Fuel Recommendation

[randy331]

Who ever said you cant run avgas successfully. The real myth is what you believe ↓↓MYTH BUSTED↓↓
You can run and tune for avgas but is it optimal? Unless you have a low compression application probably not.

There are many racers and teams that blend there own fuels but the mass just buy the general racing fuel for there application.

Copy and paste from

http://www.whitfieldoil.com/171.287/rac ... oline.html

"Racing Gasoline vs. Aviation Gasoline
Don't Substitute Aviation Gasoline For Racing Gasoline

Don't substitute Aviation Gasoline for Racing Gasoline unless your race engine operates at 10,000 feet altitude, and does not exceed 2,800 RPM.

Many racers see Aviation Gasoline (AvGas) as a way to reduce the cost of their racing operation. This may be true, but if you want the most out of your engine and want to avoid problems. AvGas may not be your first choice. AvGas is a good gasoline for low speed aircraft engines that run at 2,700 to 2,800 RPM at 10,000 feet or higher. This does not mean it is a good gasoline for racing engines operating at 8,000 to 10,000 RPM. AvGas is also illegal to use in anything except aircraft engines. Violations can carry a potential penalty of $25,000.00 per day of violation.

AvGas octane numbers are determined in a different test than motor gasoline octane numbers. Do not be confused by the big numbers from the AvGas test method. They are not comparable to motor gasoline test numbers. The 110 leaded gasoline will test out at about 160 on the AvGas scale.

AvGas is held to tighter requirements than street gasoline, but not nearly as tight as is the entire line of Racing Gasolines. Some racing gasoline blenders us AvGas as a blending component to save money.

AvGas has a lower specific gravity than most racing gasolines. This means that if a racer tries AvGas and has not re-jetted, he can burn a piston because the air-fuel ratio is too lean and/or the engine detonated. To make a good comparison between two gasolines, the air-fuel mixtures must be the same. Even after re-jetting, the racer can experience burned pistons with AvGas if the Motor Octane Number (MON) is lower than what his or her engine needs.

Another potential problem with AvGas is that there are several different octane grades. The 80/87 grade is red in color and can get you in lots of trouble because of its very low octane number. The 100LL is blue and the 100/130 grade is green. Both of these have much lower Motor Octane Numbers (MON) than most racing gasolines and will detonate when the engine octane demand is greater than the octane number of the gasoline.

The bottom line is: Feed that high dollar racing engine a good grade of gasoline so it will deliver the maximum performance. Don't use "low bidder" mentality."

Debate is over, you all can go on and stay in the dark ages without me and modern tech. GOOD LUCK

You need a much longer post if you want people to believe the AV. gas myths you post.

Randy

[B Original]

Fuel spec comparison should be irrelevant to you considering you haven't grasped the concept of oxidizing and anti oxidizing components yes it will take a library to break down fuel blending and refining crude. You've already got your mind made up being tied to the myth,s of the past and other preconceived beliefs that limit your capabilities those of others that you convince to believe the doctrine of the Flat Earth Society LOL.

I'm done responding to this thread unless someone that's more open-minded decides to contribute.

I'm beginning to understand why Chad Speier was fed up with his group and ask Don to remove him and cut his ties to the membership.

[statsystems]

Fuel spec comparison should be irrelevant to you considering you haven't grasped the concept of oxidizing and anti oxidizing components yes it will take a library to break down fuel blending and refining crude. You've already got your mind made up being tied to the myth,s of the past and other preconceived beliefs that limit your capabilities those of others that you convince to believe the doctrine of the Flat Earth Society LOL.

I'm done responding to this thread unless someone that's more open-minded decides to contribute.

I'm beginning to understand why Chad Speier was fed up with his group and ask Don to remove him and cut his ties to the membership.

Please tell me Chad didn't do that. That will SUCK. Hard.

