De-cat

[siarach]

Guys,
Anyone have any experience of decatting the E34??
My exhaust does not have long to live and I was thinking of getting a bespoke system made without a CAT.

Any advice??
1995 520i M50 6cyl petrol

Thanks
John

[Dave M]

Had this made a long time ago (10+ years, heavy gauge). The threaded collar for the O2 sensor is located where the single pipe splits.

http://img.photobucket.com/albums/v11/dave_macisaac/Bimmer/Exhaust/Exhaust2.jpg (http://smg.photobucket.com/user/dave_macisaac/media/Bimmer/Exhaust/Exhaust2.jpg.html)

http://img.photobucket.com/albums/v11/dave_macisaac/Bimmer/Exhaust/Exhaust.jpg (http://smg.photobucket.com/user/dave_macisaac/media/Bimmer/Exhaust/Exhaust.jpg.html)

[632 Regal]

Why? Stock is very efficient and tuned to the engine. grab another stock system for like $50 - $100 at the local wreckers.

[genphreak]

I've had it done in what we thought would eb a good way. Recommend against it as the stock systems are actually very, very good on e34, just not stainless behind the kat. Tailored systems are just welded on pieces that are nowhere near what was originally engineered on e34. There is little room to play with behind the catalyst when using stock components too- everything BMW engineers did there makes very good use of the available space.

However you can find non-katalyst systems from the factory- perhasp copy them with your modification, or jst find one and replace the front 'kat' section with it instead. These have a silencer or wave balancing box to adjust the harmonics in place of the converter which allows the exhaust to retain the noise characteristics. Removing it may give you mixed results at different speeds/loads.

[siarach]

Had this made a long time ago (10+ years, heavy gauge). The threaded collar for the O2 sensor is located where the single pipe splits.

http://img.photobucket.com/albums/v11/dave_macisaac/Bimmer/Exhaust/Exhaust2.jpg (http://smg.photobucket.com/user/dave_macisaac/media/Bimmer/Exhaust/Exhaust2.jpg.html)

http://img.photobucket.com/albums/v11/dave_macisaac/Bimmer/Exhaust/Exhaust.jpg (http://smg.photobucket.com/user/dave_macisaac/media/Bimmer/Exhaust/Exhaust.jpg.html)
Thanks Dave