Anybody bother to record MPG on their steeds?

jcp123 · Jan 2, 2008

Out of curiosity, I decided to start...one tank so far came out to 13.71mpg, with about 50 miles of highway time @ 70mph, two dyno pulls to 5k rpm, and a bottle of Lucas fuel injector cleaner, with another 100mi of in-town driving, much of which had a heavy right foot. The last tank had no highway drives and colder weather, but less of a lead foot...but still only came out to 12.71. Ouch. I really need to get that clutch fan...

Car's got a mild .030" over 302, headers, electronic ignition, Carter AFB carb on a Performer manifold, and a C4 with 3:1 gearing.

What are you guys getting? Post some car specs and driving style...

69 Rustang · Jan 2, 2008

I used to when I drove my '69 daily many many years ago. Seem to remember getting about 13mpg no matter how good I behaved or not.

I did once make a trip where I got nearly 20mpg once going from Kansas City to Bethany, MO and then on to Omaha on one tank. Not sure how, but I triple checked the math, mileage, and amount of gas--the only plausible explanation was someone dumped several gallons of gas in my tank during my stopover near Bethany, MO when I wasn't looking.

jcp123 · Jan 2, 2008

I can believe that. My '68 used about 8 gal/week on my commute, regardless of how hard or granny-like I drove. In the two years I had the same commute, it never varied more than a half-gallon per fillup, although when I first bought it and was driving her home from Portland, OR to the SF Bay Area in CA, I did get one tank which came out to 23mpg...a feat I never managed to duplicate again. Any my Dad's Mach 1 used to get 13mpg no matter if he drove it in-town or on the freeway...

This convertible, though, always has gotten really bad mileage. I'm thinking about either painting a flex fan black and using one of those or getting a clutch for the stock steel fan that's on there. That and opening up the gap to take advantage of the better ignition system I have on there I hope will help a bit...as it is, I work the first hour of my shift just to pay for the gas to and from work

rbohm · Jan 3, 2008

my mustang got 17 around town, and 26 on the road, both my falcons get 16 in town and 19-20 on the road. my old F250 diesel got 21-22 pretty much all the time, the lowest tank i got was 16(twice) and the best i got was 24.5. my grand marquis got 15-16 in town and 18-20 on the road.

t_chelle16 · Jan 3, 2008

I actually keep track of my gas milage religiously (maybe I'm a bit masochistic like that ) I've had the car 2 years and I have yet to put in a partial tank; I always top it off and do the calculations.

During the summer I was averaging around 15 1/2 mostly highway (when I go to work, it's about 9 miles highway and about 1 mile in town). It was pretty consistent there no matter how I drove, although I did drive about 20 miles with a horrendous headwind one day and it dropped down to 13 for that tank. And now that it's colder and I have to let it warm up more and the choke is engaged more, I've been getting closer to 13 - 14.

-Chelle

bnickel · Jan 3, 2008

no idea with the new engine but it's not nearly as good as the old one. the last one i had in the car was a basically stock 69 351w M-code motor with flat top pistons and a stock replacement cam advanced 4 degrees, e'brock performer intake, 600 carter afb, mallory unilite conversion in the stock points dizzy and 2 1/4" dual exhaust with factory manifolds. i had to run premium in it because of the compression and the advanced cam and i generally had to get out and retard the timing to get it to start on cold mornings and reset it once it warmed up but it got 24mpg on the highway and about 16 in town. never got around to putting the cam back in straight up before the engine blew because of incorrectly torqued rod bolts (i had a friend build the shortblock because i didn't have time, never again) so i don't know how it would have done otherwise. i do know it was a pain having to retard the timing to start the car, though.

pile_53574 · Jan 3, 2008

I checked it once in the 15 or so years I've owned it. Think it was around 10 or so!! 69 coupe, C4, 302, Edelbrock performer RPM package, dual exhaust, headers w/glasspacks(LOUD), Oh and 4.10 gears & a heavy right foot!!!

bnickel · Jan 3, 2008

the next engine i build should get really good mileage, here's the plan.

351w block and crank
351m/400 rods
keith black long rod hypereutectic pistons
mild retro roller cam
SVO X-305 heads
93 cobra 1.7 roller rockers
original C90X aluminum intake
ported stock exhaust manifolds

fuel and ignition systems are undecided, either;
heavily worked 650 holley or 600 autolite 4100
duraspark dizzy with MSD 6a box
or
holley commander 950 projection 700 TBI
MSD small cap TFI dizzy with msd 6a box
or
retrotek boss efi system
duraspark dizzy with msd 6a box

any of the above combos should make good power in the 350-400hp range and still get really good mileage with the compression in the 10-10.5:1 range, the long rod combo, and a fairly small cam.

this will all be going in the 69 cougar with an AOD and 3.25 gears with probably a 2.25" dual exhaust. i'm shooting for 25+mpg on the highway, we'll see how well it does once it get's built which won't be until i get the mustang sold

chepsk8 · Jan 3, 2008

Gas mileage? What's that?

Actually, the best I ever got in the Mach was 14, all highway, doing 60 on the way out to Indianapolis with the car. The worst? Well, um, 3.

