E90 only: Downpipes + Secondary cat delete. Rasp?

bradsm87 · 04-05-2016, 08:07 PM

We all know Downpipes + secondary cat delete (replace with straight pipes, not resonators) makes a horrible rasp sound if done on an E92 (which has an X-pipe instead of resonator) or when done in combination with a BMW PE or any type of PE mod.

What I want to know is if you have downpipes and replace secondary cats on an E90 and keep the exhaust 100% stock from the secondary cats back, does it have rasp? I don't really want the added weight and expense of resonators if I can just put straight pipes in and get a bit more sound too.

Thanks in advance

nyfg56 · 04-05-2016, 08:57 PM

I have an e90 with PE mod and catless downpipes. Getting my secondaries cut off this week and will post a vid and let you know!

kfrazie1 · 04-05-2016, 09:05 PM

I have stock downpipes and secondary cat delete on E90. No rasp. Sounds fine.

bradsm87 · 04-05-2016, 09:38 PM

Quote:

Originally Posted by nyfg56

I have an e90 with PE mod and catless downpipes. Getting my secondaries cut off this week and will post a vid and let you know!

Not exactly what I'm after but I look forward to hearing how it goes anyway. I'm assuming replacing with straight pipes, not resonators?

Quote:

Originally Posted by kfrazie1

I have stock downpipes and secondary cat delete on E90. No rasp. Sounds fine.

Stock downpipes stop rasp.

nyfg56 · 04-05-2016, 10:03 PM

Quote:

Originally Posted by bradsm87

Quote:

Originally Posted by nyfg56

I have an e90 with PE mod and catless downpipes. Getting my secondaries cut off this week and will post a vid and let you know!

Not exactly what I'm after but I look forward to hearing how it goes anyway. I'm assuming replacing with straight pipes, not resonators?

Quote:

Originally Posted by kfrazie1

I have stock downpipes and secondary cat delete on E90. No rasp. Sounds fine.

Stock downpipes stop rasp.

Yes. Replacing with straight pipe

AK. · 04-06-2016, 04:04 AM

Mine doesn't rasp. I have PE mod, dps, and secondaries replaced with resonators.

54VAGE · 04-06-2016, 04:25 AM

I have an E92 with downpipes and performance exhaust. I want to delete secondary cats as well and can't find a single exhaust clip of the projected outcome so I'm afraid of the rasp also. Really don't wanna add resonators but j also don't wanna chop off the mufflers either :/

bradsm87 · 04-06-2016, 05:05 AM

Quote:

Originally Posted by bradsm87

if you have downpipes and replace secondary cats on an E90 and keep the exhaust 100% stock from the secondary cats back, does it have rasp? I don't really want the added weight and expense of resonators if I can just put straight pipes in and get a bit more sound too.

Quote:

Originally Posted by AK.

Mine doesn't rasp. I have PE mod, dps, and secondaries replaced with resonators.

I'm aware that there is no rasp with resonators.

bradsm87 · 04-06-2016, 05:09 AM

Quote:

Originally Posted by Rashman94

I have an E92 with downpipes and performance exhaust. I want to delete secondary cats as well and can't find a single exhaust clip of the projected outcome so I'm afraid of the rasp also. Really don't wanna add resonators but j also don't wanna chop off the mufflers either :/

I can guarantee you'll get some nasty sounds with E92, catless downpipes, PE and secondary cats replaced with straight pipes. I would highly recommend to replace the secondary cats with resonators, not straight pipes.

54VAGE · 04-06-2016, 05:26 AM

Quote:

Originally Posted by bradsm87

Quote:

Originally Posted by Rashman94

I have an E92 with downpipes and performance exhaust. I want to delete secondary cats as well and can't find a single exhaust clip of the projected outcome so I'm afraid of the rasp also. Really don't wanna add resonators but j also don't wanna chop off the mufflers either :/

I can guarantee you'll get some nasty sounds with E92, catless downpipes, PE and secondary cats replaced with straight pipes. I would highly recommend to replace the secondary cats with resonators, not straight pipes.

What are my best options for resonators while still having the most sound output?

bradsm87 · 04-06-2016, 05:29 AM

Quote:

Originally Posted by Rashman94

What are my best options for resonators while still having the most sound output?

Short 12" bullet/bottle style ones are the go. I'd prob go 2.5" ones (Stock is 2.35" but you can only buy 2.25" or 2.5").

