Any rocket scientists here?

[SixGuns]

So...I drove to the LA area again yesterday and I started wondering....at 65mph for about 25 miles, and then 75mph for the other 25, I got 50 miles to the very top of the fuel gage, from dead topped off to the "F"..then 50 miles to the first actual 1/4 tank doing 73mph. So, my question is this.....knowing that your fuel economy sucks worse and worse the faster you go, with the R50, has anyone ever done the math and and figured out if there's a point in speed where the vehicle speed overcomes the fuel economy caused by the engine RPMs? Basically, can you go fast enough to the point where you actually increase the fuel economy? Probably not, but it was just a thought that popped into my head while driving...

[screwinitupagain]

I always get better gas mileage going 70mph than I do going 45... but I'm no rocket scientist, just a simple Art Major...

[gwhunt23]

There's thousands of factors involved that determine your fuel economy. Generally speaking, the lighter and more aerodynamic your vehicle, the higher speed at which you get peak fuel economy. Pathys are neither aerodynamic nor light, so you'd have to be going pretty slow on the highway to get those high MPG numbers you're looking for.

That's the basics. Want to get the real-world numbers? Get a scangauge.

Personally, the best MPG I've seen in my 99.5 QX4 was 22-ish. I was driving about 100 miles of country roads at about 50mph, losing elevation.
Modified by gwhunt23 at 1:41 PM 12/17/2008

[SnowSurfLax]

I generally average about 16 - 18 mpg on drives up to LA from SD when I attempt to maintain 80mph using cruise control.

If I attempt to maintain 70 mph using cruise control, I can pull somewhere close to 22mpg.

For us, I believe the peak fuel efficiency is somewhere around 55 - 60 mph. You start to slowly lose efficiency after that until you hit 70, and then the decrease becomes more significant for every 1mph you go over that.

But that's my butt gauge and my fuel up mpg calculations combined. Like he said, use a scangauge for the real numbers.

[Adnan]

anything over 110 km/h i can notice a differencei mostly blame it on the lack of a 5th gearwho knows what kinda mileage we could be getting

[Qxxx4]

the biggest factor is drag. For example "rockets" or the space shuttle need barely any thrust from their engines ones in space due to the fact of no wind/gravity

if a redneck reads this im sure hell try and throw a jet engine on the back of his qx4 for max fuel economy......LOL

[timmack]

yea that scangauge is a nifty tool, does alot more than just mpg, i like that it has a built in code reader and can clear the check engine light. it also can monitor the battery volts for you car stereo guys.

[Adnan]

if a redneck reads this im sure hell try and throw a jet engine on the back of his qx4 for max fuel economy......LOL

hahaha you just exposed my spring/summer '09 plan

[SixGuns]

the biggest factor is drag. For example "rockets" or the space shuttle need barely any thrust from their engines ones in space due to the fact of no wind/gravity

if a redneck reads this im sure hell try and throw a jet engine on the back of his qx4 for max fuel economy......LOL

Don't tempt me... lol nah, I understand about drag and all that...my mind was wandering on the drive to LA and I started thinking about it....y'know, "If I were pulling 6k RPM but doing 140 mph, would I be getting 40mpg or 2....hmm.." Ahh, such are the things that keep me awake at night...But, I did manage to pull 18.8mpg on the way back down, even with all the **** that makes the rig completely un-aerodynamic...just aired the tires up to 35psi and I'm good to go...still sucks, but better than the 16 I was pulling on 30psi...maybe I should figure out a way to bolt a Borg Warner T-56 6 speed onto the VQ...cruise at 85 pulling 1300 RPM..tell me that wouldn't be sweet.

[nissandoms47]

Im pretty sure nissan designed it all so you could cruise at whatever speed to keep the engine in its peak efficiency which on the VG33 is like 2750 and im not sure on the VQ. So if you change up the gearing it'll screw it all up. I really doubt that you wanna be going 85 at 1300 rpms haha.