sanderabernathy

Yeah. Americans using a measurement system completely different than every other country on earth. Who'd have thought we would do something so utterly stupid.

VVG

Get a set of performance winter tires/wheels. It will significantly extend your driving season, even you don't want to drive in snow. Plenty of time when the temps are cold but there is no snow/salt/sand yet on the road. I got a set of Michelin Pilot Alpin N-spec in OEM size. My driving season now lasts from mid-March to mid-December, or until the first road salting of the winter

Tief Lernen

I've never noticed any issue with California's 91 octane in daily driving.

Running on the track at high ambient temperatures (85 - 90F or higher), I noticed that the car will lose power in the latter half of a typical 20-minute session when run on 91. Most tracks here in CA have 96 octane available and this resolves the issue.

Regardless of temperature, I also observe substantially worse fuel economy at the track running 91 vs 96. Again, no obvious difference in daily driving from my unscientific observation.

ExMB

Can you quantify this, put numbers to it? Seems a lot of numbers thrown around are in the 5-6 mpg range on track in advanced group.

hacker-pschorr

Not really. The only fuel an ECU can detect is E85 with a flex fuel sensor.

While this statement is technically true, it's not the full story.

There is no way for an engine to know what octane the fuel is until the engine detonates (knocks), only then will the computers make adjustments to stop the knocking. The computers think this is only temporary and will restore full power after a set amount of time (talking minutes here, not days). If the low octane fuel is still being burned, the engine will knock again, computers pull back timing.....rinse and repeat.

This happens over and over and over again until there is fuel in the system that doesn't cause the knocking. This is very bad for your engine. Knock sensors are there as a failsafe to keep the motor from completely self destructing if something goes wrong. They should not be relied upon to run lower octane fuel than the car was tuned on.

Should also note, the highest risk of detonation is at peak torque, not horsepower. So lugging an engine around low in the power band thinking you are "taking it easy" could actually be doing the exact opposite. That awesome feeling of low end torque kicking you in the butt needs high octane just as much as the higher RPM's.

Octane enhancers like Boostane are cheap insurance.

argyleCali

For Cali folks, I use this website generally to find the nearest station. https://find93.com/

Tief Lernen

Back of the envelope math from memory suggests more like 4 mpg, but I’ve never specifically looked.

At Thunder Hill, I will burn more than half a tank per 20-minute session when running 91 (requiring refueling every session), and less than half a tank when running 96 (requiring refueling every 2 sessions).

Denny Swift

LOL

dnimi123

Totally noticeable. Just used about 3oz of Boostane in a full tank of 91octane and the car ran smoother and had as best as I can describe it more 'energy'. Also the sound was slightly different. I do run catted headers on a full Kline set up and have an ECU tune. This solves a problem for me as 100octane at the pump here is like $25 per gallon and E85 smells bad.

ExMB

Full tank = 16.9 gallons = 2163 oz and you added 3 oz.
And here is the Boostane mixing chart.
https://boostane.com/wp-content/uplo...rt_2021png.svg

c1pher

98 in Australia is 93 in America. There’s a different equation used. I thought the same thing when I lived in Europe, thinking 98 octane was higher than US 93, but it’s not.

c1pher

I use the Mississippi River as the rule of thumb for which states get 93 or 91.

ExMB

Isn't TX west of the Mississippi river?

c1pher

Rules of thumb are not abosolutes.

dnimi123

Sooo. I see to go from 91 to 93... its .17 of an ounce per gallon. 17x.13 is 2.21oz. I added a bit more so I should have said approx 3oz so that got me to maybe 94octane? The charts sows 91 to 94 is .17x 17gallons or 2.89??? Am I totally misreading the charts... mmm. Anyway the car did seem to run better. Do you think I put in too much or too little? Whats your calc with 17 gallons and say 3oz of boostane? I would sincerely like to know if I am mixing the wrong volume. But seems to track with this post at https://rennlist.com/forums/718-gts-...l#post18555521 and with this google docs chart someone put together... https://docs.google.com/spreadsheets...hmg/edit#gid=0