New RS5 Owner

4.2 V8 32v Naturally Aspirated - 444 bhp
Post Reply
sparklyman
Neutral
Posts: 2
Joined: Wed Jul 25, 2018 9:40 pm

New RS5 Owner

Post by sparklyman » Wed Jul 25, 2018 10:05 pm

Evening all,

Just signed up after recently acquiring a 2011 RS5. Hoping to find lots of knowledge, experience & insights on various topics.

First thing that's surprised me about this car is the Cold Start sequence, which I believe AUDi have programmed in on purpose to make it an "event" for owners each time.

Lots of rattles & noise, plus open exhaust valves - is this just pure theatre or is there a specific purpose.

Have read the increase rpm is to get oil pressure up quickly, reducing the chain & lifter noise, plus the open exhaust valves to help mask the noise ?

Have also read a mis-fire is programmed in to create a crackle (again, to mask the rattly engine ??)

First time I heard the car start from cold, i thought it was worn out already !

Fatneck73
4th Gear
Posts: 546
Joined: Sun Apr 17, 2011 9:02 pm
Location: Essex

Re: New RS5 Owner

Post by Fatneck73 » Thu Jul 26, 2018 8:36 am


User avatar
Brooner
Cruising
Posts: 3311
Joined: Mon Jan 20, 2003 5:12 am
Location: Scotlandshire

Re: New RS5 Owner

Post by Brooner » Thu Jul 26, 2018 10:38 am

Double FON :P
Pictures required

User avatar
Surrey Sam
Cruising
Posts: 4003
Joined: Tue Nov 27, 2012 7:34 pm
Location: Sussex

Re: New RS5 Owner

Post by Surrey Sam » Thu Jul 26, 2018 10:47 am

Hi Sparklyman welcome to the forum. The RS5 section is a little quiet on here, so it might be worth also dipping into the B8 RS4 section as well, due to them being the same platform and sharing a lot of componentry.

To answer your question, the cold start up sequence is louder due to a secondary air injection system. This system pumps additional air into the exhaust stream at the cylinder head to dilute the unburned hydrocarbons created from the cold (inefficient) engine. The now better mixed exhaust gasses can then be catalysed more efficiently by the catalytic convertor in this cold engine state. Once the engine starts warming up, the inefficiency improves to a level where the secondary air injection system is no longer necessary and it stops, the engine idle reduces and the car becomes quieter.

The exhaust valves should shut close within the start of this sequence; so maybe worth checking that happens, to ensure there is no vacuum leak.
Sepang Blue B8 RS4, MY14, All option packs, B&O, Adv Key, Adapt Cruise, Pan Roof, Akrapovic Titanium Exhaust, + more.
Previous - Sprint Blue B7 RS4 Avant, Ceramics, Sunroof, SS+, Buckets, FBSW, Bluetooth, 2010+ RNSe
Previous - Phantom Black B7 RS4 Avant, Black Optics, Titan pack, SS+, Buckets, FBSW

sparklyman
Neutral
Posts: 2
Joined: Wed Jul 25, 2018 9:40 pm

Re: New RS5 Owner

Post by sparklyman » Mon Aug 06, 2018 9:58 pm

Hey Sam - thanks for the reply and explanation of what's happening during a cold start - appreciate the knowledge share, just what I was hoping to find here.

Rear Silencer Valves are working fine, but I think I hear other exhaust valving at work during the cold start, seems to be around the transmission area....or is this the air injection shutting down, with a corresponding reduction in exhaust noise ? The ramp down in loudness starts to occur just before the revs tail off to idle.

The car always starts with Drive Select in Auto - if I switch to Dynamic during the cold start, the back end gets louder, so I assume the cold start sequence has rear silencer valves closed by default ?

Now you've explained what's happening, I'll be listening more closely at tomorrows start....

User avatar
Surrey Sam
Cruising
Posts: 4003
Joined: Tue Nov 27, 2012 7:34 pm
Location: Sussex

Re: New RS5 Owner

Post by Surrey Sam » Tue Aug 07, 2018 10:47 am

sparklyman wrote:
Mon Aug 06, 2018 9:58 pm
Rear Silencer Valves are working fine, but I think I hear other exhaust valving at work during the cold start, seems to be around the transmission area....or is this the air injection shutting down, with a corresponding reduction in exhaust noise ? The ramp down in loudness starts to occur just before the revs tail off to idle.
Yes, that'll be secondary air injection system you are hearing :thumbs:

sparklyman wrote:
Mon Aug 06, 2018 9:58 pm
The car always starts with Drive Select in Auto - if I switch to Dynamic during the cold start, the back end gets louder, so I assume the cold start sequence has rear silencer valves closed by default ?

Now you've explained what's happening, I'll be listening more closely at tomorrows start....
Sound like you have vacuum and all is normal with the valves, if it gets louder when switching to dynamic.
Sepang Blue B8 RS4, MY14, All option packs, B&O, Adv Key, Adapt Cruise, Pan Roof, Akrapovic Titanium Exhaust, + more.
Previous - Sprint Blue B7 RS4 Avant, Ceramics, Sunroof, SS+, Buckets, FBSW, Bluetooth, 2010+ RNSe
Previous - Phantom Black B7 RS4 Avant, Black Optics, Titan pack, SS+, Buckets, FBSW

wintonian
Neutral
Posts: 4
Joined: Mon Oct 15, 2018 10:45 am

Re: New RS5 Owner

Post by wintonian » Fri Oct 26, 2018 12:40 pm

Hi Sparklyman - I too have just purchased an RS5 and so far so good. How is your ownership going? Any tips/concerns you want to share?

Nick

ps - where in Surrey are you? I'm down in Winchester.

Post Reply

Return to “RS5 (8T) 2010–2015”

Who is online

Users browsing this forum: No registered users and 4 guests