El Fredo

Took my06 s to Indy a couple weeks ago to see a friend. Indy being Indy
had race fuel in a lot of the gas stations. The temptation was to great
so I spent $85 for 10 gallons of 103. Normally run shell 93 in her.
I thought she ran smooth before... well it ran very smooth. The biggest
difference the smoothness of acceleration. My wife even noticed.
Yes I am aware it had lead in it...
What do others run in there P car ???? Love some opinions ...

Fred

Ken968

Funny I was just thinking about this today. I have 100 octane unleaded available to me, and I was wondering if there would be any real benefit from using 100 octane vs 93. Your experience sounds like there maybe a difference you can feel.

I hope other chime in.

Ken

JW911

Well I think you experienced the infamous placebo effect. Ran smooth? What does that really mean? Does your engine normally run rough? You say it contains lead? I didn't think this was legal to be sold at a public fuel facility. If it had lead in it, it was doing serious damage to your catalytic converters. Yikes...

I would stick with 91+ octane that the engine was designed for. Runs very smooth and powerful on this.

Edgy01

If you ran leaded fuel in it you just trashed your catalytic converters.

The Porsche 911 of today is optimized for 93 Octane. If you put anything higher in there you are wasting your money. Literally. Generally, many of us have to deal with the crappy 91 octane California stuff which means that it just doesn't ever perform as it was designed. The trick there is to find some unleaded racing fuel and mix it in to get roughly 93-94 octane.

When I picked up my car in Germany the factory told me to buy the Blei-Frei (lead free) Super Benzin--but not the ultra high octane Super--because it would be a waste of money. (It's about 98)

Mike in CA

Hopefully the "racing fuel" you bought was unleaded. Otherwise, as Dan points out, you've likely wrecked your cats. The highest octane unleaded fuel I've found is Sunoco 100 which is available at Infineon raceway near me. I don't bother trying to boost the 91 octane stuff that we get in CA for street driving, but for autocross I mix the 100 octane unleaded with 91 pump gas to get a blend of 93+. This will give you the max performance from your engine; a higher octane is a waste for a stock motor.

KBS911

Best bet would be to use conventional 93 octane non-ethanol fuel if it is available. It has provided measurable improvement in mileage in 2 of my personal vehicles, one being the Porsche, and if you let your car sit for any length of time you can avoid the phase seperation that can occur with ethanol based fuels.

El Fredo

To your point "running smooth " means no occasional hesitation in the acceleration.
Which probably means my normal fuel has quality issues? However when I use an octane booster
preferably NOS, Lucas or Amsoil . These are good but racing fuel blended with street stuff is the best.

Skibum

I ran various mixtures of octane up to 100 last 2 summers ago. (all unleaded and approved for street use)
While I'd like to say that it made the car a rocket ship, that wasn't the case.
While I'll continue to say that the car "seemed" to have run slightly better, it absolutely was not worth the cost. Spend that cash on something else.
If you indeed used leaded gas your cats are not very happy right now.

Macster

Shell 93 (V-Power) gas is a pretty good gasoline, though you have to make sure you buy from a busy station.

(All I can find where I live/drive is 91 octane but even so Shell gas compared to 'supermarket' or off brand gasolines is consistently better. About the only gasolines I'll run are Shell, Chevron, and 76, though back east I'll run Philips.)

What you probably experienced was the difference between 'fresh' gas and 'stale' gas. In this case the race gas being fresher, or at least less stale, than the gas in the tank.

I tried 100 octane race gas (unleaded of course) in one of my Porsches and while I wish I had been able to detect some improvement there wasn't any. And while I can't recall the price/gallon I'm pretty sure it was nearly double the 91 octane gas's price/gallon.

It is your money and you can do what you want. But really the best thing you can do is just buy the right grade of octane, a name brand gas (tests have found 'supermarket' gas varies due to the inconsistency of the suppliers used), and buy from a busy station to ensure you get the freshest gas.

Also, it doesn't make sense to fill up the tank with fresh 93 octane gas and then let the car sit for weeks or longer. The gas in the tank goes 'off' pretty quick. If one makes a habit of this the engine is essentially living on stale gas.

The only time race gas makes sense is if you are taking the car to the track. The higher octane buys you some margin of safety from detonation. Sure, the engine controller will retard spark if signs of detonation are detected, but the engine runs better, runs cooler, if the engine controller doesn't have to do this. And the odds are better it won't if you show up at the track with race gas in the tank.

Sincerely,

Macster.

El Fredo

Thanks to all

RJKflyer

In Europe the 997 is designed to use Euro 98 octane - any less and it will impact performance. Remember Euro and US pump numbers are not equivalent - I forget the difference but recall 91US is 95Euro. The 'super' in Germany is 100 which is a waste as the man said. Super in UK is 97-99 depending on supplier, which is what we need.

drdrank

I put 100 and 110 in the GT3RS because it was 2 minutes before the start of my session at Watkins Glen. Omg!

But my titanium exhaust tips now have a white patina on them now.