Hi
A friend has offered me 10gal. of race fuel. I am thanking about running a 50/50 mix (Shell 93/race fuel) has anyone done this?
Thanks

 

For starters, is the "race fuel" unleaded? That's the most important thing.

Personally, I've run everthing from 93 AKI to 100 AKI to 106 AKI, and below about 5000 rpm, I just don't notice much of a difference at all. Now, I also have a stock engine, so those owners running more boost will probably notice a bigger difference.

 

I work for a racing organization and i sometimes am able to get 5 gal of Sunoco 260 GTX, which is 98 octane and i add that to 93 octane i normally run and have no problems.I have checked plugs (one step colder,15% and 2%) and look very good and no pinging.

 

I just went 50/50 of 91 Octane Chevron, and 100 Octane VP Racing gas recently. I really didn't feel a difference in the lower ranges. From the mid range to high range rpms, throttle response was better and the car seemed quicker. I'm 100% stock. The only other benefit was that the car idled noticeably smoother.

Overall, I probably won't do it again, unless I get some ECU work done. Just too much dang money for gas (6.xx/per gallon)

 

My friend just brought the gas over. He told me it was 118 unladed. I have a stock engine except for a cold air kit and Nology Hot Wires. It’s free so I thought I would give it a try.

 

Unless your motor is specifically tuned for high octane, you'll likely run slower on race gas. Higher octane itself does not make more horsepower. Its intended use is to help prevent detonation in high compression motors by burning slower. Cars will make the MOST power on the lowest octane rating that does not cause detonation. Race gas is typically used for the safety factor when people are running higher boost, higher compression, and/or nitrous, as those combinations require the higher octane rating to keep from detonating.

Now, there may be some additives in certain types of premium race fuel that will help produce more power, however not all race fuels are the same.

And if your friend's race fuel has been sitting on the shelf for quite awhile, I'd suggest only using it in your lawnmower.

 

Except the MINI ECU is smart enough to advance the timing and take advantage of the high octane...

 

The ECU can only adjust within a limited range. Therefore, the racing fuel will not produce results much better than 93 octane pump gas unless you are running with a larger than stock supercharger and can truly secure higher boost at high revs. (17% and 19% reduction pullies on a stock sc actually loose boost at high Rs)

The 118 on the racing fuel refers to research octane which will will result in an R+M/2 pump octane of about 109-112.

 

If the parameters of the ECU were designed such that it were able to take advantage of the higher octane, then why wouldn't the software engineers also have made it more able to run on 87? Read the gas thread about the problems people have experienced by running 87...

Likewise, getting a dyno tune would be of little use if the factory ECU were doing such a good job of maximizing performance capability by adapting to more air (pulleys, cam, heads, etc..) and to more fuel (bigger injectors). But we've all seen examples of just a tune producing significant HP figures on a basic setup (stock or just a pulley), and it's common knowledge that it's essential with bigger mods (cam, heads, injectors).

Ultimately, the ECU would need to be specifically tuned to take advantage of the higher octane found in race gas, and the engine would need some modifications to higher compression to actually require the use of the higher octane.

 

+1.

 

I stand corrected. Then what is with all the stories of people putting 105 or something like that in their car and having it become "a different machine"?

 

Mostly placebo effect, IMO. Same as the stories of people spending money on something like a Tornado or other typically worthless item and searching for a way to justify the expense to themselves.

Although I'm sure there are instances where the car isn't in top condition (old plugs, bad gas) and the ECU was pulling timing to prevent knock/detonation. Adding in the race gas will make the car feel better, since it alleviates that condition.

But it still stands that a properly running vehicle ranging from stock to minor bolt-ons will not benefit from running higher than recommended octane fuel. For example, a car that is designed to run on 87 will actually be faster on 87 than on premium 91/93.

 

He put stabilizer in the fuel, he's had it for about 6 months. He has a 55 Chevy with a crate motor in it that requires the high octane. Its being worked on and he gave it to me to use rather then let it go bad. If there is a possibility of it hurting my MCS I will not use it.
Thanks for all the comments.

 

I don't think it'll hurt anything since you said it was unleaded and you'll be mixing it with the regular gas. Just saying there really is no benefit to it for your application... With the cost of gas now, getting for free anything that'll burn isn't a bad deal.

 

Except in my case because...I hurt in the wallet

Good stuff Dan...I learn more and more as I read this forum.

 

Thanks for all the help. I learned quite a bit. I guess I will tell my wife I need to get a pulley, exhaust, and ECU upgrade so I don’t waste the gas. I'm sure she'll believe me