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MattBMW

Headers/Exhuast manifolds and sports cats

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Anyone looked into Exhaust manifolds? I've see these can be purchased over ebay or a few other places with no problems, however Sports cats seem to be elusive? anyone seen once compatible with the 330? There is no point doin the manifolds unless your doing the the cats too as your just loosing the gains through bottle necking at the cats....

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You know what maybe this should have been in the tuning section...mods please move

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Decat pipe is the way to go I think mate :D

Slip the cat back on for the MOT ;)

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Phantom how hard is it to put the cats back on m8? is it a simple clamp and unclamlp scenario m8

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Not sure on the E46 to be totaly honest Matt, not got underneath to have a proper look at the 46 yet, however, in the worst case scenario I would be tempted to make a clean cut at the rear of the cat ( allow a good few inches space ) and get your local garage to sort you out a pipe to slot between your fresh cut and the downpipe attatchment, tell them its for the track or something, it cost me something like 50 quid on the the 5 series, being a 91 model I did not have to refit it at MOT time thankfully :D

Maybe someone else has a little more experience if a decat pipe is a simple job on the 46 tho.

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Thanks Mark......I'll wait and see what other say.....something I would consider if it's not too much hassle...would be good it was simple bolt on and off thing....I believe... I wonder if this could be done using a welded bolt on and off custom section..that way I could always change it myself when the MOT comes along.

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I wonder if this could be done using a welded bolt on and off custom section

Thats exactly the kinda thing im thinking also...........

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I know a place that might be able to do it.....just wonder what the costs would be as you have to take into consideration the manifolds.

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Well from what I have seen of a typical BMW cat setup you would only need one flange making, as I said above, a cut behind the CAT, you can already utilise the front downpipe connection ?

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Headers or manifolds on ebay tend to come from the USA. Couple of things, first their emissions laws are different to ours so less problems with the issue of CATs. Also the ebay headers are really cheap (could pay £200 delivered to England) but they are left hand drive only.

Headers generally give good bhp returns (10 -15 bhp), especially on the 330 as the cats are built into the manifolds (certainly post 2001 I think), so change the header in essence I believe is de-cating it. Will make it a lot louder too.....

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Litchy though I also read somewhere that the 330 has 4 cats rather than the two.... 2 built into the manifold and then 2 after.

I had seen plenty on ebay from the states although i was wondering if there are some that can be had cheapper closer to home....if not maybe custom ones are an option.....Haywood and scott but thats gonna mean lots of spondooleys.

Post Manifolds CATs Here

http://www.realoem.com/bmw/showparts.do?mo...hg=18&fg=10

I also believe the heat from them is normally the reason I think the right front lower arm bush goes despite the shield.

The manifold CATs

http://www.realoem.com/bmw/showparts.do?mo...hg=11&fg=50

By removing one set of of cats you'll still be bottle necking and then you still have about passing an MOT on two cats replaced???

Although from the above diagrams it looks easily possible to decat the 330 with performace headers

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As Matt said, the 330 has 4 cats!!! Crazy, and replacing for MOT time would be a nightmare. Not sure if it would pass an MOT with just the lower two either. And you dont want to have to change the headers for an MOT. Sports CAT is a grand iirc.

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Ouch, that sucks, and I certainly learnt something today ;)

At least with me ol 320d I only have the one underneath.............wonder if thats the same on the 330d.....?

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Ouch, that sucks, and I certainly learnt something today ;)

At least with me ol 320d I only have the one underneath.............wonder if thats the same on the 330d.....?

Pretty sure the 330d does only have one. But you can imagine filling up the petrol 330 with diesel (by accident), then driven a while and realized you now have to buy FOUR new cats!!! ouch

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I wonder how hard it would be to replace the headers and CATs if you put some custom ones in time for it's MOT. they doo look a bit awkward but not impossible....

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Sorry too bring up old thread but who does performance headers for RHD 330i? I've been thinking to get performance headers for a long time now ...i could go customs but i doubt the quality would be on par with say ... Supersprint. Any info is greatly appreciated :)

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What Chris said. It's not easy to de-cat and it's a nightmare to re-cat for your MOT. You'll fail it if you rely only on the rear cats and not the ones in the manifolds/downpipes.

Also I think there are emission sensors that probably need to be tricked into thinking all is ok?

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Matt I thought you had the manifolds on... you had them at the 1st B/W meet ??!

A De cat on your motor with your zorst will sound mental... :)

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Mit is right. I believe CA autmotive do RHD ones but your looking at over 1k..th other alternative is some cheap US ones but this my involve some custom welding inorder for them to fit.....

No I still have not tried to fit mine yet, was gonna do it last weekend but with all the problems I had with that shifter I did not get enough time to have a bash at the manifolds.

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Mit is right. I believe CA autmotive do RHD ones but your looking at over 1k..th other alternative is some cheap US ones but this my involve some custom welding inorder for them to fit.....

No I still have not tried to fit mine yet, was gonna do it last weekend but with all the problems I had with that shifter I did not get enough time to have a bash at the manifolds.

Thanks for the info :) One of the local mechs here told me that it's possible to use extractor manifold from an E36 M3 3.0 with some minimal mods to the flange side ... Anyone heard this alternative solution before?

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use extractor manifold from an E36 M3 3.0 with some minimal mods to the flange side

:P:) :)

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Not sure if it would make much difference, but mine uses 328 downpipes with no cats anyway, and no sensors except in the cats in the exhaust side. And mine runs fine obviously :) And ive seen RHD headers for the 328, so might give that a go :)

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