How does someone go about using av gas. I can get some from the local air port(probably 100 octane) but I was told to mix in a litre of trans fluid for every 5 gallons. Is this true or was he full of sh**.

Dino

There will probably be alot of opinions on this...but I definately would not do that. You will probably have to rejet if you run this fuel, but IMO it is a good, cheap fuel with 100 octane and lead. (so do NOT use in a converter car!!) I have ran this in everything from my seadoo to my 90 SS 454. I started using it when I began working on P-51 mustangs (V-12, 1650 hp), and thats what we ran in those. many do not like this fuel but even Chevy High Performance's Julys engine build runs it.

Not a good idea. AvGAs may be cheaper than racing gas, but also is formulated for high altitude use. This means that the specific gravity of the fuel is much different than racing fuel or gasoline. What this means is that unless you rejet your carb, you will run lean as a devil.

Try Toluene (RON114),....it's the aromatic (along with xylene) that is added to gasoline to enhance octane. It's much cheaper to make your own. Go to my links site at http://www.inccn.net/jackstandslinks.htm and check out the fuel/octane sites.

Stick with good o'l TURBO BLUE you can't go wrong. Sure it's a little on the expensive side but it's worth it.

Sorry to invade with my import world, but 76 Gas Station are offering Cool Blue 100 Octane at 5 bucks a gallon. Where as better octane equals better boost for turbo cars some are seeing as much as 25-35 HP increases with 0 knock and ping. Just a suggestion.

Ron

Also A friend of mine uses Xylene in his car a paint thinner found at most Hardware stores. He's pressed his boost up almost 20% with no issues.

Do not use 'Av-Gas'.....period. The fuel itself is acidic in nature and will break down rubber fuel line as well as internal rubber parts of carburators. Unless you flush the fuel system or dilute the Av-Gas so much that it wouldnt raise the R/M octane number enough to do any good.

Using Av-gas or racing fuel without rejetting your carburator is an ABSOLUTE waste of money.....unless you are just doing it for the aromatics.

HOTRODSRJ has brought up some other valuable points concerning the formulation towards high altitude.

As for other additives such as xylene and tolulene, it is up to the amount of what you mix. You can always improve it, but it you mix in too much, that too is a bad thing.

You really need to figureout what you are trying to accomplish first before you just run out and start buying this kinda stuff. Like figuring out some octane numbers for starters. You will ned to pay attention to the motor ocatne number as well as the R/M2 octane numbers to get your mixture and base fuel requirements to blend the octane numbers you calculate.

Other than that it would just be a waste of time and money with out re-jetting for a peticular fuel octane and timing curve.

If you are talking about the BBC in your sig, you shouldn't need racing fuel, IMO your cam is big enough to bleed off enough cylinder pressure for pump gas. You would probably run faster on a good quality pump premium anyway.

For some reason my 383 (11.3:1 static compression Comp 294s cam) like BP 93 octane. Likes it better than even Amoco or Mobil 93 believe it or not. Race gas smooths the idle out, but doesn't really do anything for my trap speed.

That brew your own article sounds like "how to cut gas". None of the brews I saw boosted the octane over 100.

I think the 1st thing to do rather than try and play chemist is figure out what octane you need in the 1st place.

The next question I have is, assuming this is even logical: If you blend (or mix) gas how do you achieve or calculate the octane rating of say:

x gallons of premium (94) gas and X gallons of $6/gallon 115 octane gas - yields a tank of 106 octane gas.

Or is it best to just buy a drum of 106 octane gas and forget about mixing my own?

Sorry to but in guys, but I've been running avi gas in the same engine for the past 5 years. Never had a problem or a ping at 13:1. I'm not technical enough to back up with octane or specific gravity. All I know is I talked to the mechanic at the local airport and he told me that 100 is the minimum octane in the tank and that in reality it is closer to 103-105. I don't know how true that is but from experience I've never had a problem. I had this engine in my pulling truck before I put it in the 69 and at times it sat for 6 months at a time with left over fuel in the cell and never had rubber break down or carb problems. I also ran sunoco racing gas at 5 dollars a gallon and the avi gas perfomed better. So at 2.20 a gallon I'm running avi.

I've posted a whole bunch of info on this suject as well as the gallon of Toluene, quart of Diesel and pint of ATF formula.

Do a search for the info if you want to.

pdq67

Another thing to remember is that you dont get a true 'plug reading' when using Av-Gas either. This may throw you for a loop when tuning mixture without a stich guage, EGT or Ox sensor.

