Gas mileage: premium vs regular

[tsigoloeg]

Yes, another uckfing gas thread, I did a search but couldn't find any thread that actually did some comparisons, but I apologize if I missed one.

Anyway, I road tripped from Houston to Orlando last week. I did a regular vs premium gas comparo (for a 3.5l engine). I chose the Houston-to-New Orleans and Baton Rogue-to-Houston segments to get the most objective comparison, but I realize that there is no way this can be completely scientific (slightly different roads, wind, weather, temp, n=1, etc etc) but I believe this is the closest I'm realistically going to be able to get. I can say that the terrain is probably not a factor at all (flat flat flat), the times of day were basically the same (9 am - 2 pm) and the temps were reasonably the same, the weather was basically the same but no real idea on wind aside from it was not blowing much.

Houston-NO = 379.7 mi @ 14.687 gal regular = 25.6 mpg calculated (computer read 27.7)Baton Rogue-HOU = 371.2 mi @ 13.517 gal premium = 27.5 mpg (computer read 27.9)

Both were with AC on, cruise at 75 mph, both fillups were me squeezing the handle one extra time after the first cutoff.

So I'm wondering:

1) if the calculated or computer is actually accurate2) if the calculated is more accurate, could this mean that premium resulted in more efficient fuel usage? (by extracting more power per unit mass of fuel via timing advancement)

My other segments, all using regular gas:NO - Venice - NO- Tallahassee (slower speeds on LA-23 down the delta) = 527 mi @ 18.497 = 28.5 mpg (computer 28.4)Tallahassee - Orlando - Lake City 464.1 mi @ 18.231 gal = 25.5 mpg (26.8)Lake City - Baton Rogue 463 mi @ 17.55 gal = 26.4 mpg (26.3)

So the calculated vs computer is all over the map, I really have no idea which is a truer representation. But the subjective feel is that there seems to be a slightly better mileage benefit from premium that mitigates to slightly-outweighs the cost differential (+7-8% mileage, +5% fuel cost).

Does anyone have any other data?

I can't really do a city driving comparison as I live 3.5 mi from work and I fill up on average once every 4 weeks.

BTW - I saw the most Altima coupes I've ever seen in LA; I'm gonna have to say that Louisiannans seem to have good taste

[Forrest80]

my "butt dyno" tells me there is way more kick when i accelerate. May be worthless data but its enuff where i put in 91 octane all the time

[Scandinavian Flick]

i would defiately go with the butt dyno, very accurate, high tech measuring device, same reason i use premium.

[marlin29311]

I agree with the butt dyno as well...

...i also agree with the sticker on the fuel door that says "use of premium unleaded fuel is recommended for MAXIMUM performance"

[adidas2go]

Use Premium and stop worrying about saving $4 a fill up. Cut back on random soda buying or something useless, and save for a long lasting car

[blked_out130]

premium is definitely the way to go

[tsigoloeg]

Well, it wasn't a question of more power or saving money. It was more of an academic question. This is data that suggests putting in the premium stuff actually results in better fuel economy.

[adidas2go]

Yes, your right, it does. This has been proven time and time again, nothing new

[hopetriumphs]

premium does give slightly better milege on some cars. the truth is that some engined just dont respond well to premium. however, the a/c 3.5 has a thirsty engine with distinguished taste. milege is better with premium but the difference should outweigh the cost. depending on where you live this might be an issue. another fact is that the difference in premium used all the time wont be felt and noticed for over 6 years which is probably when most here will upgrade once again. so the question of cost-benefit comes up again.

as for the extra kick in acceleration. it can be from your brain trying to justify the extra quarter (give or take) a gallon.

just my .02

[hopetriumphs]

premium does give slightly better milege on some cars. the truth is that some engined just dont respond well to premium. however, the a/c 3.5 has a thirsty engine with distinguished taste. milege is better with premium but the difference should outweigh the cost. depending on where you live this might be an issue. another fact is that the difference in premium used all the time wont be felt and noticed for over 6 years which is probably when most here will upgrade once again. so the question of cost-benefit comes up again.

as for the extra kick in acceleration. it can be from your brain trying to justify the extra quarter (give or take) a gallon.

just my .02

Yes, another uckfing gas thread, I did a search but couldn't find any thread that actually did some comparisons, but I apologize if I missed one.

Anyway, I road tripped from Houston to Orlando last week. I did a regular vs premium gas comparo (for a 3.5l engine). I chose the Houston-to-New Orleans and Baton Rogue-to-Houston segments to get the most objective comparison, but I realize that there is no way this can be completely scientific (slightly different roads, wind, weather, temp, n=1, etc etc) but I believe this is the closest I'm realistically going to be able to get. I can say that the terrain is probably not a factor at all (flat flat flat), the times of day were basically the same (9 am - 2 pm) and the temps were reasonably the same, the weather was basically the same but no real idea on wind aside from it was not blowing much.