Something like this: http://vibrantperformance.com/catalo...roducts_id=290

Give_Em_The_DD · 04-06-2016, 07:09 AM

Catless + secondary delete + PE exhaust will rasp BAD.

I did it, and instantly regretted it. Imagine the worst sounding Honda Civic tractor you've ever heard

IMO using resonators is a must

kmeanor10 · 04-06-2016, 10:49 AM

I'm also looking into this. Can someone verify no rasp w/ catless DP's and resonators in place of the secondaries?

bradsm87 · 04-06-2016, 11:49 AM

Quote:

Originally Posted by kmeanor10

I'm also looking into this. Can someone verify no rasp w/ catless DP's and resonators in place of the secondaries?

There is plenty of verification that there is no rasp with that setup. You'll be fine. I'm asking about straight pipes instead of resonators.

stephenf121 · 04-06-2016, 04:48 PM

I have a 2007 e90 335i with AR hatless downpipes and secondaries removed (straight pipes in place), with stock mufflers and there is no rasp. Still very quiet in my opinion. Hopefully adding a PE exhaust soon.

bradsm87 · 04-06-2016, 07:17 PM

Quote:

Originally Posted by stephenf121

I have a 2007 e90 335i with AR hatless downpipes and secondaries removed (straight pipes in place), with stock mufflers and there is no rasp. Still very quiet in my opinion.

Excellent. That answers my question. Any undesirable sounds at all? If Not, The E90 resonator that is not present on the E92 must do an OK job at getting rid of the rasp noise.

Quote:

Originally Posted by stephenf121

Hopefully adding a PE exhaust soon.

You'll know all about rasp if you do that. Many, many people report downpipes + secondary cat delete + PE = Rasp central

stephenf121 · 04-06-2016, 07:40 PM

No undesirable noises, sounds fine, just not very loud. Cold start is pretty loud but quiets down quickly. I also think the resonator is what helps keep the rasp down. I also want a PE exhaust, so ill probably place resonators in place of the straight piped secondaries

PNWN54 · 04-07-2016, 01:48 AM

Here's a clip of stock mufflers with downpipes and secondaries removed. Seems like there's small rasp in the midrange but no biggie.

mwahlert · 04-07-2016, 10:21 AM

AR CL DP's
secondary C's removed
stock exhaust otherwise.

SONO_N54 · 04-07-2016, 08:18 PM

Quote:

Originally Posted by bradsm87

Excellent. That answers my question. Any undesirable sounds at all? If Not, The E90 resonator that is not present on the E92 must do an OK job at getting rid of the rasp noise.

You'll know all about rasp if you do that. Many, many people report downpipes + secondary cat delete + PE = Rasp central

I have an E90, VRSF DPs, Secondary cat delete and stock mufflers. Theres no rattle or rasp however at WOT there's an initial drone that goes away and repeats after shifts.

bradsm87 · 04-08-2016, 04:51 AM

Quote:

Originally Posted by SONO_N54

I have an E90, VRSF DPs, Secondary cat delete and stock mufflers. Theres no rattle or rasp however at WOT there's an initial drone that goes away and repeats after shifts.

Like a drone at a fixed RPM point at full load? If so, what RPM is it at? Cheers.

SONO_N54 · 04-11-2016, 12:32 PM

Quote:

Originally Posted by bradsm87

Like a drone at a fixed RPM point at full load? If so, what RPM is it at? Cheers.

Just at full load.

