Theprezz

Hi guys,

I am attempting an event where there will be 1/4 drag and lapping. I was wondering if real race fuel 109 octane would help me improve my 1/4 drag time I had with unleaded 94 octane fuel.

What you guys think?

California John

Nope

turbotonee

You need a tune to be able to benefit from higher octane...without it, the stock fuel trim setting will just compensate and you wont see any gains in performance.

AMG 17GT

Right, but at what octane level is it no longer beneficial?

Are we talking euro or US Octane?

MStach

Race fuel doesn't raise horsepower, you can have more aggressive tune with higher octane number that would help longevity of the engine. (Running cooler without detonation )

Jim Brady

Where are you located? Europe and Japan use a different method of rating for octane (RON). If your using the ratings of Europe or Japan multiply by .95 and you'll have the US rating. There is a Motor rating and Research method that some fuel refineries use. If you add them and divide by two you'll get the true rating.
Google is your friend.

The key is keeping the engine knock sensors from retarding timing due to heat or poor fuel. Higher octane can help performance by reducing detonation. Just watch a C7Zo6 on a hot day as the lap time worsen due to heat as the sensors pull timing.

AHI

Jim I honestly feel smarter every time I read your posts.

AMG 17GT

Good to know.

Was trying to answer what I believe OP was trying figure out. At what octane level do HP gains end? I remember Vic stating that weistec had claimed 30hp gains from US 91 to 93 with their tune. So would 95-100 octane yield even more HP?

Jim Brady

Thanks AHI, I've had many discussions with my father-in-law who's a PHd petroleum engineer. All in the hopes of gaining more power.

Jim Brady

Depends on the engine. A "tune" for an ecu can do three things (actually a lot more if you have a supercomputer) but most tuners are relegated to three, control amount of throttle or fuel, change timing, change boost. A change in timing may allow the engine to find a more power as the engine likes more advance. But too much timing advance might cause detonation with a specific fuel octane rating.

It's pretty predictable that there's more power in these engines if we put more timing in the motor but the factory has to take into consideration variations in fuel quality so they don't put has much advance as they could. I'm amazed at Ferrari running 13 to 1 with 91 octane! The higher octane allows the fuel to burn slower hence less chance to detonate. So you can run 100 octane unleaded and not have any increase in horsepower because you haven't changed timing or boost or fuel ratio at a given rpm.

Before Formula 1 regulated fuel requirements, ELF, Shell and some others had some pretty exotic blends where the techs fueling the cars had to wear hazmat suits because the fuel was so toxic. In those cases the blends reportedly had gains but were the result of using non hydrocarbon compounds. Now it's tightly regulated so it's pretty hard to cheat.
I've gone though the turbo days of more boost and fuel having to run more octane, not worth it for the gains as you lose reliability but if you ego's on the line then it's worth it

turbotonee

Their tune increases boost which in turn impacts fuel/trim ratio. Paired with catless downpipes, mid pipes, and exhaust...a lot of things will change as well. This requires countless hours of dyno and tweaking to find the usable powerband.