Help please.... Update P5. She's back :)

[bam_bam]

He may even had to blow Grizz a couple of times to get it fixed.

[Shoppinit]

Sid, I'll post what I posted on the other site to see if we can get a more interesting dialog going here:

I am trying to get my head around the symptoms. What is bizarre is that there is no boost at all, not a jot. You'd think that some boost would register before it started blowing air out of the other MAF.

I'm sure that MRC is right, but I have seen cars with a bad turbo making half boost. So why is yours not showing any boost at all.

And why does the 2nd MAF drop to zero on overrun or when the throttle closes? That's what I can't figure out.

[bam_bam]

It needs both banks to create enough boost, one side just ain't enough. The 2nd MAF reading is odd though, is there a vacuum caused on overrun and could that produce such a reading on the MAF?

Try as I might I just couldn't fit enough fnarr into my post, I must be tired, maybe it's too early. Can someone else please insert some sexual innuendo into this thread...

[Rupert]

It looks good elevens, highly illegal of course but £2.5k Audi warranty seems like a cheap option now, they don't even do an inspection beforehand, you could claim next month! Not saying I would, but it is what golfather was suggesting!!

WHAT?? Is this true? The one thing which put me off an Audi warranty is the thought of my local dealership louts doing a road test in my car.

As for Sid's problem...
Start saving. I'd go with reconditioned turbos and fix the gearbox at the same time. New turbos are about 1200 each, plus labour. Recons are much cheaper.
With a car of this age it may seem very expensive, but to get this level of equipment, performance and practicality it's either
a) suffer the running costs of an RS6
or
b) suffer the depreciation of a newer car.
So, a 5k+ bill now may sting, but losing 10k a year on a brand new motor stings more.

[monoi]

Agree with Rupert. Whatever you do, it will cost you £8-10k? Then you have a RS6 with as new engine/gearbox and the way you want it. What else will you get for that money, anywhere near equivalent?

Sucks though.

[Imola_Sid]

Firstly, thanks for all the kind words

Little update - my mechanic will hopefully get the engine out and check the turbos/manifolds next weekend for closer inspection. So I'll hopefully know what's actually gone then.

Idea of breaking the car has quickly been dismissed lol. Was walking back to the car the other day and thought bloody hell that's one sweet RS6! Would be a crime to break it. Don't care how much it costs, I'll even park it up for a while and get a run around to save some cash if need be.

Bam Bam mentioned upgrading the g/box - ZF? ACE? Costs? pros/cons? anyone share some info please.

Also, seeing as it's only rarely not engaging into 'R' and it's usually when the car has been driven for a while/hard, would anyone recommend trying a gearbox service/oil change? The previous owner told me the box was done about 5k miles ago, but the garage (Mr Transmission) don't acknowledge anything being done. No receipt but the previous owner seemed very genuine and has tried chasing them up but hasn't had any luck.

@ Bam Bam, PM sent re the manifolds. If mine are gone and I go down the cheap fix, i'll be happy to buy them off you.

Upgraded manifolds? Which ones? Costs? Pros/Cons?
Rebuild turbos to stage 2? Who can do this? What are the costs and will I need to make other upgrades such as intercoolers?

Ben - as you know mate, I'm not the most mechanically minded (especially when it comes to all this boost stuff). As you said Doug is probably right but it might be nice to get him to explain to the rest of us. These boys know certainly know their stuff!

Cheers again for all the comments and thoughts, will keep you all posted!

[Shoppinit]

The reverse not engaging is a known issue I believe. I think there's a tech bulletin for it. I'll have a look for it tomorrow. Remind me if I forget

[Imola_Sid]

let me try the search function again!

[Shoppinit]

I don't think you'll find it on here. I remember coming across it when I was looking through the tech bulletins for something else. I'm on iPhone now do it's a pain to do anything useful.

[bam_bam]

Tough spot you're in Sid. You've a lot of options depending on budget but I say just keep it simple and before you start this little project, pick a BHP number and stick to it. Try not to get off track and start playing the "what if" game, just take a path of least resistance or least stress.

Turbos: Just get them rebuilt (maybe spec'd up a bit), cheaper than new. Make sure you're sat down before they call after the inspection, the housing(s) may be shot leaving nothing to work with so you'll need to go OEM renewal anyways. There are a few outfits about the place and everyone had their opinions, I'm gunna stay out of it. MRC sent mine out and they seem good enough, they're rated to 650PS with correct mods in place, natch.

