lead or no lead

Firethebone · #1 05-20-2005, 04:15 PM

I was told that running airplane fuel in a harley does wonders for the motor due to the lead content in that type of fuel. True or false? If the lead content more than the octane grade, is the key issue, then can one use those "lead-additives" sold at automotive stores? Thanks.

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skywagon · #2 05-20-2005, 05:40 PM

Sure won't hurt it any but last week when i fueled the plane it was $3 a gallon outch!

pococj · #3 05-20-2005, 11:48 PM

The only wonders it'll do is empty yer wallet faster than a cheap Tijuana wh... Never mind!

Your engine will run best on some particular octane gas. Running lower than that octane will result in the ol' knockin' routine, and may damage something from that detonation. Running higher than that octane does nothing for your motor, only the gas companies.

Something else to consider is the gasoline additive packages. I ain't no sky jockey, and don't know how av gas additives differ from earth-bound gasolio additives. It may lack something that is beneficial to your bike's engine, but isn't used in av gas because of reliability issues, as in "sure hope my plugs don't foul!"

Since gas no longer has lead we now have plugs that last forever. No lead deposits to foul them, and no lead deposits built up in the combustion chamber. With modern metallurgy in the valves and seats, lead isn't needed to cushion the valves slamming into the seats, and will do more harm elsewhere than any perceived gain.

I've been running an experiment with my '87 Evo motor. It is bone stock internally, with modified drag pipes and the carb properly jetted. Also has stock ignition system. Here are some gas mileage figures with 93 & 89 octane:

93 - 49.5, 47.4, 48.6, 49.8, 53.3, 44.0, 50.2, 42.1, 52.4, 52.5, 48.6, 53.0, 51.2, 49.9, 47.6, 49.2 = 49.3 avg.

89 - 40.4, 46.9, 46.9, 50.2, 42.7, 44.6, 47.1, 46.1, 52.3, 46.9, 50.0, 49.1, 55.1, 53.1, 50.4, 44.5 = 47.9 avg.

The 1.4 mpg difference is statistically insignificant, especially considering I didn't closely monitor my speeds, except to note when I ran considerably above or below my normal. Seat of the pants can't tell any power difference, either. But I have noticed a very slight increase in pinging when I get on the throttle very hard. A quick downshift and the pinging is gone. Overall I'm satisfied the less expensive 89 octane is working fine.

What's all that got to do with running av gas? Don't waste your money.

JB · #4 05-21-2005, 12:09 AM

Some one correct me if Im wrong but hasn't Avgas been nolead for over 30yrs.

J.B.

SKJOLD · #5 05-21-2005, 01:42 AM

Lead levels have been reduced in modern aviation fuel but not eliminated. The poplular aviation fuel used today is 100 Low lead. Easily identified by its blue tint. Thats what I have been using when I fly.

dynamac · #6 05-21-2005, 03:22 AM

I have a friend who mixes JP-5 (military jet fuel) in his car. However it is a diesel car. He mixes it about 3 gallons JP-5 to 1 gallon of gas. The car actually burns cleaner and better gas mileage. I don't think I would put it in my bike, even as an octane booster. Heard rumors of some guys doing that, but that was back in the 80's.

mikeisglidn · #7 05-21-2005, 07:42 AM

i think people get wraped around the axle when it comes to fuel, these things are designed to run on pump gas, why would you want to pay big bucks to run some exotic stuff? thanks, but ill save my money for some other projects!!

pilot1996 · #8 05-21-2005, 01:23 PM

JP-5 is a deisel fuel. Has a very high flash point, which is why the Navy and the Marine Corps use it on ships. I don't think you could use it in a motor designed for gasoline...your buddy with the deisel should be OK, though, I've refueled all sorts of vehicles in Iraq from my CH-53E, we were giving them JP-5. Of course, they are all deisel engines.

Mac

pococj · #9 05-21-2005, 01:45 PM

Mac, what does your chopper use? When I worked on the refueling stations on the America, I only remember two types of fuel, JP-5 and Av Gas. I thought the JP-5 went into everything except maybe the C-1A Trader. Our emergency diesels ran it, the small boats ran it, even the gas turbines for the aircraft starting air ran it.

pilot1996 · #10 05-21-2005, 01:51 PM

Skip,

We run JP-5 in everything. If we go to an Air Force base, or a commerical airport, we get JP-8 or Jet A (much like JP-8). Both have a lower flash point, so the Navy doesn't want it on their ships.

Everything in the Corps is JP-5. Same goes for the Navy, and most everything in the Air Force and Army is JP-8.

Mac