Never 91.

93 only.

 

91 is fine. They don't have 93 on the west coast which is why the minimum is 91. 2/3 93 and 1/3 87 gives you 91. It's basically how they make plus, 2/3 regular and 1/3 premium to get 89.

 

The Octane level of fuel grades will change based upon elevation. At higher elevations, where air is less dense, fuel with lower Octane levels are sold.

 

I live essentially at sea level. 91 is the highest any normal gas station has. I've been up above 8000 feet where they didn't even have 91, they were selling 89 as 'premium'.

 

Yes, the thinking is from NA engines but when you have a turbo the octane is needed just as in seal level.

 

my last turbo was a 1992 Volvo 740 Turbo Wagon. 2.3L cast iron block mild turbo with 160HP and 200 ft-lbs, and a 3 speed + Oiverdrive Toyota automatic. It was pretty unhappy when it got poor grade gas, but it could limp along with almost octane...

Having had enough issues with cooling and crankcase blow-by under sustained boost, meh, I am done with turbos for awhile. we picked the 2016 e350 because it was the /last/ non turbo 6 cyl E series.

 

The whole idea of forced induction requiring premium is outdated. Many modern, inexpensive cars are using forced induction engines tuned for 87 - we own one. A 1.6 turbo with 201hp that is tuned specifically for 87, it sees no benefit whatsoever from anything higher. Mazda's NA four-cylinders use very high compression and ask for 87. Mazda's turbo 2.5s will run on either with 227hp on 87 and 250 on 91-93.

Now perhaps if we're talking German performance or whatever, sure. But just because a turbo exists does not automatically mean it has to have premium.

 

Well, I've been using the green pump at the gas station. I think it says diesel.... seems to be working fine for me.

- Had to be that guy

 

My car is turbo though. Twin turbo.

And with a Stage 2 flash,.. it's supposedly at about 550 / 650,... so I put anything less than 93 in it.

I remember when I lived out west,.. the governor decided to increase emissions by limititing octane to 91. So anyone with a fast car had to mix in a bit of race gas. Really did a number on my Ducati. Couldn't get full throttle without audible knock, without splash of race gas or octane booster.

What a bunch of idiots. Their gov at the time was a massive moron. Thought it was a great idea to bankrupt the state by buying everyone SUV's,.. just so long as they installed a propane conversion that they never used.

Anyway,... East of Arizona and Cali,.. we still have real gas.


There is a push to make 98 or so octane standard nation-wide. Would allow car manufacturers to make higher compression and more efficient engines. Octane is one of the things holding back the progress of ICE.

 

92 in Washington tho.