Vtec04

Probably a dumb question, but how does tuning an ECU increase power? As far as I know, the ECU goes into “maximum power” mode and ignores fuel efficiency at full throttle anyway. Am I right? I understand that tuning will improve throttle response at partial throttle by constantly running rich at the expense of efficiency, but it runs rich at full throttle anyway. Thanks.

1HGEJ2

iTrader: (1)

lean fuel..incrasing ignition, make power. u dont have this on stock ecu.

Vtec04

But if full throttle performance could easily be way better just from tuning, why wouldn’t they tune them for gas mileage at part throttle like they do, but tune for maximum performance at full throttle from the factory?

2x0

Two main reasons

- Factory tunes are universal and do not account for variations in each individual engine build. Therefore they have added safety factor built in.

- They do not tap every bit of power because they favor longevity of the engine.

So in most if not all cases, there is more power to be made by tuning timing and fuel for what a specific engine needs, and maximizing its potential.

Vtec04

So they may, for instance, build an engine that can make 150 HP, but they may intentially limit it to, for example 130 HP with the factory tune? So how much power can be made by tuning the timing and running on 93 octane, and how much power can be made by adjusting the A/F ratio? Thanks.

2x0

There is no way of knowing without going and getting tuned. Every engine is different.

Also glad you brought up 93 octane. Car makers have to take into account the crappy gas you may get some places, another limiting factor. Then there's substandard aftermarket replacement parts, such as ignition components, filters, and the variables go on and on.

pogeeboy27

iTrader: (3)

Good reading for tuners