regular vesus premium fuel

[Recumpence]

Hello All,

I have done some experimenting with premium versus regular fuel from a mpg perspective and have found a roughly 6% increase in mileage running premium gas. So, my refueling regime has now included calculating the percentage of difference in price between the two to see if my 6% mpg increase can offset the added fuel cost.

 

who else has noticed this?

 

Matt

[fotomoto]

Funny, I also have been trying premium on this current tank.  I, too, am seeing an instant increase in mpg's.  Early results look to be 2-3mpg but need more miles to be certain.   I'm getting a promotional 12 cent/gallon discount which lowers the price to somewhere between unleaded and mid-grade so really it's a no-brainer.

[Jus-A-CMax]

No experimenting, been on the premium stuff since my 3rd tank. I found the regular lack lustre in the performance especially in the punch & go...no stats, just by feel. Have not looked back since. I am just waiting for the nay-sayers to come onboard that theres no diff but i'm not changing my fuel type. My stats is good enuf for me :)

[mtb9153]

Well here's what I have to say about running premium.  If you can afford it, go for it, should give you better mileage because of the higher octane and certainly better performance.  I used to have two performance trucks that were turbocharged and required premium. I got tired of the high price which is why I sold both trucks.  I can see myself trying once and a while running premium but don't think it will ever become a regular thing.  Paying $50 to fill up my Max with cheap regular is bad enough.  Plus I'm not into performance anymore, it is all about economy now.  Opposite end of the spectrum from my truck days.  Come to think of it, I've never even punched my Max yet to see what it can do.  Slow and go is my motto now.

[Jus-A-CMax]

Well here's what I have to say about running premium.  If you can afford it, go for it, should give you better mileage because of the higher octane and certainly better performance.  I used to have two performance trucks that were turbocharged and required premium. I got tired of the high price which is why I sold both trucks.  I can see myself trying once and a while running premium but don't think it will ever become a regular thing.  Paying $50 to fill up my Max with cheap regular is bad enough.  Plus I'm not into performance anymore, it is all about economy now.  Opposite end of the spectrum from my truck days.  Come to think of it, I've never even punched my Max yet to see what it can do.  Slow and go is my motto now.

 

I've been playing with a "punch & glide". I know I started a thread on this sometime back to tackle the short, steep grades and save gas but thus far I am liking of blowing the slow and go and maxing up to speed asap - this leaves a lot of momentum in the car for an extra long pulse. Great for the 35 or 45 mph surface streets. CON is that it drains the battery some what - due to the extra punch initiates battery power (when batts are > 50%) which is good as it's not all ICE. However, sometimes I initiate a slow shortish burn in there as well to start some recharge as the glide does not always provide enough additional charging.  I know I sent you a PM on this mtb but not sure if you checked it.

Edited May 18, 2013 by Jus-A-CMax

[mtb9153]

I've been playing with a "punch & glide". I know I started a thread on this sometime back to tackle the short, steep grades and save gas but thus far I am liking of blowing the slow and go and maxing up to speed asap - this leaves a lot of momentum in the car for an extra long pulse. Great for the 35 or 45 mph surface streets. CON is that it drains the battery some what - due to the extra punch initiates battery power (when batts are > 50%) which is good as it's not all ICE. However, sometimes I initiate a slow shortish burn in there as well to start some recharge as the glide does not always provide enough additional charging.  I know I sent you a PM on this mtb but not sure if you checked it.

Jus yes I remember the thread and thanks for sharing it.  But I'm not sure I understand the manner in which you do this.  Are you punching the gas off the line for a brief time and then letting off to glide or coast as I call it?  How much do you gas it?  just not clear on the process.

[Recumpence]

For me, premium averages about 6% to 7% more than regular. So, it is not a performance thing. The added mileage pretty much pays for the added fuel cost and I do not need to stop for fuel as often.

 

With regular, I see 55.5 To 56.5mpg. With premium, I can hit 60mpg for the entire day.......

 

Matt

[catsailor]

Matt, U are my freaking hero...... i think you can get 70 mpg if you tired :) I for one will fill up next time with premium just cause I want to try to beat your numbers (i know this is a pipe dream, but you got to set lofty goals). I tired a very early gas tank with premium but saw no difference but that was when the car was new and it was cold outside.

Edited May 18, 2013 by catsailor

[lowbar]

So all these boasts of high mpg and 600 mile tanks need an * beside them noting premium fuel, right?  Where I live premium costs about 8.67% more.

Edited May 18, 2013 by lowbar

[Recumpence]

My 700 mile tank was done on premium.

 

That being said, that tank averaged 55.2mpg IIRC. Right now, on regular fuel (for 415 miles so far on this tank) I am averaging 55.5mpg. So, it looks like I will be able to top 700 miles on regular.

 

Oh, I have averaged 52.4mpg for the last 3,000 miles according to my Trip1 odometer.

 

Matt

Edited May 18, 2013 by Recumpence

[lowbar]

My 700 mile tank was done on premium.

 

That being said, that tank averaged 55.2mpg IIRC. Right now, on regular fuel (for 415 miles so far on this tank) I am averaging 55.5mpg. So, it looks like I will be able to top 700 miles on regular.

 

Oh, I have averaged 52.4mpg for the last 3,000 miles according to my Trip1 odometer.

 

Matt

 

That's amazing Matt.  I can get that kind of mileage occasionally but not on a regular basis.   Then again most of my miles are on the interstate system in and around Atlanta.  

