Fuel economy

[geffen928]

Evening Gents......I have a question that's most likely going to provoke a wide array of answers.  Here goes.......My plan is to have Indy build me a fairly mind 572 Hemi for street use in my '69 Charger.  For those already  running an engine of similar displacement, what kind of fuel economy do you realize.  I know, there are lots of variables to this question.  My car is an automatic w/3000 stall converter, 3:55 gear, G60-15 tired street only machine.  It will be using the Holley Sniper Stealth EFI. I'm just looking for some real world reporting on your setup and resulting fuel usage.  I clearly understand these cars are not designed for fuel economy.  They're designed for fun.  That said, when a car gets 3 MPG, that takes a bit of fun away.   I'm not expecting 15MPG, but would 10-11 be possible??   Fire away.

Geffen

[OzCharger69]

I'm in the same boat. i don't really care about fuel economy, I'm more concerned of range anxiety and living from pump to pump.

I currently have a 383/727 and am waiting for a 512 (650 HP) to be built. That will be mated with a TKX 5 sp because I firmly believe that gearing is the key to get decent economy. It all really depends on how you drive as well. My 383 gives me 220 miles to the tank with normal driving. Last Saturday I barely made 120 miles with some "spirited" driving.

[geffen928]

Thanks for the input.  I'm just wondering if it's as simple as a 50%larger engine gets 50% less gas mileage??  That said, the Hemi has much better volumetric efficiency and better flame propagation than the wedge.....All that equals greater overall efficiency.  Yes / No???

Geffen.

[c00nhunterjoe]

My 440/727 gets 3.5 mpg cruising with an 8" converter, 30" tire and 4.88s. It is worth every prius tear.

[metallicareload99]

Thanks for the input.  I'm just wondering if it's as simple as a 50%larger engine gets 50% less gas mileage??  That said, the Hemi has much better volumetric efficiency and better flame propagation than the wedge.....All that equals greater overall efficiency.  Yes / No???

Geffen.

I think "modern" wedge heads have narrowed the Hemi vs wedge gap considerably, though I agree a Hemi still has an advantage. I get a very consistent 10 mpg with a fuel inject3d wedge, but it is only a 440.

An x% larger engine will result in y% more pumping loss, which would result in z% fewer mpg is probably more reflective of reality. Bottom line, it shouldn't be "much worse."

[Bronzedodge]

My 440/727 gets 3.5 mpg cruising with an 8" converter, 30" tire and 4.88s. It is worth every prius tear.

[Challenger340]

At the risk of extending the definition of oxymoron..... as it relates to even participating in a discussion of fuel economy on a 572 Hemi Engine build ?

Customer reports 3-5 mpg light cruising/4.10's W/31" Tires .... 572 KB/Stage V on 91 Octane @ 930 hp Carbureted.

[Mike DC]

  
   The mileage is not a stupid question at all.  


Let's re-frame this:

Imagine a video clip of an electric vehicle fanboy.  He is bragging about the model's new battery: "With the 100-mile range it's safe to go on road trips anywhere."  

Do you have the urge to laugh?  It's tempting.  "100 miles?  By the time you include a few miles of safety cushion, that barely leaves 1 hour of driving between recharges.  Maybe that range is usable in New York city but in the red states it's a joke!"  

---------------------------------


5 miles per gallon x 2nd-gen Charger gas tank (19.5 gal) = 97 miles per tank.  
     

[cdr]

 
  The mileage is not a stupid question at all.  


Let's re-frame this:

Imagine a video clip of an electric vehicle fanboy.  He is bragging about the model's new battery: "With the 100-mile range it's safe to go on road trips anywhere."  

Do you have the urge to laugh?  It's tempting.  "100 miles?  By the time you include a few miles of safety cushion, that barely leaves 1 hour of driving between recharges.  Maybe that range is usable in New York city but in the red states it's a joke!"  



---------------------------------


5 miles per gallon x 2nd-gen Charger gas tank (19.5 gal) = 97 miles per tank.  
     

Yep down here in what USED to be the great state of Texas,, for some a 100 mile trip can just be a trip to the grocery store LOL, Oh & my 512 68 Charger has gotten over 14 to 15 MPG when on the road

[Kern Dog]

"Used to be great" state? What happened? Too many Californians move in?

[cdr]

"Used to be great" state? What happened? Too many Californians move in?

That & other states, they move from their shit hole to here & then what to Change Texas & make it the same crap they left, OOOPS I went political 

[ACUDANUT]

"Used to be great" state? What happened? Too many Californians move in?

YEP. 

[c00nhunterjoe]

 
   The mileage is not a stupid question at all.  


Let's re-frame this:

Imagine a video clip of an electric vehicle fanboy.  He is bragging about the model's new battery: "With the 100-mile range it's safe to go on road trips anywhere."  

Do you have the urge to laugh?  It's tempting.  "100 miles?  By the time you include a few miles of safety cushion, that barely leaves 1 hour of driving between recharges.  Maybe that range is usable in New York city but in the red states it's a joke!"  

---------------------------------


5 miles per gallon x 2nd-gen Charger gas tank (19.5 gal) = 97 miles per tank.  
     

Ive only got a 10 gallon cell in the trunk. You literally do watch the gauge drop as you cruise. Make a 1/4 mile pass and shes ready for a top off.

[birdsandbees]

I put 7.5 gallons (2.5 of AV100LL and 5 Premium 92) into my 340 Dart on Saturday. Wife and I did a 75 mile long French Fry cruise and I had to push the car into the garage when we got home. 10 miles per gallon and I was being pretty easy on it.

[Mebsuta]

Single-digit gas mileage in beat up 383 RR in the big city.  It has 3.91 and 4-speed, and there are bad roads and lots of traffic.  Going anywhere means lots of idling, speeding up, slowing down, and crawling through parking lots.

[AKcharger]

mostly stock 383 4 bbl 3:23's and 15  60's give me around 12 hiway and city combined
my last charger 363 4 bbl 4 speed with 2:76's got 18 highway..yes!

[odcics2]

Here's some perspective:

The #88 Daytona got 4 mpg at 200 mph.

12.5 to 1, Racer Brown STX-24 cam
Equal length Hooker Headers with 2 1/4" primaries into 3.5" collectors and side dumps 
950 cfm Dominator on a bathtub intake
2.76 gear, 29.5" tall tires. 
CD = .29 windows up.