406oc.co.uk

Following on from my Theiving git thread, I have now put in place a straight through pipe after someone kindly removed my cat for me. I used a pipe which is 60mm OD and expanded at one end to slip over the stub which was left attached to the centre box and at the other end I had an adapter made up in stainless to slip over the end of the new pipe and what was left of the down pipe. Couple of clamps later job done.

Result:

Pros;
No louder than before,
Better acceleration,,
Smoother and earlier pick up,
More willing to rev,
Power produced over a wider rev range.
MPG too soon to say.

Cons,
Smokes a bit when foot to floor.

I'm hoping the smoke is just soot and crap being blown out of the two remaining boxes due to exhaust flowing more gasses. Will take it out for a tune up run at weekend.

So maybe the theft was a blessing in disguise, cost to repair, or look at it as a tuning mod, £27 to include pipes, one custom made, fire gum and 3 clamps.

Glad to hear you got it sorted,

Am I wrong in thinking it's an MOT failure to have no cat if it was fitted to the car in the factory?

From what I've read on 'tinterweb cat and dpf removal is no longer allowed and the testers are supposed to look for signs of modifications and remapping that removes functionality.

Can't say i've seen it officially just when browsing various forums.

gumby6371 wrote:Am I wrong in thinking it's an MOT failure to have no cat if it was fitted to the car in the factory?

That's what I thought
But I've never got a straight answer on it.
I guess there's only one way to find out...

It will pass the diesel smoke emissions test, (cos mine does).

There has to be some risk of a tester failing it, because there's no box there anymore. I'm convinced an empty one will suffice.....

Surprised you noticed any difference TBH, (i didn't), but maybe that's because mine was clean as a whistle thanks to 60 commuting miles a day.

gumby6371 wrote:Am I wrong in thinking it's an MOT failure to have no cat if it was fitted to the car in the factory?

From what I've read on 'tinterweb cat and dpf removal is no longer allowed and the testers are supposed to look for signs of modifications and remapping that removes functionality.

Can't say i've seen it officially just when browsing various forums.

I've seen plenty about the cat, but haven't seen anything specific about the dpf anywhere. I do have to admit it has slightly slowed my moving up to a 2.2HDi as I could just see myself finding a nice one & getting it deFAPped only to have some jobsworth MOT tester find a way to fail the car on it. Even leaving the standard can on isn't a failsafe as a quick tap with a hammer would soon reveal that it was hollow inside.

On the other hand though, the FAP will probably be safe enough to remove on older diesels otherwise the testers would have to become experts in what does & doesn't have one. 407 X-Lines for example don't have them fitted, while a standard 407 does.

waue1978 wrote:
On the other hand though, the FAP will probably be safe enough to remove on older diesels otherwise the testers would have to become experts in what does & doesn't have one. 407 X-Lines for example don't have them fitted, while a standard 407 does.

the 407 Zenith is without fap as well as the x-line

trem1 wrote:

waue1978 wrote:
On the other hand though, the FAP will probably be safe enough to remove on older diesels otherwise the testers would have to become experts in what does & doesn't have one. 407 X-Lines for example don't have them fitted, while a standard 407 does.

the 407 Zenith is without fap as well as the x-line

i totally discounted a diesel 407 as a possible upgrade car, due to the fact they were alledgedly all fitted with FAP's according to honest john
http://www.honestjohn.co.uk/carbycar/pe ... ction=good
not too sure now? i usually say petrol all the way but at nearky 50 to the gallon could be worth a look at upgrade time.

6 days on since the stolen cat was replaced with a straight pipe and I thought I'd post an update.
Smoking stopped on day 2, must have been soot that had accumulated in the other two boxes. MPG is going up. No noisier than before and car is definitely smoother and more responsive. Power is produced earlier and hangs on for longer.

Nice result!

Just to clarify the cat situation......

It does not matter whether a cat is fitted or not on a diesel for mot purposes as the test is only a smoke test.

The presence of a cat is only applicable to vehicles which are liable for a full cat test, ie, PETROL engined cars.