[GARY C]

Three red flags for me are 1, when I started selling fuel I was taught to tell people that AV gas with hurt your engine among other tricks, 2 the fine mentioned in the article would be the same if you were caught by the right person running any leaded fuel in an unleaded vehicle and could also be imposed on the person that sold them the fuel, 3 all the links on the side of the article are VP links.

Fuel sales gimmicks start resembling the used car salesman if you let them... maybe why I was never good at either.

[B Original]

I'm beginning to understand why Chad Speier was fed up with his group and ask Don to remove him and cut his ties to the membership.

Please tell me Chad didn't do that. That will SUCK. Hard.

Sorry to say, hope he changes his mind as sometimes we take drastic measures in the heat of the moment. But that is what he msg'd me earlier today. He's one of the real assets on this forum.

[GARY C]

I'm beginning to understand why Chad Speier was fed up with his group and ask Don to remove him and cut his ties to the membership.

Please tell me Chad didn't do that. That will SUCK. Hard.

Sorry to say, hope he changes his mind as sometimes we take drastic measures in the heat of the moment. But that is what he msg'd me earlier today. He's one of the real assets on this forum.

The way he gets attacked can you blame him, thats why Vizard and others stopped posting here...If you are on Face Book look them up they share far more there.

[statsystems]

Please tell me Chad didn't do that. That will SUCK. Hard.

Sorry to say, hope he changes his mind as sometimes we take drastic measures in the heat of the moment. But that is what he msg'd me earlier today. He's one of the real assets on this forum.

The way he gets attacked can you blame him, thats why Vizard and others stopped posting here...If you are on Face Book look them up they share far more there.

That's a pisser for sure. I don't do Facebook. I won't do it. So it double sucks for me. DONT DO IT CHAD. HANG IN THERE.

[GARY C]

Sorry to say, hope he changes his mind as sometimes we take drastic measures in the heat of the moment. But that is what he msg'd me earlier today. He's one of the real assets on this forum.

The way he gets attacked can you blame him, thats why Vizard and others stopped posting here...If you are on Face Book look them up they share far more there.

That's a pisser for sure. I don't do Facebook. I won't do it. So it double sucks for me. DONT DO IT CHAD. HANG IN THERE.

I don't blame you on the FB thing, my sister set me up on it years ago and it made me remember why past friends are past friends, I interact with probably 4 people from time to time, read some news feeds and mess with the Global Warming people on the weather channel feed.

[randy331]

Fuel spec comparison should be irrelevant to you considering you haven't grasped the concept of oxidizing and anti oxidizing components yes it will take a library to break down fuel blending and refining crude. You've already got your mind made up being tied to the myth,s of the past and other preconceived beliefs that limit your capabilities those of others that you convince to believe the doctrine of the Flat Earth Society LOL.

I'm done responding to this thread unless someone that's more open-minded decides to contribute.

I'm beginning to understand why Chad Speier was fed up with his group and ask Don to remove him and cut his ties to the membership.

You post a link to whitfieldoil site that is an exact copy of one by renegade fuel with the renegade fuel part removed and think I should take you seriously ? Your posting BS.

From vp, VP110 specific gravity = .720-.735
From vp, Q16 specific gravtiy = .716
From shell, 110LL avgas specific gravity = .718

Tell me how to jet those since you posted a link about avgas and specific gravity.

Have you ever ran avgas ?

Randy

[F-BIRD'88]

I recommend you use the best available local premium pump gas and spike it with real, high octane unleaded racing gasoline to boost its octane up as required. About 30% to 50% by volume will get it done.

Most "octane boosters" are BS. Stick to blending real deal high octane unleaded race gasoline with your best pump gas to increase its octane as required. Ignore the "dynamic compression" BS.
11.85:1 cr is 11.85:1cr. You want a sufficient fuel octane to protect the engine from detonation
when things get hot, in the heat of battle (real racing), ( and it will),,, not under ideal conditions.

