Drivetrain specs don't seem to matter. Again, the fuel economy was the same with the FB trans, and I'm going to be rebuilding one of my FB units over the winter since I'm good and sick of the FC unit's 5th gear.

5th gear with the FC trans and 4.78 is just like 5th gear with an early FB trans and 3.91. So, imagine making 1-4 a whole bunch shorter then a huge gap to 5th. SUCKS. Gets rid of much of the advantage of using the 4.78 - bringing the closer 3-4-5 spread down to speeds where they are more useable. With the FC trans, there is no nice 3-4-5 spread.

The 4.78 probably makes for worse fuel economy than the 3.91 because of higher internal friction. I have never run the 4.78 without synthetic oil, and I never ran the 3.91 with synthetic, so I have no idea there.

You also have to know how to drive, too. Maintain momentum and all that.

 

ill start...
i get around 15mpg.

 

I get about 10. But I have to admit, that's about what I deserve due to the way I drive. lol.

 

Usually around 18-19 with conservative driving.

 

it depends on which car i'm driving...with my 80 Leather Sport, i get about 18. with my 82 GSL, about 16. with the 10AE, dunno because i haven't finished putting the new engine in. i would guess it to be somewhere in the ballpark of 12.

 

You need to state the condition of your car and modifications. Dont just say this is the mileage I get and thats it!

 

I daily drive a street ported 12A with Weber 48IDA, very short trips so the engine is barely warmed up by the time I get to work. When taking off from stop lights, I will NOT be out run if the motor is warmed up and I can help it Taking my driving style, the short trips with cold street ported motor into count, I get 16 mpg in the city. When I get out on the highway and the motor is warm for a long trip, then the mileage goes up to 24 mpg - a 50% improvement over 16 mpg.

 

get around 20-25 with a stock port 12a with header and moddifed carb with no emmisions

 

84 -SE Large Streetport
RB exhaust and a good number of other mods.

15 mpg when i dont get on it.

 

85 SE stock fi ( K&N ), catless; headers, glass packs, turbo muffler.... 16 - 19 city / hwy.

 

1984 GS, all stock except the heater flap has been removed from the air cleaner and a Purolator FPR set to 2.5 psi has been installed...19 - 21 mpg depending on 85 or 75 mph drive to work during the week.

 

84 GSL Stock, stock, stock 12a! DD and I get 22-24 on runs to work. On cruises (75+ freeway miles) I get 27+

 

ok i have a 1983 GSL 12a street ported engine w/ holley intake and carb, Racing Beat full exhaust and no a/c.

 

ok i have a 1983 GSL 12a street ported engine w/ holley intake and carb, Racing Beat full exhaust and no a/c.
15mpg

 

13-18 miles per gallon depending how much I'm in the throttle, 16 is about average though.

250whp turbo SE lots of mods

 

i got like 28 all stock all hiughway on the way back from north carolina

 

When I was at Road Atlanta 2 a couple weeks ago, I got 7.2 mpg and loved every minute of it.

 

i get 20\22 stock EVERYTHING on an 80

 

I get 35 mpg in my escort zx2. Intake,exhaust, Pulleys. Muhaha. I have not yet driven the rx7 far enough to find out what it gets.

 

lol... I get like 12-14?

 

Its hard to believe that my turbo 7 gets about the same gas mileage as it did when it was stock. Sad really.

 

i get around 25 with my t2 motor

 

my 85 GS with an exhaust and a pair of aftermarket coils running of an MSD box got 28 on a 500 mile cruise at 70...

 

Good info here.
I was searching for MPG and came up with this thread.


So lets get it going again


I am considering an FB or FC as a commuter, so this is part of my pre-purchase research

 

rx7doctor had an interesting thread about increasing mpg. I think he gets like 30+ now. I believe its in the non tech. probably still on the first page.

Ill see if i can find it for you. In general rx7's arent great on fuel, ESPECIALLY for the size of engine lol