My fd only gets 20mph highway I was just wondering if there is something wrong with my car or is that pretty normal. When I bought the car I drove it back for about 5 hours all highway driving and it only averaged out at 20mpg's.

Now that I installed a wideband o2/gauge I know it idles at only 11afr which I know is super rich for any regular engine at idle so I'm thinking there could be something wrong. Stock turbos, stock ecu, oh and it doesn't run rich at regular driving with no boost it runs at 14.5afr, 11afr only at idle

ANY HELP, COMMENTS, OR SUGGESTION MORE THEN WELCOMED

 

if you're worried about mpg, then might I suggest a hybrid.

 

I'm getting about 22ish MPG on a streetported engine, it all depends on how your driving it.

 

Did you do any research into the car before you bought it? Most people get around 15mpg combined. I get slightly less.......As the roads around here are so awesome that its impossible to resist

 

I have trekked many many 6 hours drives in the FD which was basically all highway and with the occasion WOT run I bested 23-24mpg with an average of 20-22mpg. This was on a streetport, stock twins, stock ECU (running rich), and basic bolt ons.


there is nothing wrong with your car. A PFC and a tune is basically the only thing you can do to get a better mpg in the cruising area of operation.

 

BTW....most ppl get nowhere near 20mpg....even on the highway

 

I don't know how much i get but, If i fill up about half tank or about 6.2 gallons, (20bucks on premium). And drive for 20 mins, im about at 1/4 of a tank. But my car has lots of mods like exhast, intake, power FC, injectors. 20mpg is pretty good.

whats the stock mpg for the 93 FD. because the car is 17 years old, its gonna start breaking down.

 

20mpg is not bad for the stock ECU. Power FC would make it a little better, if it is tuned properly, otherwise it could get worse

However the AFR's are rich at idle, has the smog pump been removed? What mods have been done to the car, if any?

 

6.2 gallons is not even 1/3 of your tank that's why the gas is going to 1/4 tank.

My car gets about the same mpg on the highway, it's normal.

 

What mph are you crusing at in 5th, or are you staying at 4K in 4th?

 

I get about 22 on the highway, all stock except a 3" turboback.

 

https://www.rx7club.com/showthread.p...&highlight=mpg

 

i have been looking into getting some mods for my ignition system. these are "supposed" to help improve your gas milage.

http://www.sunautomobile.com/sunPerformance.html

 

Most of that stuff has been tried already. Search for past threads on the topic if you like.

 

Im still wondering if its better for mpg to stay at a high rpm and low in vacume (4k 13-14vac) or be in fifth at 70-80mph and at a higher vacume the whole time (9-6vac). I was always under the assumption that crusing closer to boosting was a bad thing for mpg. Any insight?

 

There must be something terribly wrong with your FD b/c I have hit 140mph in my FD multiple times...

 

If I kept it at 76ish, ~under 3000rpm I would get wayyyyyyy better gas mileage. Drove from Trussville AL (near Birmingham, where I bought it) all the way to Goldsboro NC on a tank of gas. Mind you I had just bought it and was doing the easy driving associated with getting a new/unknown car home in case there was something wrong with it...

 

I-85 S
599 mi 10 hours 11 mins


Just googled it, I was on the east side of Trussville when I got gas so give or take 5-10miles for the analytical people. the zip code I used for NC was my base.

My car when I bought it had the Apexi intakes, downpipe, hollowed out cat (didnt know at the time) and thats it. i probably weighed 180-185 at the time...

 

20s about what I get on the highway, but I like to play around with that gas pedal a little too much even then. on my old FD I saw 26 on all highway once at a consistent 70 mph

 

oh, and IIRC factory EPA was 17/24, or in that neighborhood

 

The revised EPA fuel mileage using the more realistic drive cycle is 15/23 for a manual transmission car. That's still for a stock car at stock power levels.

Look it up yourself.

http://www.fueleconomy.gov/feg/findacar.htm

 

I experimented with this while watching my injector duty cycles and found that cruising at lower rpms in 5th resulted in lower injector duty cycles than higher rpms in 4th.

 

Thanks to all helping, and for the people just trying to talk **** please go else where preferably another forum!

Now I'm not too worried about economy but like I said in my post I want to know if my car runs ok. Best way to know that is to compare data. I got 20mpg all highway, very easy driving just trying to get the car home. No CEL, stock twins, stock ecu, full 2.75" to 3" exaust, magnaflow straight through muffler in place of cat, and pulleys were the only mods at the time. I drive 5th, as I'm pretty sure lower rpms in any engine uses less gas (with lil or no load)

So looks like 20mpg highway isn't bad then so my car might actually be ok

 

yup 20ish sounds about right, mine jumped to 22ish when i put the power fc in and took off the airpump, powersteering and a/c and went nonseq

 

I could get over 20 with my stock engine. My new...er, 'healthier' engine gets about 13 - 17 TOPS.
I made a hell-run the other day, drove about 25 miles and was rarely under 110 mph and got about....8 mpg. Could literally watch the gas gauge fall....