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echoRS 09-05-2011 03:04 PM

Premium Gas???
 
Hi everyone!
I was wondering if anyone has done a cost/milage comparison with regular and premium gas. If you broke each km or mile down to a dollar figure, have you found any significant savings with higher octane?
Just curious, I've seen better milage with it, but I'm just wondering if it's worth the money? I'll be doing a little test and keeping track soon.

99LeCouch 09-05-2011 03:11 PM

In my case with a turbo it is. The car is more responsive and FE is higher.

Being naturally aspirated, yours might not see a difference,

tercelguy 09-05-2011 03:30 PM

I put premium gas in my tercel a few weeks ago to see the effect on my fuel economy.

It might be from other reasons but I got 39 mpg instead of my usual 42. My tanks before and after were all at 42 mpg so i'm not buying premium anytime soon again.

endurance 09-05-2011 03:33 PM

In most cases the costs outweigh the benefits. As LeCouch pointed out, however, there are some cars that are designed with either higher compression, turbo chargers, or superchargers where performance drops and even engine damage can result from using lower grades of gasoline. You're generally better off sticking to what the owners manual tells you to use.

My tanks I've experimented with regular in my Acura were awful. My car would ping and run poorly at RPMs under 2500, so I was forced to drive in the mid-range of RPMs more, which led to poorer mileage. Then again, my engine is very high compression compared to most cars on the road.

mcrews 09-05-2011 07:03 PM

if you run a scangaugeII you can see the difference in the ign function. as the previous posted said, you need to run what the car is designed to run on.

I had a post a while back about the dramatic effect NOT running premium had on the mileage and the performance on my trip to texas from CA.

If you are just an everyday driver, not paying attention to anything, it won't ever matter.
But if your on this forum and your trying to mazimize everything.....run what your car says to run.

ps running premium when the car says run regular is a waste (in my humble opinion).

Ryland 09-05-2011 08:05 PM

I run premium in my Civic VX because it doesn't have Ethanol in it, 10% Ethanol and I see a 4-6 mpg drop, or about 10%, the premium here tends to be about 5% more expensive so it's worth it to me, my car also runs smoother.

The motorcycle shop that I used to work at would see a lot of motorcycles come in that were not running right because cheap gas was put in them, drain the gas and put in premium and they were fixed.

euromodder 09-06-2011 10:18 AM

Quote:

Originally Posted by echoRS (Post 259667)
Hi everyone!
I was wondering if anyone has done a cost/milage comparison with regular and premium gas. If you broke each km or mile down to a dollar figure, have you found any significant savings with higher octane?

See what the car is set up for.
Using better fuel than that will generally not help much.

Using worse fuel will hurt the mileage though.



We've got premium diesel here as well, but for me, the reduction in fuel used doesn't compensate the higher price.
If I want to have a shot at record low fuel consumption, I'll use it ;)

In addition, not every car sees improvements in fuel economy when using the premium fuel.

RRC 09-06-2011 12:03 PM

In my case (no turbo) and old engine difference between lower and higher octane is about 0.5L/100km when we are talking about FE.
So yes the permium gas gives me a little bit better FE.
The best what you can do is check it by self with your car.

Floordford 09-06-2011 04:38 PM

I found, in my car, that I would burn through regular faster than premium. Thats not backed up with any data but it was about three years ago on a stock tuned engine. I started running premium just because I figured it was about equal cost per mile.

Rick Rae 09-06-2011 06:10 PM

I suspect the vehicle (and driver, and environment) of interest would need to be tested. There are probably way too many variables to make a useful blanket statement.

Before the Versa I had a Cabrio; its 2L was the only VW engine rated for regular gas. Back in 2007-2008 I ran a test on Shell Regular, Plus, and "V-Power." It was real-world, not tightly controlled, and not blinded, so it hardly qualified as an "experiment." But I ran the test for a LONG time to try to get reasonable data.

In my specific car (with me driving, etc.) I saw a slight FE improvement with premium, but not enough to offset the additional cost.

