Let me ask it a different way: what are the differences between the 6cup ecu timing/cam timing, compression ratios and a street GT3??

 

Compression is the same. Cam timing is slightly different. As was mentioned manual calls for 98 ron which is the same as 93 octane in the us.

To the OP, since you have a 3.8 that is aftermarket and may have different compression i would consult the builder.

 

Sorry to bring back this old tread but I am a bit confused these days since The IMSA GT3 Cup Challenge Canada announced the mandatory fuel for the racers in 2013 is Petro-Canada Ultra 94 octane. This is not race fuel and the Series is supported by Porsche Canada: "We are proud to welcome Petro-Canada's Ultra 94 as a title sponsor right in time for the beginning of the third Porsche GT3 Cup Challenge Canada by Michelin series season," said Joe Lawrence, President & CEO, Porsche Cars Canada, Ltd. "The 911 GT3 Cup cars will be fuelled by the same Ultra 94 gasoline available to the Canadian public."

http://imsachallenge.ca/news/ultra-9...orsche-gt3-cup

 

Interesting!

 

Anyone find out any more info about
IMSA GT3 Cup Challenge Canada using Petro-Canada's Ultra 94.

Ultra 94 is 94 (R+M)/2 (AKI) http://retail.petro-canada.ca/en/fuelsavings/3925.aspx

If Wikipedia is accurate then that should be RON: 101.5

Wikipedia: Premium" or "Super unleaded" gasoline in US (10% ethanol blend): 92-93(R+M)/2 (AKI) is equal to 97RON
But vendors like Shell V-Power seems to rate 93 (R+M)/2 pump gas as 98 RON. Actually most 93 gas (US) from what I can find seems to rate at RON 98

 

So has anyone been running 93/94 US octane fuel this summer? I have heard that you are safe running Sunoco Ultra 94.

 

very interesting.

Perhaps 93 and 94 in canada is the same ROW 98 octane which is cup minimum....