E90 320i 2011 Exhaust System

[font=Tahoma, Verdana, Arial, sans-serif]Hi guys. My 320i has gradually been loosing power, accompanied with higher fuel consumption. I suppose this is to be expected from this old girl. The mackie where she currently is ran full diagnostics with no errors and all sensors are well within normal parameters. He suspects the CATS might be partially blocked. [/font]
[font=Tahoma, Verdana, Arial, sans-serif]His recommendation is to de-cat and go for branches as that will significantly improve power and consumption. Furthermore he mentioned that if another silencer is not installed my lady will sound like a UNO on steroids(no offense to uno owners ?) with a very hollow/tin sound. Are the above assumptions correct? [/font]
[font=Tahoma, Verdana, Arial, sans-serif]Regards, Dewald [/font]
 

Andre1983

Member
Im about to have my e90 330i decatted and new branches done. Viper is doing it. Nobody mentioned anything about fitting another silencer, for what it's worth. I have no blocked cat symptoms. This is purely an audiophile upgrade..

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Dr Evil

Active member
Andre1983 said:
Im about to have my e90 330i decatted and new branches done. Viper is doing it. Nobody mentioned anything about fitting another silencer, for what it's worth. I have no blocked cat symptoms. This is purely an audiophile upgrade..

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Can you post sound clips please. I have a 330i and I'm wanting to do this as well.


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Nick

Honorary ///Member
My 320i has a mid pipe to tail power flow on it. ( still have CATS though)

She doesn't sound like an Uno.

[video=youtube]

[video=youtube]
 

ibs.patel

Member
I also have a 330i and am considering if I dont sell it. I did a decat on my previous e90 323i and the car felt noticeably less restrained and the fuel consumption improved. It costed around R2100 three years ago. Whats it costing you for the 330i now Andre? Do you need to do anything additional to prevent backpressure sensor errors?
 

Kyle

///Member
Dewald_Bark said:
[font=Tahoma, Verdana, Arial, sans-serif]Hi guys. My 320i has gradually been loosing power, accompanied with higher fuel consumption. I suppose this is to be expected from this old girl. The mackie where she currently is ran full diagnostics with no errors and all sensors are well within normal parameters. He suspects the CATS might be partially blocked. [/font]
[font=Tahoma, Verdana, Arial, sans-serif]His recommendation is to de-cat and go for branches as that will significantly improve power and consumption. Furthermore he mentioned that if another silencer is not installed my lady will sound like a UNO on steroids(no offense to uno owners ?) with a very hollow/tin sound. Are the above assumptions correct? [/font]
[font=Tahoma, Verdana, Arial, sans-serif]Regards, Dewald [/font]

What's the current mileage? 

There's no real downside to performing a decat, just don't expect a significant improvement from just that. From what I recall, the OEM exhaust mani is designed quite well on these too, so again branches wouldn't give you any significant improvement on this platform. Ask your mechanic to check and clean the vanos solenoids first and take it from there.
 

Andre1983

Member
@Dr Evil I will post some soonest its done. Balls deep in work atm but will do it when I have a gap. @ibs.patel I was quoted R3500 give or take, excluding the engine miunts that are being changed will we are in there. Car will be in the shop for two days.. I did ask about back pressure, but was told as the resonator and factory backbox will be staying(for now) they just need to use cat foolers. Spoke to another customer whilst there, he did his e46 330i and was over the moon. He mentioned throttle response improvement as well as better fuel economy in day to day driving. Took me around the block and it felt like his e46 would leave my e90 behind..

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Nick said:
My 320i has a mid pipe to tail power flow on it. ( still have CATS though)

She doesn't sound like an Uno.

