mcrews wrote:bbs350,

While I'm sure you documented the tanks of gas, this is exactly why A-B-A testing is so important. The placebo (sugar pill) effect can create the exact same result in mpg improvement . This is how drug companys test the effects of new prducts 1/3 get the new drug, 1/3 get the placebo, 1/3 get nothing. THe placebo group can show up to 1/2 as much improvement as the new drug, because people 'thing' it works. Studies show that a driver will subcounciously drive better to validate the money spent.
On the effeciency issue, again I highly suggest that any one interested in real mpg improvement go to ecomodder.
In driving for mpg, the low rpms are not effected by 'performance add ons' .

well damn, this kinda puts it into perspective. maybe i did change my driving style, but as i recalled, i got better gas mileage. maybe it was a driver mod that improved the em pee gee's!

and ilyakol, i believe our diffs (both) are 3.53 same as manual g's and z's, as that was the same rpm range i was at around 70. in my old g35 sedan, it had the 3.33, when i swapped in the 3.53 diff (off of a manual z) i also was right around 3k @70 mph. there could be the possibility to swap in the 3.33 fd gears in both diffs but itd be a waste of time imho, and from what i recall, cruise wouldnt work unless we modified the speed sensors for a vehicle with a factory 3.33 final drive (such as an automatic g35 sedan)

on a side note, 08+guys, where is your rpm at 70mph with those extra 2 gears?

Yeah I'm not that worried about the MPG's to go swappin gears lol. If I was, I'd sell the car and go back to a Maxima or something.

But that ain't gonna stop me from keeping up on my maintenance, etc. to make it as easy as possible for my car to get the job done.

http://www.gearvendors.com/index.html
saw on of these at a hotrod shop last week

bbs350, imagine a 22% reduction in rpms w/ the flick of a switch!!!!

couse only gm ford.....

mcrews wrote:http://www.gearvendors.com/index.html
saw on of these at a hotrod shop last week

bbs350, imagine a 22% reduction in rpms w/ the flick of a switch!!!!

couse only gm ford.....

might be throwing a custom 4 link rear end in the z after i complete this ls1 swap. imagine 1200rpm @ 70mph... danggg


thanks for the link!

I switched to synthetic oil and my mpg went from 19 to a little over 21 (all interstate driving). I've never seen that happen after an oil change.

Blake

ellis wrote:I switched to synthetic oil and my mpg went from 19 to a little over 21 (all interstate driving). I've never seen that happen after an oil change.

Blake

This is definitely good to read because I just bought my 2007 M35x and I will be switching from conventional to full-synthetic oil at the next oil change and I was hoping for a slight increase in fuel economy with the synthetic oil change. I have 43k miles and I just had the dealership do a complete tranny flush going from the Matic-J to the synthetic Matic-S ATF along with a transfer case and differential fluid flush/change and their is a noticeable improvement in overall shift quality, the tranny seems to shift smoother between the gears now.

Although I do love this car very much and I also seem to average better mpg numbers than the EPA numbers suggest (I average about 18 mpg in the city and 25-26 mpg on the highway with a moderate foot), I do wish that Nissan/Infiniti had made the 5th gear ratio a bit taller so that it could of served as a more efficient overdrive gear, like maybe around say 0.75 rather than the current 0.84. If they had done that they could have lowered down the highway 60 mph+ rpms somewhat which would have increased highway fuel economy while still keeping the aggressive 3.54/3.69 final-drive ratios and the closely-spaced 1st through 4th gear ratios, therefore overall performance and acceleration wouldn't have really suffered at all especially considering that the overdrive isn't really used for hard acceleration anyway.

What is everybody averaging per tank? I've only been getting around 200 miles, and if I drive slow maybe 240, which is only about 14-15mpg. I do about half highway half streets. I've checked tires, changed air filter, reset ecu, and I drive like a grandpa, but still cant get over 15mpg!? I'm gonna change my spark plugs by the weekend and see if that helps, does anyone have any suggestions for me?

^Seriously? On an M35? Def change your spark plugs or something man... something cant be right.

Read this...
y50-m35-45-drivers-what-are-your-mpg-nu ... 30667.html

bbs350z wrote:+1 white wolf. antz its not that were complaining, but more so that were seeking a way to extract more mpg's from our car. id like to get slightly better gas mileage. id also like my gf's tits to be a little bigger too. i knew they were small titties getting into the relationship, just as i knew gas mileage wasnt spectacular when i got this car, but theres room for improvement, and i see nothing wrong with seeking new ways to do that. so if i can save a few dollars by getting further while saving money (not for the tits) then im all for it. we all knew what we were getting into when we bought the car, sometimes a little bitching is required to find a solution, lets keep an open mind around here

How about an aftermarket bolt on = Victoria's Secret Wonderbra? Or u could pump them up with nitrogen!

