racing gasoline

[Truckedup]

VP got back to me and without any doubt recommended this fuel ,U4-4 .The bike will be raced at the Ohio Mile,VP is the fuel you must use...




http://www.vpracingfuels.com/motoroadracing.html

[Tuner]

There is a need here to take care not confuse grams mass and milliliters in ASTM D-910.

The permissible maximum elemental Lead content allowed is .56 gm / liter = 2.12 gm / gal. That is the amount of elemental Lead by grams weight - not the volume liquid of TEL fluid.

The quoted amount of Lead per gallon is confusing because it isn’t always clear that in some references it is expressed as mass of Elemental Lead and in others it is expressed as volume of TEL fluid, which is only about 45% elemental Lead.

The expressions of volume (mL/L) and mass (gPb/L) are confusing because the specific gravity of TEL and atomic weight of Lead, while self-explanatory to some, are not immediately evident to all readers.

Here in ASTM D910 – 02, it is expressed as Elemental Lead, gPb/L, and TEL/L
http://www.aviation-fuel.com/pdfs/avgas ... tmd910.pdf

The second number in the AN Performance Number 100/130 does not refer to TEL content.

The second number in the AN Performance Number 100/130 refers to the ratio of power increase with normal combustion the fuel will provide in Rich Mixture Rating (Supercharge Test Method D 909) in standard conditions of normal combustion, no knock or preignition.

In Aviation fuel testing, knock is determined by the usual sound method and preignition by a thermocouple in the combustion chamber of the CFR test engine.

Aviation gasoline is blended specifically to be highly resistant to pre-ignition. This is why the Aromatic content (Toluene, etc.) is limited. Aromatics, Benzene, Toluene, Xylene, etc, are very high octane but have ugly pre-ignition thermal characteristics. Specifically, this very repeatable and extremely accurate thermal characteristic is why Benzene is used to calibrate the thermocouple in the ASTM Rich Mixture Rating Supercharge Test Method.

The antifreeze agents are Isopropyl alcohol and
diethyleneglycol monomethyl ether (Di-EGME)


Link to interesting stuff, Octane Test engines and methods.
http://www.runyard.org/jr/CFR/octane1.html


It seems like we go through this every year or two when a new round of “Avgas = Bad (2400 RPM, 20,000 feet, etc, yada-yada) …. Use Race Gas or Your Engine Will Die” pops up. What ever, believe what you will. I have used Avgas for longer than most of you reading this have been alive and it has never let me down, it has nearly always won every dyno HP contest (other than against oxygenated fuel), never contaminated carbs or fuel systems, rotted fuel cell foam or softened rubber hoses or power valves, etc, etc. I used to like race gas because it keeps me busy cleaning fuel systems and repairing carbs. Now, I could care less if people are stupid, pay twice or fout times as much to piss in your own gas tank.

Over the years I have had several episodes of having tuned and run engines, NA, N2O, and supercharged, some of which burned several hundred gallons of Avgas (some with MMT) trouble-free, and when the engine owner’s friends finally beat him down that race gas is what he must use, the race gas kills the engine. WTF is wrong with people? Some have done it twice. Peer pressure on this Avgas thing is crazy. I have friends with airplanes who think they want to run pump gas. Thanks, I’ll walk.

Of benefit to racers who burn a lot of fuel in a day, 50-100 + gallons, boat racing, road racing, circle track, desert racing, etc, is the fact that Avgas is Leaded Alkylate and the addition of MMT to Leaded Alkylate raises the anti knock value appreciably, in fact, several octane numbers. A bottle of Amsoil Dominator octane booster to a 55 gal. drum of Avgas ran 750 gallons through a 14.8/1 434 18° SBC in a desert racing truck with no problems at all, just check the valve lash, change the oil, maybe new plugs, go race. 20 miles with ‘race gas’ made a $20,000 pile of junk.

