As many of you have made Performance upgrades to you trucks, I was hoping you could share your experience on how certain upgrades affected your MPG too.

I'd like to do some things to improve my trucks performance, but I don't want to kill my efficiency at the same time.

Three things I can think of that might improve both are a less restrictive intake, under drive pulleys on the Engine and replacing the 11 lbs fan blade with electric fans.

Among things that would improve MPG with out effecting HP is replacing my AT tires with Highway tires when the time comes.

Now I may be wrong on the above assumptions and I know there are a lot more things that can be done for both HP & MPG.

That is why I'm hoping for some input from the many of you with personal experience.

Many thanks in advance,

Doug

 

Personal F-150 mpg increases from what you mentioned.
None with air intake kit.
1mpg with underdrive pulleys and electric fans combined.

 

My mileage varies alot anyways, but I am confident electric fans added at least 0.5 mpg to my V6, maybe up to 1.0 mpg.

I also gained significant mileage by going with a Superchip, but the cost to operate is virtually unchanged as the chip requires premium fuel.

I noticed no change in mpg with an air intake kit or with a drop in K&N filter (did the filter first, then changed to an Airaid).

 

I will second the "No Change" with a drop in K&N Filter

Dpostman

 

HI!... Well I'm making 340H.P and 450FT/LBS of TQ (FLYWHEEL) and I get 22MPG

 

I installed a Magnaflow muffler & purchased the 1715 superchip tuner, dont know what one has the most bennifit, but I have gained on average 1.5 - 3mpg without any problem

 

Neal,

I've looked at your gallery and what you have done with your truck is impressive.

But it's way beyond what I, if not most of us, have the skills or resourses to accomplish.

Of what you have done, what could be purchased off the shelf from some place such as Troyer and would improve MPG & HP at the same time?

Doug

 

The question has two different performance paremeters rolled into one and needs to be seperated into there seperate areas.
MPG is classified into minumn throttle to keep the truck rolling.
This is affected by tire rolling resistance, weight, air density and engine performance as designed.
Power (for this discussion) is classified as the engine combustion efficiency under acceleration and wide open throttle being affected by the total engine operating paremeters.
Certinaly it should be seen that air intake changes should not have any effect in the closed down throttle operation where milage would be of concern.
On a stock engine, adding air capacity both in and out has 'little' (not none) real effect over stock OEM hardware because one cannot force the engine to use the extra capactiy unless supercharging is done.
The factory has sized the overall system to be very near 100% useful without creating suggnificant restrictions that hurt power production for the use originally intended.
The programing of the computer is the bigger control restraint on engine performance.
In my opinion, paring a 4.6 in a heavy truck is not the best way to go but corporate decisions dictate these things.
The 4.6 has peak torque spec'ed at 3450 rpm. For normal driving without being aggressive on the throttle, starting from a stop and going through the gears, never revs the engine very much over 2500 rpm.
This being mostly the case, the truck is operating on the very low part of the torque curve. Is it any wonder that acceleration feels so weak?
This is one reason the wide ratio 4r70w trans is used to try and offset the poor torque, below peak, that the engine runs in 99% of the time in the lower gears.
The cruise in OD and even out of lock is still below 2000 rpm at under 70 mph with 3.55 rear gears. Again there is no reasonable torque to accelerate the 5000 lb + truck to any reasonable expectation.
Making air intake changes and exhaust changes does little for this low rpm operation.
A fan change from mechancal to electric does indeed add to performance by relieving the engine of that loading although it is still not free power reguardless of what some may think because the fan takes electrical power from the alternator that has to be run by the engine and does still cause loading on the engine the same as nite lights adds to engine loading.
This run to air intakes for the costs involved and pay back is questionable at best for performance.
I am not at all considering the looks, the feel, or the desires of the owner to want such systems as they don't count for the purposes of my opinions.
Exhaust restriction lowering is alway a plus but again at what expense.
I hear many times that there needs to be some back pressure to retain low end torque. Sorry but that is not techically correct. No engine ever runs better with back pressure. Doing so means there is exhaust gas left in the combustion chamber displacing some of the next incoming charge and that is never good for power on any level.
It has been proven on a dyno that allowing the engine to "just sniff" some of its own exhaust kills power in a big way.
The engine has to do work pushing out the exhaust through the valve and exhaust system. Allowing a restriction to build back pressure adds to this work and subtracts from "takes back" some of the power the engine has already made. This also translates into less fuel milage due to the waisted power after combustion.
Finally, to each his own as to what is done to the trucks and why they feel compelled to do so.

 

If you don't believe in the back pressure theory, then why did I lose all low end torque when I had a 2.25 inch true dual exhaust until I had an H pipe installed? I do have better throttle response now, but don't think it did anything for overrall mileage increases.

 

Don't mean to butt in here but there in lies the misinformation about the term 'loss of power'....

Eliminating back pressure in the exhaust will increase HP but at the same time it kills TQ...

A tuned exhaust gives you the best you can get of both, the highest TQ figures and the best HP in certain rpm ranges.. (one reason why your H-pipe helped balance your exhaust pressure from both banks)

That's why when you have an engine on a dyno there are two graphs for both TQ and HP....and why there is such a separation on the graph where peak is reached for each when compared to rpms...

Hope this helps....

 

Everybody wanders around these things with no knowledge of exhaust flow dynamics.
The reason why torque is lost with these system changes is the new system reduces gas flow speed due to the increased cross sections of the aftermarket system.
This does not scavenge the pipes and cylinders as well as the smaller stock system, in the lower rpm range.
There are other parameters involved as well; that is accustic tuning and temperature.
With, for example, the use of headers, the large increase in surface area causes much faster cooling. This slows gas speed still more and causes more loss of low end torque. A change in pipe and system lengths also affect accustic tuning. Accustic tuning is still another involved subject.
If has nothing to do with back pressure as the reason for losing some lower end response. All that is gained is improved flow in the upper rpm ranges. If that is the goal then by all means go to an improved flowing system.
The factory put a lot of effort into the best compromise for a truck that is already under powered with 281 cu/in.
This is not to say that an aftermarket system designed and tested couldn't keep or improve a small amount on low end torque but it is hard to have faith in any claims unless proven to the point of honesty.

 

True duals, superchip, K&N filter - maybe .5 mpg . Lost a little throttle response and low end torque.