[barkster1971]

This will concern people whose car has the Mitsubishi 13c turbo. If your 900/700 has a T3 or T25 turbo you'll have slightly different options.
Most of the 940 turbo motors have a 13c turbo fitted as standard. As these cars can and do frequently over 150k miles the turbo may be getting a little tired which can be felt by lack of performance and or smoking from the exhaust as the oil seals get worn.
You may have decided to fit a manual boost controller (mbc) (and boost gauge) to up the boost. The maximum boost figure should be around 10PSI. You can run more but that can lead to more problems rather than benefits!
The 13c turbos can crack anywhere around the turbine housing (or hot-side) and the pin holding the actuator arm on can snap off leaving the remnants blocking the hole!
Therefore you may need to replace the turbo, or if you've grown to like the increased performance from fitting a mbc you may want to fit a larger turbo.
What are your options?
The Mistubishi 13c turbo is a small turbo in the range of TD04H turbochargers.
The larger the number the bigger the turbo and the more air it flows (at the same level of boost. A 13c flows 360 CFM and 15g 430 CFM.
The larger turbochargers are found mainly on Volvo 850's and V/C70'S.
As these are FWD Volvos with tranverse mounted engines the turbos are configured differently from the 13c turbo found on the redblock RWD Volvos!