[scott135i]

Can I get some clear info... In the f10 550i, are there two sets of cats?

One set in the downpipes and another set further back in the exhaust? Or just one set in the downpipes?

[747flyboy]

I have a removed full f10 550i exhaust in my barn. I will check it out for you when I make it home from Korea on Sept. 19.
I know the downpipes are catted with 600 cpi (cell per inch) cats.

Cheers

[kthankzbye]

Yes. There are two sets of cats. One on the downpipes and the secondary cats are located right below where the drivers seat are.
I removed the secondary cats and put in resonators. I still passed inspection.

[scott135i]

Originally Posted by kthankzbye

Yes. There are two sets of cats. One on the downpipes and the secondary cats are located right below where the drivers seat are.
I removed the secondary cats and put in resonators. I still passed inspection.

Interesting... I've heard they was only a center muffler and resonators and that the only Cats were in the downpipes.

Guess we won't know unless someone cut them open.

Also recall a thread with some exhaust part description and prices and they were in line with them being resonators, not secondary Cats.

[HDEddie1]

Pretty sure the so called "secondary cats" are really mufflers. I've seen the inlet on another post and there is not the customary cell matrix facing the exhaust flow. Instead, these center mufflers look straight through with perforated pipe. They seem low resistance but sound abating.
The other one, after the center mufflers, is the fused box shaped thing that merges each exhaust flow, almost like an x-pipe, but really to further reduce sound. Looks real restrictive and that might be the one to cut out instead of the center mufflers.
Lots of challenges with our F10 550i exhaust system but not too many easy or affordable solutions...Just my 2 cents.

[F10 HRE]

Primary cats are on the stock Downpipes, secondary cats are under the gearbox... I took off both when installing my Catless DP's on my F10 550i. Yes, you can smell the gas/fumes but it's not overbearing and yes... your exhaust will be a lot louder and you can definitely hear both turbos spool down the block or two. Hope this helps

[scott135i]

Originally Posted by F10 HRE

Primary cats are on the stock Downpipes, secondary cats are under the gearbox... I took off both when installing my Catless DP's on my F10 550i. Yes, you can smell the gas/fumes but it's not overbearing and yes... your exhaust will be a lot louder and you can definitely hear both turbos spool down the block or two. Hope this helps

Sweet - pics and/or videos to share??

[Viral@ActiveAutowerke]

Originally Posted by scott135i

Sweet - pics and/or videos to share??

Below is a Video of our Exhaust System on a 550i with Stock Downpipes.

This Video is our Downpipe and Exhaust System on a 550i

Hopefully these clips could help you out with the note your looking to obtain.

[scott135i]

Originally Posted by Viral@ActiveAutowerke

Below is a Video of our Exhaust System on a 550i with Stock Downpipes.



This Video is our Downpipe and Exhaust System on a 550i



Hopefully these clips could help you out with the note your looking to obtain.

Thanks Viral - I've seen these videos. I am more interested in videos of stock muffers with the center muffler and center resonator cut out.

There is still conflicting info as to whether the only set of cats are in the downpipes or if there is a secondary set as well. I am fairly certain it is the former.

[Viral@ActiveAutowerke]

Originally Posted by scott135i

Thanks Viral - I've seen these videos. I am more interested in videos of stock muffers with the center muffler and center resonator cut out.

There is still conflicting info as to whether the only set of cats are in the downpipes or if there is a secondary set as well. I am fairly certain it is the former.

Your welcome the resonator cut out does not make a big difference in the exhaust note it's just slightly deeper than stock. As for the Cats they are in the downpipes.

[scott135i]

Originally Posted by Viral@ActiveAutowerke

Your welcome the resonator cut out does not make a big difference in the exhaust note it's just slightly deeper than stock. As for the Cats they are in the downpipes.

Thanks!

So even with the center resonator and center muffler cut out, its still not loud/aggressive at all?

If thats the case, then the mufflers must be the uber quiet-maker. :/

[badblack550xi]

Originally Posted by scott135i

Thanks!

So even with the center resonator and center muffler cut out, its still not loud/aggressive at all?

If thats the case, then the mufflers must be the uber quiet-maker. :/

lets run tonight =D

[HighConcept]

Originally Posted by scott135i

Thanks!

So even with the center resonator and center muffler cut out, its still not loud/aggressive at all?

If thats the case, then the mufflers must be the uber quiet-maker. :/

Pretty much haha.

[Viral@ActiveAutowerke]

Originally Posted by badblack550xi

lets run tonight =D

Well Videos in this case

[badblack550xi]

Originally Posted by Viral@ActiveAutowerke

Well Videos in this case

hes scured