Same Day Tuning - no removal of the ECU.
Powerchip's  Performance Chip Tuning Software Upgrades result in a very noticeable  increase in performance and acceleration, as well as better fuel economy  and smoother throttle transitions.
Modifications Made to the Software Include:
Ignition Timing
In  the old days the ignition coil(s) and distributor controlled engine  ignition spark timing.  Changes to the position of the distributor would  result in changed ignition settings, and often was a good method of  vehicle ‘tune-up’.   The modern engine ignition is controlled through  the ECU Software within a series of tables or maps. These maps give the  engine any instructions required to operate, under all load and rev per  minute points.
Similar  to the older systems, advancing the point of ignition within a cylinder  will result in increased horsepower and toque. It is important not to  advance the timing beyond the capabilities of the fuel used, or else  detonation can occur. Peak horsepower is achieved when ignition timing  is set as close to the point of detonation as possible. This is the  primary purpose for tuning the octane rating of each client, so that the  software is set to the correct level of ignition advance for the  gasoline used.
The  end result of ignition advance changes is increased horsepower and  torque, resulting in better acceleration.  Some vehicles also result in a  slight change in engine note, giving a more aggressive sound.
Fuel Mixtures
Most  fuel injected vehicles also look to a set of tables or maps for  information on fuel delivery.  Often, the vehicle will access fuel and  timing information simultaneously.  Fuel settings are an area that  Powerchip achieves excellent improvements in power and torque.
Since  the introduction of strict emission laws in North America, vehicles are  required to trim fuel in 2 different modes, known as Closed-loop and  Open-loop. Closed-loop is designed for when the car is under constant  part throttle openings or cruising.  The fuel mixture setting for this  mode is generally 14.7:1, or 14.7 parts of air to every 1 part of fuel.
When  the throttle reaches certain positions (generally above 70% throttle  opening), the vehicle switches to Open-loop operation. Most standard  vehicles run overly rich in this mode, and correcting these mixtures can  enhance performance.  Generally, when in Open-loop, a vehicle will run  between 9:1 and 11:1, with the optimal performance setting between 11:1  and 13:1.
As a side benefit, most Powerchip equipped vehicles will use less gasoline after install.
Part Throttle Tuning
Besides  the gains achieved when under hard acceleration, with Wide Open  Throttle, Powerchip spends a lot of time developing the part throttle  fuel and timing curves.  The result of this attention to detail is a  smoother and easier to drive vehicle.  The Powerchip equipped vehicle  will respond instantly and effortlessly at any point in the rev range  and at any throttle position.
Throttle Response
Since  the introduction of drive-by-wire technology, vehicles look to a third  series of tables or maps for information on throttle responsiveness.  By  changing the values contained in these tables, the vehicle becomes far  livelier.  The vehicle becomes easier to drive and responds to throttle  inputs immediately.  Rather than the vehicle having a slightly ‘flat’  feeling, the throttle response changes give the driver excellent  feedback through the throttle pedal.
Raised Rev Limit
All  engines are limited to the number of engine revolutions predetermined  by the engine designer.  This ‘rev limit’ is preset within the engine  software code, and can be adjusted (up or down) to achieve higher  maximum engine revolutions.  Powerchip will raise the rev-limit to  approximately 200-500rpm above standard.  A raised rev limit is only  available on certain vehicles.
Fuel economy and drivability 
Powerchip  will not increase fuel consumption dramatically – only when peak  performance is demanded.  Under normal conditions, fuel economy can  actually improve.  Powerchip retunes the engine management under all  throttle positions, and will improve the power wherever available  (rather than at full-throttle only).  Smoothness and drivability are  maintained and even enhanced. 
Removed Top Speed Limit
Similar  to the rev limit, the engine management system on certain vehicles is  preset to not exceed certain speeds.  Powerchip is able to modify the  parameters relating to vehicle top speed, and raises the setting to come  in above the natural top speed of the vehicle (according to power Vs  drag co-efficient).  By raising this value in the code, the vehicle is  able to achieve its natural top speed.
Modified Turbo Boost Pressure
Boost  pressure on late model vehicles is controlled within the engine  management program on a set of tables, similarly to the ignition and  fuel tables as discussed above.  By changing the values inside these  maps, the vehicle is instructed to run a higher level of boost pressure.
When  a turbocharged vehicle runs higher levels of boost, performance is  improved.  It is important that when boost is raised, other programming  for fuel and ignition is adjusted to suit.