Piggyback tuning: What?

I hear a lot about Piggyback tuning lately.

Can someone explain what it actually is?

It's a kind of powerbox with a custom map on it, prepared by your tuner?

Why isn't there such a big power gain like a normal powerbox.

What gains can be expetec in let's say a 115hp BMW 116d.

Thanks in advance
 
I assume you mean a piggyback ecu? I'm sure someone more in the profession will be here shortly to advise you but in the meantime I know the basics of this setup.

Basically it's another ecu that gets wired into the oem unit to control the way it behaves more precisely. Used when the STD ecu has limitations or difficulty controlling wilder mods. Basically a cheap way of going standalone.
 
there are other "tuning boxes" that fit in the loom and intercept the signal and send another to the ecu to alter the settings

i fitted one the other month to my cousins jaguar 2.2d - it pluggged in to the wiring of the fuel rail pressure sensor.....he said its made a big difference to his mpg!
 
there are other "tuning boxes" that fit in the loom and intercept the signal and send another to the ecu to alter the settings

i fitted one the other month to my cousins jaguar 2.2d - it pluggged in to the wiring of the fuel rail pressure sensor.....he said its made a big difference to his mpg!

Hmm curious what it will do to my BMW 116d. As it feels a bit slow now and then.
 
TMC Tuning boxes are very popular with the Abarth 500's

Have a look at Daron's site, they are also TUV approved and theres been no faults with any. Well I'm not really on their forum much Lisa is though.

The good thing with the is it doesn't show as a 'flash' on your ecu so if your cars going in for any warranty work and they're checking up they won't know its been on there.

http://www.tmcmotorsport.com/