the torque is naturally there low down.
jaguar for example aim for a flat smooth torque line, they don't use overboost BTW, they beleive a car should drive the same all the time and as far as possible, whereever you are in the rev band.
so their maps out the factory avoid overboosting the turbo's at low revs - which is what produces all of this excess torque.
the lower class manufacturer's, such as one un-named french co, overboost their turbos low down, which is why they fail at 70/80k, its only recently they admitted they were doing this, after they spent years blaming clogged egr and drive-on failures to avoid warranty claims.
A turbo will work at its hardest at low revs (on vnt vein angle), then again at high revs, just because it can produce massive torque low down does not mean we need to run it flat out and break gearboxes, torque is best dialled in more progressivly than that.
If its a 2.7 litre Jaguar Diesel your talking about, that happens to be designed/made by a 'lower class' un-named French company in conjunction with Ford.
New X-TYPE 2.2 litre Diesel S Automatic Saloon from £309 a month*
The New X-TYPE range offers the option of a 2.2 litre diesel with 6-speed Jaguar Sequential Shift™, giving you the choice of a fully automatic or one-touch sequential manual gear selection.
• 6-speed automatic transmission with Jaguar Sequential Shift™
• 145PS with 360Nm of torque
• Transient overboost delivering up to 400Nm of torque
• CO2 emissions of 184 g/km
• 27% Benefit-in-Kind tax rating
Sounds like overboost to me.
Depends which driveshafts you're talking about, the Fiat/Alfa ones in the 10v are not weak, the GM ones in the 20v are weak and do fail regularly.
Mine is a 10v, 150 bhp, it failed, they are weak.