From A6 BiTDI to S6


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Oct 20, 2015
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Considering swapping my '14 A6 BiTDI with 44.000 km for a '14 S6 with 72.000 km...

Probably will cost 10.000 euro in exchange, but the S6 is fully loaded and maybe a more exciting car, even if more expensive ownership prospect.

Anyone that has done this swap, either way, and is the S6 a serious step up in performance?
The S6 is definitely a step up. In performance and running costs. Oh and fun.....

Shame you can't remap the bitdi to 8 cylinders :racer:
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Thanks for the replies! No doubt a remap would be the cheapest and make most sense - road tax for a 4 litre is 2000 euro, for a a 3 litre 700 euro, in Belgium + a registration tax of 3500 euro, so easily 13000 euro to swap for a S6 with 30.000 km more. Also a nagging feeling about the S Tronic, especially if I were to remap.

Could start with a remap and see if that keeps me entertained for a while.
I'd say a stage 2 will get you the power and pull of the S6 (probably not quite 450bhp but the extra 350nm will certainly make up for that) but you still aint going to have the 8 cylinders.

The S6 is meant to be a sleeper so has the nice v8 sound but muted compared to the RS6. I know the biTDI has a fake v8 sound but with the right exhaust/booster addons you can get pretty close and I already think the stock biTDI is a sleeper, 320bhp ain't to be sniffed at & will out pace most cars on the road for fun while still getting good economy on long runs.

So it's down too does having the true V8 petrol soundtrack justify the costs, hopefully we can help only you can really decide that.
At 450hp the S6 is underrated. In so much as they are often found to be running 480hp to 500hp from factory.

So few of these sell in the UK as people who want a very fast large engined Audi automatically go for the RS6 (RS6 outsell the S6 by about 10 to 1 in the UK).

Take a look at the American reviews where historically they've never sold the RS6 so there's far more information in the USA about the S6.

This is the Car and Driver article where testing the 2013 420hp S6 they managed a 0-60 time of 3.7secs with calibrated equipment.

These are seriously fast cars but without all the shouty agressiveness of an RS6, which is just what I was looking for. The reality is to step up in performance and comfort from an S6 you'd probably have to spend three times as much. I think the S6 & S7 are genuine bargains. And the S8 is basically a Bentley continental in a different bodyshell.
get yourself to Holland and do a JD stage 3 remap.. 460HP and 925Nm of torque and 40Mpg .. you wont miss an s6.. and no gearbox worries either :)
get yourself to Holland and do a JD stage 3 remap.. 460HP and 925Nm of torque and 40Mpg .. you wont miss an s6.. and no gearbox worries either :)
Those guys are mental... they had an option to modify mine up to 580PS!!! €7500 and as meantioned for the DiTDI... it would still only have 6 cyclinders, but WOW!
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mental but really know what they are doing.. I cant fault them... they gave me tons more power and a better fuel economy by almost 10mpg and way way less smoke compared to the map that was on it... just wish we had tuners in the UK capable of the same with the BiTdi platforms etc ;)
Bailey, how much did it cost in the end?
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Ways to save money on this.
Pay via a Uk VAT registered company. JD enginnerign will remove the VAT element from the total. If yo udont have your own company then ask a friend if you can pay with their VAT number.
For stage 3 Install intercooler (approx 4 hours) and RS6 airbox ( 30 mins) yourself.

My costs:
RS6 airbox and K N filter approx £200 approx. Trade Prices.
Wanger competetion intercooler £628. Trade prices. Normal price £735.
Tune and DPF surgery at JD
The costs for software is € 1750,- incl. tax. (€ 1446,- excl tax).
The costs to modify the DPF's € 400,- incl tax (€ 330,- excl tax).
= £1401.
Total £2229 + ferry @£150
Gives you A6 Avant Black Edition BITDI @ 459 Bhp 912NM

Bailey, how much did it cost in the end?
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Just spoke to JD Engineering: Stage 1 does not include a rolling road, which I find quite strange. That means the remap (stage 1, at least) is generic.
It's obvious they do great things with the results we have seen but when would even a remap not involve a rolling road before and after? How would they know if the map has been successful and working correctly?

How much is the stage 1?
Trying to make an informed decision so test drove the S6 today.

First impression is that it looks fantastic on its 20" wheels, black on black and with the quilted look S Sport seats.

