Originally Posted by RickRST

Hi All,

Joined from the UK to reply to this post. I build and map engines, including Motronic in my spare time. I'm an instrumentation engineer by profession.

The three things you can really alter on a std car are the throttle response, boost curve, fuelling and ignition.

Boost is limted by the std turbos. I - and other tuners - can ask your turbos to do anything you want, but you have to decide as there are obvious durability issues.

Throttle response - because Motronic is fly by wire, pedal position is not directly related to throttle plate position. There is a map which specifies the relation. A lot of tuners increase the throttle response, which gives the feeling of the car being faster. What this means is that for example 10% throttle = 25% throttle plate angle. With 4wd this works quite well, but you wouldn't want it for relaxed driving or on a turbo FWD for example.

Ignition - Motronic is very clever at detecting Knock. There is LOT that can be recalibrated here, such as what the ECU determines as knock. It's pretty easy to get to optimum though and the key factor is fuel octane level.

Fuelling. This is an interesting one. Most tuners are **** at this. It's quite simple - you want the car to be around lambda 0.8 as soon as you go full throttle, and then richen if EGT's get too hot. Cruise/light throttle should always maintain lambda 1.

The key here is to get the injector and MAF calibration correct. Values should NOT be scaled. This is a botch, it isn't needed if you calibrate the ECU properly. If you scale anything, you upset hundreds of maps in the ECU. If you need a bigger MAF, use the RS4 item. It supports over 600hp and we have a proper transfer function. Calibrating MAF's is not something a tuning company can do very well, it needs incredibly complex flow calcs/testing.

Rick