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Discussion Starter · #1 ·
Local airport is selling gas for $2.00 per gallon.
My questions are.
Is the octane rating system the same for Aviation fuel as it is for automotive fuel?
Will aviation fuel hurt anything in the fuel system on our TR's?
TIA. -Matt-
 

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Av gas (100 LL) is very dry & needs a top cylinder lube added such as Marvel Mystery Oil to protect the moving parts in your car's fuel system. It also has a healthy dose of tetra-ethyl lead in it which will kill O2 sensors & the catalytic converter. AV gas also has a lower energy potential than automotive gas (pump or race) so you have to run the car richer to get the same result with av gas versus an auto gas of the same octane level.

The octane rating method is a little different than for cars, they use a supercharged engine to get a performance number which runs around 115~117 & then a "regular" octane engine to get the motor octane rating which can be a bit deceiving for automotive use. When run by the normal RON / MON method the RON is around 103.5 & the MON is right around 98~99.

Doug C.

<small>[ August 15, 2003, 11:30 AM: Message edited by: CaptainInsane-O ]</small>
 

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Discussion Starter · #3 ·
Ok.
Well. For the extra 20 cents more than a gallon of premium. It seems worth it.
How much marvel mystery oil do you add per gallon.
TIA.
 

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100 LL has about 2 grams of lead per gallon. Plenty to eat your o2 sensor. Use a Denso sensor in that case.

The 100LL comes pretty close to being 100 octane and actually works well in our cars as attested by many in prior threads.

The weight of a gallon of 100LL is about 5.9 lbs whereas race gas is often 6.1-6.3 lbs/gal. With a carbed car, it may need rejetting just as changing from one type of race gas to another brand. See the VP site for the variation in weights among different grades of race gas.

With fuel injected cars and conventional chips, the computer should take care of that potential difference, I believe.

AV gas has a high degree of aromatics in it which may slow down spool. Xylene is an aromatic as are Toluene and Benzene from what I have read. So this problem should not be anyworse, if as bad, as mixing up a tank of Xylene/pump gas.

AV gasolines are typically blended for fairly low rpm ranges and does not work well in an 8000 rpm pro stock engine.

As long as you realize that AVgass (100LL) is not a racing gasoline, it will work quite well. Maybe a bit better than 100 no lead, but not much.

If you do a search online, you will find some pretty factual information.

My advice is to try it and make up you own mind. :)
 

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Discussion Starter · #5 ·
Point taken Steve about using it for racing.
I just want something with a bit more kick to it than premium. I don't plan on running alot of miles on it for the remaining part of the year.
How long does a denso sensor last on this stuff.
I put a new sensor in within a year ago and I don't have many miles on it. (It was an AC sensor)
 

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~1 ounce of MMO per gallon of av gas will be plenty.

Steve, actually 99% of the various brands of 100LL av gases that I've tested over the years have used alkylate as the "base" stock & had no more xylene/toluene than good 'ol non-oxygenated pump gas does.

Alkylate is similar to toluene/xylene in that it has a fairly low RVP (4~4.5) and the RON & MON numbers aren't too far off from each other (93~94 RON & 90~91 MON) either which makes for a nice stable blending base.

Doug C.
 

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That's interesting...I was quoting the the 76 site, I think.

I always figured that was why C16 spools slow...loaded up with aromatics. Some places overseas use a lot more in their gasoline that what we are allowed to hear, so I have read.
 
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