Driving experience was a little mixed: obviously fast though the midrange of the BiTDI is stronger but also a question of getting used to using revs again and the S Tronic which is more direct than the 8 speed. Also, the V8 is very muted, only at high revs and at lower speed is it actually possible to hear a bit of the V8 bark. Ride was a bit brittle on the 20" wheels. Ceramic brakes were fantastic!

Still considering the pros and cons, and if I can live with a range that is probably 40 % less (think 75 litre tank is standard on the S6 too, thankfully)
Ceramics not an option in the UK. I went with the standard 19" wheels for comfort alone, but I also went with comfort seats also.

The S6 is everything the RS6 isn't. I explained on the Mercedes forum I'm a member of if you owned an AMG and swapped to an S6 you'd be disappointed. The S6 is quiet and comfortable and covers ground at a very fast rate with little fuss but it's no sports car. It's the equivalent of an E500 Mercedes and would be more appropriately badged an A6 4.0TFSI. The "S" moniker it's given is misleading IMO.

This is everything I wanted. I really didn't like the shouty RS6 or AMG cars but I wanted something comfortable and powerful. I'd looked at Aston Martins, Bentley's, Range Rovers and even a Ferrari FF (still love these) but the reality was with my wife being a wheelchair user an estate car is more appropriate for us.

This is when the S6 entered our radar.

If you want to mod the S6 there's a big market doing so in the USA (as they don't get the RS6 over there). A turbo swap (plug and play RS6/7 turbos), remap and exhaust system will liberate 700hp if you're so inclined, but the torque needs to be limited so it doesn't overstretch the S-Tronic.

Think of the S6 as an alternative to a Bentley GT at nearly a third of the price and it makes more sense.

Compare it to an RS6, AMG or M Car and it doesn't work, it's not that type of car.

Full tank range on my last fill was 359 miles (577km) at 23.55mpg. I use Super Premium fuel.
Thanks for the clarification! I use mine exclusively for long distance motorway driving, in France and Germany. A BiTDI is rationally ideal for this but I have come to consider it more of a tool to get from A to B, and was hoping for a bit more character with the S6. Maybe a mismatch then?
Thanks for the clarification! I use mine exclusively for long distance motorway driving, in France and Germany. A BiTDI is rationally ideal for this but I have come to consider it more of a tool to get from A to B, and was hoping for a bit more character with the S6. Maybe a mismatch then?

The S6 is perfect for long distance motorway driving, that's where it excels, if you can live with the fuel consumption. Is it better than a BiTDI? That's your call. You'll get more range from the diesel.

I wouldn't want a loud exhaust on a car I was doing a lot of motorway miles in, after the first 15 minutes it becomes droning and tiresome.

Best compromise is a switchable exhaust, loud when you want, quiet on a motorway.
Having had an E39 and E60 M5 and E92 M3, I am unfortunately keenly aware of thirsty V8 (and V10) engines, which apart from the E39 M5 that I kept for 5 years, I grew tired off after less than a year - I can accept the thirst but not lack of range. For me a minimum of 550 km on a tank with fast motorway driving would be a must. The BiTDI can do 850 km (75 litre tank, long time average 8.9 l/100 km, or 31.8 mpg), so if 22.5 - 24 mpg is feasible, it would be realistic, giving it a range of 550-600 km.
Bear in mind our S6 has COD. So when cruising if you did a full tank on motorway only then 600km is quite feasible from a 75 litre tank.

Our 577km tank included 2 hours stuck in traffic.

At 140km/h the engine is running at about 2300rpm.
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The BiTDI is running 2600 rpm at 220 kph...


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I have no idea what it will be running at 220 kph as I like to keep my licence!
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having driven both the S6 and own a BiTdi.. for me deffo the BiTDI all the way..:)
Just to conclude this thread: Didn't go for the S6 in the end, even if I test drove it twice. The exhaust was very muffled and only when pushing the engine did the V8 come through. Clearly a faster car (especially as Audi apparently underreports the real BHP that most dynos put at 480 bhp rather than 420 bhp) but the S Tronic had a clunkiness about it, and it felt like it had done the 72000 km whereas mine mechanically just felt fresher and more robust.

Will have a remap done Friday to get me through this horsepower craving, but will not exclude going for a newer S6, ideally facelift, or even RS6 when they come down in price.
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