Tuning a rear mount turbo A6 C6. The setup is very simple.
ECS Boost A Pump
ID1050x injectors
Rear mounted S475 turbo
The 3 mods listed above are THE ONLY MODS on the car period. I have tuned plenty of these setups without issue other than this being the first "A6" turbo car. I was originally going to tune it via MAF. I started pulls and the car does fine until it sees about 4-5psi then it goes lean. AFR is pretty solid up until that point. I was also able to dial in STFT at idle quickly via maf so I know the car is responding to changes. However I ended adding like 50% to the area in the maf curve where the lean condition is occuring. NOTHING. No change at all, even the INJ DC stays exactly the same. I was seeing 4+ grams of air readings so I just ditched the maf idea.
Moving on I decided to switch to a ZR1 map and go SD via VVE tuning. I converted the axis to read 2 bar vve and 7k rpm etc etc. Threw a base VVE table in from another car I had previously tuned with a similar setup. SAME THING, no matter what I do or command fueling wise the car goes lean as in .83 lambda to 1+ lambda as soon as boost comes in good. I even added 60% to the entire VVE table in the boost area and it had ZERO affect.
Before anyone asks YES I HAVE VERIFIED FUEL PRESSURE with mechanical tester on end of rail. SOLID 58-60psi the entire pull.
I'll add a few files from the maf tunes to the VVE tunes. Remember the scale was changed on the VVE tune to 210KPA and 7Krpm
The two logs are from when the tuning was being done VIA MAF. I didn't save any logs after that. Car is still on the dyno so if anyone wants to see a specific log LMK
Maf 1.hpt
Maf 6.hpt
2 bar vve starter.hpt
2 bar vve 2.hpt
d1.hpl
d2.hpl