S4 exhaust modification

[chunky79]

they quote 2-3 hours on the website to fabricate a full system but that wont include downpipes i shouldnt think, i'm just investigating a company in darlington, northeast , they do full custom exhausts fabricated on site, i requested no pre cats 100 cell main cats and the usual rear set up and i have been quoted £670 but i dont know if they're any good

It will fail the mot with no pre cats and only 100 cell main, or do you have an mot friend?

Dunc

[BlingBling]

they quote 2-3 hours on the website to fabricate a full system but that wont include downpipes i shouldnt think, i'm just investigating a company in darlington, northeast , they do full custom exhausts fabricated on site, i requested no pre cats 100 cell main cats and the usual rear set up and i have been quoted £670 but i dont know if they're any good

It will fail the mot with no pre cats and only 100 cell main, or do you have an mot friend?

Dunc

No it wont. I have the exact same set up and have passed every MOT to date. The cats have ot be hot for them to perfom at their best. Oh and I do not have any MOT firends.......

Ignore the website. They need at least 2-3 hours to alow the car to cool down before even starting ot remove the old system

[chunky79]

they quote 2-3 hours on the website to fabricate a full system but that wont include downpipes i shouldnt think, i'm just investigating a company in darlington, northeast , they do full custom exhausts fabricated on site, i requested no pre cats 100 cell main cats and the usual rear set up and i have been quoted £670 but i dont know if they're any good

It will fail the mot with no pre cats and only 100 cell main, or do you have an mot friend?

Dunc

No it wont. I have the exact same set up and have passed every MOT to date. The cats have ot be hot for them to perfom at their best. Oh and I do not have any MOT firends.......

Ignore the website. They need at least 2-3 hours to alow the car to cool down before even starting ot remove the old system

I was always told it would fail the MOT so thats good to hear. Means you can get the V8 flowing with basically no restrictions then

[nihc]

Hi,

I'm having my exhaust replaced on Monday at AAS in Newcastle. So, I'll post a sound track after it's done.

The setup is to be as follows:
New dowpipes, 4 cats replaced with 2 sports cats.
An x-pipe to replace the middle silencers.
New stainless steel pipework through out, 1/4 inch up on diameter from standard.
Keeping the original back boxes to see what they sound like with the new components.

I might investigate the h-pipe idea with them when I drop it off.


Regards, Chris.

[quattrokid1]

Just done the Cabrio with Milltec cat back system, it is a tiptronic box so it definately needs the pipes with the silencers behind the cats.

I am getting these fitted soon because the drone from the auto box is a tadge introusive, other than that it sounds the mutts nuts.

got it from Grizz @ Unit 20.

[nihc]

Well, just had the custom exhaust done at AAS in Newcastle and all I can say is that it's amazing and far exceeded my expectations.

Initially, I was only going to have the original rear silencers left in, but after trying it without they put an extra couple of tubular silencers after the x-pipe. It sounded a bit chaverish without.

I've done about 1000 miles since Tuesday and there is absolutely no drone at any revs - I did tell them that was something I wanted to avoid, if possible.

The sports cats and the scavenging effect of the x-pipe really seems to have freed up the engine quite a bit; It does seem freer revving now.

At lower revs it has a Porsche like howl mixed with a low V8 rumble and at higher revs and load that all mixes together in a crescendo of V8 raspiness.

Driving around at low revs and load it can sound quite civilized as my wife proved the other day, but put it under load and it's simply amazing. My mate's so impressed that he wants to take to Le Mans next year and get it on the track

The next mod is a REVO engine remap. A forum member P_G had a custom exhaust from AAS for his S4 and REVO remap and it made a substantial power increase - 357 after the exhaust and 388 after the remap.

The exhaust cost £830 from AAS, considering the price of the sports cats, I think it was a bargain.

Regards, Chris.

Hi,

I'm having my exhaust replaced on Monday at AAS in Newcastle. So, I'll post a sound track after it's done.

The setup is to be as follows:
New dowpipes, 4 cats replaced with 2 sports cats.
An x-pipe to replace the middle silencers.
New stainless steel pipework through out, 1/4 inch up on diameter from standard.
Keeping the original back boxes to see what they sound like with the new components.

