I live near an airport and someone told me that the Harley dealership puts aviation gas is every new Harley they sale. Has anyone ever put avgas in their car. The only thing that concerns me is the low lead. There is a gas station that offers 100 and 110 octane racing fuel for atv's and dirt bikes but its like 6 bucks a gallon. Would 110 octane be a little too much for a 93 rx7?

 

I'm not saying to do it but there are plenty of guys on here that have run 114 or better. I've never ran anything higher than 93 in my FD but I use to run 110 aviation fuel in my ZX-7R Ninja and Suzuki TL1000R with no ill effects. I think here at our regional airport that 110 is only $5.75/gallon. $6 sounds expensive for 100 if you ask me.

 

6 Is insane. But the place is the only one so its some what of a monopoly. I also live about 20 miles from Sand dunes so its all the sand rats that are willing to pay.

 

The lead in the fuel will damage Your Catalytic Converter and O2 sensor.

 

if you have a cat... i ran half 93 and half 100 before with no weird effect.. just wanted to try it.. but a friend of mine only puts race gas in his car... he got it tuned for race gas and never puts normal gas in there.. but he rarly drives the car too

 

As mentioned, do not run leaded gas with a catalytic converter in place. Depending on the gas, they will have unleaded up to about 105 octane.

Now, should you do it? No. Unless you have a programmable ECU, the car won't really take advantage of the higher octane. Higher octane is actually harder to burn, but this allows a more controlled combustion. This can help provide a little safety at higher boost levels or during extreme car usage (i.e. road racing).

On the street without a programmable ECU, you'll just be wasting money.

 

http://osbornauto.com/racing/race2avgas.htm

Racing Gasoline Verses Aviation Gasoline

written by, and thanks to Tim Wusz 76 Products Company

I am going to attempt to address the controversy of aviation gasoline verses racing gasoline for use in race cars. Some racers use aviation gasoline which is fine for some applications but does have shortcomings. There are several grades of aviation gasoline (avgas) that we must identify before going any farther.

1. Avgas 80/87: this product is used in low compression ratio aircraft engines, contains little or no lead, is red in color, and should not be used in any automotive engine due to a low motor octane number of about 80.

2. Avgas 100/130: this product that can be used in some automotive engines. It has both research and motor octane numbers slightly over 100. Avgas 100/130 is green in color, contains four grams of lead per gallon, and is becoming harder to find.

3. Avgas 100 LL: the LL stands for "low-lead" which means two grams per gallon, low compared to the avgas 100/130 that it was designed to replace. It has research and motor octane numbers very similar to the 100/130 product previously discussed. The color is blue. This product sometimes has a high level of aromatics which can contribute to lazy throttle response and dissatisfaction of the consumer.

4. Avgas 115/145: this product was developed for high performance piston aircraft engines used in world war II and in the Korean war. It is very hard to find anymore due to lack of demand although it is of very high octane quality. The color is purple.


The remainder of this discussion will assume that our basis for comparison with racing gasoline is avgas 100/130 and/or 100 LL since they are both available and have acceptable octane quality for limited applications. When the word "avgas" is used, it will refer to avgas 100/130 or 100 LL.

Avgas is less dense than most racing gasolines. Instead of weighing about 6.1 to 6.3 pounds per gallon like racing gasoline, it weighs 5.8 to 5.9 pounds per gallon. The racer must compensate for this by changing to richer (larger) jets in the carburetor when changing from racing gasoline to avgas.

The other major difference is octane quality. Avgas is short on octane compared to most racing gasolines. Many racing engines with "quick" spark advance curves or with no centrifugal advance have more spark advance at low rpm than avgas and some racing gasolines can handle. The result is detonation, especially during caution periods in circle track racing because all of the spark advance is "in", rpm is low, and part throttle air fuel ratios are too lean for the operating conditions. If the driver does not "work" the throttle back and forth, pistons can be "burned" which melts away part of the aluminum piston material. Inadequate octane quality is one of the quickest ways to destroy an engine. Pistons can be severely damaged during one acceleration where detonation is present and the racer may not know what is happening until it is too late.

For maximum performance and power from a racing engine, racing gasoline will normally provide better performance than avgas. Avgas can be a good gasoline for some applications, but since most racers do not know the octane requirement of their engines, they would be better off with a "real" racing gasoline that will give them the overall resistance to detonation that they need to protect their investment. If someone has spent from $15,000 to $50,000 or more on their racing engine, it is foolish to cut corners on gasoline be sure you have a gasoline with adequate octane quality.

 

This was originally written by Rich Rohrich of Sonoco Fuels:

The simple answer is:
100LL (Blue) avgas seems to be the most readily available version so I'm assuming that's what we are talking about. 100LL avgas USUALLY isn’t the best choice but it won't hurt anything.

