1M or N54 135i w PE with catted/catless dps

Alext · 02-10-2014, 04:45 PM

Don't want to introduce raspiness to the sound...

Has anyone got any experience with the sound from catted vs catless downpipes on the 1M or 135i with performance exhaust? I'm looking to put one on my Z 35is which has a similar stock exhaust setup and want to avoid any RASP if possible.

Thoughts on resonated dps welcome too!

PeteA · 02-10-2014, 05:40 PM

General rule of thumbs.
1. Removing cats (especially from downpipes) provides the biggest performance benefit, however makes sounds very raspy and in my opinion 'unrefined'.
2. Removing a resonator provides no performance benefit and induces drone at highway speeds (usually).

A nice refined sound in my opinion would be as follows:
1. Catted downpipes (1M N54 OEM/ N55 OEM or aftermarkets like AR Design).
2. Catless midpipes (N55 or Maddad)
3. Axle back muffler section of your liking. My favorites are BMW PE, AKRAPOVIC Slipon, Eisenmann Race and HARTGE.

Have fun

flinchy · 02-10-2014, 06:04 PM

The problem with catted 3" DP's, when making a lot of power, don't they end up just.. breaking, really fast?.. then they're just a restriction?

Zuzu · 02-10-2014, 07:04 PM

Quote:

Originally Posted by flinchy

The problem with catted 3" DP's, when making a lot of power, don't they end up just.. breaking, really fast?.. then they're just a restriction?

Where is your data to back this statement?

Alext · 02-11-2014, 05:19 AM

What about the Resonated AR downpipe? Has anyone had any experience with it?

Alpine* · 02-11-2014, 06:11 AM

What's wrong with a bit of a rasp anyway? I love the akra noise

flinchy · 02-11-2014, 11:53 PM

Quote:

Originally Posted by Zuzu

Where is your data to back this statement?

Californian N54 owners that install the catted DP's, pass straight after installation, then fail the next inspection... Some of whom have purchased multiple sets of catted DP's, then (IIRC) just bought some non-catted, then swap back to stock come inspection time.

I'm sure I can find the posts.. iirc on E90P, possibly on BB, if you really want?

Quote:

Originally Posted by Ian///M

No they don't

As above, just going off other's experiences

logically, the EGTs on a 400whp+ car over that of what's made stock, can't be good for the cats?

Personally, i like a *little* rasp, it's BMW's signature sound IMO haha.. Drone is the big nono.

Zuzu · 02-12-2014, 12:00 AM

Quote:

Originally Posted by flinchy

The problem with catted 3" DP's, when making a lot of power, don't they end up just.. breaking, really fast?.. then they're just a restriction?

Quote:

Originally Posted by Zuzu

Where is your data to back this statement?

Quote:

Originally Posted by flinchy

Californian N54 owners that install the catted DP's, pass straight after installation, then fail the next inspection... Some of whom have purchased multiple sets of catted DP's, then (IIRC) just bought some non-catted, then swap back to stock come inspection time.

I'm sure I can find the posts.. iirc on E90P, possibly on BB, if you really want?

What are you rambling about mate... that wasn't my question..

flinchy · 02-12-2014, 04:18 AM

Quote:

Originally Posted by Zuzu

[/COLOR]

What are you rambling about mate... that wasn't my question..

fair enough, didn't know you weren't capable of having a search...

i can't link to any of the decent results since they're not bimmerpost

cats are wear items

cats right near the turbos on a tuned car get way hotter than normal, increasing wear.

so the only reason to get catted DP's, is if you either want to stick to the letter of the law, and replace them every few years if you get emissions tested.... .or if you prefer the sound.

that, and you'll still need a DPfix with catted downpipes, due to the high flow nature not being what the DME expects to see.

Zuzu · 02-12-2014, 04:26 AM

Quote:

Originally Posted by flinchy

The problem with catted 3" DP's, when making a lot of power, don't they end up just.. breaking, really fast?.. then they're just a restriction?

