Better mpg with 4.56 gears???
#22
11-27-2008, 10:44 PM
Professional
Why not, you will get a performance boost and perhaps better around town MPG. Of course this will be offset by you enjoying your new performance boost.
Any engine is an air pump so the higher the RPM the more air will move through it. In order to maintain the correct air fuel ratio the higher the RPM the higher the amount of fuel it will use. A high manifold pressure low rpm condition will be more efficient than a low manifold pressure high rpm condition.
Any engine is an air pump so the higher the RPM the more air will move through it. In order to maintain the correct air fuel ratio the higher the RPM the higher the amount of fuel it will use. A high manifold pressure low rpm condition will be more efficient than a low manifold pressure high rpm condition.
#23
11-27-2008, 10:46 PM
I call BS! Find a place that will SELL YOU a set of ring & pinions, FRONT & REAR, master install kits and install them all for $600-$750 out the door and give me the phone number, because I can send them A TON of business!!!
#24
11-27-2008, 11:00 PM
Why not, you will get a performance boost and perhaps better around town MPG. Of course this will be offset by you enjoying your new performance boost.
Any engine is an air pump so the higher the RPM the more air will move through it. In order to maintain the correct air fuel ratio the higher the RPM the higher the amount of fuel it will use. A high manifold pressure low rpm condition will be more efficient than a low manifold pressure high rpm condition.
Any engine is an air pump so the higher the RPM the more air will move through it. In order to maintain the correct air fuel ratio the higher the RPM the higher the amount of fuel it will use. A high manifold pressure low rpm condition will be more efficient than a low manifold pressure high rpm condition.
Set your over head counsel to read AVERAGE MPG... if you have INSTANT MPG that would be best.
Now find a long stretch of highway and set your cruse to 2000RPMs.
Make note of how your MPG changes when on going up/down hill compared to when on flat ground.
Notice how your RPMs do not change at all... but your instant MPG reading will change from 18MPG to 14MPG when you encounter an incline... and then 28+MPG when you encounter decline... but if RPMs dictated fuel economey then you should have not seen a change in the overhead read out.
You may need to reset the overhead prior to an incline/decline if you don't have the INSTANT MPG.
The only factor that changed in the test above would be the LOAD on the engine at ANY given RPM... All else stayed the same and the load was the only changing factor and your fuel economey changed with it.
This just goes to show that RPMs alone do NOT dictate fuel economey, its the load on the engine at any given RPM that has more to do with your fuel economey then RPM's alone.
SPEED SAFE, AIR RAM
#25
11-28-2008, 07:52 AM
getting back to common sense
today any interested person
can walk into a lonely Dodge Dealership
and test drive
a 4.56 equipped Ram PowerWagon
these test drives
if done 'convoy style'
can test the 4.56 PowerWagon
against your own truck
or a otherwise similar 2008 Ram model from the dealer lot
or for that matter ... against any vehicle
use cell phone or walkie talkies between vehicles
to communicate steady speed MPG numbers
you can make the comparison better
by adding weight to match trucks
or even better by swapping two tires between trucks
it is sad to see people add $1200 to their credit card balance
without doing a simple low cost (and fun)
comparison test like this
these same people take another money hit
when they eventually try to sell their 4.56 mod'ed pickup
and find that knowledgeable dealerships and private buyers
know that such gears mark a
'ridden hard and put up wet'
vehicle
today any interested person
can walk into a lonely Dodge Dealership
and test drive
a 4.56 equipped Ram PowerWagon
these test drives
if done 'convoy style'
can test the 4.56 PowerWagon
against your own truck
or a otherwise similar 2008 Ram model from the dealer lot
or for that matter ... against any vehicle
use cell phone or walkie talkies between vehicles
to communicate steady speed MPG numbers
you can make the comparison better
by adding weight to match trucks
or even better by swapping two tires between trucks
it is sad to see people add $1200 to their credit card balance
without doing a simple low cost (and fun)
comparison test like this
these same people take another money hit
when they eventually try to sell their 4.56 mod'ed pickup
and find that knowledgeable dealerships and private buyers
know that such gears mark a
'ridden hard and put up wet'
vehicle
#26
11-28-2008, 01:34 PM
getting back to common sense
today any interested person
can walk into a lonely Dodge Dealership
and test drive
a 4.56 equipped Ram PowerWagon
these test drives
if done 'convoy style'
can test the 4.56 PowerWagon
against your own truck
or a otherwise similar 2008 Ram model from the dealer lot
or for that matter ... against any vehicle
use cell phone or walkie talkies between vehicles
to communicate steady speed MPG numbers
you can make the comparison better
by adding weight to match trucks
or even better by swapping two tires between trucks
it is sad to see people add $1200 to their credit card balance
without doing a simple low cost (and fun)
comparison test like this
these same people take another money hit
when they eventually try to sell their 4.56 mod'ed pickup
and find that knowledgeable dealerships and private buyers
know that such gears mark a
'ridden hard and put up wet'
vehicle
today any interested person
can walk into a lonely Dodge Dealership
and test drive
a 4.56 equipped Ram PowerWagon
these test drives
if done 'convoy style'
can test the 4.56 PowerWagon
against your own truck
or a otherwise similar 2008 Ram model from the dealer lot
or for that matter ... against any vehicle
use cell phone or walkie talkies between vehicles
to communicate steady speed MPG numbers
you can make the comparison better
by adding weight to match trucks
or even better by swapping two tires between trucks
it is sad to see people add $1200 to their credit card balance
without doing a simple low cost (and fun)
comparison test like this
these same people take another money hit
when they eventually try to sell their 4.56 mod'ed pickup
and find that knowledgeable dealerships and private buyers
know that such gears mark a
'ridden hard and put up wet'
vehicle
The reason you don't understand it is simple... Someone has not posted the information for you to cut & past. And since your mathematically challenged and cant think for yourself you don't have the capacity to grasp the concept to understand.