Houston-NO = 379.7 mi @ 14.687 gal regular = 25.6 mpg calculated (computer read 27.7)Baton Rogue-HOU = 371.2 mi @ 13.517 gal premium = 27.5 mpg (computer read 27.9)

Both were with AC on, cruise at 75 mph, both fillups were me squeezing the handle one extra time after the first cutoff.

So I'm wondering:

1) if the calculated or computer is actually accurate2) if the calculated is more accurate, could this mean that premium resulted in more efficient fuel usage? (by extracting more power per unit mass of fuel via timing advancement)

My other segments, all using regular gas:NO - Venice - NO- Tallahassee (slower speeds on LA-23 down the delta) = 527 mi @ 18.497 = 28.5 mpg (computer 28.4)Tallahassee - Orlando - Lake City 464.1 mi @ 18.231 gal = 25.5 mpg (26.8)Lake City - Baton Rogue 463 mi @ 17.55 gal = 26.4 mpg (26.3)

So the calculated vs computer is all over the map, I really have no idea which is a truer representation. But the subjective feel is that there seems to be a slightly better mileage benefit from premium that mitigates to slightly-outweighs the cost differential (+7-8% mileage, +5% fuel cost).

Does anyone have any other data?

I can't really do a city driving comparison as I live 3.5 mi from work and I fill up on average once every 4 weeks.

BTW - I saw the most Altima coupes I've ever seen in LA; I'm gonna have to say that Louisiannans seem to have good taste

[NissNEZ08]

Being that the Octane difference between regular and premium here in Arizona is only 4 pts (87 to 91) and the price difference is $.50/gal, and I commute apprximately 490 miles a week for work, I do use the REGULAR gas in my car. I know, everyone is like, don't worry about $4.00, cut back on starbucks, yada yada and I USED to be the first person to say all those things, but I did the math and over a year (filling up 1.5x a week, getting 418miles to a tank) I spend $2925.00 a year on gas (and this isn't including "Girls night out once a month." If I add the $4.00 to that total everytime I fill up with Premium, I add another $156 a year...$3081.00 total!

I have done the Premium and I have done the regular and even though I agree that I prefer Premium, I truly have not seen any difference in performance or gas milage. I have on two or three occasions with regular been able to do 460miles to a tank... Taking her down to 1 gallon of gas left. lol. But the hubster yelled at me and told me not to let the car get below a quarter of a tank because it is VERY bad for my fuel pump. So, that's that... I just use the dangum regular gas.

Now that I typed this all out, Im wondering, did it make sense or did I miss the point. Sorry to ramble. One of those days.

Tanya

[jmann]

I manually calculate the actual mileage after each fill up, here is what I've noticed. I have the 3.5. Last time I used regular, my actaul mileage was 19.5 mpg, combined city/highway. I filled with premium after that (it's $.20 per gallon more for 93 octane where I go, and I get 10cents off of that price.) and the combined mileage was 21.5 at the next fill up. I took it on a highway trip, and the computer display for mileage got as high as 29.1 mpg on the way there, which beat the previous best mileage reading by 2 mpg also. Manual calculations resulted in a 2-3 mpg increase every time when using premium. Then I crunched those numbers:

Even if I only get 2 mpg improvement with premium, over a 15 gallon fill up, that's 30 more miles traveled than I could with regular. At an average of 22.5 miles per gallon that I usually get, that's 1.333 gallons of gas saved, which costs about $5. Since my premium is only costing me .20 per gallon more, that's $3 extra spent on premium, netting a savings of $2. I know these numbers are marginal, and if you have to pay 30-50 cents more for premium you might see the savings eliminated. For me it's cost effective to buy premium, and I get to enjoy the benefit of the added power and a longer lasting engine hopefully.

[SHIFT_COUPE]

I love MPG number crunching

[galanw]

http://www.nytimes.com/2008/08...login

a friend sent me that review......hope u guys found it helpful.....although i don't quite believe what it says.....lol

[adidas2go]

Being that the Octane difference between regular and premium here in Arizona is only 4 pts (87 to 91) and the price difference is $.50/gal, and I commute apprximately 490 miles a week for work, I do use the REGULAR gas in my car. I know, everyone is like, don't worry about $4.00, cut back on starbucks, yada yada and I USED to be the first person to say all those things, but I did the math and over a year (filling up 1.5x a week, getting 418miles to a tank) I spend $2925.00 a year on gas (and this isn't including "Girls night out once a month." If I add the $4.00 to that total everytime I fill up with Premium, I add another $156 a year...$3081.00 total!

$156 a year is a small price to pay considering the life your extending your exhaust valves, egr valve, catalytic converters, O2 sensors, and other exhaust critical components. The higher octane burns far cleaner, leaving less carbon deposit and buildup throughout your engine. It the long run it helps

I have done the Premium and I have done the regular and even though I agree that I prefer Premium, I truly have not seen any difference in performance or gas milage. I have on two or three occasions with regular been able to do 460miles to a tank... Taking her down to 1 gallon of gas left. lol. But the hubster yelled at me and told me not to let the car get below a quarter of a tank because it is VERY bad for my fuel pump. So, that's that... I just use the dangum regular gas.

