Increase MpG on Dakota 2001 4.7L V8
#11
09-19-2008, 01:58 PM
Desperate for sales
both GM and then Ford
have done quick mods to their full size pickups
to get 1 to 2 MPG better.
Read about the mods they both did here:
https://dodgeforum.com/forum/off-brand-news-concepts-and-rumors/172908-small-tweaks-boost-mpg-say-automakers.html
Notice that neither press release mentions
the addition of a new
super-dupper-wham-bam
Cold Air Intake ..... this is because air intake systems don't improve MPG.
If you don't understand this,
study how a throttle works,
what MAP means,
and what engineers mean by "Pumping Losses".
If you understand Intake Pumping Losses you will also understand why MDS was put on the 5.7 Hemi V8s.
Notice how by adding
low rolling resistance tires,
then aerodynamic tweaks,
they follow up by adding a 6 speed transmission
and either 3.06 to 3.15 rear differential ratios.
both GM and then Ford
have done quick mods to their full size pickups
to get 1 to 2 MPG better.
Read about the mods they both did here:
https://dodgeforum.com/forum/off-brand-news-concepts-and-rumors/172908-small-tweaks-boost-mpg-say-automakers.html
Notice that neither press release mentions
the addition of a new
super-dupper-wham-bam
Cold Air Intake ..... this is because air intake systems don't improve MPG.
If you don't understand this,
study how a throttle works,
what MAP means,
and what engineers mean by "Pumping Losses".
If you understand Intake Pumping Losses you will also understand why MDS was put on the 5.7 Hemi V8s.
Notice how by adding
low rolling resistance tires,
then aerodynamic tweaks,
they follow up by adding a 6 speed transmission
and either 3.06 to 3.15 rear differential ratios.
I am not calling you out on anything or saying you are dead wrong, just looking for your insight. So you mean to say CAI or Performance Intakes in general are a gimic, they offer nothing to an EFI engine?
I am not totally sold on your CAI comment, it may not noticeably give you better mpg (like 5+ mpgs), but I like to think a more efficient running engine can do more work at the same mpgs as an engine running less effiecient. When I use the word efficient I mean the intakes offer more air to the engine, when the engine requires it, giving it an edge over a stock intake.
Another thing, "pumping loss" I dont think really is noticeable at the bottomline consumer engine. I think its more noticeable at your higher performing higher revving engines. The MDS system that they placed on the Hemi, is a higher preforming engine, whats your thoughts on it?
I agree superdak, rolling resistance is a killer to mpg economy
#12
09-20-2008, 06:41 AM
the Ram Pickup MPG Improvement FAQ is a very long read
but it does have a section explaining
Pumping Losses on the Intake side of the engine
you want to start reading at Post #31
where the words
"A vehicle that is either overgeared or undergeared will lose MPG at highway
cruise."
https://dodgeforum.com/forum/showthr...t=56153&page=4
pay special attention where is says:
Imagine that you have a disassembled engine in front of you. Put a loose
piston in a bore and pull it down against the friction of the rings. It won't
be very hard. Now imagine that same piston in the bore has the top of the
bore sealed off and has a vacuum sucked of 12 inches of Mercury.
12 inches of vacuum is about 6 psi of negative pressure. If the piston is
4.00 inches in diameter it has an area of about 12.5 square inches
(remember pi R squared but most cherry pies are round?)
6 pounds per square inch times 12.5 square inches = 75 pounds would be
required to pull the piston down - you probably couldn't do it with the grip
of just a couple fingers! An engine running with a high vacuum in the intake
manifold has to do just this, and for eight cylinders!
Engineers refer to this as one of the two parts of "Pumping Losses". The
other part of Pumping Losses is due to pushing the exhaust out the tailpipe.
Most engine owners easily imagine that exhaust loss, accept it, and spend
a lot of time and money on mufflers, headers, Y pipes etc. These same
engine owners would do well to remember the "Pumping Loss" on the intake side
and try to keep it low during highway cruise conditions.
but it does have a section explaining
Pumping Losses on the Intake side of the engine
you want to start reading at Post #31
where the words
"A vehicle that is either overgeared or undergeared will lose MPG at highway
cruise."
https://dodgeforum.com/forum/showthr...t=56153&page=4
pay special attention where is says:
Imagine that you have a disassembled engine in front of you. Put a loose
piston in a bore and pull it down against the friction of the rings. It won't
be very hard. Now imagine that same piston in the bore has the top of the
bore sealed off and has a vacuum sucked of 12 inches of Mercury.
12 inches of vacuum is about 6 psi of negative pressure. If the piston is
4.00 inches in diameter it has an area of about 12.5 square inches
(remember pi R squared but most cherry pies are round?)
6 pounds per square inch times 12.5 square inches = 75 pounds would be
required to pull the piston down - you probably couldn't do it with the grip
of just a couple fingers! An engine running with a high vacuum in the intake
manifold has to do just this, and for eight cylinders!
Engineers refer to this as one of the two parts of "Pumping Losses". The
other part of Pumping Losses is due to pushing the exhaust out the tailpipe.
Most engine owners easily imagine that exhaust loss, accept it, and spend
a lot of time and money on mufflers, headers, Y pipes etc. These same
engine owners would do well to remember the "Pumping Loss" on the intake side
and try to keep it low during highway cruise conditions.
#13
09-20-2008, 04:28 PM
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Another thing that you can do is replace the stock thermostat I did it in my RT swapped the oem 195 for a 180superstat cost me 12 dollars with the new gasket about an hour to change it out and clean old gasket off , that got me 2 more mpg's I know its not much but my truck runs alot cooler and has a lil bit better performance also.
