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

[C6Dia]

viewtopic.php?f=47&t=113607&start=0

Seem the g/box conversion topic have been covered previously.

Still 1 year on. Some clever engineer im sure could make it happen.
Bhav

[IanH755]

Good memory! I wonder how accurate the ZF guys statement would be for the C6, being designed in 2006-7?

I feel an e-mail to ZF is in order, just for info more than anything else.

[bam_bam]

viewtopic.php?f=47&t=113607&start=0

Seem the g/box conversion topic have been covered previously.

Still 1 year on. Some clever engineer im sure could make it happen.
Bhav

Rule 16.

I knew Doug wouldn't answer.

[doodlebug]

If somehow the ZF8 could be made to fit and all the electronics made to to sync. That'd be the ultimate mod.

The C6 powerplant mated to that would be a weapon in standard form. With your mods Ian... what a machine!!

I wonder if the ZF8 could handle the torque, but a newer faster changing DSG box matted to the V10 would be a match made in heaven but then you have the whole handling issue........

Audi don't have one. You might make a new PDK box, from Panamera, work, but I'd imagine that's 20k plus.

[longman h]

I'm pretty sure the stock 'box recommended limit is 600Nm.

[Shinobi675]

I'd forgotten all about that thread! What's the chances of one coming up on eBay

[IanH755]

My Rear Diff - IT GO BOOOOOOMMMMM!!!!!!

Well it's more of whine to be more accurate (sorry the click-bait )

With a 100k+ mile car pushing 900hp+ for the last 8000 miles it's no wonder there was going to be a weak spot found eventually. I was expecting it to be a driveshaft TBH but the rear diff was also a worry (front diff/transfer box all in uprated GB) as well as potentially the wheel bearings (replaced during 900 conversion).

I dropped it off at the garage last night and they've just confirmed the bearings had failed and were making some quite impressive noise on the lift

So heres my symptoms and a quick vid of the noise for those who are interested -

Whine only present when pressing the throttle, even just 1-2%. No whine when off throttle.
Noise is road speed dependant not gear/rev. I tried 2nd-6th at 40mph so 5500rpm to 1500rpm and the whine stays the same.
Noise starts from 20mph to 100+ and the whine starts as a low freq low volume noise. At 40 and 60mph the volume peaks (resonance) and then rises to extremely high freq low volume by 100mph+.
Cornering & bumps have no effect on the noise nor does braking (if you keep the throttle pressed too).
Passenger's in the back seat at the time said there was "buzzing" by their feet under load.
The rest of the car drives, stops & handles exactly as before but the MPG was down slightly (6 less MPG shown when doing 60mph on a motorway) due to the increased drag in the drivetrain.

In the video I'm just tapping the accelerator a tiny amount every 1-2 seconds so the noise appears/disappears making it easier to hear the difference.



So my initial plan was to check with Audi for costs/time for a new one. After the call I had a cry and a sit down (which was very difficult considering the vigorous bumming Audi* gave me) and then got around to finding a decent gearbox place in Kent to get it rebuilt instead for under half the price of a new one. It should be all back running next week with my new brakes fitted, new diff and a considerably lighter wallet!

PS Warranties are very important! If your current one runs out and can't be extended (car now over 100k miles) then get another one pronto! Doh!

*Audi wanted £4300 with an unspecified waiting time as they had none anywhere, not even in Germany.

[rtd]

Ian

I could help you get a new one with good discount. PM me if you want.

[bam_bam]

Is it car specific? Just wondering if the Q7 or some other tractor has the same part for cheaper.

[IanH755]

Gurj - Audi UK have none and the parts system at Audi Germany says there's only "partially built" ones in the factory where the back order to complete them is upto 6 months but they can't guarantee that time scale.

Thanks for the offer though!

Bam_Bam - It's a common A4/A6 part if bought 2nd hand (dozen plus on ebay) but there's none new and with 2nd hand I could be back in the same situation rapidly. However what I'm thinking about is uprating the diff (like we talked about earlier) so I may end up with a cheap eBay one temporarily whilst an upgrade is done but I'm waiting for a few e-mails back from Quaife etc before deciding what to do next.

[bam_bam]

This.

However what I'm thinking about is uprating the diff (like we talked about earlier) so I may end up with a cheap eBay one temporarily whilst an upgrade is done but I'm waiting for a few e-mails back from Quaife etc before deciding what to do next.

...is what I was asking for.

Have you checked in with Wavetrac? There used to be a company "www.auditorsen.com" (website is dead now), they uprated Porsche diffs to fit in 01E boxes, it'd be worth asking "albertracing" over on AudiSRS if he still has a contact. Doing research into what the various rally shops around Banbury use could be useful - ProDrive et al. There must be diff wizards in and around those workshops.

[Trups]

How do you manage 60mph Ian? I struggle when on a motorway as its just too tempting to know what it can do and just want to floor it which is why I have stopped driving daily, not that I did but drove yday for 1st time In 2 weeks lol

[GBR1198]

Did you have the diff inspected or anything when you changed the oil? The same diff in a 170 horse a6 or a4 would have about a tenth of the wear of one in an rs6 wouldn't it ?

[IanH755]

Have you checked in with Wavetrac? There used to be a company "www.auditorsen.com" (website is dead now), they uprated Porsche diffs to fit in 01E boxes, it'd be worth asking "albertracing" over on AudiSRS if he still has a contact. Doing research into what the various rally shops around Banbury use could be useful - ProDrive et al. There must be diff wizards in and around those workshops.

Cheers for the company names, I've got a few e-mails sent already but I'll chase those companies above as well.

How do you manage 60mph Ian? I struggle when on a motorway as its just too tempting to know what it can do and just want to floor it

As it's my daily there's usually at least 2-4 times a day when I can give it full throttle for a few seconds before I see traffic again.

Did you have the diff inspected or anything when you changed the oil?

I haven't posted anything about changing the diff oil so I'm a bit confused by this.

[stevo55]

Interesting that even with the massive amount of serious mods you have done Ian you still sing the praises of having extended warranty! It's been a constant discussion on these boards and I decided to get the Audi one extended until maybe I finally go to MRC later this year. It may well be worth continuing it even when the car is tuned. Incidentally with yours over the 100k miles point now which warranty would you look at? I believe the Audi one has a 100k miles limit?