Quote:

Originally Posted by Zuzu

Where is your data to back this statement?

Quote:

Originally Posted by flinchy

fair enough, didn't know you weren't capable of having a search...

i can't link to any of the decent results since they're not bimmerpost

cats are wear items

cats right near the turbos on a tuned car get way hotter than normal, increasing wear.

so the only reason to get catted DP's, is if you either want to stick to the letter of the law, and replace them every few years if you get emissions tested.... .or if you prefer the sound.

that, and you'll still need a DPfix with catted downpipes, due to the high flow nature not being what the DME expects to see.

Flinchy boy... You still havent answered the original question.

And why would I have to search for an answer to your bullshit post..

Grow up and post facts you can back up..

flinchy · 02-12-2014, 04:47 AM

Quote:

Originally Posted by Zuzu

Quote:

Originally Posted by flinchy

The problem with catted 3" DP's, when making a lot of power, don't they end up just.. breaking, really fast?.. then they're just a restriction?

Quote:

Originally Posted by Zuzu

Where is your data to back this statement?

Quote:

Originally Posted by flinchy

fair enough, didn't know you weren't capable of having a search...

i can't link to any of the decent results since they're not bimmerpost

cats are wear items

cats right near the turbos on a tuned car get way hotter than normal, increasing wear.

so the only reason to get catted DP's, is if you either want to stick to the letter of the law, and replace them every few years if you get emissions tested.... .or if you prefer the sound.

that, and you'll still need a DPfix with catted downpipes, due to the high flow nature not being what the DME expects to see.

Flinchy boy... You still havent answered the original question.

And why would I have to search for an answer to your bullshit post..

Grow up and post facts you can back up..

Wow, not my fault you don't understand how cats work?

And how didn't i answer the question? I can't post links to other forums here without risking a ban...

It's all over google

Or you can try getting smog tested after a few years of high power abuse with them..

Not to mention what evidence do you have? When there's loads of evidence of decades of catalytic converters failing, melting, being shot out at high power levels...

Zuzu · 02-12-2014, 05:01 AM

Quote:

Originally Posted by flinchy

Wow, not my fault you don't understand how cats work?

WOW....That hurts..ouch..

Its just too funny when some little wet behind the ears, keyboard warrior, is trying to explain his self worth and BS.. I have owned and engineered more high performance cars in the past 30 years than you have " walked your dog" so to speak...

And by the quality of your posts, It looks like you "walk your dog" quite a bit..

flinchy · 02-12-2014, 05:05 AM

Quote:

Originally Posted by Zuzu

Quote:

Originally Posted by flinchy

Wow, not my fault you don't understand how cats work?

WOW....That hurts..ouch..

Its just too funny when some little wet behind the ears, keyboard warrior, is trying to explain his self worth and BS.. I have owned and engineered more high performance cars in the past 30 years than you have " walked your dog" so to speak...

And by the quality of your posts, It looks like you "walk your dog" quite a bit..

Well this conversation went well

If you can't see the quality in my posts, i doubt the veracity of your '30 years high performance car engineering'

Hopefully you'll remember from your experience decades past that cats can and do fail, and heat accelerates that.

Ps. When the first thing you do is launch into baseless personal attacks, your argument loses all weight...

Sad to know a 'wet behind the ears keyboard warrior' can hold a bit more maturity than someone double+ his age..

minijet · 02-12-2014, 05:12 AM

Quote:

Originally Posted by Alext

Don't want to introduce raspiness to the sound...

Has anyone got any experience with the sound from catted vs catless downpipes on the 1M or 135i with performance exhaust? I'm looking to put one on my Z 35is which has a similar stock exhaust setup and want to avoid any RASP if possible.

Thoughts on resonated dps welcome too!

Feedback from my old 135 N54
I had the PE (but kept the stock resonated mids) with catless dp.
Was a bit E46 metallic raspy at the top end but low to mid was a nice rumble.

