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

[IanH755]

Just back at Unit20 having a post rebuild inspection before I head down to MRC on Wednesday and after a 60 mile motorway run I got this MPG reading. Not bad for 900hp although I realise it's an ECU thing with my non-OEM injectors.

[IanH755]

So back from MRC with a full bill of health and just over 870hp which wasn't helped by the I/C's poor thermal abilities on a Dyno. We made an extra 30ps (25hp) from the first run just by letting the car cooldown so that the ambient temps were 20'c rather than 50'c when it arrived which just shows how poor they are in static air.

Doug is really trying to convince me to get the Marstons for their much better flow (my KWE's are slightly laggier in comparison too) and better thermals yet I'm still struggling with the £3200+ price however Doug mentioned that Christer on here, who has an almost identical spec to mine but with Marstons, made over 70hp more than my current figure, had more torque, less lag, more revs (7k vs 6.5k) and better intake temps all from them. I'm next back in the UK around January so I may eventually bite the built and get a set (through gritted teeth admittedly).

[don0301]

In for a penny Ian

You've almost got as much torque as me now

[IanH755]

The annoying thing is I'd buy them in a heartbeat if they were closer to what I considered a more "reasonable" price, because they are awesome, but as a tight semi-Northerner it just makes my skin itch paying that much - which is again ridiculous when you consider what I've already spent

[bam_bam]

I kinda agree. A pair of (in the grand scheme of things) smallish intercoolers shouldn't be £3,200, they just shouldn't.
Now, the C7's new AM intercooler looks like it might be worth closer to that figure.

[IanH755]

Exactly, something designed from scratch with all the associated R&D and its completely unique vs OEM end tanks welded to a new core (to my mind at least) - but they're just.......so......damn.....good!

[bam_bam]

Do Marston make them in-house?

[Golfather]

Thats not bad for the Kwe's
For comparison mine did 867, stock everything just the ttes
Your torque seems to be holding better through the revs although lag low down is evident compared to stock.
But power drops off early?

[welwynnick]

Thats not bad for the Kwe's
For comparison mine did 867, stock everything just the ttes
Your torque seems to be holding better through the revs although lag low down is evident compared to stock.
But power drops off early?

Those are nice power and torque curves.

Are you really just stock plus TTE850 and (presumably) ECU & TCU tune?

Or do you at least have filters, downpipes, HPFP etc?

Cheers, Nick

[welwynnick]

So back from MRC with a full bill of health and just over 870hp which wasn't helped by the I/C's poor thermal abilities on a Dyno. We made an extra 30ps (25hp) from the first run just by letting the car cooldown so that the ambient temps were 20'c rather than 50'c when it arrived which just shows how poor they are in static air.

Hi Ian,

Do you know how much boost you're using to get those power and torque figures?

Cheers, Nick

[ThatRS7]

Absolutely epic build !

The noise this thing must make !

[IanH755]

Hi Ian,

Do you know how much boost you're using to get those power and torque figures?

Cheers, Nick

Sorry, I've got no idea.

I'm sure I logged it via VCDS when it was just done and I remember a figure of 1.2bar but I've had so many turbo cars that I might just be badly mistaken and thinking about something else.

I'm back in the UK in a few months so I can relog it and get back to you.

[welwynnick]

Thanks Ian

I was supposed to be going to view an RS6 today, but I'm looking after a poorly son. I used to have a tuned Mercedes S600 BiTurbo with 600bhp / 1000Nm, but two wheel drive was a bit limiting, and I was really looking forwards to walking in your footsteps.

Nick

[IanH755]

Just a quick update while I'm back in the UK for a few weeks -

I'm off to Scotland for a bit of NC500 action, I'm struggling to find MPS4S tyres as every website says "yes in stock" and then cancels/refunds 3 days later when they can't get any (problem at Michelin), my right rear brake heatshield detached during a "spirited" drive (same as the rear left) making a right racket so I've taken that off and I've ordered all the bits for the next servicing/MOT etc in July.

Oh, and the car is still fast as balls!

[Fatneck73]

Are you here long enough for Beaulieu on 21st buddy?