Regular vs. Premium

[Ranga14]

This might be a stupid question but I'm curious in terms of % and/or horse power, how much gain you would have from using premium gas? Or on the flip side, how much % and/or HP would you lose from using regular?

Also, say for me, I've been using regular since I purchased the car and I have about 11,000 miles on it, would switching to premium now and sticking to it cause any harm? Just curious. Still debating on if I really want to run premium since I'll eventually be modding it up.

[DAAN.]

Switching would not harm it. Using regular does not hurt.You don't lose much. 5%? 10% ? Meh

Am also a regular user.

[Rob.Vegan]

I'm a regular (87 octane) as well but I'm also running a 2.5 A while ago on these forums I was told that premium fuel on a 4cyl was probably not the greatest idea on my car due to the engines A/F ratio or something like that

[D-Roll]

I get better MPG from premium octane.

[dimitrinassis001]

I have been using 89 after I had my car for 6 months. It seems to have more pep but what I did notice was Im getting about 25 more kilometers a tank. Im not sure how accurate that is cuz the proportion of highway and city driving varies every week.

[dangeris]

Switching would not harm it. Using regular does not hurt.You don't lose much. 5%? 10% ? Meh

Am also a regular user.

You don't lose much?....Are you kidding? I've used premium in my car from day one! In fact I use premium on ALL my cars and yes, you do loose a lot especially since you have the 3.5. The 2.5 motors can get away with it but IMHO, you'll feel the difference in performance. Besides, the difference between regular and premium is minimal..I'd rather spring the extra $5 dollars per tank of premium and get maximum performance out of the motor than saving the $5 and going to TacoBell.

[dimitrinassis001]

Here are some lines from the owners manual:

FUEL RECOMMENDATIONFor 2.5L engineUse unleaded regular gasoline with an octanerating of at least 87 AKI (Anti-Knock Index) number(Research octane number 91).For 3.5L engineNISSAN recommends the use of premium unleadedgasoline with an octane rating of at least91 AKI (Anti-Knock Index) number (Researchoctane number 96). If unleaded premium gasolineis not available, you may use unleaded regulargasoline with an octane rating of at least 87 AKInumber (Research octane number 91), but youmay notice a decrease in performance.

Gasoline containing oxygenatesSome fuel suppliers sell gasoline containing oxygenatessuch as ethanol, MTBE and methanolwith or without advertising their presence.NISSAN does not recommend the use of fuels ofwhich the oxygenate content and the fuel compatibilityfor your NISSAN cannot be readily determined.If in doubt, ask your service stationmanager.If you use oxygenate-blend gasoline, please takethe following precautions as the usage of suchfuels may cause vehicle performance problemsand/or fuel system damage.c The fuel should be unleaded and havean octane rating no lower than thatrecommended for unleaded gasoline.c If an oxygenate-blend other thanmethanol blend is used, it should containno more than 10% oxygenate.(MTBE may, however, be added up to15%.)c If a methanol blend is used, it shouldcontain no more than 5% methanol(methyl alcohol, wood alcohol). Itshould also contain a suitable amountof appropriate cosolvents and corrosioninhibitors. If not properly formulatedwith appropriate cosolvents andcorrosion inhibitors, such methanolblends may cause fuel system damageand/or vehicle performance problems.At this time, sufficient data is not availableto ensure that all methanol blendsare suitable for use in NISSAN vehicles.

In Ontario regual (87 octane) contains 10% ethanol which is not great for your vehicle so I use 89 which contains 5% ethanol. Im not a mechanic so Im only taking a guess as to whcich is a lesser of two evils when it comes to gas.

[dangeris]

Here are some lines from the owners manual:

FUEL RECOMMENDATIONFor 2.5L engineUse unleaded regular gasoline with an octanerating of at least 87 AKI (Anti-Knock Index) number(Research octane number 91).For 3.5L engineNISSAN recommends the use of premium unleadedgasoline with an octane rating of at least91 AKI (Anti-Knock Index) number (Researchoctane number 96). If unleaded premium gasolineis not available, you may use unleaded regulargasoline with an octane rating of at least 87 AKInumber (Research octane number 91), but youmay notice a decrease in performance.

Thanks for the info dimitri...

So in the words of that guy who played the dad in "my Big Fat Greek Wedding"...There you go...

[BamaCoupe]

I've used 89 octane on a few occasions, but I typically use 93 octane. I did use 87 on a few occasions during the over $4 a gallon days, and I must say I did not notice a bit of difference. I personally am more picky about name brand than octane, I don’t typically use anything but Chevron, Texaco (Texaco uses Chevron formulated fuels and are typically a few cents less a gallon than Cheron stations) or Exxon fuels.

[dangeris]

I used premium despite the gas prices...I saw it as my way of "stimulating" my local economy! Hopefully, it doesn't go back up that high again!