[mtb9153]

Ok it looks like I'm going to need to try premium, at least for a tank or so just to see what effect it has on my low Average MPG levels.  You guys are killing me.

[asb]

I've been thinking about trying premium as well.  The summers here are brutal, and I want to give my car a treat.  I generally can't afford the premium, but with the savings in gas by driving a hybrid, it might be worth it.

[Edsel]

I've always heard this was a myth, but If you guys are getting results I'll give it a shot.

[Chinto]

I have heard conflicting answers to this question.  Does premium grade contain 10% ethanol?  Some say it is in regular grade only some say it is in all grades.   I don't know.   If it does not, that may explain the improved performance.   

[plus 3 golfer]

One needs to look on the pump.  Most states require a sticker that says may contain up to X% ethanol.  

 

IIRC, in reading AZ gasoline specs in the past, there was no distinction made between regular and premium gas with regards to oxygenated fuel program requirements.

[subter]

The answer is long and complex depending on many factors.  Gas differs from region to region and brand to brand.  Ultimately good quality premium with quality additives and low ethanol can increase MPG small amounts.  Most articles will just say it's a myth because the increases can be close to nothing.  Most vehicles you won't notice a difference because it's a 5-10% increase in the best of scenarios. On a Cmax or a Volt, etc., it's more noticable.  Problem is premium gas carries a 5-10% premium in price so you'd have to do the math on different brands and prices every fill up.  Ultimately it probably wouldn't hurt because even if it's a wash financially,  the gas may contain better additives so you'd realize the benefits from that.  Also, seems like it would be almost impossible for the average driver to duplicate conditions over two tanks of gas.  The odds you'd drive the exact same way, the exact same trips and have the exact same weather for two different 600 mile tanks would be mighty low in my opinion.  Especially if you're talking 3-4 mpg average per tank.

Edited May 20, 2013 by subter

[PWBarrett]

<Devil's Advocate>

I've always heard that calling it "Premium" was somewhere between a misnomer and a scam, because all that higher octane gets you is knock-reduction.

The idea being that if your engine isn't knocking under acceleration, higher octane is just a waste of money.

I've even seen it said that if an engine isn't optimized for higher compression, you'd actually get less bang for your buck out of premium.

Then there are the arguments about how old the premium gas is compared to the regular, because it sells in such lower volume.

 

But now I'm reading about how the knock-sensors in today's engines have changed the picture, and it might help after all...

I'd be wary of placebo syndrome and the notion that if you paid more it must be better...

But if under the exact-same conditions, repeatably, you get better MPG, that'd be interesting to know.

(Not just better than you got in February when it was colder.)

</Devil's Advocate>

[Recumpence]

My mileage in warm weather is 55mpg on the average with regular. It is 58.5 To 59.5mpg with premium consistantly.

 

Modern engines sense knock and retime accordingly. This boosts efficiency with higher octane fuel.

 

Matt

[subter]

I'll have to wait until my mileage flattens out to try. I'm only on my third tank and mileage has been going up on each one with the weather.  You'd really have to be consistant though.  I'm going 2 plus weeks between fill-ups.  With summer coming up, I could go two weeks with little or no air con. then two weeks of blazing hot with lots of air con.

[plus 3 golfer]

My mileage in warm weather is 55mpg on the average with regular. It is 58.5 To 59.5mpg with premium consistantly.

 

Modern engines sense knock and retime accordingly. This boosts efficiency with higher octane fuel.

 

Matt

I thought most algorithms work from a stock timing map tuned for the required octane that is specified.  So, if detonation is detected, the algorithm retards timing in increments until detonation is not detected.  Then, over time and in steps advances timing back to the stock settings provided there is no detonation detected.  In this way most cars that require premium fuel will run fine on regular as timing will be retarded should detonation occur albeit for a slight loss in performance.

 

So, are you saying that in the C-Max the algorithm continues to advance timing past the stock timing until detonation is detected? This would be the first time I've heard of that.

[plohnes]

Seems like getting premium is almost a wash price wise.....

 

If I get premium 13 gallons of gas (in my area premium is .26/gallon higher than regular) - 13x.26=$3.38

If I get 4 MPG greater on premium, at 13 gallons - 13x4=52

 

 

Then it will have cost me 3.38 (roughly price of regular in my area) to go an extra 52 miles 

 

I know there are many variables in play here ... 

[Edsel]

I'll be happy if its a wash, I'll just have to fill up less often.

 

I did a little research and came up with a couple of take home points. 

 

1. Premium is better with high compression ratio engines. (C-Max is 12.3:1)

2. No manufacturer will recommend premium unless the engine absolutely requires it.(for comparison shopping reasons)

 

It is possible that the premium gas could produce some MPG gains with high compression ratio engines.

 

Warning* I didn't get any of this from scientific journals and I'm not an engineer ;)

Edited May 22, 2013 by Edsel

[Edsel]

Just found this.

 

http://blogs.cars.com/kickingtires/2012/10/regular-cars-that-take-premium-gasoline.html

 

Kinda shoots down my point two from above. :doh:

[Recumpence]

I did the math and I am 2% better off buying premium at the current prices versus the MPG difference. Almost not enough to even consider. But, the fact that it does not cost me any more per mile (actually a tiny bit less), I will go with premium since I do not have to fillup as often and it just feels better seeing higher numbers on the dash.   :)

 

Matt