prg

The trailing throttle fireball discourages people from hanging out by my gearbox.

M758

91 pump gas for me. I figure I am around 9-10 mpg.

Geoffrey

12:1 Compression ratio and 93 octane street fuel.

stownsen914

I run a 50/50 mix of 110 leaded and high-test pump gas.

I live near NY City, and am having a harder time finding race gas suppliers these days. I usually just buy at the track, but one of our local tracks (Pocono) doesn't supply race gas at track days, so I have to buy beforehand when I go there. I used to be able to find service stations located near my route to Pocono, but they all seem to have closed. There are suppliers around -- it's just not as convenient as it used to be.

You can find suppliers at www.racegas.com (Sunoco race fuel) and www.vpracingfuels.com (VP race fuel). Note that VP is quite expensive.

Scott

Bryan Watts

110 octane here. Ran Sunoco in the past but switched to VP as it is more consistent according to those "in the know". The respective websites will list distributors.

stownsen914

Geoffrey,

I'm impressed that you can run that kind of compression on street gas. I am underthe impression that your car has a race-spec engine. Is this typical for modern Porsche race-spec engines?

Scott

Geoffrey

My engine is a race engine that has a highly optimized combustion area. I'm in the process of going up to 13.5:1 and will also run 93 octane fuel. Obviously it would make more power on 100 unleaded, but it currenly makes the same as a PMNA slide valve engine on 112 octane.

tfro

Do you have a wideband hooked up to your ECU? If you do, how often do you replace it?

I've heard the same about VP compared to sunoco, but it was from a VP dealer, so...

DogInBlack

Is there a difference between the higher octane leaded and AVgas?

Circuit Motorsports

Yes. I'm not an expert but from what a number of the formula car guys say is that it's not as good as track gas. A couple of HP and you really should tune your car to it to extract the best out of it. Also there are the legal grey areas about it with regards to non-aircraft use. While they say it is low lead (LL) it is still very high in lead content.

I know number of guys who run it and have no problem with it in their FF and FC cars.

David K.

What's the price at The Glen for 100 unleaded?

Geoffrey

Leaded fuel will clog up an O2 sensor and it will eventually go bad. I proactively replace them annually on cars that run leaded fuel.

Av Gas is no good for race cars. It is designed for cooler temperatures, steady state RPM, and other factors not encountered in a race car.

tfro

Wideband or narrowband? What brand?

Geoffrey

Narrowband is useless for anything except keeping an engine running at 14.7:1 afr. So, I don't use them in a racing environment.

tfro

Well, yes, not sure that was my question. But plenty of race cars with stock ECUs use them still. I guess you indirectly answered my question.

Do you want to tell me all the brands of wide band sensors that you don't use, so I can know which brand you do use?