EPA MPG vs real world MPG clarified
08-05-2014, 09:57 AM
#151
Senior Member
For years the automotive industry relied for the most part on three speed manual transmissions. That was all most people needed or expected. Extra gears were added to achieve a particular goal. In trucks there was a need for a more controllable slow speed so the Truck four speeds had a 'Granny" gear for first gear and for normal street use you started in second gear. The "granny gear" was useful to farmers picking up hay in the field and a host of other needs to go slow. It wasn't normally used all that much over a years time, but very helpful when necessary. In cars four speeds were used by 'economy' cars such as the early 50's VW Beetle. You needed the extra gears to keep that little 36 HP engine in it's 'power' range. Then came the muscle cars. You really needed, I say needed to hear it "Get Rubber" for an extra shift. At least me....
Early on we had many cars with an "Overdrive" to add an extra amount of economy on the highway. Later they started making four and five speeds with an actual "Overdrive gear" in the transmission. We got four speed automatics, then in the mid nineties five speed automatics. And now we have computer controlled six, seven, and eight speed automatics.
I don't think the extra gears of an eight speed add much economy to a bigger engine. They might help with a small engine. But the difference for MPG with a 3.5 EB or 5.0 are going to be less than 1 MPG overall in my opinion. Flatlanders might benefit from a more economical high gear, but any hills at all ad the computer will downshift and upshift all the time. Annoying to me.
Then there is the price we pay. More gears means more parts and they all cost. More parts the greater chance for failure. How are the Chrysler 8 speeds holding up? I don't know, but I know they added to the cost of the vehicle.
Six is enough for me.
08-06-2014, 01:16 AM
#153
Hemi Ram's, Hemi Chargers, Hemi 300's, etc all now have 8 speeds and especially noted in
the Ram 1500 you will see a 2mpg city and 2 mpg highway difference which is very good.
My brother has a 2013 Laramie Longhorn with the Hemi and 8 speed......so I can confirm it's much better real world.
http://www.fueleconomy.gov/feg/Power...WD&srchtyp=ymm
Gears are added to keep the RPM's down to a minimum......which is what saves the gas.
That is how I have maximized my MPG's in my F150 EcoBoost as well.......keeping my acceleration rpm's low.
This is especially evident in the 1993-2002 F-body Camaro's and Trans Am's with
the difference between the 4L60e Automatic with 4 speeds, and the T-56 manual with 6 speeds.
The final gear being a .50 in the T-56 gave the 6 speed a huge advantage with Chevy V8 engines.
Luxury cars have already implemented 10 speed transmissions as well. Now while the cost of repairs
obviously goes up........zero doubt, one must assess overall cost of ownership longterm if they decide to keep it.
This is one of the reasons I'm a bigger fan of manual transmissions.
Last edited by CreepinDeth; 08-06-2014 at 01:26 AM.
09-06-2014, 06:23 AM
#155
Junior Member
I drove my 2011 SCREW with a 3.7L about 150 miles yesterday with about 50 miles highway and the rest 2 lane back roads and I only got 21.5 AMPG. Man I want my 05 STX 4x4 back or my 96 XLT they both got about 14 MPG. I love my new truck.
09-07-2014, 10:17 AM
#156
Senior Member
Chrysler's success with 8 speed's & Hemi's disproves your opinion.
Hemi Ram's, Hemi Chargers, Hemi 300's, etc all now have 8 speeds and especially noted in
the Ram 1500 you will see a 2mpg city and 2 mpg highway difference which is very good.
.
.......keeping my acceleration rpm's low.
This is one of the reasons I'm a bigger fan of manual transmissions.
Hemi Ram's, Hemi Chargers, Hemi 300's, etc all now have 8 speeds and especially noted in
the Ram 1500 you will see a 2mpg city and 2 mpg highway difference which is very good.
.
.......keeping my acceleration rpm's low.
This is one of the reasons I'm a bigger fan of manual transmissions.
Gee .... and like I said on a Bigger engine, well why stop at eight let's get a fifteen speed right now.
by RPM's low you mean within the maximum torque band right,,,
I do not want to pay upfront for a eighteen speed, I'll pay at the pump as I go.
09-19-2014, 08:02 AM
#159
Did another mileage run, got 21.9 MPG's ove all. BUT I do 90% Highway so keep that in mind, I am very gentle and do not excelerate fast, I baby the hell out of it! LOL. AND I only have 380 miles on it, so after break in, it may be a little better than that!
