Thread: 300tdi Boost adjustment - Thoughts?

Yep, factory should be 15.5-16.5 psi otherwise EGT's will be too high and the Tdi needs as much help as it can get.

I'd go higher, 18-20.
Over about 20 the composite head gasket may not take it, and you'll be moving off the conpressor map anyway.

That's great thanks Rick. I'll keep tweaking.

Originally Posted by rick130

Yep, factory should be 15.5-16.5 psi otherwise EGT's will be too high and the Tdi needs as much help as it can get.

I'd go higher, 18-20.
Over about 20 the composite head gasket may not take it, and you'll be moving off the conpressor map anyway.

You haven't mentioned what your EGT's are currently.
I would strongly recommend you do some test runs up a suitable hill, before locking in the changes.

I hear your point Don.

Prior to adjustment the EGT would typically read:

400ºC cruising at 100km/h ("cruising" defender style - about as quiet as a single engine cessna )
600-620ºC struggling up a long incline in a headwind

I haven't seen the gauge read any hotter than 620ºC. This might change in the summer months of course.

Following Rick's advice above I adjusted the rod another 4 turns (11 in total) and this has effectively shortened the rod 10mm overall. The boost now reads 1.0 bar (originally 0.75 bar) @ 3000 rpm, 3rd gear up an incline, and temp still sitting below 600ºC.

Due to current restrictions in Victoria i'm unable to get to any decent roads to really test it out but will do and report back.

Originally Posted by donh54

You haven't mentioned what your EGT's are currently.
I would strongly recommend you do some test runs up a suitable hill, before locking in the changes.

There is really no point in increasing the boost unless you are also going to increase the fueling. You will have less power now than before.

Really? I think the boost was underperforming from when the new turbo was installed and I thought shortening the rod would at least return it to spec?

And yes, next step is to adjust fuel.

Originally Posted by Red90

There is really no point in increasing the boost unless you are also going to increase the fueling. You will have less power now than before.

Adding more air only robs power unless you add fuel with it. You might have gotten a bit from the boost compensator but probably not much. If you are not getting much more than 600 EGT your fueling is quite low.