allegretto

do you fellas run 93 Oct or...?

thanks

mklaskin

I would think 100 or 110.

PatK-Mpls

98 or above only. I have been told by crew chief that 92 pump is hard on heads and leads to premature power loss/rebuild

allegretto

being the fool that i am, i had been running on clean 93 (no ethanol or detergents)

filled up with 104 today and there is a BIG difference. power, smoothness and operating temps are much improved.

analogmike

I think a mixture would be ok.... the '08 cup specifies 98 octane.. but that's RON which is equal to 94 octane in the usa (PON). Half premium unleaded and half unleaded racing gas (100 Unleaded or more) should be well over the requirement. I ran that in my 04 cup a few times and it seemed fine. Have not tried it in my '08 but it would save a lot of money.

GT3 Techno

I am new in this forum and also new in the Cup car world. I will start tracking a 997 Cup (2009) next summer and I was curious to know what octane number others use in their Cup cars. The manual says 98 RON but I was told as you say that this is the equivalent of 93-94 PON or AKI (North American measure). Is that rigth ? Any issues using 94 octane fuel in a stock 997 Cup ?

I know that for performance 100 octane PON would be better but in terms of convenience, it would be much easier if I wouldn't have to carry 2 x 45 gallons drums in my trailer for a weekend and could refill my jugs at the closest gaz station with 94 PON (98 RON equivalent recommended by Porsche in the Manual). The track I am going to most of the time doesn't have race fuel available. Also the car is stock and will not be tune (ECU) at least for the moment

So my question is more about the impact on the engine wear and durability than about performance.

dwe8922

I ended up calling Sunoco, looking into running gas station race gas. He said that all of their gas station race gas has ethanol, and to be very careful in running any ethanol added fuel in a car w/ a fuel cell, as it will deteriorate the foam in the cell. Their 98 octane fuel (and their others I think) sold at the track has no ethanol, and is not a road legal fuel.

I've run into one cup driver who runs pump 93 and octane boost, and another who mixes 110 and pump 93. I don't feel comfortable doing that, so I run the 98.

Geoffrey

I run 93 octane street fuel with 10% ethanol in my 964 RSR with a fuel cell which is now 9 years old and have not had ethanol issues with the fuel cell, or the fuel cell foam.

analogmike

All the sunoco unleaded racing fuel I have seen still has ethanol in it. Has to in the Northeast by law I think, which is ridiculous...

BTW most cup cars don't have a fuel cell.

TwentySix

We use a 50/50 blend of 93 octane and 100 octane race gas, usually Sunoco...

dwe8922

I thought the E10 mandate came around '07/08? Either way, I'm glad you've had good luck running it. I'm just going on what Sunoco told me regarding E10 and fuel cell foam. Also, he said that their 260 GTX 98 sold at Roebling, Road Atlanta, and Sebring was ethanol free. Could be different up north, but I assumed that all of their 260 GT fuels were ethanol free.

RollingArt

We've got a couple drums of Sunoco "260 GT plus" here at our race shop. It's rated as 104 octane and contains a fair amount of ethanol. No problems so far with fuel cell or foam.



Phil