Project QX4 MPG is go!

[SnowSurfLax]

So here's a NICO exclusive...

Many of you have probably read my ambition to drop 500 Lbs from my rig. Been researching it quite a bit and have come up against some serious obstacles, but I'll cover that later as this project progresses.

The basic idea is to increase my gas mileage enough to not need to lose this truck. I love my QX4 and hope to turn it into a full offroad machine someday, but right now it's the daily driver for an 8 mile commute. When I change jobs sometime in the next year, I'm sure that's going to triple or more and gas will be even more of a blood letting as I'm currently paying ~ $4.30 a gallon (with my 5% AAA discount) and its only going to get higher.

So I'm going for 20+ mpg on average with minimal adjustments to my driving style. I check my mpg at every fill up and generally achieve 14.5 - 15 mpg in 50/50 city/hwy driving. Spent half hour and was able shave off the first 86 lbs.Curb weight is now down to 4,189 lbs. I removed the interior cargo cover (11 lbs) and took off my roof rack (11lbs). I then took off the plastic splash guards, the spare tire, and the spare tire rack assembly (64 lbs). I have AAA and live in a large city so I'm not worried about flats and will be putting tire goop and a small compressor for minor flats. I can strap the spare to the roof for when I go offroading.

The first three tanks of gas went as follows:

16.6 mpg for a road trip towards Santa Barbara. Made stops in LA and LBC on the way and city/hwy mix was actually 60/40.

18.22 mpg for the way back from SB. City/hwy mix was actually 65/35 as we were rolling around SB and Ventura.

15.2 mpg for the previous week. Back to the usual city/hwy mix of 50/50. Lots of AC and stomping the pedal as its been a hectic week.

So far, so good. For reference, usual trips to LA would be about 16 mpg on average. Mind you I drive fast, usually averaging 80 on all freeways. It's a SD thing, as even I get passed a lot doing those speeds. I'll slow it down when gas hits $6/gal. Next steps will be:

1. Taking off the nerf bars/side step thingies. They're ugly and faded anyway. I'm thinking I'll shave off like 40 lbs!

2. New cap, rotor, O2 sensors and comp wires and plugs.

3. Synthetic transmission, Transfer and Differential oils.

I'll post again when the next round of this project is completed.

[Infinitidood412]

OK so I have been noticing this a lot, I drive almost 100% city. I’m only 17 and my job is 3 min away from my house. At 60 mph my Qx4 is around 2.5k RPM…….how the heck can you go 80 and still be anywhere below 4k rpm

[KoukiS14]

the term "synthetic transmission" made me giggle a bit

[bmlawless]

the term "synthetic transmission" made me giggle a bit

Aren't they all synthetic? ZIP! BING! ZOW!

But seriously, folks. I think your running boards are going to weigh a LOT more than 40lbs. By the time you take the hardware off, I would bet that you will have over twice that.

[fueler]

Great idea, keep us posted surfsnowlax. Weight is one of the most important (if not THE most important) factor when it comes to performance and efficiency. Very often I see people overlook this and they don't realize why their car is so slow. I know my QXslow is heavy but i've just learned to accept it. A few other tips I may add: Our (at least my 1999 Infiniti QX4) owners manual states that contrary to popular opinion, the R50 gets BETTER mpg with the AC on and windows up, versus AC off and windows open or partially open. The best would be AC off and windows up (what I usually do at night when its cooler) Also, I get better gas mileage at 65-70, noticeably worse at 80+ Keep your engines tuned up, tires inflated, and car maintained... I would like to shave off some weight too but don't want to take anything off lol.... the running boards actually make for a comfortable "toilet" out in the middle of nowhere... I use the cargo cover to keep things out of thieves sight... Roof racks look good and come in handy.... and I love my spoiler...

The one thing I need to install which would probably help with aerodynamics is my skid plate, which I havent installed due to how difficult it would be to do and oil change once installed....

[SnowSurfLax]

the term "synthetic transmission" made me giggle a bit

I knew you were going to crack a transmission joke!

OK so I have been noticing this a lot, I drive almost 100% city. I’m only 17 and my job is 3 min away from my house. At 60 mph my Qx4 is around 2.5k RPM…….how the heck can you go 80 and still be anywhere below 4k rpm

I'm worried for you. Either you have O/D permanently off or you've got auto-tragic issues. Either way, you need to get that checked out. Something's not right.

Our (at least my 1999 Infiniti QX4) owners manual states that contrary to popular opinion, the R50 gets BETTER mpg with the AC on and windows up, versus AC off and windows open or partially open. The best would be AC off and windows up (what I usually do at night when its cooler)

Yeah, OM is correct and I do exactly what you do. It's pretty true for any vehicle anymore.

