Right now I’m just running a stock European map, they tuned the car down in the US to meet CA emissions.
http://m44.wikia.com/wiki/M44_Wiki
That is an entire site that explains how to tune these cars. My first step before I start doing any tuning is getting high quality wideband and boost gauges. I also can’t really mess with it much without doing the downpipe because that is a huge restriction.
There is a lot of good info on that site explaining everything. The info is basically all the best of what was put on a huge thread in on Volvospeed.com. It just so happens that one of the guys who developed this method of tuning sells this as a service and lives in Denver. He does tunes for these car around the world.
From the tuning site:
“RECAP: First step, accurate boost guage and afr guage. I suggest having something to datalog afr, rpm, maf and ign adv at the minimum. Start with WOT tuning as this is the easiest approach(since tuning part load on the street would require holding the car at a steady rpm/load which is extremely hard). If you find any issues with your new boost value, try adding fuel, pulling ign or reducing boost if neither of those work. If you max your MAF / go over the max load on the table (8.02) use that column to tune. If your finding you cannot reach desired boost and keep increasing requested load and you dont see any changes try playing around with max duty for boost control solenoid. Remember dont go too crazy on this map! You risk bending rods at low RPM high TPS.”
The stock ECU actually limits the boost in first gear from a dead stop. This reduces tire spin but it also protects the motor from bending a rod.
Clanging out the injectors to the larger ones requires “Calibrating for injectors requires setting the ‘Injection Basic Adjustment Factor’ and the ‘Injector Opening Time by Voltage’.” This is really easy to do.
Also another restriction on the system is the MAF.
“The stock MAF can only measure flow up to 826Kg/h, this limit can be reached on a stock 850 with a 15g fairly easily. In order to maintain accurate fueling calculations past this rather low limit it is recommended to upgrade the size of the MAF by placing the stock sensor in a larger housing. Here are a couple of housings that are a direct fit for the original MAF sensor:
2.50″ ID Volvo 850/S/V/C70 826 kg/h (stock)
2.75″ ID Volvo S90/960 1056 kg/h
3.25″ ID 540i BMW 1612 kg/h
It is very important the increase in airflow is accounted for in your bin!”