Use of Racing Gas

[PSL-Boxster]

has anyone used racing gas in their boxsters before? If you have, how does the performance factor increase? especially for the 2.7 engines . Thanks.

[heyjae]

A waste of money on the street. Not really worth it even on the track. Even on my modified 3.2, it doesn't seem to make a difference in performance. I only used it to see if it would help my smog check. Also some race gas is leaded (usually 105 octane), which will destroy your cat converters.

[boostiality]

Theres a thread on 6speed in the 996TT/GT2 section about someone asking a similar question on a stock TT motor. Now you got to take into consideration that obviously it's a different motor altogether & that its boosted, but it gives you a general idea of how Porsche's DME acts.

What was stated by the tuner/softronic manipulator is that these motors can be filled with 87 octane and not blow up on a completely stock car / unmolested DME. At the same token, when race gas was used the DME actually put on 30-40 more horsepower then stock. What this means is that the DME's are advanced enough to know that something is either going really wrong and cut back on ignition timing or it'll go more advanced when it's recognizes that knock isn't happening and goes the other way. BTW, if you want to give it a shot just buy unleaded race gas which goes up to 109 octane ala VP racing MS109.

Although it'll never be this dramatic to our motors being that they are NA, the same algorithm does take shape. So is there a gain? just slightly if anything. All the guys like softronic/giac/ etc etc do is manipulate the ignition timing. Porsche puts X amount of advance with a safety variance in mind, all the tuners do is bump it up a bit then find a way to charge people $1,000+ . Must be nice

[Lil bastard]

Actually Race Gas contains less energy (BTUs, Joules) than regular pump gas. This is because the octane boosters used contain less energy and replace a certain volume of what would otherwise be gasoline.

What it does do is allow changes in the CR, Spark curve, mechanical timing, etc. so that more energy is extracted than would be the case with pump gas. And, all this is dependent upon the fuel not pre-igniting or knocking which is where the octane boosters come into play. But, only if your engine is mechanically and electronically modified to make use of it.

There are very specially designed engines which produce much more power from pump gas - such as in Formula 1. But, these engines use exotic materials and technologies costing hundreds of thousands of $ and not available for a street car.

No doubt, the TT can make better use of this fuel than an NA car can. To accomplish this in an NA car, you're talking pistons, cams, DME flash, etc. to get any benefit from this fuel.

With any unmodified engine, using Racing Gas will decrease performance, unless the DME contains untapped maps which don't come into play on pump gas.

[Benny986]

if you have a chip that is programmed for it. otherwise, you won't be able to tell the difference. i have heard that in some cars, with equal driving, you get ever so slightly better mileage, but i have not tested this.

i run 100octance on my 100octane program, and its a BIG difference.

[edevlin]

I am curious to see if it makes any difference in my 2.7L boxster. One of these days I will go over to Performance Autosport in Richmond where I have my dyno pulls done in the past, fill up the car with the 100 octane lead-free fuel they have there and do a pull. I have done 4 dyno pulls there and the results have been very consistant with the sorts of things I have done to the car. I find learning about the car with dyno pulls great entertainment,

Ed

[Lil bastard]

Originally Posted by edevlin

I am curious to see if it makes any difference in my 2.7L boxster. ...

Yea, but unless you're going to use it all the time (@$6+/gal.), it is exactly as you say - just a curiousity.

Sure, you may see the numbers climb on the Dyno, but it's like holding your thumb on the bulb of a thermometer - you will make the thermometer rise, but you haven't changed the temperature of the room one bit.

[Topless]

On hot track days I have run 100 oct. racing fuel a few times. I felt no difference. At $8/gal I probably won't do it again.

[edevlin]

"On hot track days I have run 100 oct. racing fuel a few times. I felt no difference. At $8/gal I probably won't do it again."

I get my 100 octane at VIR and it's almost 8.00/gallon there. I sure would not want to make feeding the car that fuel a regular thing, even if I find that there is a little bump in performance. But for me, it just gives me a little more information about the potential performance envelope of the car. Such is the nature of the hobby,

Ed

[Topless]

Ed,
Your car would probably benefit more from racing fuel than mine due to the 7.2 DME and chip tuning on your car. These things should adapt quickly and make better use of the fuel. A turbo would benefit even more. My car... nada. 93 oct pump gas is the cats meow on my car.

[insite]

i have run out of fuel at the track & refilled w/ VP Racing C12. it's a risky proposition since it's leaded fuel; this can foul oxygen sensors. without a doubt the car ran much better than on pump gas. i think that's because a lot of times, 93 octane at gas stations sits for awhile before it sees our tanks. octane turns into heptane (regular gas) over time, so the true octane rating of the fuel we purchase at gas station is somewhat less than 93 by the time we get it.

still, though, i don't think the computers in our car will try to optimize spark advance for anything beyond 91 octane (california fairy juice). a re-program of the ECU can widen the parameters to allow tuning to race fuel. companies like Revo will let you re-program on the fly for this. FYI, the difference is significant.

[edevlin]

So, as I said in a related thread, I filled up my base 2000 Boxster with 100 octane lead-free racing fuel when I went to VIR last weekend, an expensive experience. I have been trying to get a sense of how the car performs with the higher-octaner fuel. It seems like it is more responsive, and pulls harder at high rpm's, but it has been difficult for me to quantify.

I went to Richmond today and as I watched the gas gauge head down to a quarter of a tank of the expensive 100 octane fuel, I impulsively decided to see if there was any difference in the performance of the car. So I gave a quick call to the folks at Perfomance Autosport to see if their dyno was free this morning.

I plunked down my 75.00 and we strapped the Boxster in for a run. Dyno-pull junkies, I guess I qualify, know that they put the car in fourth gear and run it up to redline for a pull. One thing I kept track of today was the spedometer at just over the 7K redline in fourth gear. It was 138 mph, yikes. Anyway, I will try to see if I can post the dyno readout as an attachment, if not I will put it up as a sample dyno on my car webpage below.

The results were interesting, no increase in torque over the pull I did recently with normal shell premium 93 octane fuel. But there was an increase from 204 to 210 hp, a 6 hp increase, almost all at higher RPM's. I dont know how much of this increase in inherent in our cars ECU's, or if it is a result of the programming of the Autothority chip that I have put in the car. If the graph posts, the upper graph is the 100 octane fuel run, the lower graph is the 93 octane fuel run, interesting,

Ed