Keep your engines tuned up, tires inflated, and car maintained...

Forgot to mention, I keep my tires inflated at 43-45 psi when running around on the highway. Sidewalls say no more than 35 psi cold, but I buy good tires and know they'll handle more than that. I'll lower them down to 25-30 when offroading though. Good reason to have a compressor on hand so you can reinflate when you return to the highway.

[jimmyzzer]

I would like to shave off some weight too but don't want to take anything off lol.... the running boards actually make for a comfortable "toilet" out in the middle of nowhere...

http://www.northerntool.com/we...08541but you need a hitch to use it.the skid plate is not that bad,just loosen the right rear bolt enough to let it swing back.

[ifyaknowatimean]

I took off my running boards and associated hardware a while ago. They way a lot. At least 50 lbs for the 2 of them. Plus, if you don't have a lift, you really have no need for them anyway. Another good way to loose weight is the seats. Those suckers are damn heavy.

[bmlawless]

Am I the only one who is thinking of something like, "Don't forget about the 150lbs. of ugly flesh mounted behind the steering wheel?"

[Lars]

Great post! I'm on a similar mission. My 1998 R50 gets arouns 18mpg on a regular basis (it is a 5 spd). I just replaced an o2 sensor that had failed, and will be replacing the other side within a few weeks. My commute is 80miles/day. I've been driving my wife's civic, but crave to be behind the wheel of my Pathy... So, my next step after the o2 sensor is to remove the roof racks. I'm hoping for 22-25mpg. I'm not too sure that removing weight will account for a whole lot. I've already dropped down to driving 65mph. Will post up when I get more info.

[SnowSurfLax]

Check out installing Warn hubs. Not hard to do and a lot of ppl have reported 1-2 mpg increase

[fueler]

Youre pretty much guaranteeing a 1-2 mpg increase with warn hubs. But on 99.5+ QX4s, youre also guaranteeing that the 4LO light will blink with hubs unlocked as the computer will think there is a problem. I have done a lot of research on this matter and I am 98% sure that there will be no mechanical damage to the transfer case with warn hubs installed, just an annoying blinking light.

[MagicM]

I got a easy one, Take the Catalytic converters out and run a straight pipe.

[SnowSurfLax]

I got a easy one, Take the Catalytic converters out and run a straight pipe.

No go buddy. Our ECU's will detect the cats not working and you'll get a CEL.

Youre pretty much guaranteeing a 1-2 mpg increase with warn hubs. But on 99.5+ QX4s, youre also guaranteeing that the 4LO light will blink with hubs unlocked as the computer will think there is a problem. I have done a lot of research on this matter and I am 98% sure that there will be no mechanical damage to the transfer case with warn hubs installed, just an annoying blinking light.

If I ever find out my transfer case is going, I"ll throw on the hubs and then we can tell if the damage is done by the hubs or not. You can always put a sensor in to make it think the hubs are ok.

Btw, where have you done this research? I've skipped the hubs as all I've heard is that it'll damage it. I've contemplated looking into putting in a beefier sub pump to compensate for the hubs not tossing oil around.

[Lars]

Check out installing Warn hubs. Not hard to do and a lot of ppl have reported 1-2 mpg increase

Hmmm probably more trouble than it is really worth for me... I have a 2wd

The wife called me a few hours ago... another cel. Looks like more work to come.

[SnowSurfLax]

Hmmm probably more trouble than it is really worth for me... I have a 2wd

Man, if you've only got 2wd, what's the point?! I'm sure you like your rig, but no 4wd...

[WINNIPEGS_MOST_WANTED]

Keep the gas tank at around 1/4 to 1/2 tank. Not sure on the exact weight, but im sure it counts!

[fueler]

If I ever find out my transfer case is going, I"ll throw on the hubs and then we can tell if the damage is done by the hubs or not. You can always put a sensor in to make it think the hubs are ok.

HA dont hold your breath! This isn't a Jeep, not a Dodge, and definitely not Ford!

Quote »Btw, where have you done this research? I've skipped the hubs as all I've heard is that it'll damage it. I've contemplated looking into putting in a beefier sub pump to compensate for the hubs not tossing oil around.[/quote] The aussies get down with the technical http://pcoa.org.au/forum/viewt...#3951 How I found that :

http://pcoa.org.au/forum/viewt...rt=45

[bmlawless]

Keep the gas tank at around 1/4 to 1/2 tank. Not sure on the exact weight, but im sure it counts!

Gasoline weighs about 6lbs per gallon.

[SnowSurfLax]

Thanks fueler! I tried to join that board but the bastards didn't let me on. Never emailed me to tell me I was accepted.

Gasoline weighs about 6lbs per gallon.

