Backbox/muffler delete

[rtd]

Stu - The cold start is very loud, you literally have to shout to be heard from 2m away if you are stood at the back (tested it when I did mine). You can get it mapped "out" but all that does is reduce the time spent on the cold start cycle from 30-45 secs to 5 secs but it'll still be loud for those 5 seconds.

Alternatively you could get the whole SAI system removed. It's just an air pump & 2 combi-valves which'll need blanking and you get less than 1 second of "cold start" noise.

Ian, if you get the SAI system removed do you still need to get the mapping done to reduce the cold cycle time.

[IanH755]

Yes and No

No - The SAI just adds extra air to the exhaust during "cold start", it doesn't alter the fueling. The extra air makes the exhaust gas more diluted which lowers emissions and allows the Lambda sensors and catalytic converters to start working sooner so removing it will remove the cold start completely without having to map anything.

Yes - If you do remove the SAI then you may get a constant EPC warning message telling you the pump has failed and that may need mapping out although I'm not 100% about the severity of the error code to be fair (might only be seen by a VCDS scan).

***EDIT***

Infact thinking about it the revs go up to 1200rpm during SAI so that would need mapping out, mines been mapped out/removed for so long it's difficult to remember at times.

[C6Dia]

Ill try and upload a video after work.

The cold start is loud, but no louder than a friends RS6 who has a non res milltek system installed.
It may be due to rest of the system being standard ie all cats etc are still fitted.

Bhav

[IanH755]

Good point, mine only had the small pre-cats fitted when my backbox's were removed as the bigger secondary (main) cats had been removed which will have effected the noise level.

[longman h]

Bhav, how's that video coming along?

[C6Dia]

Bhav, how's that video coming along?

Here you are mate.

https://youtu.be/m7j5uMLLlfk

Taken from my Samsung S6. Cold start so i was a gentle with the revs.

Bhav

[longman h]

Brilliant, thanks mate.
It sounds pretty good.

[discostu49]

Sounds awesome and angry I think it might just be a tad annoying for my neighbours though. I Need to move to the countryside

[longman h]

OK, so time for an update.

Paul popped round yesterday and modified my stock exhaust with the hope of creating more noise.

He removed the exhaust, cut open the backboxes, removed the insulating material, then wrapped the perforated pipes running through the backbox and welded them back up.

All in it took around 3 hours but there was a lot of chatting involved so could have been done a fair bit quicker.

The price was £260 all in which includes his travel costs getting to and from Milton Keynes.

Am I happy with the results????? HELL YES. The car now sounds like a V10 should when you get to 3500rpm and beyond.
Cold start is very loud but that's to be expected, especially as I don't have any secondary cats.
Once cold start has finished, the noise settles nicely to just a burble.

At slow speeds in auto mode, the noise is has more of a bass and burbly tone but once higher in the rev range, it just sings.
When shifting at higher revs, the noise resembles more of a break than a fart and is amazing. Even the wife was over the moon with what had been done which is really saying something, especially as she was a little sceptical about the mod.

Anyway, hopefully this provides a little more info and help for others considering a similar mod and here's a couple of photos;

[longman h]

Here are the videos.

Before


After


And here's a short video with the exhaust removed

[IanH755]

The 30-45 second long cold start can be mapped down to 2-5 seconds my MRC or alternatively start the car, switch it off immediately and then restart it. That also stops the cold start feature.

[GBR1198]

while we're on the topic of exhausts whats the best sounding exhaust people have heard?

I have heard good things about the Demand Engineering system but i haven't heard one yet, can anyone comment?

I don't really like the miltek or supersprint systems.

Cheers

[Stef92]

Or...you put the Rear Gear and come back to N then...

[longman h]

The 30-45 second long cold start can be mapped down to 2-5 seconds my MRC or alternatively start the car, switch it off immediately and then restart it. That also stops the cold start feature.

Ah, that's some good info there Ian, thanks.

When I pop up to see MRC, I'm going to ask them to do this for me.
Is it an extra cost?

On a slightly separate note, do you know why it takes so long to crank as it's a little frustrating?

[longman h]

Or...you put the Rear Gear and come back to N then...

Hmmmm.... interesting, I'll give that a go, thanks.