5.0 EFI mileage report

[Viperwolf1]

Well I've worked enough of the bugs out of my 5.0 to get my first look at fuel mileage data. On my first measured tankful I went 301 miles (GPS measured) on 22.3 gallons, or 13.5 mpg. This tank was 75% in town driving with one small bit of 4-low trail action (4-5 miles). I had a stuck open thermostat during about half of this time and there was also a good deal of time spent idling while tracking/fixing fuel, exhaust and thermostat problems. I also had the large Explorer clutch fan installed during most of this time. I have recently replaced it with a thermally controlled electric fan (more about this in a later thread).

The 2nd measured tank was the small one. I wanted to see how it did outside town. I filled the tanks, ran a few erands in town then headed out on a rural highway. Speed was between 55-65 mph. I kept going until I got near 1/4 tank when I refueled. I went 90.7 miles on 5.54 gallons for 16.4 mpg. My old 302 averaged around 11 mpg with 1" less body lift. I guess that's damn near a 50% increase in mileage. I've started a logbook to track fuel/mileage over some more significant time.

This is what I got:
89 mustang 5.0 EFI, balanced
Total Seal gapless piston rings
AFR 165 heads
9.5:1 compression ratio
Mustang roller cam, advanced 4 degrees
FMS 1.6 roller rockers
Explorer intake and 65mm throttle body
Mustang 60mm MAF, injectors (19 lb) and A9P ecm
Running EGR and CANP
Explorer serpentine minus the AC compressor
BCB 1 5/8" headers and 2 into 1 exhaust
C4 with shift kit and HD/towing converter
currently 3.50 gears and 33/12.50 MTR's
3 1/2" suspension and 1" body lift

 

[Bucky]

Sounds Awesome! Keep Talking and I'll be selling all my Carb Junk!

 

[sprdv1]

Cool buddy... That don't sound bad at all...

 

[Mark]

Phil, that's a big difference. You must be pleased.
I'm hoping for similar results. I was getting 10.3 mpg using my carb

 

[needabronco]

Thats right at where I'm at with efi. Carb'd I'd get 10-11.5 MPG's. First tank with efi was 12, and after that I'd get 13-13.5 in town or on the trail (mostly idling around in 4-low, and I managed 16.2 on an all highway tank. I'm very happy with those results, it's better than my Toyota. Now if only I could get my fuel pumps to work reliably again...

 

[00gyrhed]

I get 14 on the highway with my 87/71 302/EFI. My speedometer is calibrated to the exact foot on a measured mile too.

 

[broncnaz]

Thats only slightly better than what I get with a carb and a single plane manifold might pick up 1-2 mpg with a dual plane. If I ever get around to swapping it on. Still not to bad but it still tells me EFI is not really a mileage increaser.

 

[Viperwolf1]

It's kind of like comparing apples to oranges but the combination of 50% better mileage and the availability of probably 100% more flywheel horsepower over the old 302 is pretty cool. I imagine it may get even better once I get it a little more broken in.