[Truckedup]

Who ever said you cant run avgas successfully. The real myth is what you believe ↓↓MYTH BUSTED↓↓
You can run and tune for avgas but is it optimal? Unless you have a low compression application probably not.

There are many racers and teams that blend there own fuels but the mass just buy the general racing fuel for there application.

Copy and paste from

http://www.whitfieldoil.com/171.287/rac ... oline.html

"Racing Gasoline vs. Aviation Gasoline
Don't Substitute Aviation Gasoline For Racing Gasoline

Don't substitute Aviation Gasoline for Racing Gasoline unless your race engine operates at 10,000 feet altitude, and does not exceed 2,800 RPM.

Many racers see Aviation Gasoline (AvGas) as a way to reduce the cost of their racing operation. This may be true, but if you want the most out of your engine and want to avoid problems. AvGas may not be your first choice. AvGas is a good gasoline for low speed aircraft engines that run at 2,700 to 2,800 RPM at 10,000 feet or higher. This does not mean it is a good gasoline for racing engines operating at 8,000 to 10,000 RPM. AvGas is also illegal to use in anything except aircraft engines. Violations can carry a potential penalty of $25,000.00 per day of violation.

AvGas octane numbers are determined in a different test than motor gasoline octane numbers. Do not be confused by the big numbers from the AvGas test method. They are not comparable to motor gasoline test numbers. The 110 leaded gasoline will test out at about 160 on the AvGas scale.

AvGas is held to tighter requirements than street gasoline, but not nearly as tight as is the entire line of Racing Gasolines. Some racing gasoline blenders us AvGas as a blending component to save money.

AvGas has a lower specific gravity than most racing gasolines. This means that if a racer tries AvGas and has not re-jetted, he can burn a piston because the air-fuel ratio is too lean and/or the engine detonated. To make a good comparison between two gasolines, the air-fuel mixtures must be the same. Even after re-jetting, the racer can experience burned pistons with AvGas if the Motor Octane Number (MON) is lower than what his or her engine needs.

Another potential problem with AvGas is that there are several different octane grades. The 80/87 grade is red in color and can get you in lots of trouble because of its very low octane number. The 100LL is blue and the 100/130 grade is green. Both of these have much lower Motor Octane Numbers (MON) than most racing gasolines and will detonate when the engine octane demand is greater than the octane number of the gasoline.

The bottom line is: Feed that high dollar racing engine a good grade of gasoline so it will deliver the maximum performance. Don't use "low bidder" mentality."

Debate is over, you all can go on and stay in the dark ages without me and modern tech. GOOD LUCK

Specific gravity? I use C12 in my race bikes, SG is .717....As far as specific gravity for aviation LL100, according to Sergent Fuel, an aviation fuel distributor, it varies quite a bit which is never good for fixed jetting.....As mention earlier, there's a lot more to fuel than octane..

Avgas 100LL is one of four grades of avgas and is used primarily as fuel for piston-powered craft due to its low flashpoint. Avgas 100LL is a high-octane gasoline which allows a powerful piston engine to burn its fuel efficiently, a quality called "anti-knock" because the engine does not misfire, or "knock." The suffix LL (which stands for “Low Lead”) describes a grade containing lower tetraethyl lead than a second grade of identical lean and rich mixture ratings. Avgas 100LL is a blue liquid with a specific gravity of 0.68-0.74 @ 60ºF (15.6ºC). Sergeant Oil & Gas is a direct distributor of Phillips 66 company and we only sell Avgas 100LL that meets or exceeds the ASTM D910-02 global standards. If you have any further questions, give us a call at 713-266-5778 today!

[David Redszus]

What's wrong with using AVGAS as a racing fuel?

Quite a number of fuel factors make AVGAS less than optimal for use as a racing fuel.
Following is a parametric description of AVGAS and their impact on engine performance.

Vapor Pressure
AVGAS specifications require a Reid Vapor Pressure range of 5.5 to 7.0 psi. That
range is too wide for performance use and is not predictable from batch to batch.