The data is available if you're curious, but it's on another forum and I don't know if I'm allowed to mention it here. Hardly worth looking at anyway; the improvement in my case was very subtle.

Rick

brandonppr 09-06-2011 07:00 PM

Another thing to note when testing is that it may take a tank or pulling a fuse or disconect the battery to reset the Long Term Fuel Trims that the computer stores depending on the fuel you run. Depends on the car as to how to reset them, but the car is going to react different with differtn fuel trims when gas is changed.

endurance 09-08-2011 07:10 PM

I just ran across this reply in an old popular mechanics:
[quote]Knock Three Times
My father has a 2003 VW Passat with the W8 engine, and he uses 89 octane fuel instead of the 91 recommended. He says the knock sensor will adjust the engine timing to prevent knocking and engine damage. I contend that even if the driver doesn't hear pinging, that doesn't mean that it's not occurring, and can lead to engine damage. Can this lower-octane fuel damage his engine?
FREDERICK W.
LEONARDTOWN, MD

Your father will not damage his engine running any gasoline he can get in the United States, which might be as low as 87 in some areas. The knock sensors (many engines have more than one because they are bolted to the head, not the block) will sense the rapidly building pressure waves caused by gasoline igniting prematurely inside the combustion chamber. The engine-management computer will retard this spark and prevent this condition. The system is good enough at this to preclude any damage. The downside is that fuel economy will suffer from the retarded timing, making his bargain low-grade fuel less of a bargain.

found here

mcrews 09-08-2011 08:05 PM

Quote:

Originally Posted by Rick Rae (Post 259832)
I suspect the vehicle (and driver, and environment) of interest would need to be tested. There are probably way too many variables to make a useful blanket statement.

Before the Versa I had a Cabrio; its 2L was the only VW engine rated for regular gas. Back in 2007-2008 I ran a test on Shell Regular, Plus, and "V-Power." It was real-world, not tightly controlled, and not blinded, so it hardly qualified as an "experiment." But I ran the test for a LONG time to try to get reasonable data.

In my specific car (with me driving, etc.) I saw a slight FE improvement with premium, but not enough to offset the additional cost.

The data is available if you're curious, but it's on another forum and I don't know if I'm allowed to mention it here. Hardly worth looking at anyway; the improvement in my case was very subtle.

Rick

Rick,
you left uot the most important fact: what was the recommended fuel.

That's really the issue.
And it can't be 'retrained' by pulling the ecu.

Rick Rae 09-08-2011 08:16 PM

Quote:

Originally Posted by mcrews (Post 260160)
Rick,
you left uot the most important fact: what was the recommended fuel.

Sorry, I thought the implication was clear. As I stated, the 2.0L is the only VW engine rated for 87 octane, and that's what was specified in the owner's manual.

Rick

Arragonis 09-09-2011 05:56 PM

Not sure if this is "premium gas" or not but I tend to fill up at supermarkets over here in the UK as they are cheaper.

Some on forums related to the Aygo suggest fuel from branded garages (e.g. Shell, Esso etc.) results in better MPG and I intend to try a couple of tanks to see if there is a big difference.

Most Petrol in the UK comes from the same refineries, and the differ in terms of added chemicals for cleaning, octane boosting and so on. Supermarket fuel is the basic blend, branded fuel has more additions - maybe.

euromodder 09-09-2011 07:16 PM

Quote:

Originally Posted by RRC (Post 259786)
In my case (no turbo) and old engine difference between lower and higher octane is about 0.5L/100km when we are talking about FE.
So yes the permium gas gives me a little bit better FE.

That's a nice improvement.
3 times what I'm getting with premium diesel.
At that kind of difference, it starts paying off to use the premium fuel.

