Outer Limits 4x4 Board

Hi,
My parents have a GU 2.85 tdi, we're trying to get a little more power out of it, from the search i have found suggestions that a 3" turbo back should make a difference, I'm not familiar with Diesels and raising boost etc, any info would be great, I assume the same principal would work on a diesel more air in/out +fuel + boost usually eqautes in a nice improvement.

Also does anyone know what turbo the 2.85 has ? I've been told its a t25, a nice t28 roller off a late s14 early s15 200sx would spool quicker would it not ?

a mild increase in boost will yield some results but without an intercooler you don't want to exceed about 10 - 12 psi boost. should not need to make changes to fuelling unless the pump setup is excessively lean, and it's best to have a diesel shop make the changes as just pouring in more fuel can cause very high EGT's which will melt pistons and valves, crack the turbine housing, distort the turbine, etc etc, all bad. just chopping and changing turbos is also not a great idea, the factorry turbo is good for 12+psi on these motors, it is deliberately small to bring the boost on at lower rpms. with diesels, and especially turbos, the bigger and less restricted the exhaust, the better - it is not usually necessary to run a muffler at all with a 2.5 - 3" mandrel bent pipe from turbo back will yield a noticable improvement especially right off idle.


oh to up the boost you can use an electronic boost controller, or just a manually adjusted bleed off the wastegate actuator, or adjust the actuator by shimming it away from the wastegate, or shortening the arm if it has an adjustable arm. I would not exceed 10 (maybe 12) psi peak boost on this motor.

cheers


cheers

Thanks for your reply, We're going to try the exhaust 1st, invest in a boost gauge and then play with the boost, any idea what boost they run stock ? Also we've got the GU intercooled model, any idea if front mounting these coolers works better ? Top mount seems like a bit of a heat sink to me even tho it has the factory thermo underneath.

Noticable gains were had from the snorkel !!

Motsons in Qld are supposed to give them enough power to turn the wheels.. but it aint cheap.

stock boost is 7 - 8 psi