[greenelekta]

Just reading another thread and people are shocked with the price of replacement Cats from BMW. I was too so I did this!

I've just fitted new Cats on my 850csi. I cut the Cats open at the weld on one end and removed/knocked out the Cat insides leaving the Cat cans empty. I then welded (stainless) Magnaflow Freeflow/Race Cats inside the empty cans, they are a snug fit. Then reweld the end back on. You would never know they'd been split open. Exhaust still looks standard. Just passed the MOT. Total cost for both Cats under £300. I'm thinking about doing the same on my M5 Elekta

 

[Lantz]

How many cells are the race cats?

Sounds like an interesting proposition. And I guess the added flow/sound isn't half bad either...

Lantz

 

[greenelekta]

How many cells are the race cats?

Sounds like an interesting proposition. And I guess the added flow/sound isn't half bad either...

Lantz

200 cell, you are right sound is interesting as I have also replaced the centre resonator with straight through pipies with a crossover + opened up the back box's and gutted them.

 

[davidoli]

Great advice and good to hear that some owners are willing to think outside of the box , so to speak !

D

 

[martind]

Great bit of info there, should the need arise I would have cut out the cats & welded suitable complete ones back in from the USA.
See here for a range of universal replacements
MagnaFlow - Catalytic Converters - Exhaust - SummitRacing.com
But now Greenelekta has an alternative way :thumbsup:

 

[johnnyjumps]

you should post a video of what it sounds like

 

[greenelekta]

you should post a video of what it sounds like

Here you go Johnny


YouTube - BMW 850CSI Gutted Exhaust Back Boxes

 

[johnnyjumps]

sounds pretty gnarley

 

[HJSUSA]

HJS Catalytic Converters

Hi,
Please visit HJS North America, LLC for HJS 200 Cell Hi-Flow Catalytic Converters. We have several models to fit your needs.
Our cats are 100% Made in Germany, and 100% Stainless Steel and are Universal so they can be used on many different types of vehicles.

Also visit our How to and Why Page:
How to replace Catalytic Converter? For BMW, Porsche, Mercedes, Ferrari, Maserati, Lamborghini, Bentley, Range Rover, Ford, GM, Chrysler, Honda, Acura, Nissan, Infiniti, Toyota, Lexus, How to install a Catalytic Converter?