Your husband is right. It is harder on the fuel pump, and you have a potential to suck up trash and debris, trapped in the bottom of your fuel tank. Whenever you put gas in your car little pieces of seidment and such also make their way down there. When you get that low, the sediment thats sitting on the bottom, is now being fed through your fuel lines to potentially clog your fuel pump, filters, and even gunk up your lines! When this happens, your car will be starving for fuel and the car might damage itself by running a high lean condition. Depending on if the cars computer would sense it, and go into low rpm protection mode.

[Scandinavian Flick]

Your husband is right. It is harder on the fuel pump, and you have a potential to suck up trash and debris, trapped in the bottom of your fuel tank. Whenever you put gas in your car little pieces of seidment and such also make their way down there. When you get that low, the sediment thats sitting on the bottom, is now being fed through your fuel lines to potentially clog your fuel pump, filters, and even gunk up your lines! When this happens, your car will be starving for fuel and the car might damage itself by running a high lean condition. Depending on if the cars computer would sense it, and go into low rpm protection mode.

also, the fuel pump uses the fuel to keep cool, running the car low on gas can cause the fuel pump to overheat which will extremely shorten its life span

[AwsSkater]

Does this only affect the 3.5 model? or will the 2.5 see the same benefit from using premium?

[jmann]

I also have a 2002 2.5 altima, there has never been any benefit from using anything other than 87 octane on the 2.5.

[marlin29311]

You won't see a difference on the 2.5, as it was made to run off 87 octane gas. It only works when the engine was made to handle the higher grade fuel.

[wjm3982]

i just got my first tank of gas after buying my car, and i only averaged about 17.5 mpg. is this normal for a totally brand-new car? this is at least 8 mpg less than what i was expecting, and i would say that at least 75% of my driving is highway, and i didn't get stuck in any traffic a single time

needless to say i was very disappointed, but i can't even imagine what would have factored into it being so incredibly low

[marlin29311]

i just got my first tank of gas after buying my car, and i only averaged about 17.5 mpg. is this normal for a totally brand-new car? this is at least 8 mpg less than what i was expecting, and i would say that at least 75% of my driving is highway, and i didn't get stuck in any traffic a single time

needless to say i was very disappointed, but i can't even imagine what would have factored into it being so incredibly low

Its very possbile - my first tank was 20mpg - now i get 24 doing my work run, which is a mix of local and highway. The engine has to break in, you might have lead footed a little more than you think, etc. Nothing to worry about.

[wjm3982]

oh i'm definitely a lead foot, but that usually hurts you by a few mpg, not 8

i'll see what i'm getting after another few weeks and 1000 miles

[RobPaulson]

Ive been using premium with a lead foot and im gettin like 21-23 a fillup

[NissNEZ08]

Awww, you guys are awesome. Thanks for the analysis and break down for me of the fuel pump woes etc... And just so you know. I will never let my car get below a quarter tank now, which gets me about 418miles to a tank. Not bad = 21.44mpg and the price of gas going down allows me to put the Premium grade in again. So, thanks again for the lesson.

I know, Im a stupid girl! LMAO. but I am a lot of fun and I have great taste in cars! (And car forums obviously!) lol...

Take it easy!

Tanya

[Rellz CT]

so what should i put in mine?

93?

[SHIFT_COUPE]

so what should i put in mine?

93?

91 is fine

Welcome to the club brother! I like to see the CT name in there!

[LinkNuc]

I use 93 all the time, but the "butt dyno" thing, total 100% Bull Sh1T,

[DaCoupe]

I use 93 all the time, but the "butt dyno" thing, total 100% Bull Sh1T,

whats with the bringing back year old threads

[Jpmemcoupe]

I live 3.5 mi from work and I fill up on average once every 4 weeks.

Must be nice!!! I live 38mi one way, plus some other running. So I drive an avg. of about 550mi per week, hence the reason I decided to get the 2.5. I keep a log book of every gas purchase in the glove box. Every time I buy, I write down the trip odometer mileage, actual odometer mileage, per gallon costl, and the number of gallons pumped. My overall average is currently around (3.5er's should sit down / look away for this) 29.5 mpg on 87oct. Granted it is mostly hwy, but I'm usually cruzin at 75mph.

Its very possbile - my first tank was 20mpg - now i get 24 doing my work run, which is a mix of local and highway. The engine has to break in, you might have lead footed a little more than you think, etc. Nothing to worry about.

You are absolutely right on the break in, My first tank was 24 mpg, got the car w/ 55 mi on it, now at 2500 exactly 1 month later I'm at, well see the paragraph before.Jp

[DAAN.]

(computer read 27.7)(computer read 27.9)