To explain the key differences between avgas and automobile gasoline...... The 5 key differences are in: octane, volatility, composition, detergents/additives, and handling. Other considerations taken into account when developing their experimental fuels were: emissions, deposits, toxicity, environmental "friendliness", oil/material compatibility, and handling. To point out the difficulties in developing a fuel that was able to tolerate the large range in operating conditions (temperature, pressure, etc.) under which airplane engines operate. To also point out that any fuel problems in an automobile would mean inconvenience to the operator, whereas fuel problems in an airplane would likely result in fatalities. Considering all of the testing that must be conducted (different conditions, different engine/airframe combinations, toxicity, etc.), the approvals from FAA that must be obtained, the acceptance by the aviation industry, other petroleum companies, distributers, etc. that must be obtained, a realistic timeframe for implementation of an unleaded high-octane avgas is probably 8 to 10 years. This doesnt even touch or sum up the environmental issues...........

It was reported to a workgroup that earlier this year a lead-free NASCAR race was held and sponsored by Unical. This indicates that there is potential to move away from alkyl-lead in competition vehicles.

Here is a great thread about the blending of fuel for automotive use concerning tolulene and or xylene.....its a good read:

http://www.eng-tips.com/gviewthread.cfm/lev2/6/lev3/35/pid/71/qid/41617

This is also a great link concerning D86 100 octane Avaition fuel:

http://www.chevron.com/prodserv/fuels/bulletin/aviationfuel/8_ag_perf.shtm

And I will quote a statement about it breaking down rubber elastometers used in automotive systems and why not to use it in said system:

Storage Stability Avgas instability involves multi-step reactions, some of which are oxidation reactions. Hydroperoxides and peroxides are the initial reaction products. These products remain dissolved in the fuel but may attack and shorten the life of some fuel system elastomers. Additional reactions result in the formation of soluble gums and insoluble particulates. These products may clog fuel filters and deposit on the walls of aircraft fuel systems, restricting flow in small-diameter passageways.

I think this will just about sum it up......... :D

Aviation people dont want you using auto gas, becaues it hurts their busines, automotive people dont want you using Av gas because you dont pay tax on it. See a conspiracy here? the storage problems quoted, also goes on to say for Av gas this is less of a problem due to the lead content.I would take year old Av gas over car gas any day. The rubber parts you are worried about in automotive systems are the same in Aircraft. Aeroquip rubber hose, rubber needle in the carburetors, and the fuel injectors in aviation have more rubber parts than you can imagine and a large part have rubber fuel cells. over 50,000 STC's have been issued to run car gas in airplanes, (they use to say car gas hurt aircraft rubber parts)Now the FAA has allowed them to run car gas in aircraft. If its specific gravity you are worried about, it runs along the lines of VP-C14 fuels. A lower specific # just means you'll need to jet up, (less mass flow)and a slower burn rate which is what you are after anyway?The fuel is better refined so there is considerably less thrash in the Av fuel.I'm not saying its better than racing fuel,and I dont want to offend anyone but the stories you hear about Av gas is not consistent. How long did we complain when they took lead out of our car gas?
100 octane plus lead for a couple of bucks? :confused:

The rubber used in aviation fuel systems is made up of "viton", which just happends to be chemically resistant. So good that automotive carburator manufacturers started using it. Also not forgetting to mention that the content of any length of "rubber" fuel line is kept to a minimum, it is mainly comprised of hard line (Aeroquip uses a high viton content in its fuel line, noticable in the cost of the line itself). And as for the fuel bladders they consist of nylon, coated with urethane......which is also chemically resistant. The actual rubber content is less than conceived and the rubber parts used, do not have that much natural rubber in it either.

I can attest to automotive fuel systems having problems with Av-Gas. Half of the people running sand rails in the desert use it......and everytime I hear people complaining about their rails not running up to snuff, I ask them what kind of fuel they are running. When I hear "Av-Gas".......I go right to the jet feed wells, air corrector jet and the needle and seat on carbs (Solex, Delorto, Mikuni and Weber) and as the Av-Gas seperates it solidifies and crystalization forms on these parts, which makes them 'sticky' in their operation. So bad, that it takes brake or carburator cleaner to free them up.

Conspiracy? ABSOLUTLY!! The biggest complaint will always be the taxation.

Call your local o-ring dealer and viton is now the common for most products,Av gas has been around alot longer than all of the new elastomers like aeroquips AQP used in their hoses. As far as length? firewall forward will be flex line with a minimum of about 20" and up to several feet for a turbocharged IO-540 with the pump, controllers injector etc.,lines. My vehicles from tank to bowl might have 7". High prices are for lots of insurance, and two or three middle men to buy aeroquip parts. Nylon fuel cells? maybe in the sixties, Vulcanized rubber, in modern era. A coat of urethane if you have a wet wing(no bladder).With less toluene in Av gas, you have less problems with breaking down "rubber" than with car gas.Maybe the sand rails have brewed up fuels with toluene, diesel, ATF? I cant say. I can attest to 10 years of day in day out of overhauling aircraft fuel systems that never have I seen a gummed up system due to Av gas, they are meticulously clean. When they have used auto gas and let them sit for 2 years which is normal, then they will have problems of gumming up...... I know I will be black balled when I start asking how to get my big block Camaro to hook up and I really respect most of the input on this site it has helpful countless times....

