Well Joester there are several ways to "program" an engine
For example. If you intent is to attempt to win the Daytona 500, you want acceleration and speed, in short, preformance
If they still had the Mobile Economy Run you'd want best fuel millage
If you are going to be hauling steel like my brother does, You want raw horsepower coupled with economy (Why he drives a Detroit Diesel Series 60, Millage plus power in one package designed by a race car driver)
Most engine designs do not allow you to attain all the above with the same settings. So the engine makers set it up with a compromise, Usually performance/millage cross-over point. However with CAFE they may weight toward MPG.
Now: another issue is that the same engine may be used in several vehicles... For example the 8.1L Chevy Vortec I have in my Workhorse Custom Chassis motor home is the very same 8.1L Vortec that Chevy drops in selected Silverados. now, say 4-5,000 lbs of Silverado v/s 22,000 pounds of Motor home.. Clearly different settings are needed.
Also the same engine that turns out a bit over 300 HP in my motor home can crank out 500 HP in a boat (Improved cooling with a lake size radiator underneath you)
Again, different settings on the engine control computer
What the "Super Chip" makers do is set a different part of the curve. Also a full Banks or Ultra power setup will increase the air intake, the exhaust size and other modifications that actually can improve performance, power and POSSIBLY economy.
However, even at 5.00/gallon I don't think the economy increase will make up for the cost of installation.
And.. I know of cases where someone put dang near every modification he could on his engine to improve performance. Dit it work? I don't know
What I do know is in another thread there is a message from someone who is not having a good month.
You see, They blew the engine in THEIR motor home. Over $9,000 dollars to drop in a new motor, plug nearly another thousand to tow it in,, They picked it up, drove it home, and a storm brought down a tree on top of the rig.
(Some days it just don't pay to get out of bed) Now, the two people are not, far as I know, related (The Dude who blew his engine by over-modifying was LAST YEAR, the guy with the tree is this month) but you get the idea
Now only did he throw his money away on "improvements" but another 9-10 grand on a new Engine.
By the way I got the over-modified engine from two people
One, Alan, over at Workhorse (National Service Manager) Who reminded service centers that if you modify the engine in this way it MIGHT void the warranty thus they should look carefully for the cause of the failure.. (I Stress MIGHT)
And From a local Ford Dealer... One was a Chevy Engine in a motor home.. The other a Ford in a car.
In both cases warranty was denied and the owner had to pay out of pocket for the repairs
