Hey, new to this forum and am researching rotary swaps for a Miata. Have almost all my info I need but I was wondering, what is the verdict on running leaded fuel in a rotary engine. A station have 110 leaded for about 5 bucks a gallon so if i can run that on track days, that would be awesome. Not concerned about the catalytic converter cause that will not beinstalled after it passes smog.



-Spencer

First off, welcome to nopistons! Secondly, you might want to post this question in the engine building/porting forum, you should get more knowledgeable answers there, but it really depends on the engine. You might not even need a higher octane.

In the absence of a catalytic converter, I am not aware of any problems associated with running leaded fuel in a rotary engine. But unless the engine is turbocharged and you are running fairly high boost, I would question the need for 110 octane.

Well at the momet is to put a 13b-rew in a miata and them boosting it to somewhere in the vicinity of 400-450hp. But thats just the plan at the moment, and the 110 would be for track days only. Thanks though.



-Spencer

Ah! Well, in that case the 110 might come in handy. I am not aware of any reason to avoid using leaded gasoline in any engine. The reasons for removing lead from gasoline stem from lead's toxic effect on humans and its incompatibility with catalytic converters.

Thats what I thought. I believe it is also good for the valve train. But I mean $5 a gallon for 110 leaded is SO much better than $13 a gallon ($65 for a 5 gallon container) for C16 but C16 does have a higher octane. Any other things in C16 or lack of such as chemicals to make cold starting easier etc.?

All I know is that leaded gas is good for valve seating on conventional engines...but you may want to make sure the lead is not going to hurt the internal seals...

the engine doesn't really care if there is lead or not. bad for converters, and o2 sensors though

In a normally aspirated engine 93 octane fuel is plenty. The down side of leaded fuel is lead salts fauling the plugs and the O2 sensor will quit working until removed and sand blasted, or just replaced. The computer will go way over rich for a while then go to limp mode until reset.



In a boosted engine, the highest octane available once over about 6 pounds of boost. Octane is a measurement of detonation resistance. Detonation is when the apex seals plug the muffler.





Lynn E. Hanover

I know what octane rating means but I was wondering about issues pertaining to lead fuel regarding damage to a rotary engines components that are not in a conventional engine. Also I said that it was a boosted engine. But thank you for the input.



Also detonation in at least conventional engines is the uneven burning of fuel. Correct me if I'm wrong but that shouldn't be any different in a rotary environment.



-Spencer

The rotary was born in the 50s, when all fuel was leaded. The only current problems would be the reactor and the oxygen sensor.



Detonation is charge temperature dependant, and affects normally aspirated rotaries far less than similar piston engines.

It affects boosted rotaries far more than similar piston engines.



Lynn E. Hanover

one problem I've run into with people (myself included) running race fuel for fun is remember to drain any unused race fuel, and run normal fuel through it soon after wards. Pump gas has added conditioners for things like rubber and plastic components, to keep them from drying out. Race fuel doesn't. I've seen race fuel destroy fuel pumps, injectors, hoses, carburetors, almost anything it comes in contact with for prolonged periods. I now run no more than 75% race/25% pump. Its cuts the price a little, easier on the components, and you still get the excellent throttle response and added power.



The people race fuel is designed for rebuiled their engines on a weekly (sometimes daily basis)

There are street version race fuels now that are lead free, and oxygenated that you can run straight, but if you think 5$ a gallon was high....

Which brings up another point..there is not just Race fuel and pump. I know VP makes about 15 different 'race' fuels depending on your app. Talk to a rep that knows the biz before choosing.