Bad gas mileage...

[Hash_man_Se_i]

Well, lately, actually since my sister gave me the car, I have been getting pretty shitty gas mileage,like I am lucky if I get about 350-400kms to a tank.

The car just got a full tune up, ie: new plugs, wires, cap, rotor less than a year ago, and I recently cleaned the K & N.

One thing that I have been thinking it could be is that the Catylitic (sp) converter may be getting clogged up. I was experiencing bogging when accelerating a while ago, so is this a possibility?

Otherwise, what are some good ways of improving mileage?

[Defiant[YD]]

yo dude, i have the same gas mileage on my accord too. tahts one of the reasons i didnt' like it that much. i would go to 500km on a tank right after i did a complete tune, but 2 months later, i'd be back to 350-400km per tank. so stupid, even worse in winter too. never knew what was wrong with it.
i always suspected maybe the carbs use more fuel or something, but i doubt it since urs is injected.
i duno, my civic does around 600-650km right now. another reason why i prefer it over the accord.

[MrBen]

In the summertime I get around 500 miles to the tank, in the winter, around 350. It's cold as a mother f*ck there isn't it? If it is, don't worry about it until it warms up IMO.

[BITESIZE]

Lose weight, you and your car.

[k-roy]

Hmm, it could be a colgged cat. Is it slower then normal? Also check the tires for pressure and abnormal wear. Also replace the fuel filters for good measure.

From what I hear carbs get better mileage than PGMFI. I get 35 city and 43 highway.

[mykwikcoupe]

wow i thought I was going good at 250 miles to the tank..It just got a new tune uo and am running without a cat

[shepherd79]

the reason we all get shitty gas mileage in the winter because gas companies add somekind stuff to make sure the fuel won't freeze. some how it lowers the gas mileage.

you may want to shop around for diff gas.

[k-roy]

Good point Alex, so Hashman what brand/grade of gas do you use?

[Dibbs]

the reason we all get shitty gas mileage in the winter because gas companies add somekind stuff to make sure the fuel won't freeze. some how it lowers the gas mileage.

Alex, do me a favor and SLAP the person that told you that.

About the only place on this earth where gasoline could freeze in a car is Antarctica or the peak of Mt. Everest.

Standard gasoline used in internal combustion engines will not "freeze" in our part of the world. Gasoline usually solidifies at -60 to -70 deg F and I don't know of many places that get that cold (wind chill factors do not count).

The only fuel that even comes close to freezing is aviation fuels (jp-4, jp-5)b/c of the extremely cold temperatures at 30K+ feet. They have additives to keep the fuel from solidifying. Gas doesn't really freeze like an ice cube would, it just changes it's state of matter and transforms into a solid mass. It would more resemble glass than ice.

All gasoline has additives, some companies more than others. All depend on the octane grade and what state it will be used in. They usually all have the additive MTBE (methyl tertiary butyl ether). This does 2 things: It boosts octane and acts as an oxygenate (adds oxygen to the reaction when it burns in the combustion chamber). There are other additives used that affect it's vaporization point and flashpoint (for saftey reasons) but I've never even heard of an additive to inhibit gas from solidifying b/c the weather conditions would have to be so extreme to make this happen and are not likely to happen at all.

There are about 25-30 different standard gasoline formulas used in the US. There used to be less than 10. Each depend on each State's emmisions requirements. Wonder why gas prices have gone to shit in the past 4 years? You've got Mr. Gore to thank for that brilliant move. He thought it would be a good idea to let each state mandate their own fuel reqirements due to their own emmisions standards, then crack down on each state when their emmisions start to increase. This makes for states w/ customized fuel formulas, which require a custom process to manufacture them. Petrolium companies are forced to raise prices as a result.

I don't know who told you that or where you read it but you should call them on it b/c they're full of

[k-roy]

Damn Dibbs you laid the smackdown. Thats good information though, thanks.
The reason gas freezes is because of water contamination. Hell I have seen a less than reputible gas station owner water down his tank. So yes, gas in a car does freeze sometimes due to water.

[Dibbs]

But only the water will freeze, not the gas. Water does not mix w/ gas, ever. Since water is heavier than gas, it always settles at the bottom of the tank. Factors due to normal driving (sloshing due to normal starts, stops, road bumps, etc) will make the gas and water combine for a short period, allowing the fuel pump to capture some water and pass it through your system. You can add methanol (Heet) treatments to your tank that will mix w/ water and allow it to pass through the combustion chamber without damaging the engine or it's performance for the most part.

IMO the reason you're all getting worse gas mileage is b/c more gas is getting to your cylinders. The cold weather keeps the fuel more dense, closer to the combustion chamber. In the summer, the warmer temperatures make the gas more likely to vaporize in confined spaces such as the fuel lines. This means your getting more vapor and less fuel to the combustion chamber. The winter would have an opposite effect, allowing more fuel and less vapor to reach the combustion chamber. Since more liquid fuel is reaching the combustion chamber, more gas is being used, thus less MPG. And of course, an opposite effect in warmer weather where less liquid fuel reaches the chamber which would result in a higher MPG. I'm sure this is not the only factor, but IMO I believe this is one of them.

I hope this helps. I'm not trying to be some sort of know it all dick. It's just that the petrochemical industry is my life's work. I'm a little over a year away from my Masters Degree in Petrochemical Engineering and I'm an Engineer for ExxonMobil. I am quite passionate about the path I've chosen and what I do for a living so I take great pride in my work. I just wanted to pass a little knowledge on to you guys, that's all.

ps
Damn you Kroy! It's 7:30 in the morning! You made me think way too hard before the first cup of coffee. Where's my damn smokes?! I gotta have one after all that.

