E36 Exhaust/Cat question

[kenwoir]

Sorry if this is in the wrong section...

Couple of questions.. My m3 has a centre section which contains cat convertors, however when i called the dealers they have a centre section list with the cats and also one without he cats, which is considerably cheaper. If i was to use the centre section without the cats would this cause MOT failure (even if the emissions were ok)? and secondly would the removal of the cats mess up the readings made by the lambda sensors, bearing in mind they are situated before the cats.

Cheers

[kam-325i]

CATs are only needed by law on cars manufactured after J plate (92)

[tylerma]

august 92 is when the compulsory cat thing came in
I am lucky mine is may 92
so off it comes

[stuartgallafant]

i doubt very much that the lambda sensor readings will be affected, as like you said, they are before the cats. the reason the lambda sensor is there, is to make monitor the mixture of the air/fuel ratio, and make sure it is running like it should. its just a more accurate way of obtaining the stoichiometric ratio...

as for the emissions, im not too sure. the cats are there for a reason, to lower emissions, ergo, without the cat, the emissions will not be lower! however, as far as i know, cats were an option on some vehicles, meaning you didnt have to have one. find out if your car has the cat as an optional extra. if it does, then taking it off wont fail the emissions, as the category the car falls into will allow for the results. but talking to your local dealership will clear this up a more

also, i believe you'll release some extra horses by removing the cat....

[kenwoir]

Sorry guys, i should have mentioned it's a 94 M3, (yes an e36 ) but i didnt think the lambda sensors would cause much of a problem, if at all and was think if without the cats in place if the emissions are tested and are within the allowed parameters then how could not having the cats be an mot failure?

Yes there is always the extra horses that comes form cat removal also

The reason i'm asking is that my centre section has taken a bit of abuse from the oversized ramp were i work and it's starting the blow out, the local dealers have the cat and non-cat option listed with a price difference of over £700 so you can see my thinking here

[kam-325i]

It MUST have the cat fitted for the MOT then, its a failure if it is not fitted, even if it pass's the emissions test.

[jmc330i]

Odd the dealers have a non-Cat option on car that will need Cats, but its right, my ETK shows it too

The Lamba sensors will not be affected by removing Cats, the engine will run fine.

However, have a read on the E36coupe.com site. I think you will find that most on there say the 3.0ltr M3 is known to lose power when the Cats are removed
A lot of them get a decent rear section, but keep the BMW front section.

I would save they money, keep what you have and get it welded back up. A thick bit of plating should stop it rubbing through again.

[kenwoir]

I was thinking of droppint the centre off and getting it welded, it's only just blowing out from a very snall pin hole and as you said i may get a metal plate type guard welded onto the bottom to help protect it from the ramps. My main concern is the flexy section at the bottom end of the manifold, it's fooked and blowing out like a biatch, i went to a powerflow centre today and they can cut this part out and weld a solid section in but i would have to remove the manifold and take it to him as it would not be accessable to do on the car

[buster]

hi kenwoir,
off topic but are you or have you bid on my backbox for m3 on ebay ?

[jmc330i]

hi kenwoir,
off topic but are you or have you bid on my backbox for m3 on ebay ?

I was going to as my chance at a cheap M3 backbox fell through, but yours might of gone a bit to high for me this month
I didnt realise it was yours though

[buster]

dont bother james,it dont fit the e30 chassis.Thats why i've sold it on.
I was gutted when i bought it and then offered it up to the underside and found it was far too big and would need a lot of modding to fit,thats why i decided to sell it on.

[jmc330i]

dont bother james,it dont fit the e30 chassis. it was far too big and would need a lot of modding to fit

Huh, it must just be the standard E36 M3 box then?? I know the other E36 exhausts will fit and Henrys M3 has an AC Schnitzer E36 M3 Evo back box on his. It just needed the mounts sorting out.

Cheers for the heads up

[buster]

yeah i think others will but this sucker is massive and weighs a ton.
The 325 and 328 are smaller but the pipes going into the back of them are too small.I dont know about the standard e36 m3 exhaust as opposed to the standard m3 evo exhaust,if theres any differance.i know the evo one has a cut out along its seam to accomodate the larger rear tyres fitted on the evo.
After market ( scorpian,magnex,AC etc) look a bit smaller,but i haven't seen any for sale though.Only a blue flame one for the evo but i was unsure it would fit.

[jmc330i]

After market ( scorpian,magnex,AC etc) look a bit smaller,but i haven't seen any for sale though.Only a blue flame one for the evo but i was unsure it would fit.

Now you say it, the AC box on Henrys did look small - I didnt realise the standard E36 M3 box was so big
Was that the Blueflame box on ebay? I was looking at that one, but it had gone before I had chance to really check it out.

[buster]

yeah it was on ebay,its gone now as i was thinking of that one also

[jmc330i]

yeah it was on ebay,its gone now as i was thinking of that one also

I looked at it, went back about 2 hours later and it had gone
Oh well, best get this thread back on topic I guess