Quick question about fuel: premium vs reg.

[EvanB85]

On a good ol' carbed two-stroke, will jumping from 87 regular to 92 premium without any other changes cause any issues?

Basically I have a new head ready to be installed, and I jumped the gun and got 10 gallons of premium, premixed and ready to go. Unfortunately, between now and my vacation to the lake next week, I see NO time for ANY wrenching. Am I cool to run 92 ?

Compression on my 650 right now is about 147 and 151.

 

[Matt_E]

You'll be perfectly fine.

 

[EvanB85]

That's what I thought, just wanted to be sure. Flatwater backy here I come.

 

[Snackem]

That's what I thought, just wanted to be sure. Flatwater backy here I come.

good luck:splatt:

 

[Crab]

That's what I thought, just wanted to be sure. Flatwater backy here I come.

Translated that means "I have a lake near my backyard, and its flat water"

 

[EvanB85]

oh come on, jumping from 87 to 92 has to be worth at least another 50 or 60 hp, right?

 

[Mark44]

oh come on, jumping from 87 to 92 has to be worth at least another 50 or 60 hp, right?

Actually probably loose a horse or two if the motor was not designed to run on a higher octane.

Mark44

 

[ToddW]

Actually probably loose a horse or two if the motor was not designed to run on a higher octane.

Mark44

Exactly, and worse fuel consumption (very minor but still).

 

[Mark44]

y

Exactly, and worse fuel consumption (very minor but still).

Yup.:cool2:

Mark44

 

[Matt_E]

Nothing to worry about for a weekend. :biggthumpup:

 

[EvanB85]

Nothing to worry about for a weekend. :biggthumpup:

That's kinda what I was figuring.

 

[ToddW]

Nothing to worry about for a weekend. :biggthumpup:

That's kinda what I was figuring.

Yeah, I wouldn't worry.

I plan to run premium houseboating so we don't have to get different grade fuels for different rides.

:woot:

 

[yamaslut]

I put 93 octane in my normally 87 running truck.... I got horrible gas millage... it was a huge decrease... I won't be doing that again...

 

[SJBrit]

Don't forget that slow burning octane is an additive to fast burning heptane to reduce detonation in high compression motors. Putting high octane fuel in a low compression motor does nothing more than remove useful heptane and make you burn more fuel. High octane fuel is not high performance: it's fuel than has been degraded a little so as not to cause problems in high performance motors.

No harm done (except the waste of money), but no gain either. Fortunately for the gas companies their "super" and "premium" branding suckers plenty of people into buying more expensive fuel than they need.

Now, just to head this one off, I lose about 20hp in my 350Z if I run 87 octane, so high octane adds 20hp right? WRONG! The knock sensor retards the timing if I put low octane fuel in, which stops detonation at the expense of some power.