de cat exhausts

there seems to be hundreds of companies offering replacement exhaust systems for defenders, does any body reccomend any specific makes and models, also what gain is there from fitting a dec cat pipe as opposed to an entire exhaust system. do de cats work?

any help with this topic would be grrrreat!

Gary at Alive Tuning does one - a stainless one. Don't expect tubo whistle like a Td5 though. It just doesn't sound as nice, even with a full stainless system. It's also a bit of a pain to fit, as the heat shield on the TDCi normally secures half of itself on the cat section, so you end up cutting the shield in half to reduce the weight, and letting it hang there. Not perfect unfortunately.

It does help econony though, and probably only really worth doing with a custom remap and performance intercooler.

What about mid box replacements? Cherry bombs etc

Can't help with that. I've never tried, but I doubt you'll get it to sound like a Td5. The stainless Alive Tuning system gives it some agression though.

Anyhoo, I hear that LR intend to fit DPFs to the Defender in around 2012/13, so I guess that means you can't stay off road for days and days, because you'll have to find a stretch of tarmac to clear the filter... :doh: Not sure where the Defender is going these days.

irb developments offer a good stainless pipe mate, they were on the front or landrover magazine and had a few page spread. ian at IRB Developments - Diesel Tuning and More is really helpful, drop him an email and he'll answer all your questions. probably the only guy that knows everything about landrovers!

You on commission, Adam?

And as for DPFs, days might be stretching it, but I've left a diesel BMW idling for about 6 hours - made a stink (after about 20 mins) and a right cloud when I took off again, but never seemed to affect anything negatively.

I guess it's yet another EU emissions thing.

I've replaced the centre pipe and noticed a slight change in engine note that was marginally more pleasant to my ears. Its a first stage for me in a decat, intercooler, performance filter, snorkel then stage 1 remap so havent noticed a distinct change but in my mind it felt a little smoother.

I've done a lot of shopping about and from what I can see IRB seem to have the best price on the decat although I cant seem to get them to reply to my emails trying to buy one so cant comment on the quality yet!

ADAM is trating himself to a nice Stg3 on his Puma early in the new year....if he can get himself away from Ballaytnes Gym......lol

So whats a stage 3 involve? I like the idea of improving the engines useability but I'm unsure about pouring too many horses through and engine not speficially designed to cope, or more to the point a gearbox that isnt designed to cope!

ellebarto said:

So whats a stage 3 involve? I like the idea of improving the engines useability but I'm unsure about pouring too many horses through and engine not speficially designed to cope, or more to the point a gearbox that isnt designed to cope!

Click to expand...

Stage 3 is figurative. Not sure why but we Brits have a fascination with "stages".

It actually means nothing and will vary from person to person to firm to firm selling stuff. It does imply more mods than Stage 1 or 2, but these are also undefined nonsense touted about.

As for the engine, well you won't exactly be treading new ground, others have already been here and done this kind of thing, so just follow what is know to work and be safe.

bigred90 said:

there seems to be hundreds of companies offering replacement exhaust systems for defenders, does any body reccomend any specific makes and models, also what gain is there from fitting a dec cat pipe as opposed to an entire exhaust system. do de cats work?

any help with this topic would be grrrreat!

Click to expand...

Personally I see little point in a de-cat, I certainly wouldn't worry about who'd it was. It's a bit of friggin exhaust tubing nothing more. So as long as it fits, they'll all do 100% exactly the same thing.

In terms of decating, yes you can potentially gain a bit of performance, but you'll fail an MoT or road side emissions test. For the limited gain I can't really see the point of the hassle of fitting it and removing it, even if it is once a year.

Plenty of other ways to improve performance which you won't have to remove for an MoT.

As for the rest of the system - that's the key word "system".

An exhaust is exactly that, so you need to look at it and treat it as a whole.

But it really depends what you are wanting to achieve. A bigger down pipe, high flow cat (or decat), plus a free flowing exhaust and low resistance silencers will make it louder (which some like, some don't) and will improve the engines breathing, so make it a little ore free reving and release some power, especially in the higher rpms.


But it's a compound affect, improve the exhaust, improve the induction, alter the turbo map and the fuelling map and it'll really fly.

After a decatted mine I started to get an engine management light and a turbo over boost code. Still looking into it but someone has suggested that the lack of back pressure from the exhaust now is letting the Turbo over spin?!?

Hi, the best gain we get from decat and silencer removal is improved low down response,and best of all the stupid heat transfer ( to both front seat occupants)from the above!On close inspection to have 2 large heat sinks in such close proximity to the footwell.On a summer day the kids shoes have melted on the floor.