I hate to complain about mileage but…

[louiegz]

I drove 173.6 miles since my last fill up and yesterday I filled up the tank with 17.99 gallons of Sunoco Ultra. $55.00 $3.06/gal. As you see, my mileage was 9.65 miles/gal. Mostly city driving. This is horrible mileage. You think I was driving a Hummer or something. Good thing the tank lasted me 2 weeks. If I was spending $55.00 a week an gas, I'd be getting rid of the Q quick.

[Rex]

Funny, I was just going to post a MPG thread.

I filled up for the first time (of pure local driving) after returning from Miami. The Trip Odometer showed 254, that's an adjusted 218 miles (86% speedo error factor based on GPS measurement) and I was able to squeeze in exactly 14.004 gallons. That's a 15.6 average. Not bad for a modified car, that's being driving "briskly", on mostly "surface" streets.

I usually fill up once it hits 1/2 tank, but I let it go a little farther just to see what my mileage was.

[Q451990]

I would certainly keep an eye on it for the next tank. If you're truely getting less than 10MPG you have a problem... Maybe O2 senors, or a thermostat that's sticking open and not letting the car warm up enough to go into closed loop?

Even with a lot of hot summer in-town driving I don't think I have ever seen less than 14MPG.

Heath

[Q45tech]

If you don't buy gasoline that conforms with as designed quality and specifications expect even a perfectly tuned and operating vehicle to suffer. When Q was designed the average btu per gallon was 123,000.Todays gasoline is 111,000 btu per gallon ............a 10% decline:

http://www.epa.gov/otaq/rfgecon.htm

If you can't buy it you must make it [your gasoline] or accept the facts.

Most need to bite the bullet NOW and replace O2 sensors and clean up the inside of engine. It can only get worse from here [timewise] over the Summer.

It is not just the Q or Infiniti that is suffering every V8/V6 with 4+ liters is seeing the same results.......................short of buying a new [used] car with a smaller engine and lighter weight you are stuck.

To halve your cost you need to be driving an under 2 liter engine using regular with a manual transmission weighting about 2500 pounds or a 2200 pound automatic.

Try an older G20 manual which can average about 24-25 vs our 19 that might save you $600-700 per year at todays prices......the ratios should track.

[louiegz]

Even with a lot of hot summer in-town driving I don't think I have ever seen less than 14MPG.

Heath

My Q never does better than 11MPG in the city. I guess the fact that I have a lot of hills here or I must have a led foot. O2 sensors haven't been done in a while. That might be it.

[MJC]

Interesting, I don't think I've ever had a tank under 15.0 mpg...but don't quote me on that.

I've kept a decent record of the receipts that I've had, always trying to remember to write the TRIP and/or ODO's mileage on the back of them so that I can work out MPG at a later date. A week or two ago, I finally got around to listing them. I have an Excel Spreadsheet, if someone can tell me how to upload it (if there is a way) or something along those lines, I'll throw it up here.

I admit though, the list is FAR from complete over the last year and a half or so. Last summer when the gas prices shot up majorly, I seem to have next to no receipts...maybe I was subconciously so upset that I wanted to never remember this point in my automotive career.

Anyways, from what I recall...my average MPG is approximately 17.2...and that is mixed driving.

/Mark

[Q45tech]

Those of us that get decent MPG cannot imagine how bad some of the Q are due to lack of PROPER SUPERIOR MAINTENANCE, Tire selection, draging brakes, defective bearings, alignments, idle speeds, plugs, deposits, slipping trannies, and DRIVING LOCATION and STYLE.

All last year I had to really try hard to get worse than 15 mpg averaged over a week. Those weeks where I cranked the Q 50-60 times per day 6 days per week or idled for 8 hours per day.

[Falkdesigns]

I get 13-14 around town, lot's of redlined aggressive driving, and 98% of my driving is surface streets (is that just an L.A. term?), even freeway driving is stop and go here, except at certain times. I get 20 mpg fwy at 80-85 mph, ac on, and mountains - not hills, ie: L.A. to Vegas, much greater elevation changes than exists anywhere on the East, L.A. ~ sea level, to over 6000 feet on the way to Vegas, which is high desert.

