Catless or Catted Downpipes Z4 35is?

Dav3 · 07-11-2023, 06:46 PM

Unlike the E9x platform can’t find any catted downpipes that are below 1k. Only two options are the AR downpipes (1400$+shipping and customs) and lightweight 1800€

So considering catless, but really wonder if the smell is bad with top down? Can anyone chime in?

I know secondary’s cats do some filtering, but yeah, not a fan of crude exhaust smell surrounding the car when at a standstill

Appreciate any input
Cheers!

B21 · 07-12-2023, 03:27 AM

I run VSRF catless downpipes and never notice any smell apart from a few minutes on first cold start as that’s when the ECU runs it rich to warm up the cats..

I drive almost all the time top down..

In the UK secondary cats do a sufficient good job to pass emissions tests..

airwalk776 · 07-12-2023, 04:25 AM

VRSF catless is the way to go !! I never looked back makes a huge difference. Sound and performance

Hejnfelt · 07-29-2023, 05:37 PM

VRSF catless won't pass EU emissions check which is annually on most E89s by now.

But there is this solution:

https://www.s p o o l s t r e e t .com/threads/z4-e89-n54-downpipes-with-race-cats-and-silicone-intakes.8941/

KennyP · 07-30-2023, 10:58 AM

Are emission tests more relaxed in UK?
I thought that catless downpipes wont pass here in Estonia... but then read B21 claim that he gets passed?
Werent UK like part of EU just a while ago? So did UK not have same EU emissions standards implemented? Im sure the did not go and change them after Brexit?

B21 · 07-31-2023, 05:44 AM

Quote:

Originally Posted by KennyP

Are emission tests more relaxed in UK?
I thought that catless downpipes wont pass here in Estonia... but then read B21 claim that he gets passed?
Werent UK like part of EU just a while ago? So did UK not have same EU emissions standards implemented? Im sure the did not go and change them after Brexit?

The UK hasn’t changed its pollution requirements on MOTs….whether various National MOTs are more stringent is more likely ..at the point of manufacture I’m sure the requirements were all harmonised.

I think I pass the Uk requirement by a factor of 2 rather than a factor of 10 times with both sets of cats..

vadonchez · 07-31-2023, 11:54 AM

time for a read:

https://www.e90post.com/forums/showthread.php?t=2035170

07-11-2023, 06:46 PM	#1
Dav3 Major 949 Rep 1,027 Posts Drives: G87 M2/E89 35is/F21 M140i/GT4 Join Date: Oct 2016 Location: Europe iTrader: (0)	Catless or Catted Downpipes Z4 35is? Unlike the E9x platform can’t find any catted downpipes that are below 1k. Only two options are the AR downpipes (1400$+shipping and customs) and lightweight 1800€ So considering catless, but really wonder if the smell is bad with top down? Can anyone chime in? I know secondary’s cats do some filtering, but yeah, not a fan of crude exhaust smell surrounding the car when at a standstill Appreciate any input Cheers! __________________ Current: G87 M2 / F21 M140 / 718 GT4 \| E89 Z4 35is Gone: E92 M3 \| RS3 8V \| E82 1M \| AMG GT-S \| X3M Comp \| F80 M3 \| Juke Nismo RS \| E85 Z4 M Roadster \| R58 Coupe JCW \| F87 M2C\| F87 M2 \| F22 M240i \| F82 M4 \| E89 Z4 2.0i \| F56 Cooper S \| E92 330i \| R56 One
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07-12-2023, 03:27 AM	#2
B21 Captain 153 Rep 611 Posts Drives: E89 Atacama Yellow 35is Join Date: May 2022 Location: Scotland..God’s own country iTrader: (0)	I run VSRF catless downpipes and never notice any smell apart from a few minutes on first cold start as that’s when the ECU runs it rich to warm up the cats.. I drive almost all the time top down.. In the UK secondary cats do a sufficient good job to pass emissions tests.. __________________ Much modified 2011 Atacama Yellow 35is…previously a much modified 2012 Atacama Yellow 20i MSport Change history here… https://www.dropbox.com/s/8h1vabklgz...0List.pdf?dl=0 Build thread here… https://z4-forum.com/forum/viewtopic.php?t=131886
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07-12-2023, 04:25 AM	#3
airwalk776 Private First Class 49 Rep 152 Posts Drives: 2011 Z4 sDrive35is Join Date: Oct 2007 Location: New Jersey iTrader: (0)	VRSF catless is the way to go !! I never looked back makes a huge difference. Sound and performance
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07-29-2023, 05:37 PM	#4
Hejnfelt Private 11 Rep 59 Posts Drives: ‘13 BMW Z4 sDrive 35is Join Date: May 2023 Location: Tallinn iTrader: (0)	VRSF catless won't pass EU emissions check which is annually on most E89s by now. But there is this solution: https://www.s p o o l s t r e e t .com/threads/z4-e89-n54-downpipes-with-race-cats-and-silicone-intakes.8941/
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07-30-2023, 10:58 AM	#5
KennyP Lieutenant 147 Rep 463 Posts Drives: 2009 Havana E89 Z4 Sdrive35i Join Date: Apr 2016 Location: Estonia iTrader: (0)	Are emission tests more relaxed in UK? I thought that catless downpipes wont pass here in Estonia... but then read B21 claim that he gets passed? Werent UK like part of EU just a while ago? So did UK not have same EU emissions standards implemented? Im sure the did not go and change them after Brexit? __________________ 2009 35i DCT Havana brown with ivory white interior. Mods: Cobb stage 1+FMIC, Wagner EVO1 FMIC, BMS DCI, KW V3 suspension, M3 front control arms, Hardrace RTAB, Michelin Pilot Sport 4S tires.
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07-31-2023, 11:54 AM	#7
vadonchez Private 35 Rep 89 Posts Drives: z4 35IS Join Date: Sep 2022 Location: FRANCE iTrader: (0)	time for a read: https://www.e90post.com/forums/showthread.php?t=2035170
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