IanH's C6 RS6 - 925hp & 1150nm - Updated 06 Jun '25

[classba]

If anyone is interested in my history with the C6 I've kept a "Car Diary" over on Pistonheads with everything I've done since the day I bought her and it'll be kept up to date with constant updates - http://www.pistonheads.com/gassing/topi ... &t=1530059

This man loves to write lol

Yep he does so - but is respected and appreciated by many users who value his opinion and honesty in what he says and does.

Yes Ian is a lovely gentle giant.

[Julesm]

Way back in September/October ‘15 I chatted to MRC, Ricky Elder and classba about going for a 900+ conversion and doing it in stages (830hp first with all the parts except a Gearbox and then 900+ 3-6 months later. However, once I found that uprated GB’s from Ricky Elder were cheaper than I expected I was able to get everything at the same time. The car eventually went into MRC on the 1st of Feb after I faffed about for a month first and 3 months later in late April I picked her back up with 920hp and 1130nm.



I went with the following spec and I’ve included their rough cost incase anyone else wants to do something similar but isn’t sure of the costs involved.

TTE 850+ Turbos - £2200
Uprated Gearbox from Ricky Elder @ REPerformance - £3800
MRC Uprated Injectors - £2000 (no need for HPFP)
KWE IC’s (without fans) & Silicone Pipes - £1200
KWE 3in Cat-Back Exhaust - £700
MRC 3.5in to 3in De-Cat Downpipes - £1000
Aquamist HFS-4 - £700
Zirotek Ceramic Coating on Intake pipes - £300
MRC Race Air Filters - £120
MRC Ported Turbo Inlets - £200
MRC Mapping (50% discount) - £740
MRC Gearbox Map Tweak - £90
Labour (inc Fluids/Gaskets/Seals/Pipes etc.) - £4750
Shipping Various Parts - £330
Total - £17500 (est)

Firstly what a great opening post and thread Ian.

I'm currently considering an C6 RS6, but would like a bit more power. Not quite as mental as your build but would be happy with 830-850bhp. On this basis would it be fair to say the following would be needed using your post as a guide?

TTE 850+ Turbos - £2200
KWE 3in Cat-Back Exhaust - £700
MRC 3.5in to 3in De-Cat Downpipes - £1000
Aquamist HFS-4 - £700
MRC Race Air Filters - £120
MRC Ported Turbo Inlets - £200
MRC Mapping (50% discount) - £740
MRC Gearbox Map Tweak - £90
Labour including fluids/gaskets/seals/pipes - £3k?
Total - £8750 (est)

Have I missed anything, added items not required or under / over estimated the labour costs?

Cheers
Jules

[Trups]

You will need the gearbox too to make that level of tune safe and reliable. Even at stage 2 750ps your pushing the limits of the box and you will mess it up and it will cost more than the £3800 to sort at a later stage as the engine has to come out to remove the box.

You labour costs would be no different to Ian's if using mrc as it's an engine out job for the turbos.

[IanH755]

I absolutely agree with Trups. At anything approaching 1100nm the life of the GB will be reduced quite a bit if you use full throttle quite a bit. I mean you could pootle around at under 3000rpm and it would last for ever but who'd ever do that in an RS6!

I know there is a UK car running 850ps-ish on the stock GB but running low torque at around 1080nm I think (saw it on MRC's Facebook) but that was just waiting for a GB to be ready/affordable.

As for cost, if you're determined not to do the gearbox yet then I'd probably make it a minimum of £12-14k for those bits you mentioned above as the £2k injectors (or £1500 fuel pumps) will need to be added, then the labour/parts will always be higher than you expect, especially once the engine comes out and they find a few issues (oil seals, coolant pipes etc) plus the exhaust is now more expensive so you're looking at another £500-£700 there so the price rises quite impressively.

[Julesm]

Thanks Guys.

