Defender TD5 exhaust help

Hi I am new here,

I recently bought a 2004 Defender TD5 90 and am toying with the idea de catting her. I believe the central silencer already has been removed. A friend recommended retaining the small back box for back pressure to prevent over spinning the turbo.

Could anyone provide some insight into where this would stand with an MOT or perhaps advice me on what’s best to do.

Ideally I want her to be more free flowing and have a slightly louder purr....

Thanks in advance for any help

Cheers

Hello and welcome
decating should be an instant mot fail but depends on tester.

You friend is talking rubbish. Diesels dont need back pressure for the turbo, a more free flowing system is benificial.

Such as a full 3" or 2.75" system, standard is 2.5".

You can run full straight through systems without issue.

That said id keep the back box as it keeps the volume at a nice volume.

Technically yes a decat is an MOT fail but some TD5s came without them anyway. Mines never failed an MOT 7 years with the cat missing. That said its a landy friendly garage!

Thanks for all of your help!

Given my central silencer has been replaced with a straight pipe .... seems like a decat may be the way forward? If so is there a noticeable noise difference?

Welcome to the forum

Mot testers are being put under more pressure to check for illegal exhaust mods. Especially if they see rework has been done. It may also invalidate yer insurance if they want yo be difficult if making a claim. Why the need to remove bits?

Increase the security. They is easily nicked

De cat is MOT failure. Not that good why bother.
I agree with your mate straight pipe will open it out, keep the back box. Should be okay MOT and will open it out a bit. Probably sound gruntier too

Hippo said:

Welcome to the forum

Mot testers are being put under more pressure to check for illegal exhaust mods. Especially if they see rework has been done. It may also invalidate yer insurance if they want yo be difficult if making a claim. Why the need to remove bits?

Increase the security. They is easily nicked

Click to expand...

Fair point. Make sure you inform your insurance!

Decat = faster turbo spool.

Inform them that your vehicle is not fit for road use?
Good luck with that

RangeRoller dt said:

Inform them that your vehicle is not fit for road use?
Good luck with that

Click to expand...

Thing is yer can't drive it on the road if it's had mods done which make it fail on emissions standards it was originally designed to meet. The link below gives an introduction. Many peeps do but shouldn't. So he needs to be careful.

https://www.gov.uk/government/publi...ions-the-legal-safety-and-health-implications

If he's looking for power and eggscelleration then he bought the wrong vehicle.

There’s so many ways to get bit more out of a TurboDiesel without chewing your knuckles off every MOT time. I don’t think decat is the way unless it’s a 100% off-roader or track use.