IanH's C6 RS6 900+ spec - Updated 15 Oct 21

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VaudiGR
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Re: IanH's C6 RS6 900+ spec - Updated 15 Oct 21

Post by VaudiGR » Mon Oct 18, 2021 2:22 pm

Quick question about gearboxes. Is it worth investing in upgrading parts within the gearbox for peace of mind, or would a gearbox that doesn't exceed exceed 1000Nm mark should / would work forever given regular oil changes?

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IanH755
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Re: IanH's C6 RS6 900+ spec - Updated 15 Oct 21

Post by IanH755 » Mon Oct 18, 2021 6:35 pm

As a "not-an-expert" I'd say that the lower the torque the longer the box would last but, even with continual servicing, these OEM GB's will start to fail as the mileage creeps up, even on completely stock cars and at which point I don't even know if you'll be able to get replacement OEM boxes any more.

If you fit uprated parts I would suggest that it'll "reset the clock" on how long a GB will last as the OEM parts which wear out first are replaced during the upgrade.
***OLD*** Daytona C5 RS6 Avant - MRC'd - 500HP & 820NM (PistonHeads Link).

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Re: IanH's C6 RS6 900+ spec - Updated 15 Oct 21

Post by VaudiGR » Tue Oct 19, 2021 5:17 am

I see your point. So sourcing a GB and keeping it aside even upgrading it would be a good idea if the plan is to keep the car longterm

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Re: IanH's C6 RS6 900+ spec - Updated 15 Oct 21

Post by IanH755 » Tue Oct 19, 2021 9:46 am

Reading my post back I realised it sounded like I was saying "OMG, you won't be able to fix these boxes ever again.........." which isn't right looking back and might make you feel the need to spend extra money on something you may not need.

Instead what I meant to say was that you should still be able to find ZF specialist who can replace any worn OEM internals which would solve the vast majority of issues caused by old/worn parts. However it really is only if you physically "break" the gearbox, i.e. there's bits of metal missing from the metal casing, holes ripped through it etc that at that point - where you can't just repair it, but now need a complete replacement - I think you'd struggle as these "custom-made by ZF for the RS6 only" boxes are pretty rare in the UK (only a few hundred available).

Again, if it's just replacing something thats just worn-out like clutch packs etc (which it would 95%+ of the time) you'll be fine as any ZF specialist can fix that, but only if its something more catastrophic which ruins the box, might it be far harder to find a replacement box.

So to answer your question - ***IF*** you are keeping you car for long time (say more than 10 years) I would suggest that you don't have to buy a spare box "just in case" as they'll still be able to fix 95% of worn parts for a long time yet. However, if you still want a spare anyway then by all means buy one if you have the financial ability, but I would say it's not something that you absolutely 100% need.

Sorry if it sounds like I'm flip-flopping with my opinion, I just realised how pessimistic I sounded in that first post and wanted to clear-up what I said.
***OLD*** Daytona C5 RS6 Avant - MRC'd - 500HP & 820NM (PistonHeads Link).

***NEW*** Daytona C6 RS6 Avant - MRC'd - 930HP & 1125NM (PistonHeads Link)

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Re: IanH's C6 RS6 900+ spec - Updated 15 Oct 21

Post by IanH755 » Wed Oct 27, 2021 9:12 pm

Ah my life is just effing great :(

During a quick pop around to my folks I suddenly noticed a raw/wet fuel smell when stationary (not exhaust). Nothing with the car seemed "off" (no hesitation, missing etc) but I pulled over anyway to check and found a fuel line quick disconnect in the engine bay has had a 20p bit of plastic locking tab decide to fail, causing the quick disconnect to partially fail and introduced a small fuel leak of about 1 drop per second at idle. The black plastic "cap" in the middle on the bottom picture should be flush with the metal pipe on the right but is clearly popped out and now won't reseat so the quick disconnect is now partially open, allowing a small amount of fuel to drip out.

