, I'm currently having major sludge issues, my whole intake gummed up. VP is telling me it's a compatibility issue with defferent race fuels.

[gixster]

 Different race fuels like mixing sunoco and vp or vp u4 and mr9?

[JBraun]

The issue I had was using sunoco 98 and switching to U4. I heard the issue was specifically with the U4, apparently MR9 is okay, but I can't verify that.

The only thing I know firsthand is that U4 and sunoco 98 is bad.

[APP_Racing]

Give Spears Racing a call.  About a year ago I was talking to them and they had said a rider was testing at a track, ran pump fuel instead of U4 (he forgot it at home) and he burned up the pistons. 

I do not know if the fuel was the reason but that is what I was told.   But to lean is bad for any motor.  Just not sure how much it would lean up if mapped for U4.

[benprobst]

for carbed bikes, you normally richen the mains 2 steps going to oxygenated fuel. So unless you are already ultra lean on pump gas, it shouldnt be a problem going to oxy fuel.

[Eddie200]

All of my bikes maps have been very close Pump vs U4.  I just pour and go without any issues.

[Jeff]

If you're spending the money on VP, have it mapped for that fuel.  If you use pump gas after that, it will run fine.

You want to take every possible advantage available with that liquid gold, so spend the few bucks to have a correct map made.

For me, I have the bike mapped on U4.  I run practice on 91/93 (only due to other motor work, otherwise I'd use 89).  After practice, I drain the pump gas and run U4 for the races.  After the races, I drain U4 and back to pump gas for practice.

[J Farrell / Speed Tech Motorsp]

If you're spending the money on VP, have it mapped for that fuel.  If you use pump gas after that, it will run fine.

You want to take every possible advantage available with that liquid gold, so spend the few bucks to have a correct map made.

+1
I dyno bikes quite often. I would recommend remapping for different fuels. Don't forget different fuels require different ignition timing to gain optimum power. I've seen 3-5 HP from optimized ignition timing.