Quote:

The best what you can do is check it by self with your car.
Obviously ;)

echoRS 09-09-2011 08:03 PM

Thanks everyone for the reply's...I'm impressed, not many places you can ask a question and get responses from both sides of the Atlantic!
I think in my case I'll just stick to the 87 octane gas.

jkv357 09-09-2011 10:26 PM

You've pretty much got your answer, but I'll add that you will get the most power from a fuel with the lowest octane level that just barely prevents detonation. Additional octane, if not required to control detonation, will cost you power. I'm not certain if that translates directly to MPG numbers also, but I expect it might.

The only time a high octane fuel may give you more MPG, when not required to control detonation, is when it doesn't contain Ethanol like the lower grade. I've found about a 4% increase in mileage with my cycle when using 91 octane (87 is required) without Ethanol.

I don't think there is any definite answer to the exact penalty of 10% Ethanol - every car/cycle reacts differently.

Frank Lee 09-09-2011 10:52 PM

Quote:

Originally Posted by Arragonis (Post 260288)
Some on forums related to the Aygo suggest fuel from branded garages (e.g. Shell, Esso etc.) results in better MPG and I intend to try a couple of tanks to see if there is a big difference.

IIRC there's an old thread on EM or gassavers with extensive debating/testing of "top tier" fuels vs the others. I didn't pay too much attention to it though because I'm always going to fill with the cheapest swill I can find.

Mustang Dave 09-09-2011 11:21 PM

I tried a few tanks of 91 octane premium in my Mustang last summer. I have a Hypertech power programmer that can re-program my PCM for best performance with 87 octane regular or 91 octane premium. I had it programmed with the 91 octane performance tune. I got lower MPG with premium and the premium performance tune than I get with regular and the regular performance tune. There was a noticeable difference in performance, but the MPG loss "inverse squared" the price difference.:p I'll feed my pony the less expensive "oats". Unless I'm racing..........

steffen707 09-10-2011 05:02 PM

Not sure how this correlates, but when i use 87 octane my mpguino displays about 3-4mpg higher than what I calculate from odometer and pumped gallons, than when i use the 91 octane no ethanol added from the same gas station.

When i use the 91 octane stuff, the mpguino is basically dead on with odometer and gallons at pump calculations.

Anyways, i use the non-ethanol stuff because i've noticed the ethanol stuff screws up small engines, and i get 3-4mpg more from the more expensive stuff.

Rokeby 09-10-2011 06:05 PM

Some posters have said that when they used premium/high octane, >87,
fuel in a car requiring only 87 octane, they got better MPGs. Others have
said the opposite.

Can both camps be correct? Apparently so.

Most sites that discuss premium vs, regular gas are silent on this matter,
But thankfully not Click & Clack, The Tappet Brothers:

Finally, here's a nice irony: to increase gas' octane rating, companies add
ethanol, when they're mixing up a batch of premium fuel. Interestingly,
ethanol actually contains less energy than untreated gas, so the net result
from the ethanol component is a reduction in your MPG. Other premium
additives, however, have the reverse effect, and slightly increase your MPG.
So okay, overall premium provides a very slight net increase in MPG, but it's
so slight that we swear you won't notice the difference.


It would appear that just as when buying regular gas, finding premium
grade gas without ethanol could result in slightly higher MPGs.

FWIW, I'd bet dollars to donuts that ethanol is the cheaper/est of the
additives used to achieve post-refined premium level octane readings. ;)

From Wiki: Antiknock additives
Most countries have phased out leaded fuel. Different additives have replaced the lead compounds. The most popular additives include aromatic hydrocarbons, ethers and alcohol (usually ethanol or methanol).

steffen707 09-10-2011 06:08 PM

Quote:

Originally Posted by Rokeby (Post 260406)
FWIW, I'd bet dollars to donuts that ethanol is the cheaper/est of the
additives used to achieve post-refined premium level octane readings. ;)

I could be wrong, but when the sign at the pump says, "no ethanol added", I would assume that no ethanol was added to achieve the higher octane rating.

