Surprisingly, I get 13 with a 4100 (not original to the car) and 15.5 with a Holley I had previously installed. That's around town. I feel I should be better. The holley did better than 26 on the hiway.

 

mileage

Patrick, what are you doing ? in town average ought to be high teens and freeway ought to be 20 + LSG

 

I might get that after the fun wears off...if it does. I won't get to drive it much this week. It's supposed to rain everyday. I need to replace both window seals and all weather stripping.

 

I get 11-12 if I stay out of it. I've seen it get 14 before.

 

You are fairly modified aren't you sportsroof?

 

You could say that. The car has been mid 9s.

 

12-13 MPG. I've managed to get it to about 15 ONCE.

 

Spirited city and a little highway I get a constant 20+ mpg. She's never been out on the open road so I don't know what she'll get there.

Could I do better with my normal drive? Probably, I see the AFM drop into the 12's anytime the power valve kicks in. Me think I need a better carb than my Street Avenger to dial it it better.

 

Did you do anything special to your motor? I know a T-5 will up it a couple MPG but I've never, ever gotten upper teens.

 

I get about 12 running around town, but I think I'm running on the rich side.

 

I think I'm a little rich also. Yesterday, I turned the idle air screws in a 1/4 turn and idled it up a little. Seems to have lessened the gas smell somewhat today. I tried to go to 1 3/4 turns out but it didn't want to idle very well and the vacuum gauge dropped a bit at that setting. So I left them at 2 turns out.

 

Who has fitech efi on a close to stock build and can report MPG

 

mileage

Patrick, if your engine is' mostly stock', and you smell gas, and you're only getting 12.5, something is very very wrong with your setup or your tune. LSG

 

Patrick, if your engine is' mostly stock', and you smell gas, and you're only getting 12.5, something is very very wrong with your setup or your tune. LSG

I don't after some minor tweaks yesterday. Engine is bone stock with what I believe to 235K miles on it. Haven't pulled the new plugs yet. Will probably check those next weekend. I checked 1 and 5 after about 1 hour of running right after I fired it up a couple weeks ago. They were clean then.

 

my 1st 66 got around 15ish as I recall 302 3speed 2.80 rear G60-14's 2 barrel F4B. Now days with 2nd 66 and a 289 T-5 3.40 1406 F4B 215/55/16 25ish is the norm

 

I used to get about 15-17 with my '66 when i drove it often to work. That was with a built engine. My '82 with a seriously built engine gets about 16 around and 24 on the highway with a T5. You should not be getting 12-13 with a stock or mild build Mustang.

 

I average around 18 with a t5 and 3.50 rear end gears. I have an edelbrock 140x that I tuned with a vacuum gauge.

 

My "built" 289 + Toploader + 3.25 rears gets 15.5 city (because I can't/won't keep my foot out of it at each and every stoplight), 20 highway, averages around 18.5 or so. My tune could use some work too.

 

16-18 city and 20-22 highway. Thats with 2v 289 t5 2.8. I just finished a 3.25 install. I'm actually hoping for same/better mpog because the car will be in a better rpm range.

 

I have averaged about 16mpg over some 100 mile days. More highway than not. I have a mild build 351w, 96mph 1/4 and ~3.00:1 rear gears. The MarkVIII and Aurora get 22.5 and 24.5 per their computers over the same daycare-work-lunch-home-hardware store type days.

 

There are numerous topics on this subject. A quick search will provide you with a full days reading matter.

I got right at 24 mpg over a 1600 mile trip a few years ago. The car was a '66 GT350 with a 289 engine, vintage Paton supercharger, 4 speed toploader transmission, 3.00:1 rear end gearing. I averaged 75 to 80 mph for the entire trip. No interstate, just seldom traveled 2 lane highways. At 75 mph the rpm was just under 3,000. Tire size was 24.9 dia

For me, the key to getting good gas milage was the installation of an air/fuel ratio meter. I could really fine tune the carb and get the leanest cruise / low throttle opening fuel mixture, while at the same time make certain that the full throttle and acceleration circuits were rich enough to keep the engine safe.

If your looking for the best MPG possible, then a wideband A/F meter is indispensable, and will pay for itself if you drive very much. If you don't drive a lot, the MPG doesn't really matter.

Z.

 

Since this will soon be my daily driver, a UEGO may be in the cards.

 

Not the original engine - 5.0 roller with t5 and 3.55 get 24 Highway vs 15-17 city....

 

bone stock 351C 2V

about 10-11 going to shows and joy rides

can stretch it to about 13 on a long drive say over 75 miles

my 93 bone stock about 17/22

 

A 351C is a terrible fuel mileage engine. That is known. The ports are too large for good fuel atomization at low speeds.

 

On almost any verhicle: 90 percent of 'gas milage' is about how you use your right foot. 10 percent is about what you have under the hood.

Paul

 

On mine, I have an Edelbrock 650 cfm, engine is on the mild side, T5 and 3:55 rear end, and in town I get about 15 (right foot offender), but on the highway I get 22 or more if I can keep it under 75.


Once I get me FiTech EFI installed I will report back. It's still on back order right now.

 

15-16 mpg,