DARISC

Can't help it - I've a curious nature.

From - http://www.rxp.com/Octane.htm

The bottom line here is that, in a given engine, a fuel that doesn't knock will produce the same power as most expensive racing gasolines.

By the way, pump gas has specific energies which are no better or worse than most racing gasolines. The power obtained from pump gas is therefore often identical to that of racing fuels, and the only reason to run racing fuels would be detonation problems, or, since racing fuels are often more consistent than pump gas - which racers call "chemical soup."

By the way, pump gas has specific energies which are no better or worse than most racing gasolines. The power obtained from pump gas is therefore often identical to that of racing fuels, and the only reason to run racing fuels would be detonation problems, or, since racing fuels are often more consistent than pump gas - which racers call "chemical soup."

Steve Weiner-Rennsport Systems

My suggestion is to do what I did and get an education by talking to the engineers (not the sales types) who manufacture racing gasolines.

There is a LOT more to this subject that is not always found on the internet due to the proprietary nature of this industry. I've bought a lot of race gas over the past 40 years and developed some relationships with these folks.

Scientific proof? I've simply used the engine dyno to validate our R&D on this subject and for me, thats been satisfactory as well as lap times.

DARISC

The dyno's scientific enough to convince me, Steve. I can only guess that race gas with a higher octane number has had to have been modified in a way that not only yields a higher octane number, but also raises the specific energy of the gas.

Passing this point, I am definitely in way over my head!

Amber Gramps

Steve, you come thru again with real world knowledge you should have charged us for...

what the heck are you guys doing at midnight working on this?

it may be that some guys have there car so well tuned that it isn't a big deal to add a couple extra octane. my car, I'm sure its only on its second set of plugs, second clutch, second or third set of toyo's, and never saw 135mph in the 18 1/2 years it spent in Ohio. it was like Peter Z said once: "Waking up a sleeping dog". your dog may already be awake, mine is still wiping the sleepies out of his eyes.

EDIT: that link is kinda funny. here we sit at sea level and can tell the differance in octane, imagine what a differance it would make at an altitude of 5,000 feet. I think that article is one you put in the bathroom at the track in hope that next time the competition shows up to race with pump gas.

Steve Weiner-Rennsport Systems

Happy to help, anytime,....

I keep late night hours to get things done that doesn't happen during the day. Some of these activities can be somewhat noisy that might otherwise offend the neighbors who work close by,...

I thinks its important to mention that each and every engine's "octane appetite" is different due to differences in cylinder head and piston design, as well as spark plug locations. Air-cooled 911's are octane sensitive due to the lazy combustion chambers, poor natural swirl found in all hemispherical head engines, piston dome design, offset plug locations, and lack of good cylinder head temperature control. Twin-ignition REALLY helps these things.

84_Carrera

And herein lies the major reason Steve got my recent order: Knowledge & willingness to explain it.

Couple that with the question posted to a major p-car parts vendor, "guys, hook me up with a quote for anything I'd need to refresh an 84 911's suspension w/ Boges, 75k miles, all original..." and the reply is "you tell us what you need & we'll sell it to you". Umm, if I knew what I'd need, I'd just order it all off the site & not send a quote request.

Continued for Steve. Pete Z's another guy that seems to fall in this category too. Thanks guys.

DARISC

[QUOTE=thumbsup: for Steve. Pete Z's another guy that seems to fall in this category too. Thanks guys.[/QUOTE]

+1!
I pm'd Pete asking if he'd consider posting on this topic (a first edition copy of his book came with my SC !). I always watch for posts from these two guys in particular and always learn something.

Amber Gramps

Washed and dried the ride for the first time in two weeks and headded off to Newport Beach. Had plenty of high times octane for the first four hours of driving. Wife wanted to know why she was getting whiplash this time...I didn't dare tell her cause half the gas in the tank was 100 proof at $6.99/ gallon. when it dropped below the 1/4 tank mark I put in another 10 gallons of 91 octane and still had plenty of rocket power. We had dinner at a place in Laguna Beach called "The Beach House"....some moviestars house back in the day. The valet left my car right where I put it and still wanted money.

I guess the question is could I tell when I dropped the octane back down closer to 91? The answer is yes, but with so much extra horse power built into the engine....I didn't miss it. Will I do it again? Why do you think I only put 10 gallons of the premium in it? I left room for the juice....

so we get home and I put the car in the shed, put the car cover on it and then put a blanket over that.............. and my wife thinks its a sickness.

and lastly...to the boxter S on the 1, DUH!

Amber Gramps

pulled her out of the shed, drove her down the hill and went to the 100 octane pump for a fill. now $7.99 per gallon. next stop....$185 room in carlsbad.

Amber Gramps

I know what it is now. the gas is too good. it takes away the raw feal of the engine. yes, it does exactly what you want it to do, but you can't feel it. it takes no effort, no hesitation, no bother, it just goes. the feedback you get when an engine is winding up and putting it's heart into performing is missing. you drop a gear and say go and it is already done. the shake in the seat is gone and the intake sounds are drowned out by the rush of wind. I'll take it, but it is different, more like a rocket than internal combustion.

Mike Murphy

It is my opinion that these 3.2 flat-6s are generally more quiet than some of the other models, especially with the stock exhaust. What you do hear mostly is that fan in back, which many people have told me sounds like a jet engine or a turbo.

Amber Gramps

I still can't get over the fact that I can brake loose the tires in second gear at will with two of us in the car...back on 91 octane we went and picked up child #3 and the car runs like a dream back on normal pump 91.

Graufuchs

Tell that to my neighbors and they will not agree....headers to test pipes and 2 in one out exhaust...muhahahaaa

Mike Murphy

True, the exhaust make all the difference

Amber Gramps

Murhy, is it (the exhaust) loud with the top down at a 3,000 rpm / 80 mph cruise on the freeway? I gave up on the sterio and just enjoy the sound of the wind and the fan. adding too much sound, I don't know?