04-05-2016, 08:07 PM	#1
bradsm87 Lieutenant Colonel 603 Rep 1,693 Posts Drives: F25 LCI xDrive30d Join Date: Jun 2013 Location: Australia iTrader: (0)	E90 only: Downpipes + Secondary cat delete. Rasp? We all know Downpipes + secondary cat delete (replace with straight pipes, not resonators) makes a horrible rasp sound if done on an E92 (which has an X-pipe instead of resonator) or when done in combination with a BMW PE or any type of PE mod. What I want to know is if you have downpipes and replace secondary cats on an E90 and keep the exhaust 100% stock from the secondary cats back, does it have rasp? I don't really want the added weight and expense of resonators if I can just put straight pipes in and get a bit more sound too. Thanks in advance
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04-05-2016, 08:57 PM	#2
nyfg56 Captain 103 Rep 857 Posts Drives: 2010 E90 M3 AW/Fox Red 6MT Join Date: Nov 2013 Location: Albany NY iTrader: (2)	I have an e90 with PE mod and catless downpipes. Getting my secondaries cut off this week and will post a vid and let you know!
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04-05-2016, 09:05 PM	#3
kfrazie1 Lieutenant 65 Rep 553 Posts Drives: 335i Join Date: Aug 2010 Location: NY iTrader: (4)	I have stock downpipes and secondary cat delete on E90. No rasp. Sounds fine.
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04-06-2016, 04:04 AM	#6
AK. Lieutenant 138 Rep 592 Posts Drives: E90 M3/E92 M3 ZCP Join Date: Jan 2015 Location: California iTrader: (3) Garage List 2010 E90 335i [10.00]	Mine doesn't rasp. I have PE mod, dps, and secondaries replaced with resonators.
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04-06-2016, 04:25 AM	#7
54VAGE Second Lieutenant 17 Rep 200 Posts Drives: '09 E92 N54 335i Join Date: Jun 2015 Location: East Meadow iTrader: (0) Garage List 2009 BMW 335i [0.00]	I have an E92 with downpipes and performance exhaust. I want to delete secondary cats as well and can't find a single exhaust clip of the projected outcome so I'm afraid of the rasp also. Really don't wanna add resonators but j also don't wanna chop off the mufflers either :/ __________________ E92 N54 JB4, MHD, Alpina flash, ARM DPs, Cobb CP/HKS bov, BMS DCI/OCV, PE exhaust, 2nd cat delete (vibrant 1792), Mishimoto FMIC, Fuel-It stage 2, Msport F30 N20 EWG
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04-06-2016, 07:09 AM	#12
Give_Em_The_DD Banned 258 Rep 1,084 Posts Drives: 2010 black 335xi coupe Join Date: Sep 2013 Location: IL iTrader: (2)	Catless + secondary delete + PE exhaust will rasp BAD. I did it, and instantly regretted it. Imagine the worst sounding Honda Civic tractor you've ever heard IMO using resonators is a must
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04-06-2016, 10:49 AM	#13
kmeanor10 New Member 4 Rep 28 Posts Drives: '09 E92 335xi Join Date: Mar 2016 Location: Wisconsin iTrader: (0)	I'm also looking into this. Can someone verify no rasp w/ catless DP's and resonators in place of the secondaries?
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04-06-2016, 04:48 PM	#15
stephenf121 Second Lieutenant 43 Rep 206 Posts Drives: 2007 335i Join Date: Oct 2015 Location: Ohio iTrader: (0)	I have a 2007 e90 335i with AR hatless downpipes and secondaries removed (straight pipes in place), with stock mufflers and there is no rasp. Still very quiet in my opinion. Hopefully adding a PE exhaust soon.
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04-06-2016, 07:40 PM	#17
stephenf121 Second Lieutenant 43 Rep 206 Posts Drives: 2007 335i Join Date: Oct 2015 Location: Ohio iTrader: (0)	No undesirable noises, sounds fine, just not very loud. Cold start is pretty loud but quiets down quickly. I also think the resonator is what helps keep the rasp down. I also want a PE exhaust, so ill probably place resonators in place of the straight piped secondaries
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04-07-2016, 01:48 AM	#18
PNWN54 MR. Rocket 46 Rep 398 Posts Drives: 2010 E92 335i M-Sport Join Date: May 2013 Location: Portland, OR iTrader: (2) Garage List 2010 E92 BMW 335i [0.00]	Here's a clip of stock mufflers with downpipes and secondaries removed. Seems like there's small rasp in the midrange but no biggie. __________________ \|2010 E92 335i 6MT\\\M-Sport///225M 19" Rims, MHD PTF Stg 2+, Fuel IT Stage 2 LPFP, VRSF Downpipes, CDV Delete, ER CP & 5" IC, Forge DV, PE Modded Mufflers, BMS DCI & Cowl Delete, CYBA Tips, ST Coils, M3 Control Arms, E93 M3 Sway Bar, Michelin PSS\|
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04-07-2016, 10:21 AM	#19
mwahlert Lieutenant Colonel 97 Rep 1,659 Posts Drives: 2009 335i Join Date: Apr 2008 Location: NC iTrader: (8)	AR CL DP's secondary C's removed stock exhaust otherwise.
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