[Frank1]

This was my experience last year;


I have made an interesting observation using mid and premium grade fuel on my 04 Pathfinder. On mid grade I averaged 18.8 Mpg and was able to reach 145kmh on a steep long uphill stretch of road that I travel. The following week I filled with premium and averaged 17.8 Mpg and reached 139kmh up the same hill with similiar load and weather conditions. Based on my unscientific research I will be using mid grade and possibily trying regular.

 

[Frank1]

And this;

I've just ran a tank of regular fuel. 143 kmh up the same hill and 19.1 MPG! Regular fuel has given me the best results. I will be running regular from now on.

 

[Reverendbiker]

I actually applauded your website and appreciate the work, but you have to understand this is one test on one vehicle, to make broad statement on all is a bit over reaching.

I apologize if my answer appeared to be rude--it was never my intent, and as a minister I don't want to be in the rude business. I was just amazed that you made several statements that indicated that you had not read the information on the site before questioning it. The above quote, for example--what blanket statement did I make? In fact, the final sentence from my web site report is this: "You may draw your own conclusions from this test, but mine are clear; my truck runs very well on 87-octane fuel and no better on the high-priced stuff. With gas prices high and getting higher I'm only too happy to fill 'er up with regular, thank you."
You are correct that this is only one test on one vehicle, but what other tests do we have? At my own expense (considerable, I might add) I paid for tests and shared the information so that other 2005 Frontier owners could make informed decisions. As I said earlier, I have made mine; you are free to make your own.

 

[fredjara1]

Good Job on the tests. Thanks for making them available Rev. I ran a couple of tanks of 91 (pretty much the highest here on the left coast) and a couple of tanks of the 89. According to the gauge on my speedometer, I got better MI with the lower stuff. Of course the gauge does not measure the exact MPG, but is a good benchmark (this according to my brother who is manager for Nissan Tech Publications).

Rev, I like your web page. Hey, wife and I have been to your great State a couple of times to watch my son in law play baseball. Couple of times to San Angelo and once to Ft. Worth for the Central League All stars. Probably won't be back for awhile. He signed with the Pirates. Long way from TX!

Best regards.

 

[Reverendbiker]

Good Job on the tests. Thanks for making them available Rev. I ran a couple of tanks of 91 (pretty much the highest here on the left coast) and a couple of tanks of the 89. According to the gauge on my speedometer, I got better MI with the lower stuff. Of course the gauge does not measure the exact MPG, but is a good benchmark (this according to my brother who is manager for Nissan Tech Publications).

Rev, I like your web page. Hey, wife and I have been to your great State a couple of times to watch my son in law play baseball. Couple of times to San Angelo and once to Ft. Worth for the Central League All stars. Probably won't be back for awhile. He signed with the Pirates. Long way from TX!

Best regards.

Hey, Fredjara1--I notice that your truck is very similar to mine. What kind of mileage are you getting? As my '05 Frontier breaks in it seems to be getting better gas mileage--on the latest road trip, all highway, I averaged 22.5 MPG on 87-octane. To my mind that is just incredible for a truck with 265 HP. I have two friends with F150 Ford V-8's and they both get 15-16 on the highway--they're pretty well disgusted when I tell them about my Frontier. Come back to Texas any time! God bless,

 

[cryption]

Gee, did you even read the info I posted on my site? Let me address your concerns one at a time:
1. As I stated on the web site, dyno tests do have a margin of error. I use one of the best operators in the country, but any machine can have variances (all runs were SAE corrected for humidity, ambient air temp, and atmospheric pressure). Even allowing for a high reading on the baseline run and a low reading on the 93-octane run the variance would be very small, no more than 3-5%--an amount the average owner couldn't even feel.
2. As stated on the web site, I ran the test with 87-octane then ran several tanks of 93-octane (over 1200 miles, actually) to allow the ecm to adjust.
3. Where has it been shown time and again that premium fuel produces higher horsepower IN AN ENGINE DESIGNED TO RUN ON REGULAR? If you have that info, produce it. I can give you many quality references that show quite the opposite--that using fuel that is higher octane than recommended for an ecm-controlled engine is essentially a waste of money. Sure, 100+ octane is used in performance cars, but the compression and timing demand it. Very few vehicles have an ecm that can actually advance timing to take advantage of fuel higher than recommended; my objective was to see if the VQ40 was one of them.
4. "the premium grade is better due to the refinement process". Where did you get that idea? Oil company ads might have you believe it, but there is nothing inherently superior in premium fuel . SOME premium gasolines contain higher levels of additives, but the government requires that all gasoline sold in the US contains detergent additives. If an owner is concerned about clogged injectors it's much cheaper to add a can of injector cleaner every 6 month or so than to pay an extra $4 per tank for premium gas.
5. "you can't measure MPG on the dyno". Apparently you missed my fuel economy test (see the web site). I carefully compared tanks 93-octane and 87-octane gas in a tightly-controlled test loop for over 2,000 miles. The results? Premium fuel yielded 1.4% better mileage but costs about 10% more--hardly a good trade-off.
I'm not looking to start a quarrel here. I'm an ASE-certified mechanic with over 40 years experience wrenching on performance cars and motorcycles. I hear a load of opinions on the boards but precious little factual evidence; my aim was to provide the best information possible and share it with the other members. If one chooses not to believe it, then that's his prerogative.

good reply!