I spoke to MRC and sent them the pics below, they've seen this failure before and have already ordered the replacement part but it'll take a few weeks to get here so my trip down to MRC on Friday has been delayed slightly!

It's in the pipe in the top centre/left -

Image

The black plastic protective coating was removed by me at the side of the road so I could check for any cracks/leaks from the metal pipe underneath (none found) -

Image
***OLD*** Daytona C5 RS6 Avant - MRC'd - 500HP & 820NM (PistonHeads Link).

***NEW*** Daytona C6 RS6 Avant - MRC'd - 930HP & 1125NM (PistonHeads Link)

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Re: IanH's C6 RS6 900+ spec - Updated 15 Oct 21

Post by IanH755 » Sat Nov 20, 2021 7:09 pm

Soooooo, fuel leak issues all sorted (new fuel-line and quick connect) plus some TLC with 10 new spark plugs, 10 new coil packs & a new fuel filter then a little extra safety/fun with an uprated in-tank fuel pump fitted (Walbro) as the old OEM one was starting to drop the rail pressure from 5 BAR down to 3 BAR at 6k+ RPM which could have risking a Lean situation if it dropped any lower so it's now running a stable 4.9BAR all day long.

Having the fuelling sorted certainly helped with the MPG (LOL-PG anyway - 3.6MPG at full throttle, 12MPG around town, 24MPG on a 60mph run) and, in combination with a nice strong new spark, it helped drop my 100-200kph Dragy time down from 6.25 sec to just 5.4 sec (about the same as the Koenigsegg CCX supposedly) so I'm guessing the fuelling issue was maybe more hindering that initially thought.

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***OLD*** Daytona C5 RS6 Avant - MRC'd - 500HP & 820NM (PistonHeads Link).

***NEW*** Daytona C6 RS6 Avant - MRC'd - 930HP & 1125NM (PistonHeads Link)

RMC83
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Re: IanH's C6 RS6 900+ spec - Updated 15 Oct 21

Post by RMC83 » Wed Nov 24, 2021 8:24 pm

Great info there Ian.

Are you planning on another dyno run to see the effect of these fuelling mods? Knocking almost a second off your 100-200 time is quite a jump, so you would think that would also be noticable on the dyno graph.

Cheers
Roy

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chunky79
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Re: IanH's C6 RS6 900+ spec - Updated 15 Oct 21

Post by chunky79 » Wed Nov 24, 2021 9:55 pm

Good work again Ian. That's certainly a beast.
previous- 205 gti, 306 gti, 309 gtiGoodwood, S3, S4 V8 avant.
Gone but NEVER forgotten - C5 RS6 Misano red avant.

Now - PORK

If you don't know where you're going, any road will take you there!

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IanH755
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Re: IanH's C6 RS6 900+ spec - Updated 15 Oct 21

Post by IanH755 » Thu Nov 25, 2021 6:11 pm

RMC83 wrote:
Wed Nov 24, 2021 8:24 pm
Great info there Ian.

Are you planning on another dyno run to see the effect of these fuelling mods? Knocking almost a second off your 100-200 time is quite a jump, so you would think that would also be noticable on the dyno graph.

Cheers
Roy
Hi Roy, my guess would be the previous 100-200 runs (which were done after the new 930hp map) were hurt by the fuel problems which started during the mapping so while I'm not sure if all the new fuel stuff would make more than 930hp, since fitting it all it's very noticeable that I'm back to getting 930hp with every full throttle press whereas with the fuel pressure/leak issues it would feel like 930hp one time then 730-ish the next time the back to 930hp the next so once that happened I didn't go near FT until everything was fixed.
***OLD*** Daytona C5 RS6 Avant - MRC'd - 500HP & 820NM (PistonHeads Link).

***NEW*** Daytona C6 RS6 Avant - MRC'd - 930HP & 1125NM (PistonHeads Link)

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