race file question

[A4speed]

i have the GIAC race file that requires 100 octane fuel. theres a gas station near by that has it. my question is if i have half a tank of 91 and put in the 100 octane, is the mix ok to still switch it over or should i wait til its almost empty?

[Cincy]

That would be about 95oct. I would just wait till its almost empty and add in some 100oct. Any reason why you want to run it?

[A4speed]

just to see what its like :D i get my car back tomorrow and want to have a good time with her!

i hate this stupid cobalt rental car...

[ImTheDevil]

I'd wait also, like Cincy said. A race file is optimized for the high-octane gas, and your timing and boost maps are tailored with the detonation resistance of 100-octane in mind. Run the race file using a 95 mix like you're thinking, and you may end up disappointed as the car pulls timing back to compensate, letting you think it's not all that fast, or you could end up with damage (unlikely - these cars are pretty advanced and would likely respond quickly to detonation). Nutshell - run the tank down and then fill up with 100, then run your race map.

[A4speed]

yeah, i figured that just wanted to make sure bf i tried something dumb. :)

also, they didn't have my car ready today so i have to wait til tomorrow...

[auditech79]

Your pistons can handle it, ive done worse, then again i don't give a s*it.

[AudiTurbo]

Wait for a empty tank!

[A4speed]

also, im assuming i need to find unleaded 100 octane fuel. the gas station close by has leaded 100 octane. ive heard leaded fuel can destroy the Cat.

[Cincy]

and o2's

Deff look for unleaded unless you like changing both

[beefiveafour]

ive yet to find a gas station that sells 100 or higher octane thats unleaded. you may have to order it online or through a race shop

[Cincy]

They are mainly at race tracks. You can buy like 5-25gal barrels of them. Im thinking about having a "race file" but tuned for e85 instead

[A4speed]

e85?

[Cincy]

85% ethenol 15% gas. Its like 105oct but needs 25% more fuel. It can be found at many pumps for the flexfuel cars and it often around the same price as 87oct. So in the end, its just a tiny bit more expensive than 93 but with way more power. Evo guys are making around 500awhp on stock turbos with e85 and 1000cc injectors.

[A4speed]

wow serious? thats crazy!

what do you mean it needs 25% more fuel? would e85 work for my GIAC race file or is it strictly 100 oct pump gas?

[Cincy]

It is strickly a gas program.

It takes 25% more fuel to have the same energy as gas. But its cleaner burning and renewable. So if you need 1000cc inj for your setup, you will need 1250cc to run full e85. Some places even have e98

[FasterA4ThanUrs]

you can also find unleaded race gas at most motorcycle/atv shops... They all sell VP canisters by me.

[A4speed]

how much do they cost for a canister?

[FasterA4ThanUrs]

they come in 5 gallon cans... I havent bought any in awhile but i believe they fluctuate a lil with gas costs too... it probably comes out to like 7-10 dollars a gallon

[Cincy]

That sounds about right. Last time i checked it was close to $5 over current gas prices. The VP is good stuff, little to much for a stock turbo. Adding in wmi would be a better alternative and you could run the file daily

[Tweaked]

That sounds about right. Last time i checked it was close to $5 over current gas prices. The VP is good stuff, little to much for a stock turbo. Adding in wmi would be a better alternative and you could run the file daily

Wow, that would be one expensive daily driver!

I looked into tuning for E85 as well. Gas mileage goes down noticeably, so it's more costly per mile, but as you said, there's more potential power to be had if tuned correctly. In addition to injectors, however, new fuel lines, filter, fuel rail, etc. are needed to prevent the fuel system from corroding away. Later finding out there was only 4 E85 fueling stations in CT, the closest being over 30 minutes from my house and in the complete opposite direction of work, family, the fiance, and the gym, I just dropped the idea.

[Cincy]

All of the stock parts have held up fine for those that have run e85 on a daily basis.

Also, running wmi isnt that expensive. A 2qrt tank should last for atleast 2 fill ups depending on how you drive. It only gets sprayed in boost at the set psi for it to turn on. Plus the meth can be had in a bottle of HEET which is about a $1.50 a bottle and is almost 100% meth

[Tweaked]

No, I meant running 100+ octane race gas at 9 bucks a gallon is expensive for a DD!

Regarding E85: The tank in the A4 is plastic, so the tank isn't going to corrode. If the fuel rail is stainless, that should be fine too, but anything that's not will eventually corrode.

As for meth, I was thinking about running meth as well. One of the guys around here is running meth on his modified S4, but he said he blasts through it very quickly, so it's a bit pricey. $1.50 is cheap though, what size (liters or quarts) bottle is that?

[Cincy]

Oh, race gas is crazy expensive.

There have been people running e85 for about a year now and the only thing that has died is the stock pump because they werent using an inline pump that can flow the needed fuel. But i get what your getting at. Most flex fuel cars have different setups when it runs one vs the other. So far, no issues with the 1.8t community and i havent seen the Evo crowd change any stock parts either to run e85/e98

The heet is a 12oz bottle. How fast you go through it will depend on what size nozzle you need to run, how often you get into boost where its turned on, and how much your tank holds. Im sure the S4 has some decent sized nozzle(s) and probably gets into boost often.