E31 1997 840 ci sport - Catalytic converters? Need assistance please!

[scorpio]

I need to replace both cats on my 840. The BMW specialist has said that they will cost £700 each. I have contacted someone on the internet and they are £400 for both for the ceramic or £600 for both for the steel. Any suggestions on buying either the ceramic or steel. Someone at a show said that I could have custom fit exhausts, but will they need cats?

[Boostist]

Originally Posted by scorpio

I need to replace both cats on my 840. The BMW specialist has said that they will cost £700 each. I have contacted someone on the internet and they are £400 for both for the ceramic or £600 for both for the steel. Any suggestions on buying either the ceramic or steel. Someone at a show said that I could have custom fit exhausts, but will they need cats?

hi Scorpio,

I moved your post into a tech forum where you will get more help Im sure, I also retitled it slightly to add a little more info

8 series are fraudulently expensive for a lot of parts as Im sure you know !

But I would contact these guys in the USA and order their product....even if you do get import duty it will be a hell of a lot cheaper in the end....

8 series catalytic converter

Maybe £200-£250 all in delivered

[DSK]

On BMWs, a lot of aftermarket CATS are quite up to spec, fit isn't always spot on and neither is the design (flatter bottoms etc to aid ground clearance etc).

I would try contact F.A.B Direct BMW breakers or Quarry Motors (BMW breakers) and seeing if they can supply replacements for you.

[Boostist]

Originally Posted by DSK

On BMWs, a lot of aftermarket CATS are quite up to spec, fit isn't always spot on and neither is the design (flatter bottoms etc to aid ground clearance etc).

I would try contact F.A.B Direct BMW breakers or Quarry Motors (BMW breakers) and seeing if they can supply replacements for you.

But with replacement costs as high as on this 8 series...alternatives have to be used!!
Also, a cat is a cat. To be honest if the pipes fit together, it will be totally fine.

But I agree with other aftermarket stuff....just not cats

[rjc]

During my last Inspection 2 service just carried out I was told that one of my cats is rattling and needs repalcing. Quoted cost £895+VAT. It was also suggested I should replace them both at the same time!

Rather than replace them (even with cheaper alternatives it's still pretty expensive) it does beg the question - are they a legal requirement on a 1999 car? If I take them off and just bypass them will the car fail its next MoT test? I've seen a couple of specialists offering fabricated sports exhaust systems without cats. Is this a better way to go when your cats fail?

Views?

Thanks

Robin

[Boostist]

Originally Posted by rjc

During my last Inspection 2 service just carried out I was told that one of my cats is rattling and needs repalcing. Quoted cost £895+VAT. It was also suggested I should replace them both at the same time!

Rather than replace them (even with cheaper alternatives it's still pretty expensive) it does beg the question - are they a legal requirement on a 1999 car? If I take them off and just bypass them will the car fail its next MoT test? I've seen a couple of specialists offering fabricated sports exhaust systems without cats. Is this a better way to go when your cats fail?

Views?

Thanks

Robin

This is a bit of a contentious area Robin

'Some' cars will pass the emissions test without cats, however some will fail royally when the same thing is tried.
Main Reasons being:

Different engine sizes, makes and efficiencies
The age and condition of the engine (mileage, bore wear,etc)
The weather conditions at the time of the test, eg/ winters day (cold) or hot summers day - hot is better for these purposes I think.


A cheaper option would be this....
To get some custom de cat pipes installed by a good exahust garage like MILLTEK (custom decent systems at ok prices - branches around the yUK).

however on the proviso with them that they remove the current cats 'as is' so they can be reused. and also so they can be reattached to the system if required in the future.

Then, when MOT time comes, take the car for a decent drive and get the engine up to full operating temp before the test (put your foot down a few times)
'hope' that the car passes the cat emissions tests....
if it does, great! (keep the cats in case it doesnt the next year though)

If it doesnt, go to your friendly local exhaust place and get the cats refitted and de cat pipes removed...get the test and go back to swap them. as the bolts etc will all be newish and copper greased up it should be a really fast swap and cheap as chips.

Its potentially hassle for MOT day each year (if it doesnt pass catless) but £2000 for a new pair of cats on the car is just not worth the ££ pain IMO!

[Ronnie]

Also if you are pulled over for a road side emissions check with no cats and fail you will get fingered (meaning waved at you,dirty minded people)

[Boostist]

Originally Posted by Ronnie

Also if you are pulled over for a road side emissions check with no cats and fail you will get fingered (meaning waved at you,dirty minded people)

Yeah, but that is next to impossible in something like an 8 series.
Coppers dont even seem to do it to real filthy stinking traveller buses that belch black smoke out
Also, you would only get one of this orders to take it to an MOT station and make it pass (eg/ put the cats on)

[Ronnie]

Originally Posted by boostist

Yeah, but that is next to impossible in something like an 8 series.
Coppers dont even seem to do it to real filthy stinking traveller buses that belch black smoke out

True!

Originally Posted by boostist

Also, you would only get one of this orders to take it to an MOT station and make it pass (eg/ put the cats on)

Only if they don't suspect it's been done on purpose, as the MOT is computerised they can find out when the last MOT was, what the advises were and they can check for when the car was registered in your name. When I did my last MOT refresher course we covered roadside checks, this is what is written for the bad boys........
Where vehicles are found to be very
seriously in breach of the emission limits,
or you have neglected maintenance, you
are likely to be prosecuted as well as
being required to put the faults right. ,ouch.

When the ministry last came in THEY told us what the last 3 cars we had tested were as they had logged into OUR MOT computer with there hand held tablet and looked up , they then got one of the cars over and started testing it again to see if you had done it properly(not missed anything or failed something that wasn't that bad)