Btw, our gas tanks aren't that big, so filling up ~4 gals all the time would be PITA. That's only ~100 miles depending on your mileage. I'm not gassing up every other day.

[vliou]

Wow...

I'm not the only one doing this...

PLEASE READ:::!!!!About 10 tankfulls ago, I did a full 436km trip on one full tank. About 90% highway, 10% city.

I then took the roof rack off, I can now consistently break 500km a tank.

And that's the only difference! The damn roof rack!

I always reset my trip odo, and then print off my gas receipt. I can then work out MPG wise. I'm at about 16 city and 19 highway...

Beats 12 and 15 respectively...<--more aggessive driving as well.

I've confirmed this with 3 tank fulls of fuel now...

TAKE OFF THE ROOF RACK!

Yes, it makes the car look naked. It does look longer though (I have a black QX4)...

[vliou]

Thanks fueler! I tried to join that board but the bastards didn't let me on. Never emailed me to tell me I was accepted.

Btw, our gas tanks aren't that big, so filling up ~4 gals all the time would be PITA. That's only ~100 miles depending on your mileage. I'm not gassing up every other day.

This is all fine and dandy, but remember, now you are using more fuel to get to a gas station (even if it's along the way, you now have to go into the station, turn off your truck, turn it back on again)

It has been reported that you negate savings...

Plus, if you get stuck on a highway and run out of fuel

Congrats, you've now paid a tow truck.

[chaonis]

My QX4 will need a set of new tire soon. Do ya think that larger size tires will help, i.e. more linear coverage per rev?

[carnal_c30]

stick to stock size and if you want mpg get a highway radial, nothing aggressiveI'm pretty sure my general grabbers 255/70-16 lower my mpg by ~1mpg bigger tire more weight, and offroad/AT tires are heavier still

[TJcars2]

I took off my running boards and associated hardware a while ago. They way a lot. At least 50 lbs for the 2 of them. Plus, if you don't have a lift, you really have no need for them anyway. Another good way to loose weight is the seats. Those suckers are damn heavy.

That they are. I took my back seats out cause I only carry myself and my girl around and those bishes are heavy!!

[SnowSurfLax]

Just a quickie update for those who care. Project is still go, but...

Europe trip, Mexico trip, and a baby shower are about to eat my wallet alive. So I've got a little delay going on, but I'm thinking my birthday gift is going to be $$$ and Time on a weekend to do some of these things. (It's so easy convincing the wife since the idea is to save $$$...)

So, while researching mods for my wife's new car, I came across this (Caution! Long read!):

http://tl.acurazine.com/forums...51540

Now, he's a bit extreme, but he got me thinking. So I've compiled a new list of items that I am going to perform in the next 9 months in (no specific order):

1. Nerf Bars coming off2. New Plugs, rotor cap, wires and all four O2 sensors3. Synthetic fluids in Transfer case, Front & Rear Diffs and auto trans.4. Aluminim rear diff cover5. Warn front hubs - checked it out, shouldn't be an issue. If I trash anything, you can pick them up cheap, though PITA job.6. Cat back exhaust7. Drill 2" hole on driver side of OEM airbox. (Further modding could run me into trouble with CARB)8. Stage 1 cams9. TE37x 17" rims and 1" larger than stock tires10. Underrun pulley (if I can find one)11. Replace OEM fan with dual electric fan12. Search for any items in FSM manual that I might relieve my poor overburdened vehicle

Think I'm forgetting something, but I"ll put it on the next update. I know some of these are "performance upgrades", but I'm not adding displacement or extra fuel, so I'm only increasing the efficiency of my otto air pump. Technically, given the OEM ecu, I should only make it need less gas to do what I normally ask of it.

So far, dropping the 86lbs, I'm saving ~ $4 a tank now and I fill up ~3 times per two weeks, so $6 a week ain't bad. Hope to see that go up more!

[Mariach]

Suddenly I don't feel so bad about my '01 Pathy.I regularly get over 550kms/tank with a mix of highway and city. my best recorded tank ever was 615. i ran it it till it started to sputter. It's 100% stock, still has the running boards and roof racks( although im going to take them off soon) and i run my tyres at 32psi. I drive on the highway at around 120.My trick is being a turtle off the line. i really do not give it much until i'm rolling and up over 50-60...Just some food for thought!

[SnowSurfLax]

Yeah, but you have a different engine and I'm assuming a manual transmission. Is it 2 or 4WD? Also makes a huge difference. How much heavy city driving do you do?

[Mariach]

it is a bigger engine ! 3.5L!autobox. it is a 4wd, but i leave it in 2wd for any street driving i do.i do a good mix of city and highway. i live in Toronto, so its allot of traffic driving

[fueler]

go maple leafs!