Post your Average Fuel Mileage and Car here.

i think it's totally doable with the right combo of parts, though i don't think low profile tires necessarily fit in there, depends on tire diameter and don't forget that larger wheels actually have more mass which will hurt mileage

I'm hoping to do a mileage run this weekend and will report my data next week. It should be around 400miles of highway driving, but about half that will be through the mountains starting from 3500 ft to 4,800ft elevation and down to 15ft above sea level and back again (Bend to Portland, Oregon and back). Should be fun, informative and expensive, fat tires and all. If I hit 22-25MPG with this type of terrain I'll be ecstatic. :D
Daniel
 
with the old engine in my car which was basically a stock rebuilt 351w 4v motor, with stock replacement flat top pistons, mild rv cam advanced 4 degrees, e'brock performer intake, 600 carter AFB, mallory unilite conversion in the stock dizzy, stock manifolds with 2.25" duals with turbo muffs, stock fmx tranny with shift kit and 3.25 geared 9" with 275/50-15 rear tires would get 24-26 on the highway and did ok around town, tough i never calculated in town mpg.

new motor in the same car with most of the same components but bigger cam installed straight up, less compression (old motor had 10.75:1 new one has 9.0:1), road demon 625 carb and 2.5" exhaust with shorty headers, i haven't had it up on the highway yet but i'm guessing in the 18-20 range max.

my 86 lincoln town car all stock 77,000 mile non-HO 5.0 decent around town for a land barge about 14 or so and pretty darn good on the highway with a best of 27 but normally around 24mpg.

i'm expecting the motor i'm planning for the cougar will get north of 25 on the highway and hopefully 15-20 in town. engine will be a 351w with long rods from a 400 ford, keith black pistons and ford racing X-305 (maybe x303 can't remember which) with 64cc chambers, should make around 10-10.25:1 compression, mild roller cam probably the smallest or next up comp extreme roller cam advanced either 2 or 4 degrees, for now carb will be a modified 4100 but i'd like to go with a Quick Fuel 650 or ultimately a holley commander 950 pro-jection system, stock dizzy with unilte converision or a Pro-form duraspark dizzy with msd box. exhaust will consist of either heavily ported stock manifolds or shorty headers and 2.25" duals with turbo muffs, intake will be a massaged Ford Muscle parts C90X unit and i plan to use as many different coatings on the engine as i can afford. the 9"n rear will have 3.25 gears with a detroit tru-trac diff and the trans will be a built wide ratio AOD or possibly a built FMX with a Hone-O-Drive unit if i can swing it or maybe the built AOD and the Hone-O-Drive unit with a steeper gear, still toying with ideas on this one.

all in all, it should be good for 350-400hp and i'm hoping for close to 30mpg on the highway. i'm planning this build more for reliability, longevity and efficency rather than all out power but power will be in there somewhere.
 
My '88gt would get a best of 22 (low of 18) on the highway cruising at 75, stock 5.0L aluminum driveshaft, 5 speed and 3.55 gears.

With 2.73 gears it was worse. I would stick with the 3.40 gear set with the t-5. Don't go with anything numerically lower.
 
Sometimes daily driver (9 months a year when not carpooling or adding parts) 66 Ford Mustang with 440,000 miles on the chassis, 100K on the engine, 1997 5.0L and stock 1991 HO cam with Performer heads, 1.7 Cobra roller rockers, Torker 289 small single plane intake, Autolite 4100 480CFM carb and 4 hole PCV spacer, cast iron HiPo exhaust manifolds, T5-Z with 3.40:1 rear. Other mods include Pertronix Ignitor II billet distributor, advanced 14* and all in by 2500RPM, windage tray, and electric fan. Decent performer with dyno of 220 ft-lb RW torque@3850RPM (95% of peak from 2000 to 4800) and peak power of 200RWHP at 5450 (95% of peak from 4400 to 5500). Weight savings from heads, intake and composite monoleaf springs (Flex-a-form) more than compensate for the heavy factory A/C.:nice:

Average 16-18MPG in town (last fill-up was 18.7MPG), 24-26 on highway with 10% Ethanol regular gasoline. I need to rebuild the carb and optimize my tune and am shooting for 20 town, 30 (or more) highway just to say I did it.:D When not hypermiling and when the A/C is on, I get 14-16MPG town, 20-25MPG highway. It is possible to get good mileage without resorting to EFI, but maybe someday I'll break down and "upgrade". :p Driving habits and overdrive helps with mileage, as does manual steering and brakes. My poor aerodynamics and wide tires hinder it.
Daniel
I went on a cruise this weekend--hot (85-95°F) and mountainous driving (from home at 3500ft to 4800ft Santiam Pass, then down to 1200ft, then back home over the pass with a lot of stopping, flat out acceleration, curves and back roads thrown in). I went with 2 new GT500s, a 2003 Mach 1, two 99 Cobras and a 69 Mach 1 with a 428, so I couldn't baby it much at all and drove less than 2 miles with the engine off [full disclosure I have stick shift, manual steering and brakes, so don't try this at home]. Even with the AC on for 20+ miles and despite the windows down for much of the rest of the trip, I got 28MPG (well, 27.8mpg as per gmaps-pedometer) in 170.8 miles of driving. :nice: No, I didn't believe it either (and thought my gauge was broken), but there you have it. Filled up on leaving, and filled up on return with 6.145 gallons topped off. :D
 
2001 Explorer Sport-Track - 12-15 MPG - Only when I have to drive it

1986 Honda CB-650 Nighhawk - 42-50 MPG - As much as I can ride it

Factory Five Cobra Replica - 14 gallons to fill the tank when it needs it.
 
'65 Mustang:
New 5.0 crate engine w/600 cfm performer & intake, Flowmaster 2 1/2" dual exhaust, AOD trans, 3.00 rear gears, 225/60-14 tires.
It's too much fun, I can't drive it with the mentality "I wonder what my gas milage will be if I take it easy?". I haven't taken it on a trip with the new engine and AOD, but I imagine it would get over 20 with the 3.00 gears in the rear still.


I get about 10-12 mpg city with my foot in it.
Highway - ?

DSC04648.webp


DSC08441.webp
 
I got like 15 this past weekend mixed hwy, autocross, and city driving.

AUTOCROSS IS AWESOME!!!!!!!!!!!!!!!!!!!!

I was surprised by the way my car preformed on the really tight course. Looks like I got some stuff right for a change.
 
'67 convertible below, driven pretty sanely. Dynoed 161hp @ 4100, 229,5 lb-ft @ 3100rpm.

I have been using her as a daily driver since December '07, and in 3394,1 miles, I have used 230,63 gallons of fuel for an average of 14,72mpg. However, in the last three months I've averaged 15,3mpg and in the last month it's been 15,5, The rise is due to a lot of different factors: partially due to warmer weather, partially because I've gotten more highway time, partially because the motor's loosening up, partially because I have a lighter foot, and partially because I installed a clutch fan to replace the former solid steel fan. I have had a high tank of 17,73 over 104 miles @ 55mph and a low tank of 11,85 after I put my glasspacks on and was enjoying them far too much. Motor now has about 6k miles on it.

Take a look at my fuel log here:
CleanMPG, - Garage An authoritative source on fuel economy and hypermiling

My Harley's getting 45,7mpg so far, still breaking this one in as well. Only has 491 miles on her.
 
The '68: Mods in sig. I don't think I have ever had a full tank in it more than once. My educated guess with the rich-running tune is 10-14mpg average, but I don't try to get good economy with it.

The SVO: I got as good as 26mpg highway. With more mixed driving, it averages about 24. There again, I don't try to get good economy with it. Like the '68, it's a weekend fun car.

I also have a '94 Toyota pickup with 2wd, regular cab, 2.4L 22RE, 5-speed, and a shell. Everything has 206,000mi on it except the engine(~35,000) and of course the maintenance items. It averages 28mpg through mixed driving and I have managed just over 31mpg on the highway. That was with worn out plugs and failing plug wires to boot. Makes me wonder what it could do since I replaced those...