[pdq67]

Go the Code of Federal Regulations (CFR) fuel section if you want to know what is legal..

I deal with 40 CFR so really don't look farther is all.

pdq67

[numboltz]

The Octane scale and rating was developed before WW2 started, but it wasn't of any great interest except in military aircraft. 100% Iso-Octane* gives an Octane rating of 100, and a 50% Heptane/50% Iso-octane blend gave a 50 Octane number, both as tested in the CFR knock engine. Obviously, you can't have more than 100 Octane with this scale.
So if you had an unknown test fuel that knocked with the same load and compression ratio as a 50/50 normal heptane and iso-octane blend in the CFR engine you had a 50 octane fuel.

Pretty quickly in WW2 they realized highly supercharged aero engines needed even better fuels than 100 Octane, so developed the PN [performance number] scale in 1943. The PN scale crosses the Octane scale at 100, so 100 Octane equals 100PN. The war was fought mainly with 100/130 Avgas, This means that the fuel had a 100PN [lean] and 130PN [rich.] They used the standard CFR engine, but supercharged, to test PN.

With 100/130 Avgas a supercharged engine that was knock limited at 1000 HP [lean mixture] could develop 1300 HP with a rich fuel mixture before the knock limit was reached. Many combat piston engines were not operated at WOT and had more boost available if the throttle was opened more. That's where "war emergency" power ratings came from.

The effect of TEL on octane rating/PN varies a lot with different base stocks. It seems that base stocks like iso-octane that already have high ratings tend be be highly sensitive to TEL. 1 US gallon of Iso- Octane and 1cc TEL equals a PN of 125, and bringing that up to 6cc gives a PN of 161. So if you find some branch-chained paraffin base stock to use, adding a little TEL will help a lot. Generally speaking, 6cc/gallon is a LOT of TEL.

The highest PN numbers reported were 260/260 and the knock limit was replaced by the crank limit.

* apparently there are many Octanes [18], some of them with a very low Octane rating. Iso-Octane is the good one.

[leahymtsps]

VP got back to me and without any doubt recommended this fuel ,U4-4 .The bike will be raced at the Ohio Mile,VP is the fuel you must use...




http://www.vpracingfuels.com/motoroadracing.html

While U4.4 should produce more power than any of the other fuels you mentioned, it's highly oxygenated and does elevate combustion chamber temperatures. You
will have to jet up at least 4 sizes on the mains especially on air cooled engines. On engines that are run lean it's not uncommon to find heads with cracks from the
plug threads to the exhaust seat.

Tom

[David Redszus]

Aviation gasoline is blended specifically to be highly resistant to pre-ignition. This is why the Aromatic content (Toluene, etc.) is limited. Aromatics, Benzene, Toluene, Xylene, etc, are very high octane but have ugly pre-ignition thermal characteristics.

The aromatic content of AVGAS is limited not due to pre-igntion resistance but rather due to the formation of unburned fuel carbon deposits.

The pre-ignition characteristics of a fuel component are a function of light fraction boiling point and auto-ignition temperature. For typical fuel aromatics, both values are on the high side. Auto-ignition temperatures for selected aromatics and paraffins is as follows:

Aromatics
Toluene 1054F
Ethylbenzene 860F
oXylene 934F
mXylene 1045F
pXylene 1048F

Paraffins
Triptane 849F
224TMP 837F
223 TMP 806F
234TMP 800F

Aromatics have much greater resistance to pre-igntion than paraffins but are also much harder to ignite.

The effect of TEL on octane rating/PN varies a lot with different base stocks. It seems that base stocks like iso-octane that already have high ratings tend be be highly sensitive to TEL.