[k-roy]

Dibbs,
You smoke in the world's largest chemical processing facility? Thats fuckin great, I respect that.
I now have a new quote for my sig.

[cubert]

wow i thought I was going good at 250 miles to the tank..It just got a new tune uo and am running without a cat

thats what im getting too...and im runnin a hollowed cat

[nswst8]

But with all that information, you still haven't told us whats the best gasoline for or cars, shame on you. Give us some insight.
Thanks,
NSWST8

[k-roy]

I use Chevron 91 Octane and it runs great, but I think this is a better question for Dibbs to answer.

[Dibbs]

Dibbs,
You smoke in the world's largest chemical processing facility? Thats fuckin great, I respect that.
I now have a new quote for my sig.

I don't smoke IN the plant, no one can (obviously....KABOOM!! ). My office is outside the plant in a white building across the street, cleverly called The White House.

Yeah dude, sparks are bad in chemical plants. People here use brass hammers so they don't make sparks. Opereators use grounding straps when servicing equipment to eliminate the risk of static electricity.

NSWST8, every company's gas is a bit different but they pretty much all follow the same formula. It really all boils down to octane rating. The higher the octane rating, the more detergents and additives there are that will maintain it's overall performance. 87 octane is pretty basic. Just a minimal amount of additives and detergents. 89 is not that much different and not really worth the extra money. 92 and 93 octane are the best. They have lots of octane boosting additives and detergents. Some premiums even have additives that clean your injectors. Just be sure to read the octane rating labels listed on the pump. Try to look for 93 if you want premium. Some of the cheaper gas stations will use 92 or even 91 octane and you're still paying a 20 cent hike over regular. If you're gonna pay that much more for gas, make sure you're getting the 93. Independent stations, not tied to a company name are the most notorius for doing this. Sometimes, I've seen 86 octane ratings on their regular unleaded pumps and I'm not sure the owners of those stations even know what octane is going in their tanks. A lot of independent station owners make arrangements w/ the tanker drivers. These guys skim a few 100 gallons here and there, then take the gas to ind. stations and sell the gas cheap for pure profit. The gas in those tanks just becomes a hodgepodge of different brands which is not a good thing b/c some of the additives from the different formulas mixing together can make the mixture corrosive to rubber and or metal in some cases. You never know what the hell kind of gas you're getting from those places so consider yourself warned! The best thing is to go to name brand places like Diamond Shamrock, Total, Shell, Chevron, Sunoco, BP and Texaco. I know Diamond Shamrock and Total usually have only a 15-17 cent difference between regular and premium and their premium always runs 93 octane. Personally, I use ExxonMobil fuel for obvious reasons. I hope that helped cleared some things up.

[hkplayer]

My gas mileage in the winters is 350km if lucky...just like yours hash - and we both have sei's. Thats just how they are for our cars.

[MrBen]

The main reason you do not get good gas mileage in the winter is because some companies have different winter and summer blends; winter blends have more butane in them, ignite better in cold weather, but not as good mpg.

[MrBen]

Oh yeah, and I am in no way dismissing your reasoning Dibbs, because though your reasoning plays a huge role in determining gas mileage, so does additives as widely used as butane.

[Dibbs]

Some gasoline's have butane in them, some do not. Others have an additive called Blendstock which consists of one or more of the following: Toluene, Xylene, Hexane, Pentane, or MTBE (refer to previous posts). They all serve the same purpose which is boosting octane and oxygenating the reaction of burning the fuel. The process of adding these chemicals is called Oxygenate Blending.

I called an Engineer at an ExxonMobil fuel marketing facility in Maine. He told me that they DO have winter and summer blends in northern states ONLY. However, I asked him what the differences were and he told me that there is a higher blendstock percentage. I asked him how this is legal considering that this would raise the octane. He then replied that the percentage increase is around 1% which though it is enough to aid in fuel oxygenation to guarentee a better burn, and would consume more fuel naturally, it would not affect fuel consumption in the high percentages that everyone has posted. Maybe 1 MPG he said.

So, in conclusion, there ARE winter and summer gasoline blends in northern states and provinces ONLY. They DO NOT keep fuel from "freezing" and they DO NOT drastically reduce fuel economy.

DAMMIT Kroy! This is still your fault. You're making me work much much harder than I'm used to. <grabs smokes>


<EDIT>
No offense taken Ben. I was shocked to see you found Butane was an additive. I hope this clears things up. Good work.

[DigitaLuminescence]

Well, now I'm going to go look for some 93 octane for my trip up to Tacoma (well, it's not really much of a trip if I'm going 80).
Dibbs, you are the man.

[MrBen]

Haha, Tacoma smells and it the most stressful city!

I drive through there every weekend though! Doing about 80.

[accordlxi2.0]

uhhh . . . .what about citco or citgo? it's one of those
i used shell and the car seemed to drink right through it.
i used bp, it seem's better.
maybe it just me.

[Hash_man_Se_i]

Damn, I was without the internet for a week and I totally forgot about this thread, haha. Well, I think part is because of my cat, it has never been replaced lol.

But up here, it usually gets pretty cold, but lately has been awesome and I still get shit mileage. I always use 87 Octane gas, and usually from Petro Canada, or Shell gas stations. The Petro Canada has winter gas with gas line antifreeze blended in, which I figure is a good idea seeing as I park outside, and it sometimes gets down to a good -30 degrees celcius here, and the gas line antifreeze prevents the condensation in the fuel lines which is caused by me sometimes parking in our garage, and sometimes in parkades from freezing, and making starting my car on those freeezing mornings a real pain in the ass.