I've seen many posts about gas milage and some people were in 18-20mpg range and some people were claiming 25+ and first group was puzzled by that... I figured it out finally.

I have car for almoust 4 years now and I NEVER had gas milage better than 21mpg. Average for winter is 19.8 and summer 18.8. One year I had to drive rural 55mph roads with lot's of stop sings to work and other years I mostly use highways with 80mph average speed - still it's always the numbers I mentioned above. I monitor my milage regularly. Even on long highway trips, it's no more than 21.x.

Now, for one of my kendo practices I have to drive about 30 miles or rural higway with only few stop signs. And when I come back late at night - there is no traffic except cops. So I just put my cruise control at 64mph and go smooth the whole way. Last night I clocked my mpg and it was frikin 28.5 mpg on about 30 miles distance!!! After that I had to drive about 30 miles of empty highway so I accelerated to 78mph and set cruise control... Mileage remained above 28 the whole way! That's 40 to 45% more from my normal gas milage.

So my conclusion is - driving conditions has HUGE influence on gas milage in our Z. Smooth continuous drive at 55 to 65 mph is the best. One can drive for years and never get the right conditions to go above 20 mpg and another can always have them and always go above 25.

Was quite a revelation for me. I always thought that my engine is different somehow from those who get good milage.

 

It took you 4 years to figure that out???? I could have told you that in 10 seconds!!!

 

Hey man I don't want to offend you I was just kidding, please don't take it personal. I forget you all don't know my sense of humor. I might try to use my cruise control more and see if my mileage improves that much. I am right where you are or were 18.5.

 

I never believed you can get 50% more on 60 miles stretch. 10-15%, yea may be... it went back to normal <20 as long as I don't take that route.

 

I average 23 with my weekly driving which includes some good highway stretches as well as the in town stuff. But 26 mpg doing 80 on the interstate is no problem.

 

Mine kinda varies I guess. I've gotten 30MPG doing 80ish going to Destin from here which is about 350 miles I think. Right now I'm getting about 27-28 going about 80 but my Pop Charger is filthy (cleaning this weekend), I'm changing my spark plugs, and fixing my exhaust leak hopefully.

Maybe that will bump it up... City I get around 20-23 depending on how aggressive I drive.

 

I usually have 21.x on a highway. Even if I do 1000 mile trip. But then I never use cruise and I vary speed and maneuver around other cars just to not be bored.

 

yeah, that applies to virtually any vehicle. The vehicles use more fuel when accelerating, so constant stops, in return require more repetitive acceleration.

 

I made it to Vegas from Sac on a tank and a half. And from Vegas to Tucson on one tank. It's pretty much in how you drive it...just like in any other car.

 

I think this is the part that people miss on this topic; it's an average. The more time that passes, the more data is collected and added to the averages of the previously collected data.

If you want your in town average, reset the thing upon leaving your house, and check it immediately upon arriving at your destination. If your on the highway, get to the gear/speed you need, then reset it, and wait for a mile or two then check it. At the track, reset it at the line, then check it after the run. *Most track runs are < 1 mile, so the reading will be ever so slighly off.

If you simply reset it when you refill your tank then check it again when you next refill your tank, you will have the average of the entire tank, which means you could've spent the first 1/4 tank dragging at the strip, getting 10.2mpg, then used the rest of the tank on the highway going home, getting 26-28mpg, at the end of the tank, it'll read something like 16-18mpg. This doesn't mean your highway consumption is 18mpg. It means that over the course of the entire tank, this was your average consumption.

Yes, when you jump on it, you will get ****e mpg, if your put it in 6th and cruise down the highway doing 30mph, you'll get like 45mpg.

 

Thanks to Vlad for posting! I had seen these posts about how good of mpg people were getting and just figured my engine was not as efficient or something, lol. My previous job required me to travel 25-30 miles (each way) to and from work with a wee bit of street driving. For the whole tank of gas, I averaged about 23mpg. After I quit that job, I was mainly driving on the streets (and I would floor it and constantly shift at around 4k because I enjoy feeling the power of the Z) and continually averaged only 17mpg for the entire tank. I tried different gas stations and what... same result. I remember reading posts about how people averaged like 21mpg or so on street driving only. I mean I figured my spirited driving had some kind of effect on my crappy mpg, but I didn't think it was that much. Then one day (a few days ago actually) I drove about 30 miles on the freeway after filling up and resetting my mpg indicator and averaged 26mpg! Needless to say I was quite relieved that my low mpg was just due to my spirited driving and had nothing to do with my Z.


PS: Vlad, who's that on your avatar?

 

I figured this out the first week I owned the car. You're right, 55mhp -60 mph is the best range. I once hit 31 mpg but I think the computer is wrong. I honestly don't trust my computer so I do the math myself and found out that its about 5 mpg off.

 

Yeah. I let mine run for the whole ank. Its normally .5 mpg off too high

 

That's a fairly reasonable deviation, and about what I get when I've done mine. I'll make sure to top off until it spits gas out, and save my reciepts so I know just how much gas I started with, then when I refill, I do the same, find the difference, which gives me a fairly accurate amount of gas consumed for the milage.

 

thats pretty good gas mileage but i get like 33 to 35 miles a gallon going about 70. plus on top of that at 80 mph i get like 26.8 to 27.5 mpg. there are a few more things you can do to get improved gas mileage. for instance from houston to baton rouge la wich is like 300 miles or so i make it on half a tank every time. using 89 cant gas i cant afford 93 at 3 bucks a gallon.. but i can definatly send you tips or you can just do a serch of my previous gas mileage post but anywho congrats.. on the extra gas mileage

 

add 3-5psi to your tires and watch you gas mileage go up 10-20%..

of course your tires will wear unevenly.

 

a car as aerodynamic as the Z actually does better MPG when running at a constant high speed...

anytime you accelerate you waste gas, also a lot of hills will throw your mpg off... so a drive from texas to LA on flat land does pretty well mpg wise vs a trip to colorado.

 

I figured out how to get 9 mpg, but never past 17.5 on local.

 

Ive hit 36 MPG with cruise set on 60 MPH.

 

I've had 34mpg going 85. Unless you live in Kansas in a town with very few stop signs then you are SOL. We're lucky to get 21-24 mpg from So Cal to Vegas. So many morons go 65 in the fast lane and you eventually meet up with 2 barricading you and your mpg goes down accelarting back up.