Is it safe to run 110 leaded racing gas in a rotary? Ive heard different stories and want to be clear on it before i go and dump a few gallons of instant motor death in my tank.

 

Why do you want to run 110 leaded gas? It will foul the o2 sensor and your cat converter(s).

 

You can run all the octane you want(resistance to detonation) but lead will shorten the life of your O2 sensor

 

Exactly. It won't hurt the motor but will foul out the 02 sensor prematurely as well as the cat if you are still running one.

 

If you still have cats I can't imagine why you'd want to run 110 so I'll assume you don't have them. Otherwise, as mentioned, it's just going to shorten the life of your O2 sensor, an easy trade for not blowing your motor in my book.

 

All cats have been eliminated so the only problem i would have is the o2 sensor craping out? Its not bad for the seals?

 

No, it's not.

However, running 110 is useless unless you're getting it tuned to take advantage of that octane. (IMHO, just dumping in race gas and jacking the boost doesn't count as tuning, but it's your motor)

Dave

 

I just went through this and after looking around and talking with the people at VP Fuel they recommend using their new StreetBlaze 100-103 (103 oxygenated, so make sure you don't run lean) and they have at least 5 different levels of octane to choice from. They also have Motorsport 100-109 that works with your cat and O2 sensors. I also found that Sunoco makes unleaded 100 octane which I have used and it works great. I have my second program in my FC tuned by BDC set up for 97-100 octane. I WOULDN'T RUN LEADED GAS THROUGH A CAT OR OXYGEN SENSOR AND EXPECT EITHER TO LIVE!!!!

www.vpracingfuels.com

 

Correct. The way I explain this is with an analogy that's similar to spark plugs and their heat ranges: The hotter the load on an engine, the colder the fuel that is needed. If everything else remains the same on an already-tuned platform and "colder" (higher octane) fuel is used, there can actually be a drop in power, not to mention a higher risk of fouling plugs, misfiring, etc. This is what Dave is referring to here. The octane of 110L is great compared to 91/93, but it's worthless if the engine isn't being put through more load and generating more heat where it would otherwise demand the use of that kind of octane fuel. So, the hotter the engine load, the "colder" (higher octane) the fuel needs to be. At some point, the octane of the fuel will be challenged when the load of the motor hits a critical area. In our rotaries, I am a firm believer that the cause of so many of our engines is due to the use of an inferior fuel (pump gasoline) that's "too hot" for the type of loads we're trying to generate. The problem with ours more specifically I believe is the autoignition of that fuel during the compression stroke just prior to the timed spark event. Run 20psi of boost, on a big turbo w/ lots of spark advance and a skinny trail-split advance, with good, high-quality race fuel and you can beat the crap out of it forever without risk of it blowing up.

On the issue of lead vs. not, even though it's a terrific chamber lubricant, lead apparently causes the failure of catalytic convertors and oxygen sensors. I'm not sure what the mechanism for failure is. Wideband sensors from what I've read seem to last about 50 to 100 hours while operating with fuel that contains lead. Their lives are dramatically shortened so I feel that their use (wideband O2 sensors & meters) ought to be temporary on a vehicle that's using leaded race fuel.

Hope this helps,

B

 

Just as a footnote to Brian's post: I run a techedge wideband with the 7057 5 wire o2 sensor, which is pretty damn cheap to replace (around 30 bucks) b/c it's a VW part.

B, you've almost convinced me to run race gas. I found a local source, and although I havent popped a motor in a long time (knock on wood), I have in the past from a tank of shitty 93 octane. Are there any problems with letting the car sit for a month or more with vp c16 in the tank?

Btw, for those interested in reading more about the techedge:

https://www.rx7club.com/showthread.p...hedge+wideband