HODY905

Do the 993 cup cars and 996 cup cars, as they come from the factory, use race gas or normal 93 octance pump gas?

ltc

993Cup:
http://www.cupcar.net/993cup.asp
Fuel requirement 98 octane

996Cup:
http://www.cupcar.net/gt3cup.asp
Fuel requirement 98 octane

DrJupeman

Careful, as I believe that is Euro '98 which is the RON rating only. In the U.S. we use a RON/MON average and it is not clear or widely known whose gas is mixed in a way that might have 98 RON contributing to the 93 pump octane rating in the U.S.

I have spoken with an ex-Exxon engineer who owns a GT3 Cup and his comments were basically, "You could probably run U.S. 93 pump gas in the car, but why risk it?" He ran U.S. 100 in his cup...

PatK-Mpls

The following was copy/.pasted directly from the GT3 Cup MY 2005 Manual:

Fuel 98 RON Super Plus unleaded

JC in NY

Since the beginning of the Cup concept, all Cup cars are designed to run premium pump gas. European 98 RON is *roughly* equivalent to our 93 pump gas. I run 93/94 in my type 964 Cup. The GT3 Cup has the same engine as the street GT3 - both of which are designed to run 98 RON.

I suppose very expensive racing gas can't hurt, but why?

DrJupeman

John, its the "roughly" that may be of concern. Otherwise I was very tempted to run 93 in my GT3 Cup when I had it. Climate conditions might lead you to go one way or the other, too. If it is 90+ degrees at the Glen in the summer you might want to run 100. If it is 50 degrees at Lime Rock in April, 93/94 is going to be fine.

Or you can do what I do with the turbo: run a 50/50 mix to confidently bump up the octane enough so that I don't worry about detonation.

kev

https://rennlist.com/forums/showthre...&highlight=cup

Seems to need at least 95 octane.

I mix 109 with street 93 to get to 101. Is there any chance of "layering" if you mix street with race fuel?

amondc

We have always run 93/94 in our '00 and '04 car with no ill effects. I am sure you might get an extra .4hp if you run the race gas but we have never had a problem with pump gas in it.

kary993

You guys are luck you can get something greater than 91 at the pump. California there is only 91 or race gas

Jay Gratton

What is the price cost of a fill up between a 93 fill up and a racing fuel fill up on a cup car?

38D

Race gas is ~$5/gal vs. high $2s. It adds up fast.

Bill935K3

I have never seen unleaded race fuel higher than 103 ???
Are you mixing leaded race gas with unleaded pump?

I don't know much about cup cars but I would suspect that you might encounter sensor proplems. (air fuel and or O2)
I know with my car our A/F sensor must be replaced 2-3 times per season running leaded.

amondc

there is usually 2 of us driving and in a 3 day weekend we go thru about 65 gals of gas roughly 325 for race gas or 146 on pump gas.

kev

VP has an unleaded 109 fuel called "Motorsports 109": http://www.vpracingfuels.com/vp_01_f...AF222#unleaded

Where I get it at, it is the same price as 101 unleaded.

Bill935K3

Dam !! I have not looked at full range of VP products in a while, lots more unleaded options than when I started pushing the boost on my street car many moons ago.