I know that you are supposed to use Premium in these cars, but ive been using Unleaded. My question is, Since im using unleaded, is my timing being retarded? Causing a loss of power and a drop in mpg?

Thanks!

 

bumpp

 

All gasoline today is unleaded so I assume you mean you are using 87 octane. Higher octanes burn more slowly so by running 87 octane instead of 93 you are actually advancing the timing slightly.

 

yeah but since its burning quicker, wont the knock sensor catch something and retard the timing?

 

Higher octane over what an engine needs, only benefits the retailers wallet.

I aways run 87 & track my mpg. I actually tried 91/93....whatever octane the highest Super Unleaded was, for several months. Even disconnected the battery to resey the PCM so it could "learn" & re-tune for the higher octane. Made zero diferrence to my mpg, so I went back to 87. My wallet is much happier now!

 

okay good to know, Thanks Stephen!

 

GM Recommended regular (87 octane) in these cars.

 

Over in sweden is 95 octane the lowest one you can get.
We have 95 and 98...

Im using 95 cause its little little cheaper.

But it still costs $6,5 / gallon (95 octane) or 12 SEK / liter or $1.71/liter [litre]


we have ~70% taxes on the gasoline, thats why its so ****ing expensive....

Someone care to ship some gallons to me ?

 

im almost positive you have to run premium in these cars, or else you will ruin your catalytic converter

 

The main things that will ruin a catalytic converter is leaded fuel or an extremely rich/lean condition and burning oil. Fuel octane rating will have no effect on the cat.

 

That is why I installed a bullet proof car, so that I could run 87 octane.....

 

Worked at a GM dealership from the late 80's, to early 90's. Regular gas is what they want. If they wanted premium, there would be a little label on the gas door, and the gas cap. (provided it was still stock....)

We actually saw a fair number of these cars that the premium gas available there (ann arbor michigan) would eat the injector windings, and lead to shorted injectors, and cars that ran like crap. We would do at least two a month. I don't know what insane blend the yuppies in ann arbor wanted in their gas, but, it just wasn't friendly to the GM injectors.

 

Found this in the Camaro manual, Check it out!

 

Ok I have always been under the impression that 93 is just better for you car no matter what. I have always used 93 in my formula 350. Never tried anything lower. What are the differences between the grades as far as the car is concerned. Like will diferent grades make the car run better or prolong its life, etc? I have tow repair manuals (Chiltons and Haynes) and Im certain they both show 93 as the recommended gas. I remember when I drove my 87 with the 305 carb it ran like crap on 87. Sometimes the carb would flood itself. That car was stock. Anyways just thought it would help if someone who knew their stuff regarding this matter would outline for people running stock set ups the differences and the plus and minus' of running our car with each respective grade.

 

Your octane number on the pump is the RON, in the US PON is listed, they take RON, add MON and divide by 2 so your 95 has a lower octane rating than US 97. MON is usually about 5 to 7 points higher than RON, and it can be even more depending on ethanol an winter/summer blends and what not. Basically the 95 we have here is about the same as 87 to 89 in the US. Don't be fooled, our gas is ****!!

PON (pump octane number) = ( RON (research octane number) + MON (motor octane number) )/2


As for the gas prices...The Netherlands has the higherst gas prices in the world unlike what some claim not to be true but it is, a litre costs $2.10 and a gallon costs $8 It's been as high as around 10$ a gallon here back when a barrel was 175 dollars or whatever it was at it's highest.

 

Our engines aren't exactly high compression, and they are naturally aspirated. There isn't any reason that 87 octane gas should cause a problem. If you're 'feeling' a difference on a LG4 with 93 octane, it's just a placebo effect. Even the higher output cars only had 9.3:1 compression. These aren't Ferraris, we're safe on cheap gas. Unless the engine pings under load on 87, don't worry about it.

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