E-Bodies.org Cuda Challenger Forum

My engine ran remarkably well on fuel consumption this last hot week-end.
Went on a long drive and gas gauge stayed pretty steady.

Running a little higher Octane certainly helped.

I estimated my Hemi was getting around 15 MPG.

Would like to hear how you all are doing on long cruising gas mileage.

700 mile round trip the 'cuda 340 got 13.5 (estimated) w/ 3.23's 727 on 14" and the AAR got almost 12 (estimated) with 3.91's 4-speed.  It probably improved a bit once we fixed the fuel leak.

I'd be surprised if I get 10 mpg.  And with the small tanks on the E-Bodies it seems like a stop for fuel all the time. 

shouldn't we be measured in Smiles Per Gallon?

Under optimum conditions I was getting 17MPG's , now that I went from 3:55 to 4:10 .... not sure yet but I'd expect a drop?

Hey Brad, just for clarification, is that 17MP US gal or Imperial gallon? (17mp/Imp. gal. = 14.2 mp/US gal)

Can't remember what my Cuda got but my 71 Road Runner averages 7.5-8.5 mpg. Cuda probably similar. That's mostly highway. 340 with a huge cam, Quick Fuel 650 vac secondary carb and Edlebrock RPM heads with 3.55 rear gears. Automatic transmission with a 2800 stall converter.

13.5 mpg on the highway at 85 mph. 416 CI, 750 Dp, 3.73 rear end, 727 with gear vendors and 26" tires. less on the city  :)

Quote from: chal340 on May 23, 2017, 06:06:40 AM
13.5 mpg on the highway at 85 mph. 416 CI, 750 Dp, 3.73 rear end, 727 with gear vendors and 26" tires. less on the city  :)

Damn good numbers for that combo!

last time I calculated, it was 10 miles on the way out and 7 on the way back.  :stayinlane: 440 with 500HP.

My speedometer is fast, I think I am about 12, country driving, non ethenal hi octane. AND I STAY OUT OF THE 4 BARRELS. 

As I recall the best I have done with a 440 Challenger 3.23 gears 727 auto was 23 MPG at 70 mph  [can gallon]
the other remarkable one is a 67 Coronet R/T 440/512 A833 OD Dana 3.54 making 398 RWhp /460 ft lbs tq doing 17.8 @75 mph [can gallon]

Quote from: Chryco Psycho on May 23, 2017, 08:52:41 AM
As I recall the best I have done with a 440 Challenger 3.23 gears 727 auto was 23 MPG at 70 mph  [can gallon]
the other remarkable one is a 67 Coronet R/T 440/512 A833 OD Dana 3.54 making 398 RWhp /460 ft lbs tq doing 17.8 @75 mph [can gallon]

Those are some really great numbers.

Thanks  :drinkingbud:
Honestly it comes down to 2 things
Using a very good carb such as Proform & taking the time to fully tune it , I am not talking baout an hour or two but days tweaking every circuit
& the second is some very innovative porting in the heads creating clean flow , high velocity & as much swirl as possible to mix the air fuel very well
Making the engine as efficient as possible both in peak power & economy
Both of these engine were running stock iron heads not aftermarket alum as well .

Quote from: Cuda Cody on May 22, 2017, 10:25:14 PM
I'd be surprised if I get 10 mpg.  And with the small tanks on the E-Bodies it seems like a stop for fuel all the time.

Tougher to do with all stock parts
Next time i am up there I should port a set of heads for you & tweak the crap out of  carb & see what that does !!
An engine can still look stock but it doesn't have to perform stock !!

I figured out on my '70 Challenger, SL6 with a 904 (Auto) and 8 3/4, 3.23's about and I believe the weight factor 2800-3200#, 14", 60 series tires, 2 barrel, dual exhaust at 65 MPH, comes in at 18.5 around town stop and go. On the freeway 21-23 on 87 octane. Surprising for a heavy car.     Thanks,   Al

  Last summer I went to a car show in eastern Idaho--about 350 miles round trip. Running 85---100 mph both ways, with 3.55 gears I got just over 9 mpg.  Really need to fix my broke fuel gauge someday.   

Quote from: Jay Bee on May 23, 2017, 05:35:34 AM
Hey Brad, just for clarification, is that 17MP US gal or Imperial gallon? (17mp/Imp. gal. = 14.2 mp/US gal)

Just over 300 miles on a tank, 300 divided by 18 gallon tank.   So whats that US gallons?  :dunno:

The U.S. liquid gallon is defined as 231 cubic inches and equates to approximately 3.785 litres. One imperial gallon is equivalent to approximately 1.2 U.S. liquid gallons.

I'll be annoyed if I can't eek out 20mpg on the highway with my new setup. The 318 got about 10mpg, on the loud pedal quite a bit.

Quote from: Brads70 on May 23, 2017, 02:58:41 PM
Just over 300 miles on a tank, 300 divided by 18 gallon tank.   So whats that US gallons?  :dunno:

Yup, that would be US, an 18 gallon US gas tank =  15 Canadian (Imperial) gallons. That's awesome mileage, now with those new gears..........

My Challenger did great (before the teardown) with the 340 / 727 and 2.96 (or is it 2.93?) in the rear I got 18-19 MPG cruising at 55-60MPH. Brand new Holley Street Avenger and electronic ignition. Way more in city traffic though.

 The best I ever got with my 71 vert 340 4 speed, 3.23 was 22 mpg at 60 mph going from Kennewick Wa. to Portland Or at 60 mph and keeping my foot out of it. Usually, 17.5 to 18 mpg. I'm on a trip right now with the 2015 Challenger R/T 5.7 and averaging around 27 mpg at 75 - 80 mph. Best with it was a 4600 mile trip last Sept to the Midwest and averaged 29 mpg until I got back to the mountains. Then for the rest of the trip, I finished at 27.2 mpg
Terry

Funny common theme here is " when I keep my foot out of it"  :rofl:

Tough thing to do with these cars for sure!  :yes:

I never really gave it a though about my MPG. I'm always thinking about how I can burn more fuel.  :thinking:   :yes::yes:

Quote from: bentpshrods on May 23, 2017, 01:18:28 PM
  Last summer I went to a car show in eastern Idaho--about 350 miles round trip. Running 85---100 mph both ways, with 3.55 gears I got just over 9 mpg.  Really need to fix my broke fuel gauge someday.   

I used to count my mileage with my old car that got 6 MPH. I got caught once short by a mile and that motivated me to fix the gas  gauge. I hope you don't have to walk a mile in my shoes.

Ha, ha. I remember I was driving my 69 Hemi GTX 200 miles to a job some years ago. It was getting phenomenal gas mileage but was pinging on the hills. I had a look and the distributor had moved a bit and it was advanced about an extra 10 degrees. I think I got near 20 MPG that trip.