300tdi More Power Needed!

[Richtharris]

My 1991 Defender 90 300tdi is very flat in the power and acceleration department....
What can I do to improve things??
A new turbo? Or something else? Tweaks here and there??
Any suggestions, specifications and details welcomed!
Thanks!

[300bhp/ton]

Richtharris said:

My 1991 Defender 90 300tdi is very flat in the power and acceleration department....
What can I do to improve things??
A new turbo? Or something else? Tweaks here and there??
Any suggestions, specifications and details welcomed!
Thanks!

There are lots of options, depends what you want to spend and what has been done already.

Are you sure it's a 300? 1991 would be a 200Tdi.

Although they both tune the same.

For a cheap home improvement, you can tweak the injector pump. It will give more power, but not loads. However it will make it feel like you've gained loads. It's a bit of a balance, too much and it'll smoke loads and you'll get high EGT's. But it's quite simple to do. Loads of guides on the internet, just Google.

Some fit a different boost pin in the pump too, although you can get the same results using the stock one if you want to play about a bit.

A bigger intercooler will also help out, can be pricey depending on where you get one from, although generic ones from ebay can be had for about £100.


Improving the exhaust can help, especially on a tweaked one. For most people, these tweaks will be more than enough.


You can go to the expense of a hybrid VNC turbo and even a ported head. But you will rapidly be spending huge sums of money for only minor gains.

[Richtharris]

Thanks so much for the rapid response! There seems to be a few ideas there.
I read about changing the boost pin, also about installing a ‘dynamic timing spacer’ on the injector pump...
Do you know anything about that? What I read said it was a fairly easy install, but it mentioned that the timing would need to be advanced slightly to compensate for the early injection?? But that is where it lost me!!
Is it something I can do? I’m pretty practical, but I don’t know much about timing!
I’ll look for an intercooler...
so you think that changing the turbo might be more expensive than it would benefit??
Thanks again, Rich.

[300bhp/ton]

Richtharris said:

Thanks so much for the rapid response! There seems to be a few ideas there.
I read about changing the boost pin, also about installing a ‘dynamic timing spacer’ on the injector pump...
Do you know anything about that? What I read said it was a fairly easy install, but it mentioned that the timing would need to be advanced slightly to compensate for the early injection?? But that is where it lost me!!
Is it something I can do? I’m pretty practical, but I don’t know much about timing!
I’ll look for an intercooler...
so you think that changing the turbo might be more expensive than it would benefit??
Thanks again, Rich.

If your turbo is ok, then yes it's probably an expense not worth worrying about. A hybrid turbo will set you back £700-1000.

Tweaking the injector pump is free and will produce good gains.

Have a look here:
https://www.landroverweb.com/Pdf-files/Tuning_Land...

And this one. This covers the same as the first one, but also the Power Screw on the back of the pump:
http://www.dividingcreekimports.com/TdiInjectionPu...


A bigger intercooler will benefit all the pump tuning and is pretty much essential for tweaking the power screw, as it will increase EGT's a lot, so you'll want to lower the intake charge as much as possible.

[bakerstreet]

If you are keeping the vehicle for the long term, then could also be worth considering Discovery Transfer box. Would at least up cruising speed for lower RPM. Not a power gain as such but might help.

[Hard-Drive]

Before you go modifying have you checked all the hoses on the turbo and that everything is working as it should?

I had a Disco with a 300Tdi in it that had slowly got very sluggish...as is often the way with cars when something slowly gets worse you don't really notice it. It failed it's MOT terminally on rust and the guy who bought it off me to break said the turbo pipes were in a very bad way.

I immediately replaced it with a Defender 110 with a 200Tdi retrofitted and it felt like a rocket ship by comparison. Even with fairly big 265/75/16 tyres and a Disco t/box on it, I am always impressed how well it goes and how much grunt it's got for a standard engine. Clearly it's never going to go like a V8 or a "soft roader" but I always think it has "adequate" power for a big utility 4x4 (and I'm used to a 5 series and a Porsche as DDs)