Gene

iTrader: (1)

So the price of race gas at the track is getting retarded, and I'm thinking of buying avgas at a civil airport instead, but it's leaded. I could have sworn I had read about O2 sensors that can be used with leaded gas but I can't find anything.

peejay

Technically, all of them can be used with leaded fuel. You just need to replace them much more frequently. How much more frequently, I'm not sure, but it's probably under the thousand mile mark.

bean13

iTrader: (1)

If you are buying real race gas at the track, that is leaded to, far more than 100LL. I would assume any o2 sensor for race purposes would be good for leaded fuel, as that is what most race cars run...race gas. Try Motec, Pi Research, CDS, AIM systems, or any other data logging company. They should have ones that are ok with lead....I would assume.

Gene

iTrader: (1)

Tracks on the east coast anyway sell Sunoco 100 unleaded.

bean13

iTrader: (1)

get outta here!? Can you still get 110 and the leaded stuff? What about the cars that require it?

Black91n/a

Is there any really compelling reason why you need an O2 sensor all the time? Why not just tune the car then take the sensor out and drive it like that?

bean13

iTrader: (1)

.

I was thinking to tune for temp and conditions with IDA's. Some EP guys in SCCA used to use EGT's for tuning, but are having better luck with A/F ratios. Shouldn't any race-specific wide-band sensor be ok to use with lead?

peejay

No cars require leaded fuel. That is a load of BS that Chevy introduced in the mid-70s as an excuse for why their engines were burning valves left and right. They compensated for the poor engine controls of the day by basically having them run overly lean and with late timing, which eats exhaust valves/seats. To save face, they blamed the unleaded fuel required for catalysts.

Other manufacturers had no problems with seat erosion, running the valves right on the iron.


Incidentally, the biggest problem with leaded fuel when it was widely introduced was "guttering", where the deposits would build up so thick on the valve seats that it would break away in chunks, leaving gutters for gases to blow by, causing burned seats and valves. Trick was in scavenger chemicals to clean the lead OUT of the chambers.

bean13

iTrader: (1)

Sorry peejay, I am going to go with the guys who build engines for pro teams for a living, and say, yeah I am going to stick with the leaded fuel the recommend on my engine.

If they didn't need it, then there would not be any and they would not recommend it. We are not talking stock, low perf engines here either. I was thinking in terms of race only engines, and I think you are thinkin in terms or street engines.

And now that I think about it, no rotory that any of us have needs leaded. Really, according to Sylvan Tremblay, if you can find 85 octane, that is ideal for stock rotors. I doubt anyone here is into making here own high comp rotors.

Black91n/a

One of the big problems back in the day was that you COULDN'T get high octane unleaded, which caused many problems with high performance engines and that may still be part of the reason for leaded gas reccomendations.

Gene

iTrader: (1)

Yeah they have 110 leaded at the track as well.