Seeing as I had a 200 mile trip ahead of me and the countless gas concerned owners I did a little experiment.

I intended to try all the various situations when driving the Z related to gas consumption. The below results were taken on Unocal76 91 octane gas each test was done for exactly 10 miles at 71MPH. I felt that the elevation changes for these tests were comparable with no significant grades.

A/C turned off : 30.1 MPG
A/C turned on : 28.4 MPG
Windows down: 27.2 MPG


The 350Z has a 20-Gallon fuel capacity.

A/C turned off : 602 MILES
A/C turned on : 568 MILES
Windows down: 544 MILES


Price gas fill-up at today's average price per gallon in my area $3.09 that is $61.90 for a tank of gas.

A/C turned off : $0.102 per mile
A/C turned on : $0.109 per mile
Windows down: $0.114 per mile


A person driving 15,000 miles per year would save. (Just for fun of course no person is immediately only running @ 71MPH on a flat freeway for 15,000 miles.)

A/C turned off : $1539.87 per year
A/C turned on : $1632.04 per year
Windows down: $1704.04 per year

Thanks for hanging in there. Yes I was bored. Hope someone appreciates the footwork.

 

nice. I usually drive with the ac on.. this arizona heat kills

 

well, thanks for the info! didn't realize you burn more gas with the window down than the a/c

 

What no pie charts!

 

Pie? Where?

 

the z feels so slow with ac on tho...

 

Thanks for the study. That's actually pretty darn interesting.

I'm getting used to driving around with the AC off, mostly becuase it cuts down on engine bay heat. I wasn't aware that windows down would actually give you less mpg.

However, I'm not sure if the windows down at lower speeds would make gas mileage drop as significantly. I'm thinking that cruising around at 20mph with the windows down and AC off would cause a lot less drag, and actually give you better mpg than driving with the AC on. hmm...

 

so the person driving w/ the windows down saves the most..?

 

Come to think of it I should have tried the heater on full-blast. Perhaps if someone in cooler climates could indulge us.

 

Are you sure Z has 20 gallon tank? I ran mine just about dry... 17.7 gallons when i filled it up and I had been running with no dte for forever... the gas guage was so low it was touching the E... and u know thats below the last line already. I figured i only had .3 of a tank left.

 

No..they save the least. It costs them the most in gas.

 

I'm taking a road trip Friday. Thanks for the info. I believe you'll save even more keeping the rpm around 2100 which is probably 55 mph in 6th gear.

 

These same test would interest me coming from a ZR.

Yes, you save 22% more gas at 55MPH than 70MPH.

 

I believe the Z has a 15gal tank, no? the study is interesting, I just drove from Denver, CO to Salinas, CA via hwy 70, 15, 80, &101. At no time did I turn on my AC, had my windows down all the time and I average 30.2 mpg at a set speed of 80mph on cruise control.

 

I'll be doing 720 miles friday. I'll log some data

 

The manual says 20 gallons. BTW interesting thread.

 

Thanks for the work and the data. Unfortunately, it can't be counted on as being accurate. That MPG reading on the dash is horribly inaccurate. In order to get good data, you need to fill up the tank, reset the trip meter, drive, fill up again, and then divide the number of miles on the trip meter by the number of gallons the pump registers.

My first fill up my MPG gauge said I had 19 MPG, but I actually had 22. The second fill up the gauge said I had 24 MPG, but I actually had 22. See where this is going?

 

The Mean Elevation of the state of Colorado is 6,800 feet above sea level.

The Mean Elevation of Salinas is 53 feet above sea level.

This is all I can think to explain it.

 

Excellent point. I contemplated contacting my Attorney at Law to draw up a Terms and Conditions but decided that because I am using the same instrument to measure in each of the different tests they could be utilized in accuracy even if they are not precise. Furthermore, the MPH digital gauge is accurate at 71MPH compliments of a Garmin GPS.

 

Unfortunately, this test will be forever flawed. In order to fill the tank each time I would have to discontinue traveling at 71MPH and likely stop-n-go a few times to reach a gas station at which time I would have to ensure that only 20 gallons were available for consumption (while were on the subject what about the volume of the pipe to the gas tank probably .5-1 gallon itself.)

It is to be taken for what its worth. If the ZR could also do these tests using the same Z gauge pod we could appreciate the difference between the two vehicles perhaps we could even get a top-down measurement.