Milltek cats & downpipes.....again!

[S4driver]

What with me being a good lad all year, Santa left me a set of Milltek cats and downpipes for my S4

Will the car still run OK with these put on? The car already has a MTM 306 bhp upgrade and the Milltek exhaust......but will it need mapping again to release the extra ponies?

[wazza]

Yes

[Dippy]

To expand on Paul's correct answer, yes you need a remap to release the FULL potential of the cats. However if you put them on with your current map, you will see an increase in torque and power.

This is based on my experience when AmD were unable to remap my car at the time of fitting, so I had to go back a week later. This made it clear to me that with a stage 1 remap, the cats did give me more power, but delivery felt coarse and it also felt restricted at the top end.

When I went back for the remap (which was basically the fuel map, with a significant increase at the top end), it transformed the car again: The torque delivery became much smoother and more power was released at the top end, so now I get linear acceleration to the redline, whereas before it would still tail off. For your info I got a roughly +30lbft and +30bhp to peaks after fitting the DP/cats and remap.

Your question is now how to you get the right remap? As far as I know, all you can do with an MTM chip is to get a standard stage II map which was designed on another car with free-flow cats (possibly not Miltek because it would have been done in Germany). Ideally you need to have a custom remap which takes account of YOUR engine and YOUR exhaust, because every setup is different.

This was one of the reasons I chose AmD as my tuner.

P.S. before the argument starts, I agree that in general AmD do NOT do custom stage I remaps, but they DO do custom remaps for stage II and beyond.

[BlackShadow]

The sports cats and stage II with the remap are worth it, even if a little pricey. I'd agree totally with comments on the linear power delivery. The car basically feels more sporty; you want to rev it more; and power increases all the way to just short of the redline; whereas with the stage I, I think the power peaks about a 1,000 rpm short of the redline. Even the girlfriend thought the car was faster with Stage II, when pulling away from junctions rapidly to fit in gaps in the traffic.

The difference between my Stage I (remap & cat back) and Stage II (remap and sport cats/exhaust), was 322 bhp and 345 bhp, according to the dyno. This was the inferior MTM remapping as well (MTM actually call it Stage III; Stage II being remap and cat back, and Stage I just remap)

A cheaper and more powerful alternative is get a custom made exhaust without any cats (naughty but nice ). There is bugger all back pressure then. However, you need to know the MOT garage well to get them to pass your car; and if plod inspects it with a wizzo jig thing, then they would pick up the emissions.

[moktoya]

I have MTM's Stage 1 remap (am told 1 & 2 maps are identical) with Milltek sport cats and dual catback. So i take it that i can free up the top end even more if i go for the Stage 3 MTM remap? I felt a significant diff after adding the cat and am wondering if there's more to be gained from the MTM Stage 3 map. According to Dippy this holds true for AmD, so would appreciate your view on the MTM map, Black Shadow. Thx

[moktoya]

I have MTM's Stage 1 remap (am told 1 & 2 maps are identical) with Milltek sport cats and dual catback. So i take it that i can free up the top end even more if i go for the Stage 3 MTM remap? I felt a significant diff after adding the cat and am wondering if there's more to be gained from the MTM Stage 3 map. According to Dippy this holds true for AmD, so would appreciate your view on the MTM map, Black Shadow. Thx

[BlackShadow]

Well, my car previosuly had what QST call the 320 bhp upgrade (remap with dual cat back only). I took it in to QST last November and they fitted the free-flow cats and down pipes and stuck in a new chip, and dynoed it at 345 bhp (basically what their web site claims for this coversion):

http://www.qstuning.co.uk/list_for_car.asp?car=s4v6

So these two conversions are all I can really compare. Thus, just to recap:

The power delivery is now more linear. The car basically feels more sporty; you want to rev it more; and power increases all the way to just short of the redline; whereas previously the power peaked about 1,000 rpm short of the redline, and the delivery felt more stiffled. The car now revs more freely - presumbly due to less back pressure. It also sounds nicer, and when you overtake people doing high revs, it scares them more. Well, at least big ears in his Rover flashes his lights at me more when I overtake; or maybe I just drive like more of a t*at.

The difference in performance is not a greate as when you first have a standard car chipped (well we are talking a step up of 40-50bhp as opposed to a step up of 25-30 bhp). However, the car is smoother as well as more powerful.

[moktoya]

Gotcha. Well with my setup the high end was definitely freed up noticeably after the cats, but with the stage 1 chip i still feel the pickup tapering off at ~5.5K, hence still need to short shift like before, albeit at slightly higher rev. Thx

[tricky]

And out of curiosity taking a standard car to AMD stage II with downpipes, cats and exhaust would set you back approximately how much?

[KayGee]

When I asked about six months ago, £1000. Politely declined.

[Mik]

From their WebSite :

AmD Stage 2 RS4 Turbo Upgrade giving the S4 a massive 400 bhp approx. Includes rolling road time, mapping, fitting, 'before/after' plots of power and torque, test drive. Workshop time about 4 days. £4750.00 fitted

Thats what I call Stage II and includes all the Milltek bits.

Mik

[DavidT]

I think if stage II is turbo back (Milltek downpipes, 200 cell cats and catback exhaust), plus fitting and mapping, you are looking at around £2800 + VAT from AmD.

[S2tuner]

Jesus, you guys are talking about prices to go from Stage 1 to Stage 2 here? £2800?????

[KayGee]

Sorry thought you mean't just the remap. With parts David is about right just over £2.8-3K depending on single or dual pipe exhaust.

[Verruckt]

You guys really spend too much money on tuning in Europe.

Believe it or not, many people in America gut their pre-cats (main cat remains intact) and gain 80%-100% as much power as a full downpipe setup. It's basically free if you do your own or $400 or so to buy a set...and it fits with OEM quality.