Regular gas is so very cheap just now, I find it a real temptation. I've heard that if you mostly drive around town and are not putting great stress on your engine that the 87 is okay and that the
engine adjusts to the decreased octane using antiknock sensors. How dangerous, or is it, to use the 87 instead of the 93 octane fuel?

 

I have 92 where I live (no 93) and that's all I use since the car was brand new. It's recommended by the manual, so why take the chance.... as it is it already has lots of ethanol in it...

 

You could save even more if you would trade it for a Prius.

 

..

 

I would say "if you can't run with the Big Dogs Stay On The Porch" Bad plan.

Dennis

 

To DIRECTLY answer the question. Yes, you can run 87 octane. No, it will NOT hurt anything and your engine will adjust as needed. If you don't care, neither will your LS.

 

My, my a respectful answer; I appreciate it. I take it you are an educated person.

 

LOL. Yes I graduated.

You're welcome.

 

But what's de $$ difference between 87 and 93? A dollar? Maybe $1.50? Times 21 gallons (if you're totally empty) is just over $20 difference per tank -- is it worth it? Manual says use Premium. The Japanese engineers must have a reason to say that.... just my .02

 

Yes, there's lots of reasons, but none of which have anything to do with risk or harm to the engine. CAFE regs, mpg ratings, consumer performance expectations,etc. As for the manual, somewhere in there it says you can use lower octane, but performance will suffer somewhat (or words to that effect).

Anyway if you want a more educated answer than mine:
http://www.edmunds.com/fuel-economy/...g-premium.html

http://www.caranddriver.com/features...results-page-2

 

Doesn't Premium have 5 x the cleaning additives than Reg? Would reg have a better change of causing fuel injector problems or cleaning?

 

Although you can run lower then recommend octane the engine was designed to run the recommend octane for peak efficiency taking advantage of the higher compression ratio.
Lower octane fuel will yield less power and less miles to the gallon. The savings at the pump will be a lot more narrow then realized and you will have a slower car. Not worth it.

 

Although I have never run regular in my tank, I did go through a faze where I'd alternate between super and mid grade every other week. What I found was some power loss and hesitations with the midgrade stuff...I still throw midgrade in it once in a while, but not nearly as much as I used to. And the car drives much better now.

The only reason I even tried the midgrade is because I drive so much, try putting 600 miles a week on your car, you end up looking for a few ways to save on gas. I've got to hand it to the LS though, I'm averaging 26.8 miles per gallon. Pretty good.

 

Premium is just as dirty as regular unleaded. Regular unleaded is actually more combustible fuel but more unstable. It is the stability of higher octane that allows more power by increasing the compression of the engine because it resists detonation and pre ignition.

 

^^^ Where'd they find this guy??