Rokeby 09-10-2011 06:21 PM

I wholeheartedly agree. :thumbup:

And now we, or at least I, know two new things about premium vs. regular:
1. Why all premium grade gasolines are not ethanol free, and
2. When used in premium grade gasolines, ethanol functions as an octane
booster, and not as a tailpipe emissions reducer as when used in regular
grade gasoline.

However, there is at least one new question that comes from all this:

What percentage of ethanol is added when used as an octane booster?

steffen707 09-10-2011 07:59 PM

There is a gas station in my city that has 89 octane with no ethanol added, I should try that. Also i've only used the 91 premium no ethanol added gas from kwik trip as its right next to my house. But the Shell station has 93 premium with no ethanol added and I should try a tank of that too.

Trouble is with my d15z1 swap, I get like 500 miles to a tank. It will be some time before I have to fill up.

RH77 09-10-2011 11:08 PM

I need to run Premium in both Acuras (the TSX for sure due to factory design, and the Integra due to mods -- the fuel savings outweigh the upcharge). Not having that efficiency reduction with ethanol would be nice. (I wonder what they do for Winter blends???)

Anyway, pure-gas.org has a listing of non-Ethanol fuel stations available by State, with the option to add new locations -- and looks to be legit.

Note that some States do not require Ethanol labeling (including my home area of Missouri and Kansas -- so self testing would have to occur). The Site gives details and instructions for the entire determination process.

Best FE,

-RH77

Ladogaboy 10-16-2011 03:46 PM

This topic actually comes up a lot with my family of cars (requires 91 octane). The car has a knock sensor and will retard the engine if the octane isn't adequate. However, as has been stated earlier, the question is whether increased engine wear and damage will result from not using fuel with the octane level that the engine is tuned to run on.

Regardless, I think people also tend to forget the most pertinent detail in this situation. @ ~ $4.00 per gallon for premium versus ~ $3.80 per gallon for regular, the difference in price is only $0.20, or roughly 5% cost savings. Basically, $4.00 on a 20 gallon tank. So, as long as you are not worried about potential engine damage and the switch to regular gasoline does not result in a measurable decrease in fuel economy, it *might* be worth it to use regular instead of premium.

99LeCouch 10-16-2011 04:12 PM

Any engine damage will cost more. And, the difference in performance on a turbocharged or high-compression naturally-aspirated engine might well be worth the premium.

Another difference is that the systems designed to prevent damage are reactive instead of proactive. Sure the knock sensor will cut timing, but engine damage might already have occurred from the knock it sensed.

Using premium in a car that calls for it is a proactive way to prevent damage.

blownb310 10-16-2011 04:46 PM

Has anyone here purchased the Fuel Testers kit and checked to see if the ethanol free fuel they buy is really ethanol free?

Mike

Andrei_ierdnA 02-14-2016 06:44 PM

Sorry for reviving a 5 year old thread, but I thought it's better than starting a new thread just for a post.

My mom's boyfriend claims that on his 2010 Nissan Versa hatchback w/ 5 speed manual he gets about 10% better FE than with regular. He also claims premium (91 octane) is better for the internal components, keeping them clean and keeping the catalytic converter in top shape for the life of the car. He's a car salesman, started with Subaru & with GM now, so "he knows cars". :D

I just get the regular gas from a brand-name pump since they have great points & rewards and 2% discount with the card. I basically get all the free car washes I need with the points.

Anyways, I've found something interesting produced by CBC - Marketplace. Hope you guys find this informative and I'm curious of your opinions.
YouTube 20 mins:

https://youtu.be/FPPkPAbzwbU

https://www.youtube.com/watch?v=FPPkPAbzwbU

user removed 02-14-2016 06:52 PM

For me in eastern Va, USA, the difference, if any in mileage, isn't worth the added cost per gallon.

2.6 cents a mile on the cheapest gas. Funny thing, the last tank was Shell.

regards
mech

Xist 02-14-2016 08:17 PM

Ha! I was waiting to get to the end of this thread to share the CBC video! :) I enjoy their channel!


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