Specific Gravity
AVGAS does not have a Specific Gravity requirement. Aircraft engine fuel mixtures can
be adjusted while in flight and in fact are changed radically from take-off to cruising mode.
The variable Specific Gravity of AVGAS makes it less than desirable for a race car where
mixture is tightly controlled.

Fuel Stoichiometry
The fuel stoich value of AVGAS is undefined. It can range from 14.0 to 15.0, depending
on fuel composition and Specific Gravity. This makes it more difficult to tune air/fuel
mixtures accurately and consistently. Note that neither fuel specific gravity nor stoich
value alone can be used to predict fuel enrichment. Both factors must be used to determine
the fuel amount to be used for a specific air mass.

AVGAS deicer additives
Cold temperatures at high altitudes require the addition of deicer additives to prevent
fuel from freezing. Permissible additives are: ethylene glycol monomethyl ether,
diethylene glycol monomethyl ether and isopropyl alcohol.

AVGAS anti-oxidant additives
Long term storage of AVGAS dictates the addition of anti-oxidants to prevent gum
formation. Anti-oxidant additives are added at the distribution point, not the refinery,
and no control mechanism exists to ensure consistency.

AVGAS additives have the known effect of reducing fuel octane value.

AVGAS Octane
Four grade of octane are available: 80, 91, 100, 100LL based on the motor octane scale.
Fuel enrichment during take-off can raise the effective octane considerably (up to 130 PN).
Since the effective octane is pilot controlled, fuel octane is less important.

Lead content
All AVGAS contains lead additives to increase octane as follows:
80- 0.14 g/l
91- 0.56 g/l
100 - 1.12 g/l
100LL - 0.56 g/l
Lead, while raising octane quite effectively has the undesirable property of building
deposits. Aircraft engines are subject to frequent rebuilding and deposits are not
permitted to accumulate over time.

Distillation curve
The distillation curve for AVGAS specifies certain maximum distillation temperatures but
defines only one minimum temperature point. Therefore, dozens of distillation curves can
be produced while still remaining within specification. Since carefully shaped
distillation curves are critical to the tuning of high performance engines, AVGAS comes
up short on throttle response. Race engine throttle response is finally being recognized
as a critical performance factor while aircraft engines operate a nearly constant
engine speed and throttle with variable propeller load.

min max
10% 167F
40 167 210
50 221
90 275
100 338
Note that the 10% fraction is quite high making the fuel somewhat difficult to
evaporate with a marginal fuel system such as carbs. Aircraft are injected.

In summary
The design of AVGAS is not suitable for race engines due to uncontrolled variables in
RVP, SpG, distillation temps, and additives. While AVGAS comes up short as a good
race fuel, it is still a considerable improvement over ANY pump gas which can only be
conservatively described as horrible.

[FC-Pilot]

While AVGAS comes up short as a good
race fuel, it is still a considerable improvement over ANY pump gas which can only be
conservatively described as horrible.

...And I finally got a good laugh from somebody in this thread. Thanks David.

I know guys that use it in their "hot rod" boats as well as go-carts and lawn-mowers and other stuff. Reason for that is they don't have to worry about the fuel sitting for a while like you do with pump gas. When a friend told me why he uses it, I then started thinking about putting it in my boat over the winter to keep the fuel system (basic carb and mechanical fuel pump) from having the pump gas go bad.

Each tool has a use. I don't grab a hammer when I need an allen wrench.

Paul

[zums]

What's wrong with using AVGAS as a racing fuel?

Quite a number of fuel factors make AVGAS less than optimal for use as a racing fuel.
Following is a parametric description of AVGAS and their impact on engine performance.

Vapor Pressure
AVGAS specifications require a Reid Vapor Pressure range of 5.5 to 7.0 psi. That
range is too wide for performance use and is not predictable from batch to batch.