Sounds like if I was to uprate the turbos then for the cost involved going the full hog and 900-950bhp is the way forward. I was hoping there was a cost effective in between solution but it appears not, so the remaining option is 750bhp. My current car is 600bhp / 700lb/ft, so want a step up performance wise.

Appreciate the advice.

Jules

[rtd]

There is no half measures with this car julesm, do it half heartedly and she will bite you in the ass hard.

[Jim Haseltine]

Wait until you've got the car. Putting the power down through all 4 wheels makes a hell of a difference to just 2. I thought I'd be short of power when I bought my first quattro, which at 200hp was a good 80-100 below what I had been driving but in all the time I've owned it I've never seen the need to add to it.
My RS6, while on paper it isn't the most powerful car I've driven, on the road its different, nothing else I've ever driven (with the possible exception of a NASCAR in Florida years ago) seems to come close.

[Julesm]

Thanks for the advice, it's appreciated.

MRC offer an MRC 800 upgrade at £13k. There is no mention of the gearbox needing replacing so guess the power and torque are capped to be safe as mentioned by Ian? Makes spending another £5k a no brainer to go to 950bhp.

Jules

[rtd]

Why don't you go to 700/50 see how you feel as its a significant increase then build towards 900 if you want more power?

[Julesm]

Why don't you go to 700/50 see how you feel as its a significant increase then build towards 900 if you want more power?

I think my best option is to try one first. If 750bhp ticks the box then it's job done.

To go any higher gets really expensive, to a point where it's crossing over into newer cars that have similar power potential (newer Merc E/CLS bi-turbo). A £25k C6 RS6 becomes a £45k car. Whilst 900bhp is great I could be in a newer E/CLS AMG Biturbo Merc with 750-800bhp for £10k less.

I love the RS6 and have wanted one for quite a while. Let's see how it goes.

Jules

[rtd]

Ye that's the issue suddenly the price creeps up and you get into a bracket where other cars are available. But I'm pretty sure a 900+ C6 would see off any of those cars! Never been in a 900 car waiting for my turn but I'm told it is phenomenal.

[Trups]

Why don't you go to 700/50 see how you feel as its a significant increase then build towards 900 if you want more power?

I think my best option is to try one first. If 750bhp ticks the box then it's job done.

To go any higher gets really expensive, to a point where it's crossing over into newer cars that have similar power potential (newer Merc E/CLS bi-turbo). A £25k C6 RS6 becomes a £45k car. Whilst 900bhp is great I could be in a newer E/CLS AMG Biturbo Merc with 750-800bhp for £10k less.

I love the RS6 and have wanted one for quite a while. Let's see how it goes.

Jules

I do like the latest E63s but its RWD, just wouldn't cut it and it defo would be a struggle getting it down.

IMO its the perfect investment, the cars that are at the state of tune at the end of the day when/if comes to selling will still be worth the money you put into. and I don't think you would be letting the car go in a hurry, il be keeping onto mine for a while that's for sure as nothing else for the money will come close.

Trups

[IanH755]

I fella I work with has a MB SL65 running 700-ish HP (6L Twin Turbo V12) and we've each taken the other out for a quick passenger ride. While mine was obviously faster and more stable under power his felt more "exciting" as the car actively tried to kill you every time he touched the throttle and the poor TCS was having a nightmare trying to rein all that power in LOL

[stevo55]

I hear you on that one Ian-my old Z4M roadster was way down on power from the RS (around 340 bhp and 269 lb ft torque) but jeez it was a lairy beast! Proper adrenaline express and if I hadn't driven it for a while I had to treat it with kid gloves or I'd be in a hedge backwards. Evo likened it to a TVR which is very un- BMW like.

[Julesm]

I drive an RWD AMG (CLS55) now so hear what you are saying, to be fair it adds to the excitement along with the incredible noise most AMG's make, I currently have the use of an E63 Biturbo and was hoping I'd enjoy it more than I am, it's quite quick but doesn't feel that "special" or that much of a step up from my CLS. I'll seek out a test drive in a 700bhp + RS6 and take it from there.

Jules