All these smart folks and yet the actual question remains unanswered-

If 93 octane is used in a 2000 or later v10 superduty instead of 87 octane, will there be a noticeable performance and or mileage improvement without external custom tuning?

Is it that smart? If so, why isn't it mentioned in the owner's manual?

 

The answer is No.
JL

 

Actually I did answer it back on post #38, but if you still don't understand I'll make it easy for you, like some others already have.

Question #1 = NO!

 

to get more power out of 93 you need a tuner like a diablo, SCT, or super chip programmer. That's how they get the advertised 30 hp over stock,( although i think its inflated but what ever)

 

There is a gain to be had even with 87 octane. The gains with 93 would be around what they're claiming.
JL

 

O.K...I am convinced. You are right and I am nuts. But you still have a number of other people in here who sound like they are reasonably sane, and who report facts that are consistant with real world physics, and how computer-controlled knock sensor "loops" work. So, go convince THEM they are nuts too, and everyone will be happy.

 

There's alot of ignorance on this forum-I see it and most of the time just click the big "X at the top of the page-it's not worth my time to argue FACTS with people all day long. Myths and beliefs seem to become "fact" on internet forums since people regurgitate the same old crap they've been fed over and over again by those that DO NOT understand the control system at all. It's like a small plumbing problem..starts out an annoyance and soon blows up into a stinking pile of crap that you are stuck with cleaning up.
JL

 

Excellent idea...wish I'd thought of that. If I see something that disagrees with what I want to believe CENSOR THEM !

So, not only am I nuts, but all these guys in here who report their cars "ping" on 87, but the ping stops when they use premium, are nuts too ?

Makes sense to me...everyone else is crazy but you!

 

Screw it..you're not worth the time-you just can't fix stupid.
JL

 

Many new car adds have disclaimers on mileage and horsepower saying that premium fuel must be used for these results.

If it is enough to add a disclaimer then it must be a worthwhile difference.
I belive Toyota/Lexus is big on useing premium for these tests.
George

 

I have the Diablo using 93 tune on 03 V10 and this engine is running like a dream. At least 30HP and a nice feel where you get the power at low speeds where the V10 is normally a little flat.

 

teserra,


The new 08 toyota 5.7L bomb does not require 93. 87 is speced, surprisingly. I wonder what happens if you run 93 in this engine?

 

Only if the OEM tune is setup with ignition spark tables for higher octane fuel.
JL

 

The new FJ Cruiser is set up to run premium. And it does make a difference.
But throw some regular in there and the milage and power drops accordingly.
Initially owners were thinking they were getting free power when they put premium in. What I don't get is why they ignored the sticker by the filler that informs only to use premium fuel for the best performance? No free power here, the engine was mapped that way.
My Supercharged Xterra was the same way. I will never again buy any vehicle that doesn't run on regular fuel.

 

I remapped the spark tables ion the Navigator recently to be able to use 87 octane in it without damage. It's down on power by about 5-10 hp,but mileage is identical-no changes whatsoever to economy.
JL