Stick to pump gas, like Eric68 said, you should be able to run it.
Some race fuels leave a black (carbon like) film in the runners, this alone
will hurt performance.
I noticed in your sig you wanna run low 12 / high 11... pull your time in that,
and not fuels, (I've seen too many cars pick up 1 to 3 tenths by switching TO
pump gas) So swap those 4.88 gears for some 4.10s and get a good single
plane for it - it should run 11s easy, if not 10s. ;)

LL100 AV gas is all I have ever used in my engines. I have had no ping, no rubber deteration problems, and have had GREAT performance with the stuff.
I am no chemist, nor claim to be an expert on fuels, but from my experience and in my applications...........the stuff has been great!

AS you stated touchngo, meticulously clean.....someting most automotive systems are not. Not to forget to mention that we normally drive our vehicles enough that it doesnt have time to sit around and culminate (with automotive petrol).

As for the nylon in fuel cells....it is still used today in the experimental and production aircraft I have been associated with (which you have heard quite a-bit about over the last two 'Desert Wars' we have participated in) so I find you're comment to have very little if any validity to it.....not to mention that nylon and urethane bladders (wet or dry) are used specifically in aerospace (military and private) as well as NASCAR, SCCA, SCTA and other sanctions for fuel cells today. Meaning nylon, kevlar or other aramid woven fabric, encased in a 'rubber'/urethane coating....a soft bladder, not rigid like I think that you were going towards in though.

AS for urethane, it too is used in fuel cells right next to nylon in dry and wet wing configurations. I know this because I have been in the aerospace development community for the last 15+ years, specifically dealing with and developing these products. Not to mention being around aviation for my entire life, (I have maintenance and stick time dated back to the early/to mid 70's). It is most likely that you are working with aircraft that were produced back in the 60's, 70's and 80's (most of Cessna, Piper, Mooney and Beachcraft that are still flown today were produced in that time frame).

Fuel, when in contact with metal fuel cells (aluminum, steel-stainless or other and titanium) will have a reaction from a thing or two....the main being a thermal characteristic difference which add's to the avialable possibility of creating condensation in the cell itself. Most bladders or 'wet wing' (urethane) systems being that they are coated, dont fall victim to this because it acts as insulation to combat condensation inside or out the cell itself (de-icing and condenasation).

An answer to the sand rail part; The system includes an aluminum tank, brass fittings or aluminum AN, rubber fuel hose, a fuel pump/regulator and the carbs themselves. Those whom I have delt with who run AvGas dont add tolulene, xylene, diesel or ATF......they run strait AvGas. I am not saying that all systems that I have come in contact with have these said problems but 90% of the time when there is a fuel related problem, it is related to AvGas.

TOUCHNGO- These are just my findings and I am NOT saying that you are wrong in any manner but dealing with things that most people dont get the opportunity to experience, and solving the problems at hand, may shed some new light on things not yet experienced by many.

smile.gif smile.gif

Desert Storm?? I thought we were dealing with Av gas, not Unical,sunoco, or Jet A..... The validity of my point is as stated, If you buy a bladder for 110LL it will be Rubber, not nylon. Since your "stick" time and maintenance goes way back, then you should know they produced a nylon tank but stopped in 1969 because they were too brittle. Nylon may be used in forming, then encased in rubber, so is cotton and many other fibers. Yes I'm dealing with Cessnas etc.....thats what uses this fuel, not Boeing, military...

As for fuel not contacting metal in wet wings, the entire wing is not coated, just the joints, flap hinge brackets etc. So fuel is in constant contact with metal. Maybe in jets but not 100LL applications.

As far as condenastion, this happens too. The worst enemy of fuel cells is water. As you know, you check the sumps before flight to check for water. Keeping tanks topped is most important! 1) to help with the condensation and 2) the fuel lubricates the bladder.

These are not my findings, just how it is with real applications using 100LL.

The higher ignition temp of about 500 celsius,(which is where the "blended for high attitude" comes from) less potential to vapor lock, cleaner, longer lasting, some amounts of lead,lower specific gravity is all fine if your application needs it. If not, dont consider using it.

No not Jets, not Boeing and yes AvGas....the UAV facet (tier 2 and tier 3). I was not eluding to Jet aircraft.

The nylon type I was refering to in the first place........a non rigid or 'encased' cell. The only place they really use rigid or semi rigid anymore is in off road racing (class 7 and class 10 unlimited). But you're point is now understood, I see where you're going with it and I agree. I see that we were basically talking about the same things, just not fully explaining some needed specifics.

graemlins/thumbsup.gif

Aviation gas is 6lb/gal. I don't think trans fluid is advisable since you'ld be looking worse than a 2 cycle engine burning oil.

whats the RPO number for the "wet wing" option in a first gen anyway? ;)