SUPERCHIPS FOR PETROL INJECTION ENGINES
All efi engines have an ecu, chippable ecu,s are fitted with a simple chip which has a 3d map in side, the ecu gathers information from all the engine sensors and using this information it looks at the 3d map to find a point on the map telling it how much fuel to put in and how much advance or retard to give.
A standard map is programed to give a smooth economical reliable engine, and also to work well in a very wide mannor of temprature ranges across the world, inturn it robs an average petrol engine of 10% of its power.
When you fit an aftermarket chip to a n/a petrol engine the major thing that is altered from the standard map is the ignition timming by advancing it, in fact most chips alter only this!
Advanced ignition timming improves the engine bhp and torque by making the most of the rapidly exspanding gasses inside the cylinder when the engine has fired. When the piston is moving towards the top of the stroke with a fresh charge of air and fuel, it will be ignited before the piston gets to the top, this is because gasses take time to exspand and by the time the pistons is just creeping past top dead centre the fresh charge will have started acting on the piston crown pushing it down, if the mixture is ignited too early then the charge will act on the piston while it is still on its way up,,,,,to forces acting on each,,,,,something has to give, and thats normaly the piston crown! this is called detanation (not to be confused with pre-ignition!)
However as the engine gets faster the amount of timming advance is increased to the point where the spark plug may be firing when the piston is only half way up the cylinder at high revs, as a rule more advance is more power until BANG too much! time for a new engine.
You may wonder if more advance is more power then why didnt the manafacturer just do that in the first place!!??
Well like i mensioned earlyer cars have to work at -35 and 100 degrees,and i also mensioned that too much advance will cause dreaded DET, well take your chipped car to death vally and cane it,,,,it wount last long with the chip, this is beacuse the air there is very hot and hot charge temps make fuel more likley to exsplode rather than exspand so where as the advanced igntion works well here over here the limit of max advance is lessend because the hot air would cause detonation at those high lelves of advance.
Chips can also be made to combine with a popular level of tune for example, if stage 1 for your car is an air filter,exhaust and manifold then the chip will be programmed to give just the right increase in fuel and advance to work best with the increase in airflow, go outside of those mods and the fueling will be wrong and you wount be gaining alot.
So chips increase ignition advance to give increases in power and torque and can be matched to an engine spec to give fuel increases and better economy.
A chip is good but the best by far is a remap (custom is best) because the map can be tailored to your engine spec!!
Maps and chips are differnt for turbo cars and diesels!!
