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Discussion Starter · #1 ·
I've read about every topic imaginable on this forum from how much $$$ we have in our Zs to where we live to the best springs to put under the car, the best head to put on it and the trickest seats to put in it. The only thing I haven't read much about is mileage. Here in California, gas prices for premium have been pushing the $2.00 per gallon mark lately. Being (apparently) among a decided minority of Z owners who is perfectly happy with the power output of my stock '82 Turbo, I am lately concerned with eeking the best mileage possible out of it. Right now, it's averaging low 20s mpg. Best it ever got was 24-25 mpg when I drove the speed limit (yuk) as an experiment.

Any of you out there keep track of your mileage (# of miles between fillups divided by number of gallons = mpg)? If so, what are you getting — and just as important, where do you live (CA has different gas formulation) and how aggressively do you drive? Thanks!
 

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Discussion Starter · #2 ·
RE: Gas Mileage

I get around 16 or 17 in my turbo. When I drove to my last job all interstate at somewhere around 70 mph, depending on weather and traffic I will jump up to 100 mph on regular basis. I push pretty hard on those occasions and get 270-280 miles to a tank. Now that I drive a two lane road the same distance at 50 mph, I get 300 miles to a tank. When I bought this car with 204,157 miles on it I got 300 miles to a tank. It had a very restrictive exhaust put on it by the former owner, the original cat was on it and from there back it was 1 3/4 or at best two inch pipe to a crappy silencer muffler. I took this off and installed 2.5 with a flowmaster. Power went up and mileage went down due to the uncorked power and the unresistable urge it provided. Mileage should go up temp as I think I've got a air/fuel problem.
 

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Discussion Starter · #3 ·
RE: Gas Mileage

I have a 71z with a 81 motor su carbs and early type 5 speed, I am getting 22-23 mpg with mostly back and forth to work, some highway some streets and a little freeway
i would call my my driving spirited with the ocasional heavy foot on the happy pedal
I am in Calif
 

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RE: Gas Mileage

I have a dead stock 78 with and automatic. It gets 19 in town and 22 on the highway. I am changing out the automatic to a late model (high ratio) 5 speed. I hope this change ups the mileage 3-4 mpg.
 

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RE: Gas Mileage

I have a '77 with an '83 5-spd & 3.90 rear end. Combined highway/city mpg is 20-21 with 168,000 on stock engine. I have recorded every gallon of fuel that has gone into the car since I bought it and calculated the mpg at every fill-up. Tis is the best the car has done since I got it. The 5-spd had little effect on the mpg since it really only helps on the highway. mOst of my gains came through careful tune-up actions - including wrapping my timing as full clockwise as the distributor would go.
I live in Texas, DFW area.
Phantom
 

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RE: Gas Mileage

I get around 27 mpg on my na engine with header and 2.5 inch exhaust. the highest it ever got was 30mpg. I can go over 400 miles on a tank of gas. I drive 20 miles to work 10 city and 10 highway. when i'm get on the highway i cruise around 80 most of the time. The lowest i've got was around 18 mpg, that was right after I rebuilt the engine ( the engine was still tight.)
 

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Discussion Starter · #7 ·
RE: Gas Mileage

When I had my 83 ZXT, after putting on (reman) Bosch fuel injectors, a better coil and a few other minor modifications I was able to get close to 30, but 25 consistantly no matter how hard I pushed it. The Turbos tend to get better milleage unless you bary the boost needle into the dash all the time.

Scott Milella
 

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Discussion Starter · #8 ·
<b>RE: Gas Mileage --BULL</b>

average of 27 mpg sounds a little too much.
I got same mods as you and get 23-23 average probably cause i drive on highway mostly about 320 miles out of a tank. I also average 75mph on the highway. Which sound normal to me since nissan says 21MPG on average. Take in acount the ground effects I have and mine sounds normal.
But when Nissan says 21 for going 65 and you get 27 going 80MPH ----I think that is bull
yeah we have all gone 27 at some point...... but we also wait for the tank to empt before measuring...not after 20 miles.
PS: You should be getting 565+ miles per tank if your mpg is true and not more than 400.
It is a 21+ gallon tank you know
 

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Discussion Starter · #9 ·
RE: Gas Mileage --BULL

Yes I remember the Turbo one really HURTING to fill up when I went to the gas station, my 82 280ZX I believe either has a 16 or an 18 gallon tank. As I stated before I was getting close to 30, but average around 25, with moderate driving, that was after a lot of work, and with new Injectors all accross, good wires, etc. My MPH did not average 80, it was mostly just 65 for a 30 mile commute I was making. Again this was on the Turbo modle I used to own the 83ZXT, unfortunatly I loaned it to an ( EX ) friend, and he wrecked it.

