how do I tune a diesel

[Peter]

I have a 1996 405 TD Estate, I use this car to tow a caravan, some of hill's I clinb tend to take the power away from the turbo, I would need to drop down to second and floor it , just to get the boost, if I put it in to third, the boost pressure drops and I am back to second again, this is how it goes, , the turbo starts to boost somewhere between 2,400 and 2,500 rpm, idealy I would like it to boost at about 1,800 rpm,
I'm not looking for performance, just more torque at a lower rev
Thanks
Peter

[Admin]

I'm guessing that's going to be hard as the turbo boost characteristics will be set by the engine management. Any changes would mean messing around with the cars "brain".
More manual ways to change the turbo characteristics would be to have a smaller turbo which would spin up more quickly, though this would only reduce lag not change the revs at which power comes in.
1800 rpm is very low. Normally you would look to supercharging to provide boost at low revs.
The 405 TD is a well regarded towing car. I would check that you are not loosing boost to a wastegate sticking slightly open.

[kevin]

The XUD 9 TE engine does not have an ECU as with the new type of diesel engines so tuning is restricted to improving the effeciency of the air intake/ filter and the intercooler and modifying the pump and injectors. This is best left to the lucas/bosch agents.

In the past you could uprate the lucas DPC pumps fitted to certain tractors, but in time these would seriously damage the engine very quickly.

Any increase in power/torque will have an effect on the drivetrain and brakes. One tractor manufacturer supplied a 100bhp machine in the 1980's with 50bhp brakes from the 1950's. They only imported 10 and all broke down with brake failure!!

[Michael]

Your 405 ought to be starting boost at 1800rpm. You may have a leak in your intercooler or the wastegate valve on the turbo may be faulty.