Originally Posted by eatont9999

To replace an ALDA unit, you likely are not going to be using any bits or attacking any screws. To replace the whole unit, you need to unscrew it from its base where it attaches to the IP. You will need a thin, open end wrench to remove it. You may find it necessary to need a second wench to hold the nut on the IP as you remove the ALDA. Don't mess with the flat head screw on the upper face of the ALDA if you are replacing the whole unit.

I suggest taking this time to test out your fuel mileage and performance changes while the ALDA is off. As I understand it, the ALDA is an altitude compensating device that also limits/controls fuel flow/delivery based on boost levels. Removing the ALDA will not over-boost your engine as boost pressure is controlled by the waste-gate. It will provide more fuel flow at lower RPMs and thus more boost, sooner. Nothing wrong with that. Let's say your waste-gate is limited to 12PSI of boost. The sooner in the RPM range you get to 12PSI boost, the better the low range performance will be. If boost was always at 12PSI, you would see very responsive pickup off the line but since that is not realistic on the OM617, you only have a few options.

Just like on my truck, over a certain boost pressure, the air is too hot and not dense enough to be effective. An intercooler will solve that issue but cooling the air and making it more dense at X PSI. For example, if you have 15 PSI of air at 250F, it is just as effective as 12PSI at 190F. (Not scientific or realistic values but for illustration purposes only!)

For stock specs, you are looking at a new/good ALDA and a well performing turbo coupled with a tuned, timed and adjusted vale and injection system. Costly, yes but it would go a long way towards restoring power to OEM spec. That or you can ditch the ALDA and limit the power with your right foot. Either way works well and both have low risk.