as the title says--i am having a discussion about the possible benefits of leaded gas on our engine(and especially a fi engine)) on another thread. anyone what to share?
olddragger

 

Damn, always trying to find a way to get an edge up on someone...hehe!

I have no stance on leaded gas but have read some articles supporting it for track purposes, I've even found some discussions on adding lead additives to unleaded pump gas. I wish I knew more or even understood more about the benefits they were claiming.

 

You catalytic converter would be toast.

 

I doubt someone running leaded gasoline in a car for racing purposes would be worried about their cat, considering it was probably one of the first things they removed...

 

^True dat! haha

 

yeah im pretty sure OD is running a mazsport midpipe.

 

Theory is only that, but ...

The Renesis was never designed/intended to run leaded fuel, but it's also not an FI setup from Mazda

The Formula Mazda cars run a special blend 95 octane unleaded VP fuel, but they're NA

If you need the octane and are catless it probably won't hurt anything other than the environmental contribution

 

I've read of issues with leaded gas fouling O2 sensors.

 

I have no experience with leaded gas in the RX8 specifically, but have run it in other modern street cars for occasional track use. First off, there will likely be no benefit in an NA mototr unless you have somehow managed to increase the compression. For an FI motor you can use the extra octane (although unleaded racing fuels are pretty widely available these days as well).

-Any lead will quickly kill your cat (on your car, although it is not good for pets either), but you've probably already removed that.
-Leaded gas will shorten the life of your O2 sensor(s), but with occasional use, I never had any problems. Unless you are running leaded gas all of the time, you can probably expect at least 30-40K before you need to replace the sensors.
-There might be some risk for lead deposits causing the apex seals to stick similar to the concern for synthetic oil. Again I would think this is a pretty minor concern if you are only using it for occasional track use, and not running it all of the time.

 

Yep--no cat here. And I agree --folks with cats--dont do it!
Doesnt leaded fuel also have a differant flame propergation of sorts?
I will be doing this NOV 8/9 and give feedback--it will be interesting.
I do have data collection capability.
OD

 

Leaded fuels have a slower flame propogation and require slightly more ignition advance for best power.

 

When Canzoomer and I where experimenting, we used various unleaded fuels as high as 118 octane in NA cars, with no noticeable effect.

Unless you can advance the timing (to levels we were not prepared to approach) you can't take advantage of it.

S

 

thanks guys--i will post results of this.
what you are saying makes sense. i really dont know the timing ranges that is with my Pettit reflash--need to speak with Cam.
OD

 

post results of what exactly???

an event or two won't tell you much of anything ....

 

one day on the track with leaded race gas and one day without lead
i want to see what if any difference occurs in monitoring timing, temps, afr, etc.hell you have to start somewhere and that is all i can do right now.
OD