Hi Mark

I’m sorry, I just don’t see what you’re seeing, and i'm very keen to learn as I believe this would be very beneficial.

I understand the effect of an EGR not sealing correctly at full load, the resultant effect on the VNT vanes and the displacement of clean airflow, I just cannot see what you have identified purely from the boost against maf without knowing compressor flow charts and some in depth research into flow characteristics of the turbo in question, you seem to have been able to just look at the first graph and instantly notice an irregularity in the shape of/ relationship between the actual boost and maf....

Comparing the shape of the before and after, boost and maf, they are pretty comparable, the difference being around a 3:1 delta before and a 1.9:1 delta after ((boost mbar / (maf g/str)), how could you have known what to expect without flow knowledge of the compressor in question?

I don’t want you to give me the answer, if you are prepared to help please just give me a nudge in the right direction and I will study further.

I own/run GotBoost Performance, it started as a hobby around 7 years ago mainly working with Honda aftermarket ECUs, I got pretty popular and decided the next step to be a dyno purchase, again working mainly with aftermarket ECUs on older ( simpler ) vehicles. The business has grown to a point over the years, where we now primarily take care of a range of race vehicle for clients, providing a full service from build/repair and maintenance to trackside support. Due to the current economic climate, and customer demand, we are seeing more and more OEM vehicles, we quite often get vehicles other people have given up on, I like these as it often provides an opportunity for me to develop a new skill/though process.
I still run GotBoost around my main occupation; it will always be a 'hobby' even if it is run as a business, hence my willingness to learn. I've always said that if/when I start not to enjoy it, I will pack it in! Whilst I openly admit that diagnostics is not our strongest point, we do offer honest, impartial advice and offer what we believe to be a much higher level of service compared to most others locally. There are many benefits to running a business like this without having financial commitments, added to the fact I run it simply because I want to, allows me to spend as much time as I choose with vehicles I decide to take on Customers really appreciate our approach, and most of our return business is through word of mouth recommendations.
I am not at a level where OEM ECU modification is going to be possible in house, equipment or knowledge, although I am learning. OEM ECU tuning is a completely different ball game to aftermarket. We currently operate with a number of file developers that we have found to be reliable and provide a good quality product. You would be surprised how many 'tuners' claim to be developing their own work, when in fact they are mostly supplied through a few select people.