Increasing mpg's? How about carpooling with a bunch of little persons who are four extremity amputees (to keep the overall weight down) with solar voltaic cells strapped to their backs, in a Prius tuned to run on kisses and hugs?

nolmt50 wrote:What is everybody averaging per tank? I've only been getting around 200 miles, and if I drive slow maybe 240

wow. If I drive how i prefer, I get 200. But that is harder than most people drive. If I drive like "most people" I get around 280-300 miles per tank. If I drive easy I can get 350-380. I am currently trying to break 400 miles in a single tank, going well so far.

I am taking pictures of when I filled up the tank this last time, at halfway, and at empty, as well as the average MPG screen and the trip screen for proof on my current tank. Once I finish this tank I will be posting all the pictures and things in Blanco's thread about peoples average MPG.

pedsemdoc wrote:a Prius tuned to run on kisses and hugs?

They have such things?!?!?! I must have one, now.

I just changed my plugs today and so far my computer says im averaging 17-19 mpg on the streets compared to 12-14. On the highway I'm averaging 25-28 mpg compared to 17-19mpg before changing the spark plugs. Gonna fill up the car today and see how many miles I can get on a full tank. Hopefully no more 200 mile tanks, and maybe I can get back to 320+ miles.

^Good man, that's more like it!!! How many miles on your car?

Just hit 70k.

Really? That's crazy, we're not supposed to change spark plugs til 105k miles... maybe I should change mine out as well, I'm at 75k miles right now.

a.blanco0905 wrote:Really? That's crazy, we're not supposed to change spark plugs til 105k miles... maybe I should change mine out as well, I'm at 75k miles right now.

Thats what I thought too, my cars performance never went down, and the only problem I had with it was the gas mileage. The plugs werent too expensive and it was pretty easy to do, so might as well change em.

You used NGK plugs right? Just making sure...

IlyaKol wrote:You used NGK plugs right? Just making sure...

yes

Good.

what kind??

What kind of NGK plugs?

I think the OEM ones are the Iridium's, but you can really go with any of them. On the Maxima I used copper which had to be changed every 30k, but if you go for the more expensive ones, they are "supposed" to last longer (such as platinum laser, iridium, iridium IX, etc. - if I recall correctly those are the other types).

As long as you put NGK's into a Nissan, you're fine. Doesnt' really matter which one.

Thought I'd throw in my mileage on my new 2011 M37x that has about 3500 miles on it currently and is obviously not completely broken in yet. Anyway, it's currently getting 21-24 back and forth to work -- which is ~21 miles each way and is admittedly 70%-75% expressway driving.

On the only trip that I've taken so far with it, ~380 miles (one way) through NY, PA and NJ I got 26.1 MPG. There were two of us in the car with weekend luggage. I did not use the A/C and had cruise set at 75-78, depending on traffic -- in standard drive mode. I did get to 85 or 90 MPH a few times. When I got home, the trip computer said I'd averaged 71 MPH. In less hilly terrain, I might get a bit better MPG.

But, honestly, all of this is higher than I expected from a 330 HP/4000 pound vehicle.

As they say: Your mileage may vary!

Earlier in this tghread I had writtern:
"...Don't leave you tires at 33psi. Go to 39-41psi. That's what i run daily and when I'm on the road longer than 2 hrs, I run by Radial Tire Store in Sacramento and go to 46psi. (see Ecomodder.com before making comments)"

Here are reaulta from a very recent MYTHBUSTERS

MythBusters: Tire Pressure Test : Video : Discovery Channel
TV Review: Mythbusters 8.23 – “MiniMyth Madness” | Fandomania


Control, 35psi (manufacturer recomendation)
tires at 10psi = 3.7% increase in consumption
tires at 30psi = 1.2% increase in consumption
tires at 40psi = 6.2% decrease in consumption
tires at 60psi = 7.6% decrease in consumption

im amazed that even at 5PSI over recomended pressure there was a 6% decrease in fuel consumption OR a 6% increase in mpg!!!

lflorack wrote:I did not use the A/C

If I recall correctly, MythBusters also found that the windows down gives a much much larger decrease in MPG than running the A/C. I know lots of people (mostly older) say they dont want to run the AC cause it brings mileage down, but with modern A/Cs in cars it is much better to use the A/C.

EniGmA1987 wrote:

lflorack wrote:I did not use the A/C

If I recall correctly, MythBusters also found that the windows down gives a much much larger decrease in MPG than running the A/C. I know lots of people (mostly older) say they dont want to run the AC cause it brings mileage down, but with modern A/Cs in cars it is much better to use the A/C.

Yup. You are correct and I knew that. Sorry that I wasn't clear that I also didn't have the windows open. If it had been warm enough to open the windows, I'd have turned the A/C on instead.

