Hey guys i decided to do an experiment with my cobalt running a tank of 87 octane, then running 93 to see the mileage difference. I drove to all the same places and shifted at the same rpm (3k) to try and make sure that it was as accurate as possible. WHen i switched from 87 octance to 93 the tank was on fumes.

i got 26 mpg with regular gas which if the price of gas was 4.00 a gallon it equals spending 15.3 cents per mile (if you put 10 gallons in at $4/gal= $40/260 miles driven on the $40 is 15.3 cents per mile)

I got 28 mpg with the premium fuel. Premium us usually 20 cents more per gallon where i am from so if the price of the premium would be 4.20. This would equal spending exactly 15 cents per mile.( if you put 10 gallons in at $4.20/ gal= $42/280 miles driven on the $42 equals 15 cents per mile)

premium cheaper! Couldnt really notice a performance difference though.

anyone else try the same thing? thoughts?

 

thats cause the car is meant to run on premium, on regular it retards timing taking away hp making you press ahrder on the pedal to move.

 

all I know is when my ex used to drive the balt, she'd be cheap and put regular in (and that's when gas was still, oh, less than $3 a gallon)....... I noticed a lack in peppiness and I could hear a worse ticking noise from the engine, dunno if it had anything to do with the engine changing timing for the "shitty fuel mode"......

 

GM recommends 91 or better in the 2.4... Where I live they sell 92. I have noticed better mileage with 92 over 87..
I could be wrong but I think the computer adjust the timing when using lower octane fuel and you do not get as good mileage..Thats were the VVT come into play at.. plus the 2.4 has a somewhat high compression so premium fuel is probably best, plus in your case cheaper so why not use it..

 

i did it in my neon a while ago lol when 93 gas was like 2 dollars.... and i got worse gas milage lol.. i havent done this with my cobalt yet just beacuse i dont feel like spending 20 cents more on gas but good write up.. and good math!

 

I could of sworn our cars it says 91 or better recommended whcih to me meant it doesnt matter the computer will adjust cause i had a gtp and it said only premium

your the first to ever say that

 

yeah i used 89 since i got the car and then a couple months ago i switched to 91/93 and the car runs much smoother, but i can't keep my foot out of it lately and i am getting poor mpgs but i have hit 40 mpg in my car.

 

what are u supposed to put in the 2.2?

 

did you read the article? you will most likely also SAVE money by using premium. you're not getting the full performance of the car on lower octane, and your gas mileage is not as good. i don't get the cheap bastards that buy a certain car knowing that it takes a certain octane, and then they cheap out to save $2.00 per fillup. you're talking about most likely about $10 a month "savings"

regular only. unless u have a turbo or super or are tuned to take advantage of the higher octane.

 

Higher octane in an engine tuned for low octane won't really make a difference. It might even be worse since high octane technically has a lower energy potential, but the higher compression more than makes up for it.

91 octane is the highest I can get here in California. Does anyone know of an octane additive that I could use to boost it up to around 93-95? I don't trust the stuff I see on the shelf right next to the slick-50 additive that promises 50 extra hp and better mileage....

 

thats because its not designed for 93 octane. increase the spark timing and yeah you will need some higher octane but a normal neon will run perfectly fine w/ no knock on 87 (unless you had an srt-4 that is)

 

...how many times do we have to beat this horse?

 

You know, Chevy could've prevented everyone one of these posts with a "PREMIUM FUEL ONLY" sticker on the gas cap.

You'd think putting it in the Manual would've been enough.

 

Beating horses is fun

i started putting premium gas in my car 3-4 weeks ago, definitely a difference. I'm able to get premium cheaper than the price of most stations regular gas, so i'm really saving money with about a 2-3 mpg gain

 

lol I'm not a cheap bastard... my car gets 33 mpg and i don't drive that much highway so thats pretty good... we don't need to make it seem like we drive Ferrari's here

 

its very easy to see someone just put in regular gas rather than premium. no supercharger and we bought the car to save money on gas so why put premium? most people dont read the manual of the car because it has a lot of very basic stuff in there like how to turn the radio on.

 

Only 93 in my tank since I bought the car brand new in Oct '06. 49k on the clock and I'm even still on the stock fuel filter......though I guarantee its clogged as my car dosent run 100% and has a lumpy idle. But I'm changing it out next weekend.

Exxon or BP only for the most part.

 

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this week

 

Yeah, the point is that your car is recommended to use 91 or greater octane. This is what it is tuned to run from the factory.

While there may or may not immediate differences, a strongly worded factory recommendation in the manual should mean something to most people - and who's to say what the long term effects may be in terms of knock, etc.

The point is, you wouldn't go use the wrong weight in oil just because Autozone had a sale on 15w40 or something weird.

I'm not saying the effects would be as potentially catastrophic as the oil example, but why would you use something that you know will provide reduced efficiency, economy and potentially cause long term engine damage to save $2 every time you fill up..

 

I never noticed to use 91 octane since i bought the car I'm at 20k miles would it make a difference to switch

 

Wow, this thread topic again. ****, run your car on ketchup for all I care. It's cheaper than premium fuel. Maybe throw a little vinegar down the tube as well, I hear that **** is pretty high test.

Can this topic please be put to rest already. Please for the love of all things right.

 

They are irritating, but I understand where the confusion comes from. Unlike when we bought the SC, the dealership didn't even inform me the 2.4L prefers premium fuel.. in fact they filled it up with regular for its 'first fill up'.

I think a sticky on the topic may not be a bad idea, as it does come up very often.

 

...I had to read the owners manual to the salesman before he would believe me....

 

I'd be willing to bet that most 2.4L owners put regular 87 in the tank from lack of knowledge. 99% of people out there don't know anything about cars.

 

btw, to those of you still using regular, your not saving any money, your spending more. thats what that test the guy ran was trying to prove to those of you still saying you use it to save money.

On the receipt it looks cheaper but now you would have to stop for gas sooner then someone who used premium, get less performance and harder wear on your engine.

So lets review for the few here that still arent getting it:
1. in the long run, running premium in the 2.4 is CHEAPER then regular
2. your engine will run better
3. its less harmful to the engine

Theres no reason to be using regular when you have been told the facts