Amber Gramps

Vp Racing Fuel has a station around the corner and are now offering (at $6.99 per gallon) 100 octaine at the pump. in a 7-11 accent the guy said "30% more horse power"....WTF?

should I try it or not?

no, I'm not make'n it up!

Graufuchs

Higher octane = hotter detonation, no good for air cooled

Plus.......youll never get 30% more Hp.....thats funny.

Bearclaw

This is sold at a very unassuming-looking 76 station in my area. I think the highest unleaded pump is listed at 104. The leaded versions are 111 and 114 here, I think...

http://www.trickgas.com/

I've mixed a half-and-half tank and didn't really notice much difference. Hell, the only difference may have been the placebo effect.

Higher octane provides knock resistance. Unless you have a highly modified engine, you're not gonna get much out of it. My guess is the ricers buy the hell out of it, as there were a couple there on the Saturday I was there.

VNTGSPD

The 100 octane works great when mixed about half and half with 91 octane for the guys with 993s in Calif. These cars require 93 octane so the 91/100 mix does a good job of reducing detonation in these cars and allowing the ECU to dial in maximum advance.

For your 3.2 it's a waste of money IMO.

Amber Gramps

thanks guys, I remember as a kid mixing an entire bottle of 102plus to a gallon for my atc 90. may as well have been rocket fuel!!!!!

I'll pass on the 100 pump gas 'cause it already acts turbo

Ed Burdell

Forgive my ignorance, but what octane do 3.2's require?

911S3.6

The higher octane WILL make a difference if your DME has been chipped to advance the timing and adjust A/F mixtures. I have a Steve Weiner "massaged" DME and there's quite a noticeable difference when running 104 versus 93 pump gas. Unleaded of course!

///Nick

84_Carrera

As I understand it this is exactly backwards.
lower octane = hotter / faster / "energetic" burn, more tendency toward pre-detonation.
higher octane = cooler / slower / less "energetic" burn, less tendency toward pre-detonation.

Also AFAIK, the lower octane is more prone to carbon deposits due to the combustion vs. higher octane. There is more energy in the fuel at lower octane, but you can take advantage of timing changes with higher octane and the timing changes are what make more power, not the fuel itself.

I ran 100 unleaded at the strip on my old blower SHO, and it actually ran like crap, because the chip was optimized for 93 octane. I mixed in street gas, and things were better. I was back to normal power levels after getting the 100 out of there. The rule of thumb I've always used is: always "run the lowest octane you can safely get away with", and make sure you keep the engine clean as any deposits will hurt your performance.

Brian_77_3.6

My 3.6 (track car) which is chipped runs fine on 93 but during very hot weather if the oil temps climb I fill it with 100 and it runs cooler.

Graufuchs

allways thought it ran hotter due to the larger explosion, i understand its a cleaner burn inside the engine but thought it created more heat....are my physics backwards??

My terminology is wrong...sorry...

High octane fuels burn better (smoother, not larger explosion) but Do run hotter but at times engines run better with higher heat inside the engine depending what the car calls for, and if the car is setup correctly for it, higher compression engines require higher octane.

Amber Gramps

91 here in california is the normal "premium" gas and it works great. one of the rice rocket kids I sell to actually went over the entire 100 octaine x NOX system thing and told me my computer would just limit my fuel injectors and I would have a zero sum gain. he did say mixed 50/50 with 91 is going to give best results.

Steve W. where are you on this?

theiceman

If you car is deined for 87 and your running 100, you don't have the capacity to burn it and I am pretty sure you are going to blow it out the exhaust .. and increase emisions.

84_Carrera

I messed that up a bit, on deposits. The hotter the burn, the cleaner the burn. HIGHER octane fuels will create more deposits (probably why all the Supers have more detergents?).

Again, if I understand correctly.

On the OBD-I SHO's (1 knock sensor), the timing's advanced until knock is detected, then retarded 2 degrees (basically). Since no knock is detected with 87, I run it here in New England. "Premium Fuel Recommended" however, officially. On the 911 with no knock sensor, I run 93 all the time, though the PO told me it's not necessary. I figure with the Weltmeister chip in there, why chance it?

DARISC

Simply put, if the engine ain't pinging/knocking/detonating it don't need mo octane! Mo octane won't yield mo powuh in and of itself. Mo octane simply allows the timing to be advanced w/o pinging/knocking/detonating (which timing advance can yield mo powuh - but you better be careful and know what you're doing!).

I'd luuv to be corrected if I'm wrong here! (this understanding that I have goes back to jr. high school days)

Steve Weiner-Rennsport Systems

Its what you DON'T hear that can be one's undoing,...

Take a look at http://www.rennsportsystems.com/2a.html for some useful information on this topic.