Gabbyness

Is it general practice that if I drive my happy ass to a nearby race track that I can sip into the sweet nectar that is 100/105 octane racing gas? I have a Mitsubishi Evolution and I've been thinking a hearty tank of racing gas would be a great way to spend a weekend. I've been scared off of the 100LL that airports use due to warranty issues. Plus I ran into a guy who had a corvette and blew out all kinds of intricate engine parts using 100LL, so I don't think so.

Anyone with high performance cars have experience with happy gas? Let me know!

MSD

If it isn't detonating, higher octane won't help. Most likely, it'ss start missing unless you have a boost controller that can tell it's missing and kick up the turbo a bit to increase the pressure. I'll bet that your engine ins't designed to run nitro or leaded fuel anyway. You'll just fuck up the cat(s?) that way.

On a side note, this reminds me of a contest from hot import nights a few years ago. They wanted to see whose car could run the highest octane, and around 130, all but one had dropped out. The one guy left had an Integra with huge amoiunts of bottom-end reinforcement, and kept turning the boost up until the trubo couldnt' put out any more air. I think his final number was 174

Peryn

Yeah, unless you have set up your car to up the boost, higher octane gas will hurt more than help. Plus, Mitsu will be more than happy to void your warranty if you race it. Also, read the fine print carefully, because they may possibly void it if you simply turn up the boost.

Also, doesn't teh Evo come stock with something close to 19psi boost? If so, im not sure how much more i would really trust the engine to handle, or how much more the turbo could even put out.

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stingc

That gas probably contains lead (not sure). If so, you will destroy your catalytic converter(s), and could damage some engine management sensors.

Gabbyness

Roger that. I guess it's not such a fab idea. Thanks for the tips.

The turbo can put out some more, but, I don't think I'll risk it.

BigTruck1956

lots of times Racing Gas has either lead or lots of alcohol in it, which can harm an engine not designed for it. do NOT put 100LL in your car. not only will it void your warranty, (and they will find out when your cats are full of lead), I will destroy the cats in a matter of hours and will leave all kinds of lovely deposits inside your engine.

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sci

leaded gas kills o2 sensors quick......we get about 10 hours use out of a wideband sensor on leaded fuel.

get a bigger turbo, and make more power

Amano

you have an Evo. I am insanely jealous.

slimshaydee

In Australia you can buy 98 octane at any general service station (10c per litre dearer), and regular unleaded is 95 octane. I thought our fuel was shitty!

iamnormal

Here is a site that tells what octane means. For people like me that are not sure.
http://auto.howstuffworks.com/question90.htm

stingc

In most of the US, you can get between 87 and 93 octane. In Kalifornia, 91 is best you can reasonably find (and it's more expensive than 93 everywhere else too). You might be using a different rating system, though. In the US, the ratings are (RON+MON)/2.

flightlessbird

http://www.elektro.com/~audi/toluene/

If you get an ECU that will let you swap maps on the fly you can make on for city driving on 93 (or 91 if you are so unlucky) and one for the mix. You can then switch maps when you go to the autoX/track/twisty hill and decide to run the mix.

Disclaimer: Bad mix | bad gas = motor rebuild

2sheds

some local (dallas) guys around here with turbo- and supercharged miatas will add toluene to their gas to boost the octane for track days in the texas heat.

tho like a previous poster said, if there's no detonation/pinging you won't get any real benefit from the higher octane.

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dirtyrascal7

unleaded race gas isn't very hard to find... i use 105 octane unleaded all the time for my jet skis ever since they outlawed leaded fuel for racing.

telekinetic

higher octane only delays detonation, allowing you to run more compression, timing, boost, or some combination of the above. If you don't tell your car's computer to do something different with the fuel, it will actually run worse. My friend and I ran around in his car at 5lbs higher than normal boost and an advanced timing map when he filled up with 110 unleaded.

Regarding higher octanes in places other than the US, that isn't entirely accurate...there are three ways to quote octane numbers-RON, MON, and AKI

In places other than the US, it is common to quote RON numbers instead, thus making it look like they've got 'better' gas.

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twisted no more

hubie

twistedmosaic is correct. Without doing anything to the spark timing or in this case turbo boost this will cause more damage than it's worth. You would be better served buying some sort of ignition upgrade, and a cam shaft, and a better exhaust, and, and, and, and ...