SANDIEGO

rave426

Gotcha. I've been in the South too long. I can't remember the last time i've seen 91 octane. lol. I'd assume Porsche has ECU managed this, but it indeed may cut power efficiency a bit at 91 octane.

Zeus

I'd be interested in knowing if anyone has ever ran race gas (i.e. high-octane fuel other than pump gas) exclusively in their street car? And if so, were there any detrimental effects to the engine or catalytic converters over the long term? Car enthusiasts in general seem to care a great deal about the quality of the motor oil & other fluids they put in their pride & joy, but I've always wondered why there are no "ultra-premium" fuels on the market.

If VP, Sunoco, Rocketbrand, etc., fuels offer the same long term benefits with detergents & such that the Tier 1 pump fuel brands offer but at a much higher octane level and won't hurt your car or emissions, why not? Other than cost of course...

orthofrancis

Using 100 octane fuel in a car designed to run at 93 may actually lose power, as the 100 octane fuel may not detonate as easily. At least that's what I've heard auto engineers say. Other than wasting money, the race gas may not have all the detergents in them.

aCayenneFan

Speculative at best. Check the website for the vendor of the race gas. If the race gas is being sold at the pump, there is generally some statement regarding detergent(s) added to the gas (like Tier Two or whatever). Running 101/100 unleaded race gas exclusively only makes sense if the engine is retarding timing with lower octane blending. If the race gas does not have detergent added, that is a simple problem to solve - add a bottle of Techron detergent at fill-up.

aCayenneFan

Plus if you go back to unleaded, you are going to have to run a bunch of unleaded fuel through the engine to wash away the trace amounts of lead before fitting the catalytic converters.

HamiltonSeth

So what is the general consensus on this one?

After spending $200k on a 2018 GT3 I could care less if I spend an extra $15 per tank by adding a fuel additive if it gives me the recommend 93 octane that I cant get here in CA.

I run Torco on my highly modified 91 turbo and supercharged M3 and I am 100% certain it works well on those, because without Torco the Turbo runs like garbage. I don't want to store multiple 5 gallons of race fuel due to the space needed and hazard of storage as well as danger in filling up/splashing the car (plus its a huge effort to even get them home). I like the idea of using Torco (or similar) if anyone feels it actually preserves the motor in spirited driving, like a canyon run. For a full track day the real deal race fuel is the only way to go.

Additives are such an easy solution- Amazon purchase, delivered, grab a bottle on the way out the door when filling up with 91 octane at the pump. Done.

Does anyone have any experience on any reason NOT to use an additive? That is my biggest concern.

Thanks,
Seth

FourT6and2

I would not personally use "additives." But I would (and do) add a few gallons of 100 octane in with 91 at the pump. If you don't have access to a gas station near you with 100 or something like that, then I guess you've got no choice but to try an octane booster. But you will need a lot of it in order to even raise the octane to 93.

Sun Ra

No issues!! Do it! I add octane booster to bring octanes up for low pumps [91] that are all there is in the boonies of NZ, add to 95 for the track and even sometimes to 98 for the track. Your pipe tips look rusty but who cares. Proven in my 991.1 GT3, GT4 and 991.2 GT3. Over 20,000 km.

SANDIEGO

I live in CA but am lucky enough to live near a gas station with 100 octane. I routinely put in 4+ gallons per tank which brings my Octane close to 93. It does feel stronger with the extra Octane. I agree with the idea that if you live near a station with 100 Octane that is much better than going with octane boosters which can create problems when used long term.

GrantG

I wonder how much more power/torque is made with 93 vs. 91 (at sea level and mile high)?

I set my fastest ever lap time after throwing in a few gallons of 98 Octane (non-oxygenated) race fuel at 5,000 ft. Wouldn't normally expect any improvement over 91 at altitude - could be a coincidence (very few laps on the GT3, so small sample size)...

HamiltonSeth

Your last statement is what I am looking to get some real world feedback on since you mentioned there are long term issues with boosters.

What is the better solution when driving the car aggressively but not on track- Allowing the ECU to retard timing to preserve the motor, or using Torco on every tank of gas?

pissedpuppy

VERY COOL - thanks!

GrantG

If you go to Sunoco Race fuel, I recommend this Non-Oxygenated version (no Ethanol to raise octane):
https://www.sunocoracefuels.com/fuel/260-gtx

Our local track has the stuff above (98 Octane) or the 100 Octane Oxygenated stuff and I see people buy the 100 all the time without realizing the 98 may be better for performance and their car...

FourT6and2

Beggars can't be choosers. My go-to gas station has Sunoco 260GT 100 octane. Sunoco says it has oxygenators. Why is non-oxygenated better? You imply the "oxygenators" consist of ethanol.
And another question. What real difference would it make when simply adding a few gallons of either 260GT or 260GTX to a tank of 91 pump to merely raise the octane up over 93?

There is another gas station farther away that has cans of Torco 108 and higher, and then at the pump they mix Sunoco SS100 (CA legal; 260GT/X/Plus are illegal here) with regular 91 to get 94, 96, and 98. But it's too far away to make any sense.