Thread: Discovery TD5 catalyst ...

Originally Posted by White Pointer

G'day,

The down-pipe is the bellows type.

I spent some time under the car and in the engine bay trying to find a cause and was convinced it was the catalyst because of the loss of power at 2,200rpm through to around 2,700rpm and the horrendous noise that sounds like a concrete mixer with nothing but 3/4 gravel in it in this range. Below 2,200rpm its smooth and quiet. Above 2,700rpm it quietens down and gets a huge power boost - therefore I'm convinced it's obstructing gas flow in the most usable rev range.

MR Automotive in Redcliffe confirmed my suspicions that the cat was stuffed a few weeks ago.

Regards,

White Pointer

The flat spot up to 2700 rpm will still be there without the cat. Its in the fuelling map with the stock ECU.
i thought the decat pipe would also cure mine of the same thing, but it didnt however it wasnt quite so bad, but still there.
This tends to be the most common rev range the engine for everyday driving and in the interest of economy fuelling seems to be dropped back.
Funny thing is i find exactly the same thing in exactly the same rev range in my 3.9 RRC also.
This is the area a good chip like Tombies will address but with increased fuel comes higher EGT's. My stock map will run to 400-480 degrees in this range depending on how quick i stick it to 2700-3000rpm. Cruising it will range from 250-350 degrees.
The rattle may also be muffler and i am going to do a straight pipe conversion to see if that helps cure it. Mind you i may not be able to hear it with no muffler!!

Cheers

Andrew

Originally Posted by White Pointer

G'day,

Thanks for all the responses. This has been very helpful. For future fun I will indulge you to help me deal with LHF window regulators and bloody XYZ switches.

I've written a very nice letter to Queensland Transport asking for a modification to remove the catalyst. I'll let you know how I get on.

I haven't heard back from Microfresh filters so I guess they are not interested or just rude.

Any other recommendations on brands of bits to buy?

Regards,

White Pointer

G'day,

This gets more and more frustrating.

Firstly, Microfresh Filters came back to me and offered me a catalyst that would improve my emissions to EURO4 standard with lower back-pressure. The price was around $2,000. Now that's cheaper than replacing with OE but there was a hitch. They told me that a catalyst has to be mounted directly below the manifold on a diesel to get hot enough to work. I described the layout of the exhaust and the limited clearance between the engine and the chassis and they told me it wouldn't work and therefore they wouldn't sell it to me.

I have to respect somebody to ditches a $2,000 sale for honesty - but they said my current catalyst probably doesn't work either and that combined with 4 years of sulphur clogging courstesy of the FEDS letting the oil companies go on producing dirty fuel is why the catalyst failed in the first place.

Armed with this I looked for a high flow catalyst that will fit in the limited space available. Delphi make one but (based on what Microfresh told me) it will have to be directly below the manifold on a custom made angled pipe with the flexible joint mounted beyond it. This can be done locally for about $450.

So I talk to Queensland Transport and tell them all that I have found and they tell me to replace OE with OE or be prepared to prove that my car still complies with manufacturer's emission levels - never mind what the ADR standard was. How do I do that? They tell me to go to NSW where they have an environmental testing lab and get a compliance certificate.

This is insane. The Queensland Government are advocating a policy that supports manufacturer's over priced spare parts business even though their parts are probably deficient in meeting ADR requirements. I have found two solutions that will probably improve the emissions performance of the car but (1) one won't fit and (2) the government puts a huge obstacle in the way of the only practical and affordable solution. And to add insult the governments caused the damage in the first place.

Sorry for the rant, but I'm P^$#^ off.

Regards,

White Pointer