Scott Milella
 

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Discussion Starter · #10 ·
<b>RE: Gas Mileage --BULL</b>

Sorry scott, I was refering to Russ83 that was getting 30mpg going 80mph +city driving. it seems that he is not aware of how the drug resistance increases with speed.....that would mean that he can probably get 46-47mpg if he was going 60-65mph.
unless ofcourse your speedometer is not working right.
Or maybe you have it adjusted right, but the tires are 205/80-15 or something
Anyway his statements are overstated
That would mean more than 620 miles per tank...but he claims more than 400...which is ok according to nissan that claims average of 21mpg.
 

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Discussion Starter · #11 ·
<b>RE: Gas Mileage</b>

Hmmmm, sounds like I represent the low end of the scale if I'm getting 18-19. I do about 60 miles a day on the interstate, avg 70-75mph, in a '77 5spd, and have
to run the a/c all summer but that doesn't seem to change the mileage. My AFM is only about a year old,
so there maybe another contributing component.
Car idles dead on 800 and is so smooth and quiet even after a hard run I find passengers checking the tach to see if the car is still running. So mileage isn't everything!
 

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RE: Gas Mileage --BULL

I said I go 10miles city driving and 10 miles highway driving. For about 5 of those highway miles i go 80 but not all the time due to slowpokes in the fast lane.
For the 30 mpg the car was running very lean and backfiring out the intake. That time I was around 490 on the odometer and about 1/16th of a tank on the fuel gauge when i filled up.
 

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RE: Gas Mileage

With my '75 280Z, 4-spd and mostly stock except for motorsport headers and 2.5 inch exhaust, and the lid off of the air-box, I get about 16 in town and 20-22 on highway. In town means tromping around campus and sitting in traffic. I live in IN, where no one cares much about fumes.
 

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RE: Gas Mileage

My 76 280(79k) Z averaged 19.3 MPH when I filled up this morning. I check it at every fill-up and seem to average about the same. Longer highway trips it's reached as high as 26 I think. 230Miles to the tank is when I begin mainlining for the gas station.
My 81 ZX (non-turbo)(170k) averaged (I swear) 28HWY for the entire last 16months I drove it. When I first got it, it coughed along at 18-20tops. Both cars are essentaily stock. Proper tire size, and stock 81 rims on both cars. I've gauged the speedo and odometer and it's accurate. I live and drive in Seattle.

any suggestions to get the Z up to the ZX average? I've tried all the same tricks that brought the ZX up to a economical average, but the Z just won't cooperate.
:(

Oh yeah. I try to drive the speed limit, but average 70-80.

Stephen
 

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I disagree

I went, in my 83 N/A with header and 205K on it down to LC, from where I live 220 miles. Anyways, with my brother and the car fully loaded, probably over 500# with my tool box, clothes, us, etc, we made it in under 1hr 45 min. That is about 130mph. When I got down there I had a ton of gas. Very surprised for it being summer and using A/C. So, I went and filled up and figured gass mileage. Guess what, 29mpg! This is no joke. It was running a little rich as well, but not overly, definitely NOT lean and back firing. Nice and smooth. I get about 22 in town tromping everywhere I go. That is now with about 200# in the back, K&N, Header, and just tuned properly, still rich though. Not trying to argue, but I get good mpg also on an "old" car. Now it has a newly rebuilt engine, by me.
Joshua L.

P.S.- I tune by driving, get out and change the settings, get in and drive, get out and change...No machines or anything, so I know it is not perfect.
 

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Discussion Starter · #17 ·
<b>THANKS EVERYONE -- INTERESTING! </b>

Wow, never thought there would be so much variance. And Joshua, don't touch a thing on your car, man! If it's getting that kind of mileage, it ain't broke.

As mentioned in my original post, my '82 turbo used to get as good as 24, occasionally 25 when driven sanely, which of course I hate to do. Part of the reason it now gets only 19-20 is, I believe, the reformulated gas here in CA, which incidentally caused so much leakage in the rubber hoses and O-rings that I ended up having to replace all fuel lines and even injectors. The mileage never went back up to where it was before, tho.

Here's another Q for you tech types out there: From what I can figure from these posts, the cars getting better mileage seem like they're from the midwest/south where the humidity is higher. That means denser air, right, especially in the winter. Which may contribute to better mileage? Isn't this also why it's good to intercool a turbo -- so the motor gets a cooler, denser charge of air? Just a guess.
 

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[email protected] RE: Gas Miles

In '91 I got a verified 25MPG with a 71 240Z from Corona CA to Blythe CA (186.6miles). Timed with a stopwatch, my trip took 2 hours exactly from the mobil station in corona to the ultramar station in blythe. My gallons divided into the miles averaged to 25.2 MPG.
My next 147 miles to the Phoenix city limits was done in about 1:35, and gas consumption was similar. This car would run 104 MPH in 3rd gear, and had SU's! I was soooo amazed (as was my partner in the chase vehicle, that the numbers stuck in my mind. Especially since my 73 got around 17 to 19 MPG...
 
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