Unless you have specific experience with a .67 overdrive with 4.56's and 32" tall tires your opinion is WRONG and worthless. You clearly refuse to do the math... which I would think you would at least attempt to understand since your always calling for independent testing... Math brings that testing right to your lap... you can do your own testing, math has only ONE right answer... But you cant even get MATH to agree with your own theories... so now Mathematics are out to get you as well. Yes your right I have conspired with Mathematics to make my point... which points out your WRONG ... AGAIN!
Your opinion is based on 70's thinking. There where no overdrives back then so in that case your opinion would be VALID. So I cant say your all wrong... Your opinions are valid to about the early 80's... after that your opinions are dated and rusty at best.
SPEED SAFE, AIR RAM
#28
11-28-2008, 10:06 PM
Professional
Test your theory out with a simple test.
Set your over head counsel to read AVERAGE MPG... if you have INSTANT MPG that would be best.
Now find a long stretch of highway and set your cruse to 2000RPMs.
Make note of how your MPG changes when on going up/down hill compared to when on flat ground.
Notice how your RPMs do not change at all... but your instant MPG reading will change from 18MPG to 14MPG when you encounter an incline... and then 28+MPG when you encounter decline... but if RPMs dictated fuel economey then you should have not seen a change in the overhead read out.
You may need to reset the overhead prior to an incline/decline if you don't have the INSTANT MPG.
The only factor that changed in the test above would be the LOAD on the engine at ANY given RPM... All else stayed the same and the load was the only changing factor and your fuel economey changed with it.
This just goes to show that RPMs alone do NOT dictate fuel economey, its the load on the engine at any given RPM that has more to do with your fuel economey then RPM's alone.
SPEED SAFE, AIR RAM
Set your over head counsel to read AVERAGE MPG... if you have INSTANT MPG that would be best.
Now find a long stretch of highway and set your cruse to 2000RPMs.
Make note of how your MPG changes when on going up/down hill compared to when on flat ground.
Notice how your RPMs do not change at all... but your instant MPG reading will change from 18MPG to 14MPG when you encounter an incline... and then 28+MPG when you encounter decline... but if RPMs dictated fuel economey then you should have not seen a change in the overhead read out.
You may need to reset the overhead prior to an incline/decline if you don't have the INSTANT MPG.
The only factor that changed in the test above would be the LOAD on the engine at ANY given RPM... All else stayed the same and the load was the only changing factor and your fuel economey changed with it.
This just goes to show that RPMs alone do NOT dictate fuel economey, its the load on the engine at any given RPM that has more to do with your fuel economey then RPM's alone.
SPEED SAFE, AIR RAM
OK, but I thought the question was about gears and fuel efficiency. Take my truck with 3:55s and the identical truck with 4:56s and do the same test at the same speed over the same course. The truck with 4:56s going up the same will be at a higher RPM with slightly less throttle pressure but will still use a little more fuel.
My Corvette gets better mileage in 6th gear than in 5th gear on the freeway at the same speed. Both are overdrive but 6th gear is about 400 RPM less than 5th and on the instant MPG readout there is about 2 MPG difference. I flew for about 35 years and to get the longest range the book said higher manifold pressure lower RPMs was better. A caveat to all of the above, it is entirely possible that I misunderstood the concept of the whole thread.
That's all I know. As the old saying goes your mileage may vary.
Rick
#29
11-28-2008, 10:57 PM
OK, but I thought the question was about gears and fuel efficiency. Take my truck with 3:55s and the identical truck with 4:56s and do the same test at the same speed over the same course. The truck with 4:56s going up the same will be at a higher RPM with slightly less throttle pressure but will still use a little more fuel.
My Corvette gets better mileage in 6th gear than in 5th gear on the freeway at the same speed. Both are overdrive but 6th gear is about 400 RPM less than 5th and on the instant MPG readout there is about 2 MPG difference. I flew for about 35 years and to get the longest range the book said higher manifold pressure lower RPMs was better. A caveat to all of the above, it is entirely possible that I misunderstood the concept of the whole thread.
