A point I forgot to ask about was that someone had posted that high octane fuels burn cooler. Is this true? I have seen engines, that were run on avgas or with too much octane boost, which melted valves because the fuel was too hot. If high octane runs cooler what then would have caused this situation? (We use to use a percentage of avgas or octane boost in our street rods especially on drag night even with stock engines)

 

The one thing nobody has talked about with high octane fuels is the cleaning additives that are put in. In the case of fuel injected engines this will completely eliminate the need of cleaning the injectors. I can prove this with real world test. I have owned three Honda Accords, each one for two years. The mileage in two years runs to about 100,000 Kms. on the first one the mileage dropped off at around 70,000, I then had the injectors cleaned and the mileage was back. In the two other cars I used only high octane on advice of a friend and sure enough no decrease in mileage over the two years. I can tell you that there was no gain in fuel economy, and I probably paid for the injector cleaning twice due to the added cost, but I am confident that the engine is running cleaner. I would be curious to know if an ATV engine would also run cleaner.

Regards Jim Bell

 

Yes the 2-stroke runs very differently and there are other factors than the duration of the power stroke that come into play on a 2 stroke & race fuel...

But.... All the research I have done suggests that race gas does not "burn more slowly" than typical pump gas. It is only harder to cause to explode (less likely to explode without an ignition source) which also brings up an interesting point concerning engines with large bores & race fuel & the need for dual spark plug heads...

Another interesting point that no one has brought up is that you are likely to experience more consistant jetting on race gas, since it is blended with a more demanding & higher paying audience in mind....

 

There is an article on fuel terminology at hondaex.com. I've ran only 85 (standard octane) in my f250 and mountaineer with a v8 and have tried higher octane with no noticable difference. However on my atvs (400ex and 200sx) the higher octane helps slightly. I don't think it justifies 20 cents a gallon more for what it does.

 

I don't know anything about octane, never even heard of it! You should try what I use. To 2 gallons of "Wild Turkey" add 1 pint of "Absolut". With this combination, your quad will gobble up ground like there is no tomorrow and without a doubt, you will be absolutely the fastest out there. Now, this is for a stock machine. If you have a really hot set-up, add 3 ounces of "Tobasco" ("Franks" doesn't work) to the mix. It will really put you into the hot seat! Just one word of caution. Don't ever try to siphon this stuff by mouth, it will make you delirious.

 

I've been reading this post with interest.

AV-Gas is not sold for auto engines. It is designed to be stable fuel at all altitudes. It is designed to have the same characteristics at sea level as well as 30,000 feet. It is difficult to burn, and gives off less vapor. It contains special additives that keep fumes to a minimum. The last thing you want in a crash is the fumes igniting after the aircraft has crashed. By nature it is a tad less explosive.

I know a few people who run AV-Gas in their cars. It is not racing fuel. Small aircraft engines are rugged, mostly air-cooled hotter than hell engines for their rpms. On takeoff, you will see no more than 3000 rpms and that would be incredibly fast. If you run an engine for a length of time on the tarmac, the engine recieves more wear than flying at 15,000 feet. They are cooled by having air blow across them at 200-300mph.

If you run AV-Gas in your car, you're really wasting your money. It lacks the additives that the newer engines require. My truck's on board computer wouldn't have any clue with the new emmissions requirements burning AV-Gas. You would probably see the check engine light often. Imagine what it would do to your quad.

Older engines may actually see minor benefit, but at 2.50 a gallon plus, what are you saving? It's not like your backing up to the fuel pump and filling 'er up. How much extra performance do you need unless you are racing?

I'm waiting for someone to tell me they are running Jet-A in their car. Jet fuel is ultra high octane kerosene(that's why we were charging 20 bucks a segment a little while ago) There's no reason you couldn't run Jet-A, except your car would again lack the additives for clean burning. At takeoff at 100% thrust, I see only 2800 rpms on the turbofans. That lifts a 174,000 lbs off the ground into the air.

I wondered a while back if I should spring for the premium. I'm quite happy with the cheap stuff, I have yet to see top speed, and actually have no need to go that fast. If you need or want the extra kick, go with racing fuel, leave the AV-Gas for the planes.

Best Wishes,
Jack

 

Avgas is made for piston-powered engines, JetA is made for turbine engines (as I understand it), big difference there, your playing russian rulet by burning fuels that were made for a fundamentally different engine. If Avgas ran so much hotter, then you'd notice your car's engine heating up faster and overheating easier. I have not noticed this, my engine runs more or less the same temp on premium and Avgas. If you don't care how much power your car has, don't bother. If your looking for a little extra punch, give it a try, you may notice a difference.

"If you run AV-Gas in your car, you're really wasting your money. It lacks the additives that the newer engines require. My truck's on board computer wouldn't have any clue with the new emmissions requirements burning AV-Gas. You would probably see the check engine light often. Imagine what it would do to your quad."

I wouldn't run Avgas in a newer engine, just because I'm afraid of damaging the injection system (injector seals, fuel pump seals, etc.(probly an unwarranted worry, but I'm cautious when it comes to expensive parts). Most newer injected vehicles that I've seen run Avgas have run just fine, it didn't trip up the computer any (all it's got are knock and O2 sensors, it doesn't care what other addatives are there). In a carbureted engine I've got no problem trying it out. I've seen carbureted V-8 engines live a long life on a diet of only Avgas. My friend's cousin, and most of his friends, race 2-stroke 250 motorcycles in their spare time, and they run Avgas all the time because they say they get more power out of it, and they haven't burned down the engine yet.

"Older engines may actually see minor benefit, but at 2.50 a gallon plus, what are you saving? It's not like your backing up to the fuel pump and filling 'er up. How much extra performance do you need unless you are racing?"

Your right, your not saving a dime, your spending more money. However I've "backed up to the fuel pump and filled 'er up" with Avgas many times. During the summer I don't go through near as much gas in my rig, so I don't mind spending a little more on the gas and I enjoy the power increase (and the cool smell). No, I'm not racing, I don't NEED the performance, I just like to have it.

If your happy with the cheap stuff, don't need the extra power from Premium, or just can't tell the difference, then that's great, buy the cheap stuff. Some people do feel the difference, and are willing to pay a little extra for it.

Don't take this wrong Thunderthud, I'm not trying to pick a fight. I'm just trying to show that some people don't feel the need to spend the extra money for a little more performance (like you), and then there are the people (like me) that don't mind the extra cost for the added performance. And Avgas is a nice balance between cost and performance (race fuel costs almost twice as much as Avgas in most cases, more than I want to spend on gas).