TURBO BOOST

12psi in itself won't pose a problem, but you need to do it in the context of a total engine performance check. By that, I mean that there may be nothing gained from increasing boost alone.....any performance increase may only be achieved by also tweaking the fuel pump. This is an area where (AFAIC), expert advice needs to be employed. The diesel experts at Berrima tuned my 4.2 TD in 2001 and added a length of rubber hose from the turbo to the air filter housing. I was never sure what this actually did until I recently fitted a boost gauge. With the rubber hose in place the maximum boost is around 11.75psi. I remeoved the rubber hose off the brass barb on the air filter housing a screwed a bolt into it and went for a test drive. The maximum boost was now under 9psi.
So, getting more boost can be quite simple, but tuning needs to be "right".

I used to have the 2.8 Tdi in my GU until I did an engine conversion. Factory boost on these is 11.5 PSI and I fitted a Turbosmart Gated Boost Control valve and uped it to 14 then 16 then 18 PSI to see what would happen. Did absolutly nothing. Even if it did you could not notice it. Actually I got better gains from sticking a bag if ice on top of the intercooler. I also did a 3" exhaust with minor results but didn't worry about a dump pipe which I think was a mistake. The 2.8's are basically the same as the 3 litres (ie electronic diesels) and you can get 14% gain by fitting a dump pipe and larger exhaust (contact Motson's, 4WD systems or Beaudesert Exhausts). There is very little else you can do on electronic diesels except for rechipping or piggyback ECU's.

I ended up fitting a piggyback computer from Motsons for a 33% gain. In conjunction with this they set the boost to 14.5 PSI and I was extremely happy (I have it for sale if interested).

Regards
David

As pointed out by somebody else, adjusting the boost on a turbo diesel engine will achieve little to nothing if the engine is correctly tuned (and maintained).

This is different to a petrol engine, where increasing the boost will result in additional air AND fuel. On a diesel you only get increased air. Air by itself does not contribute to more power.

If you want to increase the power you will need to have additional fuel injected in the appropriate quantities, and at the appropriate times. Since you have an electronically controlled engine, this needs to be achieved via electronics.

A friend of a friend has the same vehicle as you, and after fitting a diesel tuning module from ENG-TEK to increase the performance close to the latest 3.0litre Patrol engine without any other modifications (the friends car).

The car can now accelerate up hills that would previously have it changing down a gear after running out of momentum. Its also much better offroad in the midrange power.

Dave