That's all I know. As the old saying goes your mileage may vary.
Rick
My Corvette gets better mileage in 6th gear than in 5th gear on the freeway at the same speed. Both are overdrive but 6th gear is about 400 RPM less than 5th and on the instant MPG readout there is about 2 MPG difference. I flew for about 35 years and to get the longest range the book said higher manifold pressure lower RPMs was better. A caveat to all of the above, it is entirely possible that I misunderstood the concept of the whole thread.
That's all I know. As the old saying goes your mileage may vary.
Rick
Im not speaking from OPINION... I'm speaking as a matter of FACT.
In my 2002 Ram with the 45RFE (.75 overdrive) and 32" tall tires I in fact went from 3.55's to 4.56's and GAINED 3-4MPG @60MPH.
Those with a 2003+ 3rd Gen Ram with the 545RFE (.67 overdrive) can expect slightly better MPG to 65-70MPH with 4.56 gears.
Also, I only gained three hundred RPMS at 60MPH... Your fuel economey will NOT get worse by FIXING/IMPROVING/OPTIMIZING the Overall Gear Ratio... Worse case, your MPG will not change but performance will improve greatly.
Your corvette weighs over a thousand lbs less... and is shaped like a door wedge! Not the same. Sure if we put our trucks on a diet and improved the Aerodynamics we could see better MPG with a 3.55... but thats not the case with our 3rd Gen Rams as delivered.
This is a new subject on Dodge Forum... and its clear the members are new to this idea... but check around and you will find that the subject has been beaten to death and found to be HIGHLY PLAUSIBLE and backed by many people who have in fact improved their overall gear ratio swapping their 3.55's for 4.56's!
Again, not an opinion.
SPEED SAFE, AIR RAM
Last edited by AIR RAM; 11-28-2008 at 11:02 PM.
#30
11-28-2008, 11:53 PM
Professional
I think you have misunderstood.... with one person trying to cloud the facts... I can see how its easy to get knocked off track...
Im not speaking from OPINION... I'm speaking as a matter of FACT.
In my 2002 Ram with the 45RFE (.75 overdrive) and 32" tall tires I in fact went from 3.55's to 4.56's and GAINED 3-4MPG @60MPH.
Those with a 2003+ 3rd Gen Ram with the 545RFE (.67 overdrive) can expect slightly better MPG to 65-70MPH with 4.56 gears.
Also, I only gained three hundred RPMS at 60MPH... Your fuel economey will NOT get worse by FIXING/IMPROVING/OPTIMIZING the Overall Gear Ratio... Worse case, your MPG will not change but performance will improve greatly.
Your corvette weighs over a thousand lbs less... and is shaped like a door wedge! Not the same. Sure if we put our trucks on a diet and improved the Aerodynamics we could see better MPG with a 3.55... but thats not the case with our 3rd Gen Rams as delivered.
This is a new subject on Dodge Forum... and its clear the members are new to this idea... but check around and you will find that the subject has been beaten to death and found to be HIGHLY PLAUSIBLE and backed by many people who have in fact improved their overall gear ratio swapping their 3.55's for 4.56's!
Again, not an opinion.
SPEED SAFE, AIR RAM
Im not speaking from OPINION... I'm speaking as a matter of FACT.
In my 2002 Ram with the 45RFE (.75 overdrive) and 32" tall tires I in fact went from 3.55's to 4.56's and GAINED 3-4MPG @60MPH.
Those with a 2003+ 3rd Gen Ram with the 545RFE (.67 overdrive) can expect slightly better MPG to 65-70MPH with 4.56 gears.
Also, I only gained three hundred RPMS at 60MPH... Your fuel economey will NOT get worse by FIXING/IMPROVING/OPTIMIZING the Overall Gear Ratio... Worse case, your MPG will not change but performance will improve greatly.
Your corvette weighs over a thousand lbs less... and is shaped like a door wedge! Not the same. Sure if we put our trucks on a diet and improved the Aerodynamics we could see better MPG with a 3.55... but thats not the case with our 3rd Gen Rams as delivered.
This is a new subject on Dodge Forum... and its clear the members are new to this idea... but check around and you will find that the subject has been beaten to death and found to be HIGHLY PLAUSIBLE and backed by many people who have in fact improved their overall gear ratio swapping their 3.55's for 4.56's!
Again, not an opinion.
SPEED SAFE, AIR RAM
I still believe the laws of thermodynamics are still in force and that consensus is not science..... "backed by many people who have in fact improved their overall gear ratio swapping their 3.55's for 4.56's!"
We will have to respectfully agree to disagree on this one AIR BLADE. If I didn't have a Procharged Corvette and a Honda 954RR I might consider putting 4:56s in my truck.
Rick