Audi sent mine out the door with around 150 HP and 160 ft-lbs of torque. That level of power is okay while getting around 22 MPG but when you use it to move the quattro permanent all-wheel-drive system in a car that weighs around 3800 lbs, 150 HP is a little low. The 150 HP 1.8T makes more sense in a VW Golf or Jetta as they weigh less. Later model A4's came with higher HP levels. Thankfully the 160 ft-lbs of torque gets the A4 moving decently enough and can eventually take you all the way up to the 130 MPH electronically governed speed limit.
I liked the way the car drove but I really wanted a little more power. I had already changed out the diverter valve for a Forge 007p and the filter for a K&N box filter. Since the car is already has a factory cold air intake and is turbocharged, the motor's ECU (electronic control unit or engine control unit) is expecting the extra airflow and since Audi uses the ECU to control the turbo, adjusting the ECU should allow for more power.
Thats exactly what APR Tuning has done with their stage 1 EMCS (Enhanced Modular Chipping System). By adding a different chip to the ECU they've allowed for a truly modular system to adjust and actually change the ECU's firmware. Depending on the ECU you can have up to 4 different programs that are tuned to different situations. If you have more than 1 program you can use the cruise control stalk to change to a different program.
For example, the stock configuration will allow for 91 or 93 octane fuel with a stock engine and turbo boost pressures of around 8 psi. After installing EMCS, I chose the 91 octane program which tunes the motor for 91 octane fuel and increases boost levels. I'm sure there are many other parameters that APR has made changes too but for simplicities sake we'll just go with those. APR's EMCS took the motor from 150 HP and 160 ft-lbs of torque to around 200 HP and 240 ft-lbs of torque. If I had upgraded the exhaust and the turbo I would go for the stage 3 upgrade not stage 1 (200 HP is about as good as you'll get with the stock setup). The stage 3 upgrade would put me around 280 HP and 300 ft-lbs of torque but requires the better hardware.
I initially wanted to have 4 programs; stock, 91 octane, 93 octane and valet mode, along with the security lockout, Fault Code Erase/Throttle Body Alignment and Anti-Theft system options. Unfortunately, my ECU would only allow me to have 2 programs and of those I could only have 91 octane mode and 100 octane mode. I later decided to just have them flash the chip with the 91 octane program since I don't see myself running 100 octane at anytime and it was $50 cheaper at that time.
It turns out that programs are dependent on the ECU and motor version. I have an AEB 1.8T which doesn't allow for the 93 octane programs and valet programs or DirectPort. This also means that I can't use the stalk to switch the programs. If I had gotten the 91 octane AND 100 octane program I would have needed a special switch to switch the programs back and forth. That isn't really an issue for me as it just brought down the price.
Now, I didn't install the EMCS chip myself though I did install my VW Golf's Techtonics Tuning chip. I took the car over to ECS Tuning's new location in Wadsworth, Ohio. They were helpful and courteous and provided quick service. The process took about an hour but I was there for 2 hours due to a misunderstanding with the ECU (that's how I found out about the variations in ECU and program options). I chose to go to the shop as opposed to ordering online and shipping my ECU to them. By showing up I got to talk to the people and test the car immediately. It was the fastest option as the shipping option could take as little as 3 days.
ECS Tuning isn't the only place you can get the APR chip but for me was the fastest way. One of the best ways to upgrade your ECU is to go to a car show. A lot of times, companies like ECS (APR) or Haus of Dubs (who carries Unitronic) might setup a booth and offer a discounted price and will do the upgrade right in front of you.
Despite the mild complexities, the upgrade is completely worth it. It really opens the performance up and puts the car onto a new level with an OEM plus feel. APR did a great job and created a very well engineered product. As well, ECS Tuning made the process nearly painless. Chipping is probably the fastest way to make more power and usually offers the most bang for your buck. Next I plan on swapping in an APR Carbonio intake so I can hear the turbo spool up and the diverter valve. Stay tuned ;)