The factory tunes your ECU for general fuel economy while driving lightly, and a balance between power and engine-component safety while driving hard.

Typically speaking, the factory ECU always will bend to the safety side. The car is usually overfueled (especially when your foot is on the floor) and they never run ignition advance as far as the mechanicals will allow.

Remember, the stock ECU should be able to run the engine safely on the cheap gasoline, at all altitudes, and under duress of stupid owners. If you are capable of always using good gasoline and don't let the engine degrade due to lack of maintenance and upkeep, then you can run tighter programming without harm.

A fully standalone engine management system can sometimes find 20+ horsepower in a stock car just because you can fine-tune the fuel delivery and ignition timing to get rid of all the "safety" built into the stock ECU.

 

I know the Honda boys have had this done with the Hondata ecm... I've considered try to research it, but i see all the computer language crap that scares me and say fuggit lol.

 

So it could be possible to gain an extra 10-15 horse in my Accent {trying to be conservative} just by altering the messages the ignition timing and fuel delivery systems recieve from the ECU? Sounds good to me.
Is it reasonable to assume, then, that reprogramming an ECU on my 1.6L won't provide the power gains that, say, the 2.0L Beta or 2.7L V6 get. From what I understand, when identical modifications are made to different sizes of engines, it isn't a set power increase that arises, but rather a percentage of the initial power is your power increase.
An ECU might gain 8%; on my 106hp, that'd be an extra 8.5 horse. On the Beta's 140hp, it'd be an extra 11 horse. Please keep in mind that I took 8 % out of my a$$.

 

You are generally correct. The gains you will see depend on the engine itself and how conservative the manufacturer was.

I wouldn't expect 15 horsepower on a stock Accent; I might believe that much coming out of the stock V6 Tiburon because there's just a LOT more motor there. But you have the general idea.

Also keep in mind that "chipping" your car is not the same as truly tuning the ECU to YOUR car. A "chipped" ECU makes a few concessions as well -- that "chip" must apply to the whole market of cars they sell to and thus cannot be tuned to 100% of what your car is still capable of. This is especially true if your car has been modified beyond stock.

Each engine is slightly different, even when stock. There are some that just have sealed a bit better, push just a tad harder, flow just a scant bit more that make those engines just a bit overrated from the factory -- and vice versa. There's generally a 10-80-10 rule: 10% will be under, 80% will be dead on, and 10% will be over what the manufacturer claims. It's just luck of the draw which one you get.

That's a general rule, but gives you an idea of what the manufacturer and even "chipped ECU" manufacturers need to consider when building a ubiquitous computer program.

 

The important part about being able to reprogram the ECU is not necessarily the power gain (from stock form), but the ability to change the fuel curve and timing when the engine gets modified. An extra 10hp from stock form is good, but being able to run 14 pounds of boost with bigger injectors without having to change the ECU is even better wink

Red: There is more than 15hp to be gained from the new V6. Installing reprogrammed ECU in our (Hyundai Motorsports) racing Tibs showed an increase of at least 18% hp. Remeber Cheuk saying those V6 were running pig rich? Well, I guess he was right.

 

Good luck on the project. This is definately interesting. I think it would be fun to learn all of this. If this works out good you can make a killing selling new ecu's.

 

maybe this can help you...

http://www.bgsoflex.com/megasquirt.html

good luck!

 

Just a quick note ECU all have to be OBDii so there is some universal language out there its just a matter of how the computer is sending the data... but what would i know its one of those things that i could be total wrong about.. at least with all cars from 96 are the reason was so that you didn't have to go to a dealer everytime you had a check engine light on.. this OBDii complaince is suppost to allow a home/professional mechanic work on his car.. and not rely on dealers and pay high dealership rates.. hears a little fact

At first there were few standards and each manufacturer had their own systems and signals. In 1988, the Society of Automotive Engineers (SAE) set a standard connector plug and set of diagnostic test signals. The EPA adapted most of their standards from the SAE on-board diagnostic programs and recommendations. OBD-II is an expanded set of standards and practices developed by SAE and adopted by the EPA and CARB (California Air Resources Board) for implementation by January 1, 1996

Just trying to help in some way... i could be totally wrong just keep that in mind