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Av Fuel

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Posted by: bigred455---------------------

I have my head set up on border line with race fuel. I tested it at the track the first day. No problems,I am running mobil 93. The next day the usual mobil I go to was shut down for a hr ,so I wen't to another one on the way to the track.I started getting into the next batch of gas and she was knocking way down low, came home tore it apart and everything looked good whooooo!!!!! Kind of makes sense why she was knocking down low and not up top corrected compression ratio(longer effective stroke) Their is no way I am paying 6.00 a gallon for race fuel,the airport is right up the street 2.35 for 100LL. This fuel is really clean and highly regulated,stays for a year also!!!!!!!!!!! So did my bike run lean with this fuel, no she was rich up top,stock main is 165,I have it pretty dam close with a 160.Pump fuel specific gravity .73 and av is .71,but I will tell you this she ran richer. So all you hear about lower specific gravity fuels running leaner is false well with av fuel anyway.Going down on the main, believe it or not woke up the bottom also. I was really amazed how well this fuel reacts to jetting changes very positive. Their were times when I made a jetting change with pump fuel and I could not for the life of me tell the difference.I am taking my needle clip for a walk on the wild side and see what I get,then the pilot.This fuel burns very clean,I have a few lead deposits on my plug,but I guess that is normal with the lead. I love jetting with this fuel and the price is only .70 more than premium unleaded,plus you know it is quality fuel. How can you go wrong!!!!!!!!! I am a jetting junkie now.


Posted by: Okiewan---------------------

uhhh...


Posted by: MikeS---------------------

Oh boy

 

If you are happy we are too.

Av gas may be better than some pump gas but I will leave it at that.


Posted by: bigred455---------------------

mistake


Posted by: bigred455---------------------

Quote:
Originally posted by Okiewan
uhhh...
..........


Hmnnnnnnnnnnnnnnn!!!!!!!!!!!


Posted by: Okiewan---------------------

Tried a search in these forums for this topic?


Posted by: MrLuckey---------------------

Sorry my post can't be longer but I am headed to the airport. Apparently they are having a big run on av gas all of a sudden


Posted by: Jaybird---------------------

I have run avgas LL110 with no problems. You will sacrifice a bit of throttle response and ability to obtain peak performance opposed to a proper race fuel, but the consistency of Avgas is far superior to that of the pump albeit not the cleanest buring fuel you will find.

If you are a serious racer looking for optimum performance, stay away...if you are looking for something more consistant than the pump, go for it.

Alot of guys will blow you off of Avgas, but I'd be willing to bet most of them are giving "I read it" advise and never used it. But again, it's not the best choice for a short intake motorbike. It was designed for a longer intake and running at consistant RPM's at high altitudes. More pains are taken at the refinery to keep it more consistant than pump fuel. But, there is stuff in it that doesn't suit our needs.

If you are torn between mixing a good fuel like C12 with pump fuel, and running Avgas...run the airplane fuel and save your money.


Posted by: bigred455---------------------

Good reply Jaybird,You are correct about riders who say, stay away from av gas they are the ones who read all the bad myths about it.I know when I buy avgas I do not have to worry about it being bad or inconsistent. Like I said it is highly regulated think about it,lives are at stake!!!!!!!!!! . I really get a kick out of making a jetting change and the way it responds, being better or worse. Very definite compared to pump.


Posted by: rv6junkie---------------------

When I drain the tanks in my aircraft I always put the fuel in my airport moped. Man, I tell you, this is the fastest moped in the world. I can get over to the FBO about 3 seconds faster than anyone else. That 100LL makes it scream! The lawn mower doesn’t seem to run any better on it though. The lawn mower likes a 50/50 mix of Jack Daniels and septic sludge.

100LL (don’t be fooled by “low lead” because is has Lots of Lead – just less than the 130 AvGas it replaced) isn’t 100 octane, at least by the pump standard you are use to. Using the auto pump formula it works out to be about 91 octane. That might be a higher number than what you are getting from 92/93 from a gas station. AvGas just wasn’t designed to work in a 2-stroke dirt bike environment. It was designed to run at low rpm’s with constant throttle positions at high altitude. And as you stated, part of its milspec is that it have a long shelf life.

Something to think about…To obtain good throttle response and reduce detonation, most airshow performers mix their AvGas with RACE fuel!!!


Posted by: bigred455---------------------

AV GAS LL RON:105-110.
MON 100-102.

PREMIUM UNLEADED RON:96.
MON 85-86. .

We will take the lowest numbers for av. 105+100/2=102.5.

now for premium unleaded. 96+85/2=90.5......

With all do respect your statement is false.

You are correct though on the lead being less than the 130,but still plenty of lead.,


Posted by: rv6junkie---------------------

Now you've done it! I'm gonna have to dig through about 2 feet of paper to prove my point. I hate that!

I do stand behind all of my other comments though; well except for the moped and the lawnmower comments.


Posted by: Jaybird---------------------

I think red may be correct on the ron/mon ratings of 100LL.


Posted by: bigred455---------------------

Quote:
Originally posted by RV6junkie
Now you've done it! I'm gonna have to dig through about 2 feet of paper to prove my point. I hate that!

I do stand behind all of my other comments though; well except for the moped and the lawnmower comments.
........

LOL .


Posted by: PeteN---------------------

RV6junkie, bigred is right on the octane #s. I work for the company that very likely makes the fuel contol in your plane, so I am familiar with 100LL specs. I also run 100LL/pump gas mix in my CRF.



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