[Jesda]

My last Q, after new plugs, MAF, and other things, got 14 city and 19 highway. This one drives better but is due for alignment, o2, knock, etc, so Im doing 12/17.

Once I take care of maintenance this summer, I expect to do 15/20.

Or I'll take a shortcut and buy a Miata like I've been wanting to since I was 14. If only I could find roads where one would be enjoyable.

[elwesso]

Just remember yearly costs assuming 12k for 3-4MPG difference is not really that much!!

I will note that I hardly ever got above 14mpg in my Q's in my city driving.. this was about 15 miles per day (7 per trip give or take)...

If you dont DRIVE your car for at least 15mins (not including warm up time) you will never get good mileage, because the car spends most of the time warming up..... o2 sensors wont do anything until you get it up to temp anyway...

From what I can tell summer you get better mileage even if you idle more and have the AC.. Less time spent in warm up mode...

I have seen as low as 10MPG inmy Q... winter time lots of city..... I can still get 20-21 on the highway so i know its my driving cycle, not the car!

[Q45tech]

Due to quirks in blending gasoline Summer blends actually contain more BTU.........not counting the ethanol which of course is constant minus the percentage of water transported in it.Ethanol is temperature phase sensitive.......the warmer the fuel in tank the more water can be dissolved in the ethanol.

But the average temperature inside gasoline station below ground tanks is 60F................imagine what happens on a warm/hot day with high humidity in Florida/Gulf coast as you fill the tank.......the velocity of fuel going in sucks air in.

[maxnix]

I get 20 mpg fwy at 80-85 mph, ac on, and mountains - not hills, ie: L.A. to Vegas, much greater elevation changes than exists anywhere on the East, L.A. ~ sea level, to over 6000 feet on the way to Vegas, which is high desert.

Old time members know many a SoCal Q45 had cooked transmissions from this run.

Constant uphill, high speed, high slipage and no external ATF cooler will overheat ATF with all the wear and tear ATF decomposition implies.

[Q45CALIBER]

It is not just the Q or Infiniti that is suffering every V8/V6 with 4+ liters is seeing the same results.......................short of buying a new [used] car with a smaller engine and lighter weight you are stuck.

To halve your cost you need to be driving an under 2 liter engine using regular with a manual transmission weighting about 2500 pounds or a 2200 pound automatic..

This is excatly why I am puting my Toyota Supra up for sale today and pickup a 2.0 manual this weekend. VW Golf... I am not going to complain I am just going to improvise. I dont what a 6 cylinder give me a 4. Hell Ill take a 2 cylinder with the price in New York...$3.31 premium with 10% ethanol.....yeah ok

[Falkdesigns]

Old time members know many a SoCal Q45 had cooked transmissions from this run.

Constant uphill, high speed, high slipage and no external ATF cooler will overheat ATF with all the wear and tear ATF decomposition implies.

It's not constant uphill, my ATF is still bright red, still shifts seamlessly, but yeah, I'm sure it will explode tomorrow.

[sijoko]

Maybe it's time for the topic of Acetone again.

[tkd_q45]

Or maybe it's time for....

The Turbonator!!!!!

What about the guy who stated he got better MPG w/magnets on his fuel lines?

Maybe Robert needs to make us an ECU that can shut down cylinders while idling or at fwy cruise?

Maybe we need to convert to diesel and run off cooking oil from resturaunts?

[Q45tech]

When you shut down cylinders you must HOLD the intake and exhaust partially open otherwise the pumping action is a NET drain on the remaining cylinders.

When you have a single misfire not only do you lose the 12.5% torque but another 5-6% due to friction [FMEP].

[tkd_q45]

So you're saying cars that do this have a valve train that can hold the valves partially open?

[Q45tech]

Some old designs just disengaged the valve train and didn't open valves at all, however the atmospheric pressure tried to force air into the cylinders via the rings] and then it was compressed.........why fight nature.