[marlin29311]

A car like the 3.5 should use 91 or higher octane because of the compression ratio of the engine - lower octanes can cause pre-detoniation and knocking in certian instances.

2.5's see 0 benefits from using a higher octane, minus the fact that a premium fuel usually has additional detergents and stuff, such as Shell V-Power.

[superblackcoupe]

A while ago on these forums I was told that premium fuel on a 4cyl was probably not the greatest idea on my car due to the engines A/F ratio or something like that

It's not a bad idea for your car, it's just a waste of money.

In Ontario regual (87 octane) contains 10% ethanol which is not great for your vehicle so I use 89 which contains 5% ethanol. Im not a mechanic so Im only taking a guess as to whcich is a lesser of two evils when it comes to gas.

Most (all?) of the gasoline here in Pennsylvania contains E10 regardless of octane, thanks to our idiot governor trying to be "green."

Speaking as a former Honda owner, I find it kind of strange that Nissan recommends 91+ for their V6 engines while V6 Accords say to use regular unleaded in the manual.

/rambling

[marlin29311]

Speaking as a former Honda owner, I find it kind of strange that Nissan recommends 91+ for their V6 engines while V6 Accords say to use regular unleaded in the manual.

The V6 Accord could have a lower compression ratio than the VQ in the altima's...i don't know for certian, but that could be the reason.

[ESP]

2.5's see 0 benefits from using a higher octane, minus the fact that a premium fuel usually has additional detergents and stuff, such as Shell V-Power.

I gotta disagree with you man. I've been using 91 (Shell V-Power FTMFW!) for the last month. My power has improved negligibly, but my gas mileage is phenomenal now. Previously, I found that some days my coupe would have more power than others...now, using premium, it seems to be much more consistent.

It's not a bad idea for your car, it's just a waste of money.

I, like Rob, have heard it's a bad idea too. Running premium fuel in an engine that's supposedly designed to run on regular can lead to carbon build-up.......or something. I can't remember and it was a couple of years ago that I read that article.

[dimitrinassis001]

So I just off the phone with 2 Nissan dealers and they both said it would just be better to go with an 89 octane becuase they have UP TO 5% ethanol as opposed to 87 octane which may contain UP TO15% which would cause loss of performance and build up. Now if anyone can check with their dealer and ask to see if there is a difference cuz I notice when it comes to dealers they are almost never consistant in their recommendations.

[dimitrinassis001]

So in the words of that guy who played the dad in "my Big Fat Greek Wedding"...There you go...



[/QUOTE]

Your welcome. And in the words of my father and his father before him "re pout some garlic in it and is good"

[mrodrig2]

I personally think that its in your head if you feel that you get more power from 91 or 93 than 87. Seriously speaking, you would never feel a 2 or 3 whp difference from another modification so why would you feel it from gas? You guys have to realize that the timing retardation when using a lower octane is an instantaneous and temporary change made if the sensors detect detonation conditions. They are not a permanent ecm change so its not like you are cosntantly a few horseys less by using 87.

And as for better gas mileage? Well there are so many untraceable variables in gas mileage that you could attribute any loss or gain in mpg however you want. You could be subconsciously feathering your gas pedal easier when you fill up with 93 and you'd never know; yet afterward you will still come here and post that its due to the 93 octane. I have a feeling that mpg will vary more by gas batch and gas brand than it will by just 87 to 93. To date I have yet to see a controlled test to back up all of the anecdotal evidence.

I think that the bottom line is to use the octane rating recommended for your car.
Modified by mrodrig2 at 2:15 PM 4/24/2009

[superblackcoupe]

I, like Rob, have heard it's a bad idea too. Running premium fuel in an engine that's supposedly designed to run on regular can lead to carbon build-up.......or something. I can't remember and it was a couple of years ago that I read that article.

From what I recall reading and hearing, all grades of fuel cause carbon buildup, it's the additive detergents that decrease the amount that does build up over time (and they may possibly remove some).

Random useless anecdote: out of the five older Hondas that my relatives have owned (three Accords, two Civics), none of them had any significant issues relating to carbon buildup by feeding them premium (this was back when 93 was $1.20/gal and 87 was $1.10).

I've been using 91 (Shell V-Power FTMFW!) for the last month. My power has improved negligibly, but my gas mileage is phenomenal now. Previously, I found that some days my coupe would have more power than others...now, using premium, it seems to be much more consistent.

I've been using V-Power for a few months now (after actually finding one in this area - it's all Lukoil here) and I haven't noticed any significant improvement in power or mileage - it's still as crummy as ever, barely 20mpg. Again, useless anecdotal evidence...