** For those of you in a hurry, or just sick of me rambling on about this crap skip down to the bottom of the thread to the >>>>>> for a summation.

For those of you still with me, here are some details.
Contrary to popular belief this isn't 100-octane fuel. Aviation fuels are rated on an ASTM Lean/Rich performance number system. 100LL is rated at 91/96 By comparison; Unocal Leaded race gas that is used in lots of spec fuel racing classes has performance number of 112/160. 100LL is closer to 91 octane (MON); by comparison VP C12 is rated at 108 (MON).

For our purposes avgas has a couple of problems:

1) The 90% boiling point for 100LL blue avgas is set at 275 degrees F, which in an engine that turns over 7000 rpm will likely make less power than a fuel that has it's 90% point lower. Pump gas has similar problems, but most good race gas will have 90% point MUCH lower. As an example Phillips B32 has a 90% boiling point around 235 degrees F and VP C12 has a 90% boiling point around 220 degrees F.

2) Depending on the refiner 100LL can have fairly high aromatic hydrocarbon content, in the 30% by weight range. This level of aromatics will tend to make the throttle response mushy and flat in applications that see big throttle opening transitions on a regular basis. It's similar to what happens when you dump a lot of toluene based octane booster in your fuel. Throttle response becomes a distant memory.

3) The vapor pressure and distillation curve of avgas just doesn't seem right for our purposes. The distillation curve of a fuel determines to a large degree the warm-up, transitional (on & off) throttle response, and acceleration characteristics of an engine.
Here's the simplified version:

A fuels distillation curve designates the maximum temperatures at which various points between 10% and 90% of the fuel will be evaporated as well as the maximum end point temperature. So for any engine/air temperature combination there is a minimum volatility that is required for proper running. As you probably know gasoline is made up of different hydrocarbons, with different boiling points. By combining these hydrocarbons together you get a distillation curve. Some hydrocarbons (light ends) boil off at low temps while some do at much higher temps. Depending on the intended application, a petrochemist will blend hydrocarbons to get a curve that matches the rpm range, temp, altitude, and acceleration characteristics for the application. The problem with avgas as a race fuel is the fact it is blended for an application where acceleration and throttle response are not high priorities. If you think about the average light airplane application, you're talking about a fairly low compression engine that runs in a fairly narrow rpm band, and is rarely called on to provide the type of transitional throttle response that a high rpm, acceleration critical application like motocross does. What's more important to the avgas designer is controlling mixture strength by eliminating the possibility of vapor lock and icing while making sure that light end hydrocarbon fractions don't boil off too early. The lowered rpm ranges used in these engines allow them to push the boiling point up on the upper end as well. As you can see, by using straight avgas or by mixing various types of fuel together you are modifying a number of important fuel design parameters. You may hit on a combination that works well, but more likely you'll have an engine that doesn't detonate, but doesn't accelerate very well either. So avgas is SAFE, but not a very good choice. The high paraffinic hydrocarbon content of 100LL makes a very good base stock if you want to play back yard petrochemist, and I believe this is how some of the smaller race fuel blenders start out. I can tell you from experience that it's a pain to document and test various changes unless you have a lot of time and patience, so trying to come up with your own Super Fuel is probably more trouble than it is worth.

So it sounds like avgas is really bad for our purposes, and for the most part it is, but given the sorry state of pump fuel today, avgas is looking better all the time.

>>>>>>

Here's my short course take on things based on my experience and personal biases, (keep in mind this is pretty generalized)

- In almost every case 100ll avgas is a better choice than alcohol pump fuels

- If you don't need the additional octane that 100LL provides, then MTBE based pump premium (especially Amoco) will tend to provide better throttle response than avgas assuming you have any jetting skill. If you can't jet you're just wasting your time worrying about any of this stuff on a stock bike.

- Mixing 100LL avgas with a good race gas designed for your application and rpm range is a reasonable way to save some money.

- Mixing alcohol based pump fuels with ANYTHING in an attempt to make it BETTER is just a chemical circle jerk, and if you're that cheap or that ignorant you deserve the crummy performance and the insurmountable jetting problems that you will invariably be blessed with.

- Milspec avgas is a different animal entirely, but isn't readily available so we won't worry about it.

- The correct race fuel for your application will outperform ANY of the above, regardless of whether the engine is stock or modified. The more demon tweaks hiding in your engine, the more you have to gain.

 

too much information! for me to read!!

 

do i know him

jk

 

In a piston engine it would be suicidal. In a rotary its just plain sadistic.

Try an octane booster for no additional horsepower and potential hazard.

 

no of course not hes new... has black rims with red trim, and a yellow FD, similar to yours