Hard to even start to dual balance a V8/V4..................look a Chryslers V8 with cylinder cut on recent test under typical freeways it only worked less than 10% of the time and doesn't work under acceleration and only works at idle when warmed up............net net maybe 6-10% improvement.......these things don't tend to last 300,000 miles maybe 100k.

"7-Year/70,000-mile Limited Powertrain warranty.

The system deactivates the valve lifters. This keeps the valves in four cylinders closed, and there is no combustion. In addition to stopping combustion, energy is not lost by pumping air through these cylinders.

Customers will experience estimated fuel economy gains of up to 20 percent under various driving conditions, and a projected 10 percent aggregate improvement"

Why buy a 5.7 liter when you can just get a 4.5 liter which should get 21% less under the same conditions.

Not sure I believe 17/24 vs Q 16/22. Maybe?Test 300C averaged 14.4 mpg in mixed city/highway driving, 17.9 mpg with more highway use. Over a 12,000 mile test CG® Observed Fuel Economy: 15.9 mpg

[tkd_q45]

Maybe we just have to drop C6 Vette engines into our cars. It's unreal how much MPG those new (even C5) vettes get. Wife is complainig about how it cost her $70 this week to fill her tank.

[Q45tech]

Drop one in and couple to our AT transmission and the mileage would be less than our 4.5...........within a narrow range a HP consumes the same amount of fuel to create............however 2 valve engines do do better at cruise rpm and can run a lower cruise rpm so the higher displacement might just wash.Install a matched transmission/engine and reprogram ecu for weight increase and it just might beat our Q motor in mpg.

Why Cadillac is offering such engines with manual transmission.

[elwesso]

People see the numbers for the vette and they forget that the car weighs very little compared to the Q (500lbs less?).....

Dennis isr ight, if you dropped in the 7L or whatever size it is, MPG would be the same AT BEST but probably lower...

You will never see 30MPG in a Q45 unless you seriously decrease acceleration by putting in a small engine.

Notice that nearly all 4L-5L with 4-5-6speed AT get roughly the same mileage... Mileage is more related to vehicle weight than engine displacement, all else the same.

[paranoidjack]

oh come one guys. When you're driving a car that cost over $50k you just deal with it! I travel for work, at my expense, and after my first two tanks I'm getting roughly 15.4 mpg, combo of highway/city. I spend about $40/day in gas. Bah, it is what it is. Quite supersizing fast food meals and that'll pay for the difference.

The rest of the world has a bellyache from laughing at us, we've had half their gas prices for 15 years!

[BlueC]

The rest of the world has a bellyache from laughing at us, we've had half their gas prices for 15 years!

We pay far less than other countries. Until gas hits $5/gallon, im not complaining.

[elwesso]

We pay far less than other countries. Until gas hits $5/gallon, im not complaining.

Agreed... When it costs me a benjamin to fill the Q up then ill whine, and likely just bust out the huffy

[Q45tech]

Drove 239 miles yesterday filled to overflowing averaged 68 mph peak speed 93 mph.. AC on for 50%.......11.02 gallons $34.15 [again to over flowing [gas came from exact same QT pump as first fill......no ethanol 93 premium.21.688 mpg not bad for 305k with oem injectors and cats, stock exhaust and intake with Dinan ecu program. Been at least 30 days since BG44k and 500 miles since oil changed 10w40. Michelin Pilot H4 235/60/15 at 35 psi cold.

Still meeting 22 mpg specs [rounded up] after 16 years at a faster than designed average speed [plus 50% AC] is sure something amazing.Plus I was going up in altitude by 700 feet to 1670 AMSL.

[maxnix]

Agreed... When it costs me a benjamin to fill the Q up then ill whine, and likely just bust out the huffy

Two years, at most. Better get in shape now.

[widebodyq]

If you guys want to complain about gas get a 6 or 4 cyl. Big boys drive 8's or better and dont complainI drive over 100 miles a day to work with heavy chrome 20's. Im not going to lie, it hurts spending all that money on gas every week but the trade off is im riding in luxary. I chose to buy this car so what sense would it make to complain?