Yikes! High alcohol fuel did this?

Scooter trash

Been Around the Block
Been running 110 octane fuel. I know that it will absorb water like a bitch. The last batch was out of a bulk tank instead of a 5 gallon pale. Never has the tank had less than 1/4 level. This happened over just one season, bike was indoors. The bike was 30 mph down on the big end of the 1/4 mile, normally it hits over 150 mph. This is what I found. 255 lph fuel pump was stalling too.
 

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Most race fuel has specific instructions to drain it out at the end of the day/weekend. That is doubly appropriate with race gas with a high ethanol content. On a carb bike I drain the tank and then the carbs. ON EFI I guess you drain the tank and then run no oxygenated gas through the injectors for a while to flush them.


That is really nasty.
 
It's Sunoco 110. I'm going to map it for pump gas, pull the timing back, it could actually make more hp.
 
What about running avgas? I mean the stuff they put in Cessna 182's. Usually about 106 octane I think. I've run it in my ZRX from time to time and it likes it.
 
If it is an oxygenated fuel you have to drain that crap after every weekend...some of that stuff is not worth the cpl of hp you gain imo.
 
That's odd. I just checked Sunoco 110 (Standard) and it has zero oxygen ie no ethanol. I wonder what was in that fuel or was that damage caused by street gas prior to use of Sunoco.

Stay away from Avgas which is slow burning fuel designed for very slow revving motors. You want great throttle response try U44 but flush it out after use. Drag motors need enough octane to resist detonation at WOT and high revs. C12 is a basic race gas that works well but something like Maximal from Sunoco is pretty tolerant of hot motors, high load and hot days and works with a lot of ignition advance.

Try different fuels on the dyno where you can adjust different parameters safely and get repeatable results.
 
teazer said:
Stay away from Avgas which is slow burning fuel designed for very slow revving motors. You want great throttle response try U44 but flush it out after use. Drag motors need enough octane to resist detonation at WOT and high revs. C12 is a basic race gas that works well but something like Maximal from Sunoco is pretty tolerant of hot motors, high load and hot days and works with a lot of ignition advance.

Didn't know that about avgas. My bike always likes it just fine. I used to get free avgas for the bike now and then when I spent alot more time on the airport.
 
Free is good.

I just spent/wasted a bunch of time checking lower heating values for a selection of fuels and most race gas I checked had less energy per pound than street gas and some were much lower. The real benefit of race gas is the resistance to detonation and that allows for more compression, hotter running, more advance, before detonation sets in and for a tuned motor, those attributes are all positives, but like most things, they are a compromise. Raising compression improves power but lower energy density cuts it, and it's a series of compromises to get the best out of a given motor combination.

Most of use go heavy on octane - just in case - because a meltdown costs more than the extra fuel cost. With a stock or mild bike we have found we get better results with 89 or 91 octane street gas than most race gas but the risk of meltdown is increased.
 
It's true that the flame propagation of Avgas is designed around an approximate 4000 rpm cruise engine speed. I doubt any human could outwardly tell the difference, but it's likely measurable via data logger. I run 91 or 93 in my bike and get noticeable pinging with 87. However, I think 87 when not pinging actually gives better performance. So again, it's a balancing act.
 
teazer said:
That's odd. I just checked Sunoco 110 (Standard) and it has zero oxygen ie no ethanol. I wonder what was in that fuel or was that damage caused by street gas prior to use of Sunoco.

Stay away from Avgas which is slow burning fuel designed for very slow revving motors. You want great throttle response try U44 but flush it out after use. Drag motors need enough octane to resist detonation at WOT and high revs. C12 is a basic race gas that works well but something like Maximal from Sunoco is pretty tolerant of hot motors, high load and hot days and works with a lot of ignition advance.

Try different fuels on the dyno where you can adjust different parameters safely and get repeatable results.

Your right! there isn't a drop of alcohol in the standard 110. I did add octane booster when it was on pump gas, probably too much. The water had to have been from the 500 gallon bulk tank that was above ground. I replaced the pump, and filter sock, cleaned the tank and it ran great until it warmed up. The fuel pressure was steady until it got to the track. Then back to the gauge needle bouncing between 15 and 23 lbs while revving the engine. The Fuel regulator was hot to touch. After it cools down back to normal pressure.

I have a 6:1 regulator so I'll give that a whirl.
 
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