JumpinJim

With all the talk of the tuned TT engine blowing up I was thinking of running race fuel when I go to the track next time in mine. Obviously I'll want unleaded fuel, but then there's oxygenated vs non-oxygenated. I hear that oxygenated race fuel can make an engine run leaner which is to be avoided unless tuned for it. Would I take it I would want to run an unleaded non-oxygenated fuel then? Or will our cars and the renntech tune I have not care about oxygenated fuel? I notice that most unleaded race gas is of the oxygenated variety.

_AMG_

Oxygenated fuel uses a blend of ethanol were non-oxygenated is pure gasoline.
Just go with some MS109.

BenJ

VP MS109

hyperion667

don't forget about this one too

JumpinJim

What the.....

JumpinJim

Interestingly in the Porsche forums some shy away from MS109 as they say it runs much leaner, about a full point leaner than pump gas. I've run TrackTek 105UL in my 911 Turbo and it ran very well, however the tune in it is adjusted for 100 octane race fuel. I've asked Renntech about the CLS 63 tune and they indicated it was tuned for 93 pump gas. I've been doing some research on what race fuel has a similar oxygen content, specific gravity, and stoich to pump gas to keep everything happy.

JumpinJim

Here's the reply I got from RennTech.

Quote:

We suggest running only non-oxygenated unleaded race gas and between 100 and 104 octane. The specific gravity of the race gas is heavier, but the variance is much less that the variance caused by the use of (hydroscopic) ethanol to augment regular pump gas. The pump gas can vary greatly simply based on how much water the ethanol has consumed.

That would exclude MS109 as it's one of the most heavily oxygenated unleaded race fuels out there.

_AMG_

So which specific fuel does Renntech recommend?

JumpinJim

They didn't suggest any specific brand, just specs. Will have to do some homework to figure out which to use.

kohjul

Sorry to ask in this thread but since you guys talking about fuel, I want to know what is the best gas company in socal that I can use in tuned cls? Chvron? Shell?

Saeedg48

MS109

freefall

What is MS109?

_AMG_

I see, hope Renntech chimes in and says which one they recommend.

I used to buy MS109 in 5 gallon drums from Manning Fuel in Sun Valley, CA.
Give them a call.

http://www.manningfuel.com/

MS109 is 101 octane unleaded/oxygenated race fuel supplied by VP Racing.

BenzoBoi

Another vote for VP MS109.

JumpinJim

After more discussions either Track Tek(Chevron) 105 or Shell URT 110. Shell for the better anti knock running high boost in the TX heat. Otherwise the Track Tek 105 is perfect. Neither are heavily oxygenated. Price difference is about $80 between the two for a 55 gallon drum, the 105 being cheaper. I ordered a drum of Shell URT 110 for $670.

_AMG_

Where did you order the Shell race gas from?

JumpinJim

Motorsport Sales in Dallas.

freefall

JJ - Renntech tunes are made for 93 oct. Any issues going to 100?

JumpinJim

No, in fact it's recommended if you're going to be running the car hard at the track for extended periods. Note you won't pick up any power, but it will be safer. Higher octane race gas has much better anti knock and detonation properties.

JumpinJim

Now that's what I call a barrel of fun!