One thing that I noticed that's interesting regarding fuel economy of the M35x is that the EPA fuel economy numbers are very similar to other V6 AWD midsize luxury-sedans in its class, yet a lot of owners and reviewers alike seem to bash the M35x for it's "below average" fuel economy. I did the research and discovered (this is from Edmunds and includes the new 2008+ more stringent EPA testing figures):

2007 Infiniti M35x AWD: 16 mpg city and 22 mpg highway

2007 Mercedes E350 4-Matic AWD: 16 mpg city and 23 mpg highway

2007 Acura RL: 16 mpg city and 24 mpg highway

2007 Audi A6 3.2 Quattro AWD: 17 mpg city and 25 mpg highway

2007 Lexus GS350 AWD: 18 mpg city and 25 mpg highway

2007 BMW 535xi AWD: 16 mpg city and 25 mpg highway

2009 Cadillac CTS 3.6DI AWD: 17 mpg city and 26 mpg highway


Looks to me like the M35x is only very slightly lower than the competition while still managing to equal or exceed a majority of them in acceleration/performance. The exception to that is the Lexus GS350 which seems to have an amazing combination of performance with good fuel economy. But the RL which is a FWD-based Honda with AWD gets the same mpg in the city and only 2 mpg better on the highway than the M35x even with the MUCH wider and taller gearing, plus it's slower than the M35x. The Audi A6 get only slightly better fuel economy but is significantly slower than the M35x, the Mercedes E350 4matic gets the same in the city with just 1 mpg more on the highway.

It's also worth mentioning that the M35x has overall more aggressive gearing then all of these cars and revs a few hundred rpm higher at highway cruising speeds yet still manages to get only marginally less mpg on the highway than most of these cars, and also the city mpg figures are nearly identical to all of these cars (either the same or only 1 mpg better) with the exception of the Lexus. And with the exception of the Mercedes, all of these cars have 6-speed automatics with one or even two tall overdrive gears.

The point I'm making here is why do so many critics, reviewers, owners, etc. complain and criticize the gas mileage of the M35 and M35x when according to the EPA numbers they get very similar or only very slightly less mpg than most of it's competition? I'm not saying that anyone on here is complaining or criticizing, I'm just saying in general that many owners and reviewers seem to bash the cars regarding fuel economy when in reality they really aren't much worse than most of the competition.

Also many of the reviewers that I've seen bashing the M35x for it's fuel economy don't seem to be as harsh with the Mercedes E350 4Matic and the Acura RL when they get the same mpg in the city and only 1-2 mpg more on the highway... it seems as if the M35/M35x seems to gets unfairly and excessively bashed for fuel economy when in reality it gets just slightly less overall mpg than most of its primary competiton.

EniGmA1987 wrote:

mcrews wrote:THe 02 Q45 is blessed w a 2.76 rear ratio, the 03-06 and all Ms are 3.XX(not sure the exact gear.)

M45 = 3.39
M35(s) = 3.54 I think
M35x = 3.69

The lower your ratio, the lower your RPMs for a given speed.

So does anyone know if us M45 guys can change the ring & pinion to a lower ratio from another Nissan or Infiniti model? If so, which one fits and from what model car?

Just an fyi, (again, an 02F50 has a lower rear ratio so it's not really fair to compare), I just went to Abilene Tx from Sacramento Ca. 2 days 1500 miles.
I WAS trying to beat 30mpg on the trip.

I got 30.4mpg average speed 59mph. Pretty much stayed close to the posted limits. Sacto is at 300 ft and I went thru Flagstaff at 7000 ft and then on to Abilene at around 2000ft.
kept a log


Ran a/c as needed but the temps were high of only low 70s
Ran nitro and 46psi in tires.
sealed front under panel.
Clear rear whweel skirts.
ran 91-93 octane

ps. thanks for letting me post!!!

Just out of sheer curiosity, but if someone wanted to change their M35x final drive gear over to the factory OEM Nissan 3.3 final drive gear from the M45s and/or 1st gen G35s, what would be involved and approximately what would something like this cost? Also, would this taller final drive ratio give even a modest increase in overall fuel economy and would it significantly hurt overall acceleration/performance?

The reason why I ask is because I own a 2007 M35x which I do like A LOT, however my work commute could be changing in the near future to a much farther commute that would be mostly all highway driving, and I figured if I could get the highway cruising RPMs down some with a taller final drive that it could help me out.

I love my M35x so much, but the ONLY thing that I wish I could change was the highway speed RPMs to be dropped down even just a few hundred RPMs. If I could acheive that then this car would be PERFECT. Especially since right now I dont do a lot of highway driving and that could be changing very shortly!

antzrus wrote:
An M or a Prius? You obviously made your well informed decision. You are on this site; an M enthusiast site. What's the problem?

My old friend. I am with you. Buy any M and it is not a MPG machine by any means. But it is a good sleeper. Just dusted off someone who thought their new VW was a power car. I get 17-22 MPG depending on how I drive. I generally drive easy, coast to stop lights, don't power off on starts. But when I want to I can hammer that car and leave many sucking my exhaust while my A/C is running and my Bose is playing. Thats a luxury sports sedan to me.