slipstream444

It blows my mind how many times this kind of post creeps back from time to time. Bottom line - Av Gas is not good for your car.

Leaded gas will cause all sorts of problems with just a few uses. Cats and O2 sensors are just a couple examples. Modern valve seats are not designed to run a leaded gas.
Additionally, anything over approximately 98 octane will actually start to slightly hurt performance in a N/A S2000.
Free is not 'free' if you have to repair the engine and other components.

Frankly there is no place on the planet giving away gas, so this sounds like bull from the get go. Av Gas is very expensive and the only way you'd get it for free is if it was contaminated, stolen, or Daddy owns the FBO where you work ... and that's still stealing - it's just called embezzlement.
I'm a pilot (military), work out of an international airport (where we operate overseas) and one of my ground jobs involved managing the fuel funds. If I were getting fuel for free they'd call it stealing and Court Martial my butt. Fuel is expensive all over the world my friend and no one gets it for free.

Say you're getting it for free (for some crazy reason - and I don't care to hear your explanation) - here's food for thought:
What if they were offering diesel fuel for free - would you put that in your car?

Better yet ... I'll give you a few gallons of piss for free ... try that in your tank.

Point - Av Gas is specifically designed for aviation engines and is no more appropriate for your car than diesel - or piss for that matter.

Final note - if you get caught running leaded gas (or running without a cat) on the street, you may loose a lot more ... some states will gladly take ownership of your car.

slipstream444

I agree ... up to a point.
I tried 101 (unleaded) in different mixture levels from 101 octane down to 94 octane. My car ran the strongest (butt dyno) when the mixture was between 95 and 97 octane. Performance leveled off and started dropping off above 98 octane. I did this 'experiment' over 20,000+ miles and the results were consistent. I ultimately reverted to 93 octane for every day use. I had to drive 14 miles to get the 101. When I had the time I'd make a run and mix in a partial tank of 101 with 93 for a little more kick. The 101 at the time was $3.89 a gallon and the 93 was $2.15. That was last year before I shipped out.

fperra

Free?? Does your employer know about this "fringe benefit"?

S2oooNvegas

chiming in*
agreeing with whats been said and a few more tips. AV gas is strictly that. as most aviation engines run at a nice fixed ,and relatively low RPM band. so you dont have the dynamic compression band that you would on a street engine, not to mention the very low intake temps they live with. just these 2 combined should help you to get the point. do not run AV gas in a car...EVER. this is hillbilly tech. LOL. later dave

S2K KiDD

can you use 100 octane unleaded on a stock s2 motor and if so why do you have to reset the ECU??? never understood why you have to do that..

Mr RX7

OK, in the rx7 i used it for track days, obvisously to run a few more pounds. Not just out driving on the street. I can see that doesnt have much advantage. But the higher octane and the fact it has lead in the fuel would reduce chance of detonation. Being that the S2000 is a relatively high comp. motor I thought it would benefit some. much like how my rx7 did.

My family does run an FBO, BTW. So taking to much fuel would obviously hurt myself, and the family. Even then it doesnt take much fuel to run to the track and get a few runs in. Maybe 2 gals at the most, combined with fuel already in the tank.

Thanks guys... i see it isnt advised in the S.

Thanks slipstrem444 for your intuition, but not for your arrogance.Im just lookin for info and maybe other people can benefit as well, not a war with words.

Mike

Intrepid175

If I'm wrong about this I'm sure someone will correct me but, the ECU actually learns what the engine needs in the way of mixture and timing advance as it's being driven. These parameters change depending on how the car is being driven, the conditions it's being driven in, and the kind of fuel it's being fed.

This is an on going process. If you change to a more aggressive fuel, the ECU will eventually learn to compensate but it takes time. Resetting the ECU essentially wipes it's memory, like rebooting your computer. It can then start fresh with figuring out what's going on and adjust things accordingly which, I assume, speeds the process up a bit.

Sound about right guys?

Drive Safe,
Steve R.

slipstream444

Resetting the ECU allows it to adapt to the fuel a little more quickly. The ECU does have a learning cycle, but it's not that long. Resetting the ECU just speeds up the process a little.

Higher Octane gas is not more aggressive, contain more energy, or directly give you more power. The higher the octane, the more stable the fuel. Octane is a measurement of the fuel's resistance to detonation. In a N/A car, it allows you to run higher compression and advance the timing. There is a point (based on your compression ratio and how much advance your car will allow) that you hit a wall and gain nothing, and increasing octane actually hurts performance due to the fuel's added stability.
I found with my AP1 this point was reached around 97 octane. I played with mixtures for over 20,000 miles of driving. My baseline octane was 93 and I added 101 unleaded race gas in varying mixtures up to full 101 over that time period. My car ran fantastic between 95 and 97 octane. Smoother more than anything though. The butt dyno definitely detected a little more performance - but not enough to justify a dyno run.

Is it worth running a higher-octane gas in your N/A S2000? I think so ... up to a point.
If you're running FI, I believe it's an absolute must.

slipstream444

Didn't mean to sound like the fun police. I apologize if I came off sounding that way.
I do get a little frustrated with eternally repeated posts, and that came out in my post.
Part of that problem is the search engine on this site. It too is frustrating, and you have to sieve through a lot of garbage to get to what you're looking for. I use it because I want to at least make the effort.

As for the 100LL: It's really only appropriate for aviation use, and possibly rare '60s muscle cars that have their original (unmodified heads) engines (designed to run leaded fuel). Other than that, forget about it.
Running even a little leaded gas through your S2000 could cause several thousand dollars in damage. The lead is not as bad for a rotary engine, but the turbo can suffer. Of course, all CATs and O2 sensors will be damaged by leaded fuel use.

MattG

I just got home from a big night out drinking...will my piss be able to power my car now? Should I add an octane booster to it?