I might investigate the h-pipe idea with them when I drop it off.


Regards, Chris.

[chunky79]

£830!!! Thats a really good price. Shame they can't knock one up and then post it so i could fit it my self. How long did it take all in all Chris?

Dunc

[1781cc]

Hi Chris, that sounds amazing mate, just what I am after as well - balance of both!

Can you post some pics and dare I say it, a vieo or audio file up on youtube or somewhere else mate? be good for all of us to see and hear what you have done.

Lee

[nihc]

Hi,

Sorry for the delay in posting, but I've been in South Africa and looks like I've missed some typical summer weather in Newcastle
The whole exhaust job took 2 days at AAS, it was only supposed to take one day, but they had to spend 5 hours trying to get one of the downpipes off, apparently.

I did ask for some photos when it was up on the ramp, but they forgot
I will get a photo and some sound tracks posted as soon as possible.
Another thing that I've noticed is the fuel consumption has improved - if you're stuck behind traffic and not trashing it, as I normally do. I got an average of 31 MPG at about 40-50 for 15 miles, which I've never seen before. The average over the last 1300 miles has been 23.6 and I would normally expect to see around 20.
Stuart from AAS did say that the scavenging effect of the x-pipe would make the engine more efficient and powerful - I guess he was right.

Cheers, Chris.

[BlingBling]

Good stuff all that is needed now is a remap to bring it all together.

[1781cc]

Hi Chris, hope all is still going well with your new setup - did you get it mapped? any pics or audio clips yet mate? were all interested!

[P_G]

£830!!! Thats a really good price. Shame they can't knock one up and then post it so i could fit it my self. How long did it take all in all Chris?

Dunc

They may well be able to now Stuart has done a few S4's, my old car included. If Stuart has kept a template he'll fabricate and post, he has said he will do simialr for the x-pipe I have on my current RS4.

Best to contact AAS and ask. What they fabricate is far better quality and sound than anything Milltek will sell you it nearly a third of the price.

Also the biggest gains weren't in bhp but torque with this system and a REVO remap, 388 bhp and 365 ft lbs of torque against OEM 343 and 313 and it was freer revving as the throttle agression can be turned up from 4 to 1 and mpg improved by about 20-25% all thrown in.

[Glen]

Hi,

Ive got my S4 booked into MIJ on Wednesday, are the MIJ owners still happy with there exhaust?

Also what exact set-up did you guys have?

Thanks, cant Wait till its done!

[1781cc]

keep us posted on this, I have been looking at MIJ for a while but had other bills that have scuppered it.

videos people, we need videos! lol

[BlingBling]

Hi,

Ive got my S4 booked into MIJ on Wednesday, are the MIJ owners still happy with there exhaust?

Also what exact set-up did you guys have?

Thanks, cant Wait till its done!

MIJ fabricated and installed the following on my S4. Downpipes, Hi flow sports cats (100 cell), H-pipe, resonators and back boxes. All using 2,5" piping. The total cost was less than 1K. If your getting all of the above carried out the O2 sensors on the main cats will need relocating to the rear. They are originally placed at the front.

Before anyone starts harping on about paasing MOT’s. The work was done approx. 2 years ago and I have passed every, 2x, MOT’s to date.

Depending upon what work your having carried out I advise you get there early, if possible before the open. They will not start working on your car until it has cooled. The exhaust gets pretty hot.

After all of the above was carreid out I got a remap Has it all worked? IMHO Yes. I am not 100% convinced by RR numbers, prefer real world performance data.

My best 0-60 and ¼ miles times are as follows. The numbers were gathered using a G-Tech Pro SS. The had had varying fuel levels from ¼ - ¾ tank, differing ambient temps plus other carp inside.

0-60mph (Stock 5,6s)
5,34s
5,12s
5,07s
5,25s
5,17s
Avg. 5,19s

¼ Mile (Stock 13,85s)
13,49s Trap Speed 103,56mph
13,59s TS 102,86mph
13,47s TS 104.72mph
13,46s TS 102,57mph
13,55s TS 103.75mph
Avg. 13,51 TS 103,49

All numbers are better than stock with a better start and smoother gear changes the number could well drop. the important thing with the 1/4 mile times arethe trap speeds and I think that +100mph is good.

Good luck.