Zuzu · 02-12-2014, 05:13 AM

Good night Miss Flinchy. This at least twice your age, old timer has to go to bed now.
Have to get up early and start my Google search on the longitivity and functionality of a high flow catalytic converter. Xx

flinchy · 02-12-2014, 05:21 AM

Quote:

Originally Posted by Zuzu

Good night Miss Flinchy. This at least twice your age, old timer has to go to bed now.
Have to get up early and start my Google search on the longitivity and functionality of a high flow catalytic converter. Xx

Goodnight *Mr* Zuzu

Sounds good, I await your apology. Hopefully you wake up with your happy pants on tomorrow

Cheers!

thewafflecaust · 02-12-2014, 05:21 AM

The hell happened in this thread..

I have the AR catless DPs with an otherwise stock exhaust system. It rasps.

02-10-2014, 04:45 PM	#1
Alext Banned 138 Rep 2,042 Posts Drives: B M W Join Date: Apr 2008 Location: Everest iTrader: (2)	1M or N54 135i w PE with catted/catless dps - SOUND? Don't want to introduce raspiness to the sound... Has anyone got any experience with the sound from catted vs catless downpipes on the 1M or 135i with performance exhaust? I'm looking to put one on my Z 35is which has a similar stock exhaust setup and want to avoid any RASP if possible. Thoughts on resonated dps welcome too!
	Appreciate 0 Tweet Quote

02-10-2014, 05:40 PM	#2
PeteA Major 127 Rep 1,054 Posts Drives: E30, E82 Join Date: Sep 2012 Location: Melbourne iTrader: (3)	General rule of thumbs. 1. Removing cats (especially from downpipes) provides the biggest performance benefit, however makes sounds very raspy and in my opinion 'unrefined'. 2. Removing a resonator provides no performance benefit and induces drone at highway speeds (usually). A nice refined sound in my opinion would be as follows: 1. Catted downpipes (1M N54 OEM/ N55 OEM or aftermarkets like AR Design). 2. Catless midpipes (N55 or Maddad) 3. Axle back muffler section of your liking. My favorites are BMW PE, AKRAPOVIC Slipon, Eisenmann Race and HARTGE. Have fun __________________ Pete's Build Thread
	Appreciate 0 Quote

02-10-2014, 06:04 PM	#3
flinchy Brigadier General 126 Rep 3,099 Posts Drives: E82 135i Join Date: Nov 2011 Location: QLD, Australia iTrader: (0)	The problem with catted 3" DP's, when making a lot of power, don't they end up just.. breaking, really fast?.. then they're just a restriction?
	Appreciate 0 Quote

02-11-2014, 05:19 AM	#5
Alext Banned 138 Rep 2,042 Posts Drives: B M W Join Date: Apr 2008 Location: Everest iTrader: (2)	What about the Resonated AR downpipe? Has anyone had any experience with it?
	Appreciate 0 Quote

02-11-2014, 06:11 AM	#6
Alpine* Brigadier General 1282 Rep 4,093 Posts Drives: M2 G87 Join Date: May 2008 Location: Australia iTrader: (0)	What's wrong with a bit of a rasp anyway? I love the akra noise
	Appreciate 0 Quote

02-12-2014, 05:13 AM	#15
Zuzu Major General 2816 Rep 7,637 Posts Drives: M2C HS 6MT Join Date: Mar 2008 Location: Sydney Australia iTrader: (0)	Good night Miss Flinchy. This at least twice your age, old timer has to go to bed now. Have to get up early and start my Google search on the longitivity and functionality of a high flow catalytic converter. Xx
	Appreciate 0 Quote

02-12-2014, 05:21 AM	#17
thewafflecaust Private First Class 4 Rep 133 Posts Drives: 2009 Rattling Wastegate Join Date: Oct 2011 Location: Melbourne iTrader: (0)	The hell happened in this thread.. I have the AR catless DPs with an otherwise stock exhaust system. It rasps.
	Appreciate 0 Quote