Specific Gravity
AVGAS does not have a Specific Gravity requirement. Aircraft engine fuel mixtures can
be adjusted while in flight and in fact are changed radically from take-off to cruising mode.
The variable Specific Gravity of AVGAS makes it less than desirable for a race car where
mixture is tightly controlled.

Fuel Stoichiometry
The fuel stoich value of AVGAS is undefined. It can range from 14.0 to 15.0, depending
on fuel composition and Specific Gravity. This makes it more difficult to tune air/fuel
mixtures accurately and consistently. Note that neither fuel specific gravity nor stoich
value alone can be used to predict fuel enrichment. Both factors must be used to determine
the fuel amount to be used for a specific air mass.

AVGAS deicer additives
Cold temperatures at high altitudes require the addition of deicer additives to prevent
fuel from freezing. Permissible additives are: ethylene glycol monomethyl ether,
diethylene glycol monomethyl ether and isopropyl alcohol.

AVGAS anti-oxidant additives
Long term storage of AVGAS dictates the addition of anti-oxidants to prevent gum
formation. Anti-oxidant additives are added at the distribution point, not the refinery,
and no control mechanism exists to ensure consistency.

AVGAS additives have the known effect of reducing fuel octane value.

AVGAS Octane
Four grade of octane are available: 80, 91, 100, 100LL based on the motor octane scale.
Fuel enrichment during take-off can raise the effective octane considerably (up to 130 PN).
Since the effective octane is pilot controlled, fuel octane is less important.

Lead content
All AVGAS contains lead additives to increase octane as follows:
80- 0.14 g/l
91- 0.56 g/l
100 - 1.12 g/l
100LL - 0.56 g/l
Lead, while raising octane quite effectively has the undesirable property of building
deposits. Aircraft engines are subject to frequent rebuilding and deposits are not
permitted to accumulate over time.

Distillation curve
The distillation curve for AVGAS specifies certain maximum distillation temperatures but
defines only one minimum temperature point. Therefore, dozens of distillation curves can
be produced while still remaining within specification. Since carefully shaped
distillation curves are critical to the tuning of high performance engines, AVGAS comes
up short on throttle response. Race engine throttle response is finally being recognized
as a critical performance factor while aircraft engines operate a nearly constant
engine speed and throttle with variable propeller load.

min max
10% 167F
40 167 210
50 221
90 275
100 338
Note that the 10% fraction is quite high making the fuel somewhat difficult to
evaporate with a marginal fuel system such as carbs. Aircraft are injected.

In summary
The design of AVGAS is not suitable for race engines due to uncontrolled variables in
RVP, SpG, distillation temps, and additives. While AVGAS comes up short as a good
race fuel, it is still a considerable improvement over ANY pump gas which can only be
conservatively described as horrible.

You can always tell the guys that copy and paste long articles that are supposed to perplex you from the guys that actually test or run it through the gears on the street, "pump gas is horrible" really, not if you get it from a reputable company that is consistent and dosert mind putting you in touch with the tech info needed, i run an iron head 372 on the street, its 11.1 3500 lb car,92 octane with drag radials through the pipes with small valves and heads it pulls the wheels off the ground, in street trim it runs 11.1 in the 1/4, id be a fool if i couldnt tune 2-3 more tenths out of it with open headers and tuning, pump gas cant be that bad, and maybe the people posting on here have had success with AV gas, even though the internet says differently
Tom

[tresi]

The specific gravity does change a lot but so does pump gas. As an A&P I had to weigh many planes. To do this accurately you either have to defuel the aircraft or account for the weight of the fuel. This would be easy if the fuel was consistent. Since it isn't consistent we were required to weigh the fuel with a hydrometer every time. I've use Avgas 100LL in 12-1 engines with no problems just jet for it, if I were trying to duplicate race gas I would use 115/145 but my gas is that race gas would be cheaper and it defiantly be easier to find. Most aircraft are low compression but I have worked on a low altitude 11-1 compression aircraft and it's specified fuel was 115/145.