[Chuck2417]

I have used premium also since day 1. We spend the extra money to get the more performance oriented of the two coupes and then when it comes to using the higher performance fuel you say I will save my money... To me that doesn't make sense. I know the economy is pretty bad right now and gas prices are horrible. But the extra $5-$10 dollars when you fill up does make a difference. You don't end up going to the pump as much as you would using regular fuel. Also I have to agree with dangeris in using premium fuel helps. At least for the 3.5's anyways. The fuel is recommended for our engines so I say use it

[ESP]

I personally think that its in your head if you feel that you get more power from 91 or 93 than 87. Seriously speaking, you would never feel a 2 or 3 whp difference from another modification so why would you feel it from gas?

I never said that I felt more power, just that it seemed to even itself out from drive to drive. I know a few 2.5ers have complained about how some days it seems like their cars are really sluggish, then other days they're really ballsy...using premium seems to have solved that for me.

My buddy only uses V-Power in his M3. He dynoed using 91, then the next tank again using 87...he lost about 15hp doing that. That could simply be attributed to other factors though...just though I'd throw that out there.

And as for better gas mileage? Well there are so many untraceable variables in gas mileage that you could attribute any loss or gain in mpg however you want. You could be subconsciously feathering your gas pedal easier when you fill up with 93 and you'd never know; yet afterward you will still come here and post that its due to the 93 octane. I have a feeling that mpg will vary more by gas batch and gas brand than it will by just 87 to 93. To date I have yet to see a controlled test to back up all of the anecdotal evidence.

I thought I might be subconsciously be feathering the gas pedal more (self-fulfilling prophecy and all), so I tried to avoid that where at all possible. If anything, I'm flooring it more now than before...much more. I drive pretty much the same route every day. So far, I've gotten 500km on a half tank whereas before I was usually around 400km. The first time I used premium, I did 150km of solid city driving then went for a trip into the mountains (on the highway). That yielded 650km at the half-tank mark. Prior to that, I could only squeeze out 585kms at the half-tank doing only highway driving. That's proof enough for me.

[DAAN.]

I'm baffled ! - your car can go 1000km+ per tank?

that would be a sweet counter to TDi

[ESP]

I'm baffled ! - your car can go 1000km+ per tank?

that would be a sweet counter to TDi

I've never had the opportunity to do a solid 1000km run on the highway, but I don't see why not! I guess I'll be finding out this winter on the way down to SoCal! Still, I'm incredibly impressed with the highway mileage the 2.5 gives me...it's not much worse than what my Echo used to get.

Keep in mind that (on my car at least) the "half tank" mark is more like the 1/3rd mark.

[stankydanky]

last time I filled up at a Valero and the reg had 87 rating, premium had 89, and supreme had 93... So was I suppose to use supreme cause it had atleast 91+ rating or was the 89 premium good enough?

[Chuck2417]

Nissan wants you to chose 91+ or the highest octane available. Premium fuel goes by many names, some stations call it Supreme others V-power (shell). Where I gas up it goes regular, medium then premium. The 89 octane is still better than the regular... However people will argue if the extra money for the higher octane is worth it. I say go for the highest octane (premium/91+) for the 3.5's. So the long answer to your question yes you should be using the supreme then.

[DAAN.]

I'll start using premium as soon as I will 'recharge" my tires with nitrogen and replenish my headlight liquid for increased visibility

[rjdmmfl1]

As per the last discussion on this topic, I repost this

http://www.edmunds.com/advice/...60233

here's a quote from the principal Engineer of the auto club of California

When choosing what grade of gasoline to use, Steve Mazor, principal auto engineer for the Auto Club of Southern California, said it is important to read the owner's manual carefully. The key is to figure out whether premium gasoline is "required" or "recommended." If it is recommended then a driver could opt to use a lower grade of gas, if they were willing to accept slightly reduced performance and fuel economy.

Other reports have reported that using lower grade fuel could decrease 0-60 times by as much as a half a second...

this debate has gone on for years now... and experts on the subject don't even agree on everything... but it sems clear that acceleration and fuel economy suffer in an engine that can run on regular but prefers premium for optimum performance...

[DAAN.]

a driver could opt to use a lower grade of gas, if they were willing to accept slightly reduced performance and fuel economy

on another note, ^ mm mm sexy car

_______________________Click Cardomain!

[Ferguson]

I'll start using premium as soon as I will 'recharge" my tires with nitrogen

Well... actually... nitrogen is the best thing to inflate your tires with! When I circuit raced, that is what was preferred, as it is virtually unaffected by temperature. Cold tires, hot tires... no pressure change!

[Chuck2417]

Well... actually... nitrogen is the best thing to inflate your tires with! When I circuit raced, that is what was preferred, as it is virtually unaffected by temperature. Cold tires, hot tires... no pressure change!

Agreed, especially for us Canadians eyh!

[Ferguson]

Yeah, but stay from the liquid stuff!