Fuel requirement

[quicksilverdon]

What exactly is the octane requirement for the GT?
Can you get by with "plus"?
I think "regular is 87, "plus" is 89, and "premium" is 91 octane.
Any downside to running "plus"?
being offered a great deal on a GT.....

[Mean Green]

Even if it's $1.50-$2 extra a 15 gal fill up and you fill up once a week it's only $6-$8 extra a month. I don't know about you but I can blow that much in a week and not remember what I spent it on....To answer your question if you burn less than 92 octane the computer will pull timing and the result is less hp. Why have a GT with less hp? It amazes me how people think about pinching pennies when it comes to buying premium gas.[:I]

[quicksilverdon]

The question was what octane requirement is specified?
From what I've read, to use octane higher than required buys you nothing. I understand going lower invokes the knock sensor and less HP, but if you put 91 octane in a car that isn't tuned for it, you get nothing extra.

[bigdogdad]

QSD, the book says 91 octane for the GT high output engine, for the regular 2.4L, 87 octane. Per weekly fill ups, like Mean Green said, whats 2 bucks or so. You get the GT for the enjoyment, not economy.

Quick story on fuel and cars. I had an '87 Grand Am many moons ago and it was a small 4 cylinder. That car hated anything but high test. Use something cheaper and you actually had to fill up more often, therefore with that car anyway, it was cheaper to use high test and the car ran better.

[CHROMEDCRUISER]

I have been using 91 octane in my N/A PT for about a year and a half now. I notice a difference... every so slight difference, but it's there. The engine seems to like it better, and from what I've heard and read, the higher octane creates more heat, and requires less fuel, and is better all around for the engine. I figure a couple bucks extra every couple weeks is worth it if it gives me maybe another horsepower and ft/lb, and if it will help keep the engine running longer.

[Red GT]

I use only 91 from Chevron and it purrs with that low rumble that I love so much.It's runs beautifully on 91 and I'm pretty sure that's what the owner's book says to use. I wouldn't use anything else.

[Jeff V]

I could be misremembering, but I think when you open the GT fuel fill door there is a sticker that reads: "Premium Fuel Recommended", but the owner's manual says something about 91 octane.

In my area, Premium Fuel is 93 octane, 91 is "Midgrade".

I've only used 93 since bringing my GT home.

What was the question again?

[ElectricBlueGT]

Jeff,

Nice to see you are back! Where've you been?

Anyhoo, 91 octane is the minimum requirement. GT motors are 50-state certified, so they all have to use the same minimum octane requirement. In California and a few other places, 91 octane is considered premium fuel, that's why 91 is considered the minimum. Technically, we could blend a 50/50 mixture of 89 and 93 to generate 91 octane and engine performance will not suffer *supposedly*. It has been my experience that anything less than premium fuel causes a performance decrease since engine timing gets pulled due to the knock sensor noticing light knock. In my area, premium fuel is 15-20 cents/gallon higher than regular. At worst, it is a $3.00/fillup (15 gallons max) "penalty" to make sure the engine is healthy and won't knock. It's a small price to pay for the smiles you generate everytime you stomp on the gas pedal.

My two cents,

Scott

[Jeff V]

quote:Originally posted by ElectricBlueGT

Jeff,

Nice to see you are back! Where've you been?...

In my area, premium fuel is 15-20 cents/gallon higher than regular. At worst, it is a $3.00/fillup (15 gallons max) "penalty" to make sure the engine is healthy and won't knock. It's a small price to pay for the smiles you generate everytime you stomp on the gas pedal.

My two cents,

Scott

Scott,

Thanks, I've been here on occasion, but during football season all my computer time is devoted to fantasy football.

I think what you say about the small difference in price translating to the smile when you put the foot down is the bottom line. Plus, if you have pride in your PT, feeding it the best gasoline kind of feels like feeding your kid!

[SteelBlueGT]

Putting higher octane into a stock engine than is called for by the manufacturer is a waste of money. And since the lowest octane gas available commercially for automobiles burns at a lower temperature (compression) it gets better mileage. I was told that our GT's are optimized to use 91 octane premium so anything more is a waste and anything less is not optimized for perfromance. Remember that the turbo lite engines use regular and are optimized for it and they are rated lower because of it. Also premium gas in California does not burn any cleaner than regular. Gas here is highly regulated as to its formula and its effect on the air quality.