Indeed the response of a fuel to TEL very much depends on the base stock and TEL level. Each fuel component has a specific response to the addition of TEL (or TML). For selected fuel components:

First number = octane @ 0 TEL (g/gal)
Second number = octane @ 4 TEL (g/gal)

Aromatics
Toluene 109...114
Ethylbenzene 98...105
oXylene 100...100
mXylene 115...121
pXylene 110...122
Indolene 107...104
Paraffins
Triptane 101...120
224TMP 100...118
223 TMP 100...115
234TMP 96...109

apparently there are many Octanes [18], some of them with a very low Octane rating. Iso-Octane is the good one.

There are 18 octanes including 17 iso-0ctanes. Iso-octanes will range in octane value, i.e. nOctane = 0, through various iso-octane values of 23, 35, 39, 56, 89, ...up to 100. There are only two iso-octanes that have octane ratings of 100. Some iso-octanes have very similar boiling points (but wide ranging octane values) which does not permit easy separation by fractional distillation but requires more expensive sepraration techniques.

It is interesting to note there are over 40,000 different hydrocarbon compounds, each with different physical and chemical characteristics. Only about 500 such compounds are normally found in fuels.

[Tuner]

David, I am aware of the self ignition temperatures in atmospheric conditions and the apparent contradiction in a running engine regarding Toluene.

My remark stands, “Aviation gasoline is blended to be highly resistant to pre-ignition” because it is so.

Aviation gasoline is blended for aircraft safety. Aromatics are limited for several reasons other than combustion characteristics. Your observation about carbon buildup and soot formation by Aromatics is a good point. Carbon deposits cause preignition.

Another reason Aromatics are limited is they cause deterioration of soft parts of fuel systems, seals, gaskets, diaphragms, etc, and that is obviously not safe.

The remark, “This is why the Aromatic content (Toluene, etc.) is limited. Aromatics, Benzene, Toluene, Xylene, etc, are very high octane but have ugly pre-ignition thermal characteristics,” is referring to the “ugly pre-ignition thermal characteristics” and specifically the high temperature spike resulting from aromatics when they do ignite in such conditions. (Hence the reference to Benzene for setting the Match Temperature in the Aviation Fuel Test.)

I know you study the NACA literature, take a close look at Report 1926, “NACA Investigation Of Fuel Performance In Piston-Type Engines” by Henry C. Barnett (and other reports) and you will see Aromatics have very high anti-knock values but in a running engine they don’t have as good preignition characteristics as alkylates, in spite of high self ignition temperatures in atmospheric conditions.

Interesting that the lower Hydrogen to Carbon ratio of Aromatics results in less water formation and so a higher combustion and exhaust temperature. Water acts as an internal coolant whether it results from combustion or is introduced.

[BrazilianZ28Camaro]

Excellent topic.

A factor that got my atention is why the N/A airplane engines have such a low CR if they can breathe cold air and burn higher octane fuel?

If the air is scarce at altitude, wouldn't higher CR be desirable to better fuel efficiency?

Those engines also have the Air fuel charge heated before entering the heads/intake (for obvious reasons).

This, along other factors makes me believe AV gas must have specific characteristics to work very well , on those engines.

[David Redszus]

Excellent topic.

A factor that got my atention is why the N/A airplane engines have such a low CR if they can breathe cold air and burn higher octane fuel?

If the air is scarce at altitude, wouldn't higher CR be desirable to better fuel efficiency?

Those engines also have the Air fuel charge heated before entering the heads/intake (for obvious reasons).

This, along other factors makes me believe AV gas must have specific characteristics to work very well , on those engines.

Piston powered aircraft engines must operate over a wide range of conditions; from sea level to high altitude. The inlet air density varies considerably. At higher altitudes, lower air density, and partial throttle operation allows a leaner mixture to be used for the sake of economy. At take-off, higher air density, and full throttle operation required a lower compression ratio and higher octane numbers. The compromise is to substantially enrich the mixture during take-off and then lean the mixture back to normal values. Rich take-off mixtures are on the order of of 13.4:1 (assuming a stoich of 14.7).