[video=youtube]

[video=youtube]

Lekker. Definitely no Uno


Kyle said:
Dewald_Bark said:
[font=Tahoma, Verdana, Arial, sans-serif]Hi guys. My 320i has gradually been loosing power, accompanied with higher fuel consumption. I suppose this is to be expected from this old girl. The mackie where she currently is ran full diagnostics with no errors and all sensors are well within normal parameters. He suspects the CATS might be partially blocked. [/font]
[font=Tahoma, Verdana, Arial, sans-serif]His recommendation is to de-cat and go for branches as that will significantly improve power and consumption. Furthermore he mentioned that if another silencer is not installed my lady will sound like a UNO on steroids(no offense to uno owners ?) with a very hollow/tin sound. Are the above assumptions correct? [/font]
[font=Tahoma, Verdana, Arial, sans-serif]Regards, Dewald [/font]

What's the current mileage? 

There's no real downside to performing a decat, just don't expect a significant improvement from just that. From what I recall, the OEM exhaust mani is designed quite well on these too, so again branches wouldn't give you any significant improvement on this platform. Ask your mechanic to check and clean the vanos solenoids first and take it from there.

Current mileage 260k. The solenoids gets cleaned with every service.
 

Kyle

///Member
Dewald_Bark said:
Current mileage 260k. The solenoids gets cleaned with every service.

Ok, definitely worthwhile performing a decat at this mileage... With regard to the sound from a full exhaust, being a 4 cyl, the only thing I would suggest is a decent sized mid box and a 1-2 rear silencer to give it a deeper sound.
 

Captain_Stealth

Well-known member
do the decat and check for yourself, you not going to gain much in terms of performance maybe slightly more that when it first came out but not much.

to be honest sounds like he is trying to make a meal of it

BTW what does he want to charge you

Found a link of what a n46 decat looks like

http://garage808.co.za/decat/
 

Kyle

///Member
Captain_Stealth said:
do the decat and check for yourself, you not going to gain much in terms of performance maybe slightly more that when it first came out but not much.

to be honest sounds like he is trying to make a meal of it

BTW what does he want to charge you

Found a link of what a n46 decat looks like

http://garage808.co.za/decat/

Agreed, it's not going to be a night and day difference or anything, and branches would be a total waste of money if you look at the original manifold.
 

Captain_Stealth

Well-known member
Another thing with branches is what type

4-1 branches will make better power up top but low rpm performance is affected
4-2-1 branches will make better low and mid power but 4-1 branches make better power up top compared to these.

I say cut out the cats like in the link I posted previously and leave it at that


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Captain_Stealth said:
do the decat and check for yourself, you not going to gain much in terms of performance maybe slightly more that when it first came out but not much.

to be honest sounds like he is trying to make a meal of it

BTW what does he want to charge you

Found a link of what a n46 decat looks like

http://garage808.co.za/decat/

R4800. De-cat and Branches. My main issue is with the fuel consumption. Low end performance are where are my issues are. Open road...no complaints except the consumption. 
 

Captain_Stealth

Well-known member
Dewald_Bark said:
Captain_Stealth said:
do the decat and check for yourself, you not going to gain much in terms of performance maybe slightly more that when it first came out but not much.

to be honest sounds like he is trying to make a meal of it

BTW what does he want to charge you

Found a link of what a n46 decat looks like

http://garage808.co.za/decat/

R4800. De-cat and Branches. My main issue is with the fuel consumption. Low end performance are where are my issues are. Open road...no complaints except the consumption. 

sho pricey I recon call garage808 see what they say and how much
 
Captain_Stealth said:
Dewald_Bark said:
Captain_Stealth said:
do the decat and check for yourself, you not going to gain much in terms of performance maybe slightly more that when it first came out but not much.

to be honest sounds like he is trying to make a meal of it

BTW what does he want to charge you

Found a link of what a n46 decat looks like

http://garage808.co.za/decat/

R4800. De-cat and Branches. My main issue is with the fuel consumption. Low end performance are where are my issues are. Open road...no complaints except the consumption. 

sho pricey I recon call garage808 see what they say and how much

I bit the bullet and had it done. The mrs needs the car back. Throttle response has definitely improved. Fuel consumption has improved....and I think it she definitely doesn't sound like an Uno.


[video=youtube]
 
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