There tends to be much discussion of "what octane should I use" and many respond that they use less than 91, with no problem. So, I thought I would add a little "fuel to to fire" with this article I read in the April issue of Corvette Fever in the C5 Solutions section.

The question asked is, "Will 87 octane fuel do any damage"?

"GM recommends 91-octane as the minimun to run in the car, though the factory also states that the engine can be run on 87. Basically, the engine was designed for the higher octane, and that includes mechanical aspects, such as the cam and compression that affect cylinder pressure and the complex fuel and timing logic in the PCM computer. When you run a lower octane fuel, the engine-management system will try to compensate and you will get the well-known drop in power. One thing most people don't figure on is that typically there is also a significant drop in economy too. You may well see a drop of 2mpg or more with the lower octane fuel and at that point even a 10-percent savings in the price of fuel will be a wash. Add in the potential for detonation, which can rapidly cause real engine damage, and the cheap gas is a suckers bet".

(By Steve Dulcich - Corvette Fever:c5solutions@primedia.com)

 

Interesting article and I hadn't considered that.

My worry is that if the knock sensor is compensating by retarding the ignition, by definition the pre ignition has occurred. It's a compensatory action. If that happens over a period of time, damage has to occur no matter how minor the damage. Is it worth it for a few cents on the gallon compared to the cost of a rebuild?

JMHO

 

I saw that article too. Interesting read.

 

Most of us paid a hell of a lot of money for our cars. Why anyone would want to scrimp on the cost of fuel is beyond me! Like has been stated, it is only going to take more fuel to do the same job, your mileage is probably going to go down and you're going to have problems down the line (probably expensive problems). So why not just put in the best possible fuel you can find. It's sad that here in CA the best we can get is 91 octane. If we could get 100, I'd buy that! And yea, I know, there is octane booster. We'll save that for the race cars.

 

We're talking what, 20 cents per gallon?
My baby gets top of the line premium, period.
Cheap crap is like taking your prom date to Dairy Queen.

 

 

or a ham sandwich to a banquet.

 

I have always used 93 and still get some ping under load. Any ideas on how to make the ping go away??

 

Dairy Queen? How about McDonalds instead?

 

Its all in the tune. Get a good dyno tune and the problem will vanish.

 

I have to agree that the money saved on 87 isn't worth the potential damage. I only use 93 octane.

 

You don't always get what you pay for,(not with fuel anyway) it may say minimum 93 on the pump, but could be 90, it is seldom tested at the pump anymore. Also keep this in mind, gasoline breaks down relativily quick, very little Premium is sold in relation to mid and low grade(this is expecially true with the higher prices) so many stations the premium is old and weaker.