There is a difference between automotive octane ratings and aviation octane values. Below 100, they are almost the same. Above 100 they are not and are called Performance Numbers. An AVGAS Performance Number 130, running in rich operation would have an equivalent automotive octane value of approx 110.

So the question then becomes, what is the true octane value of a race fuel when run in a rich condition? How rich is rich?

AVGAS blends often contain isopropyl alcohol as an anti-freeze agent. The addition of isopropyl will reduce the octane value of the fuel.

[pdq67]

I'm going to say this one more time!!

Hunt up a supply of regular unleaded gasoline and then add Kemco130 Lead Supreme up to the octane number you want that will run the best in your engine.

As always, jmho.

I gotta feeling that too many here are over thinking this is all. Trying to help....

Oh, and btw, EPA is SLOWLY going after lead-containing Avgas, so beware.... They are monitoring airports for lead fuel pollution now...

pdq67

He, He!! Altho not funny at all because next will be the exterior ventilating systems at indoor gun ranges....

[just primer]

I cannot speak to " Kemco130 Lead Supreme". However, I once had a barn burner that "Darrel and his brother Darrel built and I use many octane boosters in an attempt to meet the flat top pistons that they installed in my junk yard special. None of them seemed to do anything, I still had the same detonation. Even with two bottles or more. Then latter I read that the octane point as described on the bottle was really in tenth's of a point and I would have been better off putting the dollars in a jar and save up for some new pistons. I too ran half AV gas half 91 and it ran great. Should have seen the airplane guys look at me as I brought a gas can into the airport. I was also told that It was a dry gas and it would ruin my engine. I didn't see any negative results from fuel.

[David Redszus]

TEL, tetraethylead, is a very, very dangerous compound to handle and be around in undiluted form. It is extremely hazardous and can be absorbed by vapor inhalation, or exposure to the skin. It will kill you.

If you insist on handling this stuff in pure (98%) form, wear the proper respirator and gloves.

It makes a lot more sense to buy a very high octane race fuel (119-120) which already contains a substantial amount of TEL, and then blend it back using some other hydrocarbon fuels. Avoid pump gas since it is so very inconsistent from batch to batch, month to month.

The overall best additive to increase octane numbers is mXylene which starts as 115 MON unleaded and is very responsive to the addition of lead.

Some oxygenates are also very responsive to the addition of small amounts of TEL.

[eikoor]

I'm going to say this one more time!!

Hunt up a supply of regular unleaded gasoline and then add Kemco130 Lead Supreme up to the octane number you want that will run the best in your engine.

As always, jmho.

I gotta feeling that too many here are over thinking this is all. Trying to help....

Oh, and btw, EPA is SLOWLY going after lead-containing Avgas, so beware.... They are monitoring airports for lead fuel pollution now...

pdq67

He, He!! Altho not funny at all because next will be the exterior ventilating systems at indoor gun ranges....

I looked this up and it looks good but about $4 more a gallon than you can buy VP110 for and you don't get near that octane, have you used this with good results and how much compression?

[raynorshine]

TEL, tetraethylead, is a very, very dangerous compound to handle and be around in undiluted form. It is extremely hazardous and can be absorbed by vapor inhalation, or exposure to the skin. It will kill you.
If you insist on handling this stuff in pure (98%) form, wear the proper respirator and gloves.

It makes a lot more sense to buy a very high octane race fuel (119-120) which already contains a substantial amount of TEL, and then blend it back using some other hydrocarbon fuels. Avoid pump gas since it is so very inconsistent from batch to batch, month to month.

The overall best additive to increase octane numbers is mXylene which starts as 115 MON unleaded and is very responsive to the addition of lead.

Some oxygenates are also very responsive to the addition of small amounts of TEL.

-X2 on the safety...worked in a refinery and only a very very small group had access or anything to do with TEL

[Cashflow]

I just have one quick question regarding this discussion. Does anyone know if VP fuels owns a supercharged knock engine?