GenVibe - Community for Pontiac Vibe Enthusiasts

2003 VibeAutomatic1.8L engine VIN code 8("FuelThe 8th digit of your vehicle identification number(VIN) shows the code letter or number that identifiesyour engine. You will find the VIN at the top left of theinstrument panel. See “Vehicle Identification Number”in the Index")-user manual pg.6-3Page 6-4 in the user manual tells me that I am to use regular unleaded gasoline with a rating of 87 octane or "higher".Can I and should I use Plus or Premium? And, if so what are the pros and cons of doing so?Will using a higher octane wear anything out faster?Will I get better millage? And is that millage worth the few extra cents on a gallon?When switching to a higher octane fuel should anything else on the vehicle be replaced or changed?Does burning a higher octane pollute less?Let me know what you think.

There is absolutely no benefit in putting premium fuel in an engine designed for regular except perhaps more cleaning agents. It's a really expensive way to clean your engine, I prefer to use a bottle of Techron every 6,200 miles when I change my oil.

It's been said time and time again with our engines that people claim it runs better, smoother idle, and better gas mileage. I Personally have seen an increase in gas mileage when I use shell v-power. That is shell's premium line

Quote, originally posted by keithvibe »It's been said time and time again with our engines that people claim it runs better, smoother idle, and better gas mileage. I Personally have seen an increase in gas mileage when I use shell v-power. That is shell's premium lineI swear I got better mileage too....in the base 1.8l 1zz.

I asked Shell if their regular gasoline (87 octane) had lower cleaning additive levels than their premium (higher octane) gasolines. They would not give me a straight answer. I don't know if they didn't want to admit that using their lower octane gasoline provided the same benefits as the higher octane versions, or if they didn't want to admit that their lower octane gas was inferior in that respect.I am pretty confident that if in fact the the higher octane gasolines actually did provide higher mileage that they would be advertising that advantage. Personally all this advertising has caused me to stick to branded gasolines (Shell, BP/Amoco etc,) and avoid the generic or off brands. For a couple pennies a gallon I prefer not to take a chance. But I stick to 87 octane.I would like to avoid the gas/alcohol blends but at least in Ohio they are no longer required to disclose that information. That is a rip off since alcohol has less energy than gasoline so your mpg will suffer.

don't you me ethanol not alcohol LOL

Ummm... Ethanol=alcohol...In any event, you might well see a very marginal mileage increase from using premium, but the cost of the fuel will far outweigh the savings gleaned from the increase in mileage. In short, you won't hurt your engine, just your pocketbook.

Ok ok so say yes others no. hmm, I haven't put regular in the car since I got it couple months ago. I have no idea what the previous owner put in it. I'll fill up next time with regular and see how that goes. I'll post about it next week.

Quote, originally posted by keithvibe »don't you mean ethanol not alcohol LOLJust as "sugar" generally means "sucrose", "alcohol" generally means "ethanol".BTW - Ohio AG tells me that the federal FTC is the one that does not require any labeling on the gas pump for gasoline containing not more than 10% ethanol. That is half an answer as I believe the State could have a stricter rule. Ohio requires that milk from cows not treated with rbST be labeled with a statement that there bis no difference between milk from cows treated with rbST BUT when it comes to gasoline - well we are on our own.

Quote, originally posted by wayofthemetal »Ok ok so say yes others no. hmm, I haven't put regular in the car since I got it couple months ago. I have no idea what the previous owner put in it. I'll fill up next time with regular and see how that goes. I'll post about it next week.Word of advice... When you change grades, drive the car for a little while before putting it away. Not letting the computer adjust the mixture to the new octane of fuel might cause starting problems the next day...

Reviving an old topic but...I always use the ethanol because it is the cheapest, but it has a higher octane rating than regular. I believe it is 89 or 90 for ethanol here.

Quote, originally posted by L5K »Reviving an old topic but...I always use the ethanol because it is the cheapest, but it has a higher octane rating than regular. I believe it is 89 or 90 for ethanol here.Are you refering to e85? Was the '03 designed to run on it? If not, you will damage the engine. And e85 is not as effecient and your MPG will suffer compared to regular fuel.Also, the higher the octane, the slower the burn. If your car was engineered to run on regular and you run "premium", you end up with unburned fuel and carbon build up - doing more harm than good.

You may actually be buying gas that came from a Mobil well at a Shell station. It is all pumped through the same systems and the only difference is the additives that are added to the tanker trucks just before it is put in the station tanks. I've always used 87, never had a need for anything higher as I don't drive a turbo, S/C, or premium car that requires 91 (like most German makes).

I had a FLEX-FUEL engine in my 2004 T&C but I never used that E-85 stuff. I would be surprised if an engine not designed for E-85 would even run on it.My main complaints about the 90/10 gas/ethanol blends are that since ethanol has less energy you get cheated, and from all I have read I think converting crops to ethanol to burn in cars is not of any environmental or economic benefit. The govt. (that's us) pays to subsidize the crops. Then we pay more for food because crops get more expensive (supply and demand you know)..

...depending upon how well the "mapping" is done, todays ECU's can actually adjust to improve both performance and fuel economy when higher octane gasoline fuel is used...timing can be advanced more under load to produce more HP...so, when lightly loaded, you can ease off the throttle slightly and get better economy....it's basically a "subtle" benefit the same as how "flex-fuel" engines can run both regular gasoline and alcohol-based fuels (E85)...just open up the computer tolerances and install/use wider output sensors (gasoline and alcohols have vastly different stoichiometric ratios).