I have never measured the Cobra, as I cannot keep my foot out of it, but I can stretch a tank out to a full day on a race track.

bdepedro · Jan 3, 2008

I actually thought about keeping track to MPG but then figured what the heck, I really don't care since I don't drive my Stang daily and gladly sacrifice mileage for performance. If I want good gas mileage I'd drive a Honda.

68keyblr · Jan 3, 2008

I keep an Excel workbook on my PocketPC for gas mileage on all of my cars.

My '68 with C4 gets 13-15 with normal around town driving. I've gotten 18 on long trips before and as low as 11 when I've played a bit too hard.

My '88 GT with T-5 and a warmed up 331 averages 20-22 and it's still got less than 4K miles on it. Haven't gotten below 19 on it even when driving it hard, which I do frequently. It's gotten as high as 23 so far. I'm hoping for 25 when it's completely broken in.

jlangholzj · Jan 3, 2008

lol, with frequent spirited drving, uumm 13 ro so, but if i drive sensibly I'm in the 16 range. it will be interesting to see how much this drops with the new cam in....

289-C4-3.00 rear-600 cfm holley

jcp123 · Jan 3, 2008

68keyblr said:
My '88 GT with T-5 and a warmed up 331 averages 20-22 and it's still got less than 4K miles on it. Haven't gotten below 19 on it even when driving it hard, which I do frequently. It's gotten as high as 23 so far. I'm hoping for 25 when it's completely broken in.

That's amazing. I, too used to keep track of MPG religiously in my last three vehicles, and in particular my SVT Focus (which I'm selling to drive the Stang ) still only averages 25 or so. I've gotten mid-high 30's with a best tank of nearly 37mpg on the freeway, but we don't have a freeway here so I don't get to take advantege of that. Hmm...331ci @ 25mpg or 121ci @ 25mpg...I think you got the better deal

shatter · Jan 3, 2008

I used to track mine when my 69 Coupe was a daily driver. It has a 302-2v engine, 2.79 gears and a C-4 auto tranny. I could get 20-22 mpg on the highway and mid to high teens in town assuming I drove it easy. This was on a bone stock engine, no mods.

jcp123 · Jan 3, 2008

I'm getting kind of discouraged here...my engine is so mild it should be getting WAY better than ~13...

StangDreamin' · Jan 3, 2008

Yeah, that does seem kind of short...... gears, maybe?

My only true "performance car", the '73 Gran Torino regularly got on the high side of 22 on highway runs; although it did once post a dismal run from Tucson up through Show Low, Arizona to the little town of Overgaard: only 11.8 on the trip up. Now, Mrs StDr had picked me up after work (1530 hrs); and we did get up there by 1845 for my Dad's surprise Birthday party, so.... ummmm.....

Was lots of fun passing everybody I could see while climbing out of Salt River Canyon

351C-2V engine, 60 thousand-ish on the "unopened" stock short-block; Edelbrock F351 (now they call it the "Performer #2750"); 600 CFM vac. sec Holley; 1970 timing set (got rid of the rotten 1973-spec 10* cam retard for "Emissions"). FMX, 3.00:1 pegleg. Ran it on 89 octane pump gas ('course, that was the "low-end" leaded regular in the early 80's..... 87 octane wouldn't sell).

jcp123 · Jan 3, 2008

Won't be gears...she's got the 3:1 economy cogs in there. Had 2.73's in my '68, don't care to do back to those. Eventually, though, it'd be nice to have an AOD with some 3.73's or 4.10's. I think some of it goes back to the Carter AFB - it dynoed with a pretty good A/F mix, but as good-natured as it was this morning when it was ~25* out and with all the soot in the tailpipes I have to think it's jetted a little fat. Oh well, at least the throttle response is amazing and the mornings aren't a battle to keep her running in the cold. I'll read what the plugs have to say on the subject, too. For now, I hope it'll come up when I gap out the plugs for the hot ignition and I might stick a clutch fan on there as well. I know it's not real popular, but I think it'll come up again, too, when I start running Mobil1 synthetic in there too.

bnickel · Jan 4, 2008

you can pretty much bet that the synthetic oil will help a little bit, probably not much though, i'm guessing 2mpg max and likely less than that but every bit helps

coolblue65 · Jan 4, 2008

I got 20/21MPG on the highway during a 200 mile drive with the new 347. That was at 70/75mph in 5th gear the entire way.

68keyblr · Jan 4, 2008

jcp123 said:
That's amazing. I, too used to keep track of MPG religiously in my last three vehicles, and in particular my SVT Focus (which I'm selling to drive the Stang ) still only averages 25 or so. I've gotten mid-high 30's with a best tank of nearly 37mpg on the freeway, but we don't have a freeway here so I don't get to take advantege of that. Hmm...331ci @ 25mpg or 121ci @ 25mpg...I think you got the better deal

Also keep in mind that 25mpg is about an 80/20 freeway/city mix of driving, but still not too shabby. Granted, I have to shift before 2K RPM and really be light on the pedal, but I have the option of murdering a LS-1 camaros or Hemi whatevers if the situation arises

Anybody bother to record MPG on their steeds?

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