 

[fredjara1]

Hey, Fredjara1--I notice that your truck is very similar to mine. What kind of mileage are you getting? As my '05 Frontier breaks in it seems to be getting better gas mileage--on the latest road trip, all highway, I averaged 22.5 MPG on 87-octane. To my mind that is just incredible for a truck with 265 HP. I have two friends with F150 Ford V-8's and they both get 15-16 on the highway--they're pretty well disgusted when I tell them about my Frontier. Come back to Texas any time! God bless,

Haven't been on the road with her yet, but I'm working on between 17 and 18 in and around town. My commute to work is 16 miles each way, both freeway and surface street. So I'm not complaining!

By the way, I'm a "Rev" myself. Spent 9 years as a youth minister, then decided public education needed some missionaries. So there I am now...8th grade. And content to boot!
Fred

 

[Reverendbiker]

Haven't been on the road with her yet, but I'm working on between 17 and 18 in and around town. My commute to work is 16 miles each way, both freeway and surface street. So I'm not complaining!

By the way, I'm a "Rev" myself. Spent 9 years as a youth minister, then decided public education needed some missionaries. So there I am now...8th grade. And content to boot!
Fred

8th grade? Fred, you're a better man than I.......

 

[fredjara1]

8th grade? Fred, you're a better man than I.......

Don't know about being a better man...remember, I teach 8th grade. And I actually like doing it. I must, this year marks my 31st year of working with that age group! (6 as a volunteer, 9 as a youth pastor, and 16 as a public school teacher). So better?... not. Insane probably

My 05 Frontier is the LE model, white with the desert tan interior. Only complaint I have is that my AM radio reception is weak. I have the Nismo system, which you probably do too. Also, I wish it had a moon roof. My 00 Frontier had one and I really liked it during the hot months. I could leave it open to help circulate the air when it was in the parking lot.

Another thing I had a hard time adjusting to was the wimpy horn. So I replaced it with a couple from Pep Boys. It doesn't sound like a MAC Truck, but at least it no longer sounds like a Yugo with strep throat!

 

[cryption]

My question is that in the manual it says use 89 octane, the medium, and I was always using tht but just switched to regular. Is there something I can do to get my ECM to be happy on regular?

 

[Reverendbiker]

My question is that in the manual it says use 89 octane, the medium, and I was always using tht but just switched to regular. Is there something I can do to get my ECM to be happy on regular?

Nope. Please note that my truck is the 2005 Frontier, and my manual specifies a minimum of 87 octane. If your manual specifies 89 octane I wouldn't run anything less.

 

[rabbit121]

Hey guys.. your thread peeked my interest to try some regular 87 in my pathy. I've always used premuim 91 becasue my VW's never ran right without it, chugging and stalling...they hate 87.. And I've been told the regular will leave more carbon deposits over time..

anywho... today I filled up with some 87 ESSO regular so I could check my milage but I only made it a few KM before I noticed the god awfull gurgling backfiring noise I was getting when I let off the trottle. almost sounded like a hole in my exaust so I was looking for that first... nothing.. happened to have a bottle of octane boot sitting next to me so I dumped it in and voila, only a few seconds before the noise stopped.

I don't know if I happened to get some water at the pump that worked itself out or something but it was quite a coincidence...


back to 91 for me...

P.S. my owners manual states 87 or higher aswell...

 

[Reverendbiker]

Hey guys.. your thread peeked my interest to try some regular 87 in my pathy. I've always used premuim 91 becasue my VW's never ran right without it, chugging and stalling...they hate 87.. And I've been told the regular will leave more carbon deposits over time..

anywho... today I filled up with some 87 ESSO regular so I could check my milage but I only made it a few KM before I noticed the god awfull gurgling backfiring noise I was getting when I let off the trottle. almost sounded like a hole in my exaust so I was looking for that first... nothing.. happened to have a bottle of octane boot sitting next to me so I dumped it in and voila, only a few seconds before the noise stopped.

I don't know if I happened to get some water at the pump that worked itself out or something but it was quite a coincidence...


back to 91 for me...

P.S. my owners manual states 87 or higher aswell...

The symptoms you describe don't sound like problems that arise from the use of low-octane fuel, they sound more like use of bad or contaminated fuel. Still, some older vehicles with high miles will require higher octane as deposits build up in the combustion chambers. Best advice is still to use the octane recommended by the manufacturer for your vehicle. If it pings, move up a grade.

 

[rabbit121]

Well Reverendbiker, and everyone else, I finnished a tank of regular 87 (also worth noting is it was mixed with one bottle of Winns octain boost) and I got an extra 50km+ out of my tank.. this is the best milage I've got yet!

with supreme 91 I got 12.5 to 13.9 MPG, and on my first tank of regular (with the winns) I got 16.5 MPG!!!

I filled up with regular again and this time I didn't add the Winns so We'll see what happens this time.


Rabbit