The corn debate has yielded that it offers no significant benefit and hurts the farming industry more.As for the E85 in any tank. I am sure most modern cars would be able to run on it. The issue is with wearing. The hoses, couplings, etc. of the engine are built to different standards to handle the E85 mixture otherwise you would have lots of premature wear on a standard engine.

Quote, originally posted by L5K »Reviving an old topic but...I always use the ethanol because it is the cheapest, but it has a higher octane rating than regular. I believe it is 89 or 90 for ethanol here.octane is a good thing, but I thought blends with more ehtanol have less power, so if might not knock, and it might be cheaper, but you might get fewer miles per gallon out of it. Don't know if it's enough to offset the lower cost or not.

Quote, originally posted by Old Tele man »...todays ECU's can actually adjust to improve both performance and fuel economy ... and get better economy.e85 is not as effecient as regular gas. Take a look at the EPA ratings of any e85 compatible car example; 2009 Chrysler T&C mpg rated 17/24 on regular gas and 11/16 on e85.

Quote, originally posted by Scooter Dave »e85 is not as effecient as regular gas. Take a look at the EPA ratings of any e85 compatible car example; 2009 Chrysler T&C mpg rated 17/24 on regular gas and 11/16 on e85.e85 isn't as efficient as regular gas, that is correct (IB it's like 10-15% less)... But e85 is also about 105 octane... !!!! A lot of the Subie guys are making big power on e85, they just run through more than normal.. But they are also running turbos and whatnot..

Quote, originally posted by Sublimewind »e85 isn't as efficient as regular gas, that is correct (IB it's like 10-15% less)... In this example it's 33% less.

...oops, should've been MORE specific! Better economy on gasoline (more energy than alcohol), but not true on E85....almost ALL gasoline sold during winter months is close to E10 due to "state/city" boutique gasoline "enhancements" and C02 reduction, so most "normal" hoses, materials have already been "alcohol-ized."

Quote, originally posted by Old Tele man »...oops, should've been MORE specific! Better economy on gasoline (more energy than alcohol), but not true on E85....almost ALL gasoline sold during winter months is close to E10 due to "state/city" boutique gasoline "enhancements" and C02 reduction. We get "winter" blends in the colder states in the winter too... gas mileage drops nicely in the winter...

...gasoline has MORE energy content per unit volume than alcohol, but has a lower compression ratio limit than alcohol. See page five (5) of this document for example comparison: http://www1.eere.energy.gov/ve...t.pdf...but, alcohol can produce MORE power under higher compression ratios (which todays cars cannot change)....so, the more alcohol there is, the less fuel economy you'll get, but the MORE unrealizable hp potential there is *if* the engine had variable cr (which it doesn't).

A lot of people and myself included have seen a smoother running engine and better gas mileage with the midgrade gasoline (89octane) than with regular or premium.

If one Googles 'octane', there are more articles than one can possibly read stating that higher octane will NOT increase mpg, unless the engine is designed for higher octane. Has anyone found an article saying that higher octane will increase mpg on an engine designed to run on 87????????

Quote, originally posted by joatmon »octane is a good thing, but I thought blends with more ehtanol have less power, so if might not knock, and it might be cheaper, but you might get fewer miles per gallon out of it. Don't know if it's enough to offset the lower cost or not.The difference between the 90 octane ethanol blend and premium is 30 cents per gallon. Regular to Premium is about 16 cents. On my last calculations, using the ethanol blend I got 30.12mpg with a combined highway/city ratio of about 60/40. Not bad for an 03 GT. I think I'm going to wean it off the ethanol and see what I get mpg wise with a couple tanks of premium, and if the extra 1 octane boosts performance any noticeable amount. I have a suspicion that going from 90 to 91 won't make too much difference in mileage, power or the life of the engine, but the engineers do specify 91, not 90 so who knows....

When you say "ethanal blend" do you mean e85 (85% ethanal) or regular gasoline w/ 10% ethanal?

I use reg in the base 1.8 auto.Gulf Or Sunoco,whatever is cheaper since i pass both,the sunoco was 2.59,i got the Gulf for 2.37the wife uses that WAWA reg in her 2.4 G6the grand am's v6 will burn anythingpremo in the vettes

Gasoline with ethanol blended in. I think it's 10 percent, but I don't know for sure. It's not e85 though.

gasohol is 85-90% gasoline + 15-10% alcohol (usually ethanol).E85 is 85% ethanol + 15% gasoline....and, I believe I wrote: alcohol can "...increase hp..." not "...increase mpg..." -- and, that increased hp is only realizable if the compression ratio (CR) is increased....to my knowledge, only the Atkinson (sp?) engine can vary its CR (although I know GM/Allison made a variable-CR diesel engine for their XM-1A/B competition to the Chrysler Turbine tank).

HI,I am pretty confident that if in fact the the higher octane gasolines actually did provide higher mileage that they would be advertising that advantage. Power Plant Developers

I don't know whether it makes a difference or not, but we (my mom & I) always use 89 octane. It is actually the lowest grade of gas at the local Citgo we go to, whereas most other places 87 is the lowest and 89 is mid grade. We definitely have never had any negative effects using the 89 octane.