Gearbox: Replacement from Audi, exchange from ZF or rebuild. IMO, avoid the latter, it's just not worth it. An Audi supplied unit would come with 24 month warranty, however, I think that's only if Audi fit themselves (I could be wrong as I think Grizz puts Audi units in whilst keeping warranty). The ZF exchange unit is a sound idea but only carries a 12 month warranty. This is kinda all moot because it'll be a massive ballache if it goes wrong, whatever happens, the engine has to come out, again.

TC: The ZF exchange box can be ordered with or without a TC, price reflected accordingly. There are a number of US based outfits that will rebuild your TC stronger (IPT Performance trans, Level10, A.C.E race converters), my thoughts are still out on this. The A.C.E converter I have is good, it's strong but I can't help thinking it's a bit rough or just not matching up to the 'box properly. If I was to do it again, I'd eliminated as much doubt and just have got a replacement, alas, not my decision so I did what I could. That said, I'd be very surprised if this A.C.E TC ever fails.

Manifolds: Upgrading these will require custom fabrication and you might not have the time. Talk to MRC, they commissioned the ones I have.

Intercoolers: You don't need to uprate your ICs for stage 2 turbos, I haven't... yet.

Other stuff: Get the usual engine out jobs done, it'd be a PITA if you got it all back together only to have the water pump fail or the thermostat play up etc. I'm sure someone else will post up this little job list.

Best of luck and keep us posted.

[Shoppinit]

Right, I had a look. The reverse not engaging is listed in the "Frequently occurring faults":

No power transmission in reverse gear

- Fault:
Clutch piston F deformed -arrow 1-, sealing lips damaged -arrow 3- and -arrow 4-, retaining rings deformed -arrow 2-
- Cause of fault:
Main pressure valve in valve body is worn, leading to excessive pressure on piston F, piston F is thus deformed, sealing lips on piston F are damaged and the split retaining ring is bent.
- Fault rectification:
Dismantle complete gearbox and clean all parts, renew ATF pipes.
Clean ATF pipes and ATF cooler.
Dismantle and check all clutches.
Check friction lining of torque converter clutch ? Chapter.
If ATF is suspected to be very dirty ? Chapter, renew torque converter (cannot be cleaned).
Renew valve body.
Check cylinder F for scoring, eliminate scoring or renew cylinder F if necessary.
Renew ATF strainer.

or

Power transmission delay (approx. 5 6 seconds) after engaging reverse gear

- Fault:
Radial wear of rectangular section seals -3- on sun shaft.
- Cause of fault:
Excessive roughness on internal contact surface of bearing bush -2- in cylinder D/E-item 1-.
- Fault rectification:
Check internal surface of bearing bush for roughness and renew bearing bush if necessary; renew rectangular section seals.

Either way, unless it's an easy fix (which those aren't) then you might as well nuke the whole box and put a new one in. It would be a nightmare to fix one thing only to realise you missed another when you get it all back together.

[Doug_S2]

Sid, I'll post what I posted on the other site to see if we can get a more interesting dialog going here:

I am trying to get my head around the symptoms. What is bizarre is that there is no boost at all, not a jot. You'd think that some boost would register before it started blowing air out of the other MAF.

I'm sure that MRC is right, but I have seen cars with a bad turbo making half boost. So why is yours not showing any boost at all.

And why does the 2nd MAF drop to zero on overrun or when the throttle closes? That's what I can't figure out.

This is really common on the RS6. If one turbo does not spin at all - either broken shaft or a manifold collapsed and stuck in the hotside, then only one side spins - but the easiest path for that flow of air is not into the manifold but out the other side of the bipipe - through the dead turbo and flow out the intake side. That is why when not on boost and on engine sucking you get air flow on both banks but as soon as one side that works spins up, that side airflow increases but the opposite side goes from 20-30g/s down to 0 as the air is flowing backwards over the maf. Now you get zero boost on vagcom - nothing significant registers at all. You do need to pressure test to make sure there is not a massive leak (which can also cause really low boost)

[JCviggen]

This is really common on the RS6.

Brilliant, one more thing to keep me awake at night.

[Shoppinit]

Thanks, Doug. Good explanation. One more thing to worry about. I knew this was a problem on the B5 S4 but I would have thought that audi wouldn't make the same mistake twice. Wait, what am I thinking... DRC. Duh

[Shoppinit]

I wonder if oil starvation could have caused this problem. If this is not the first time the car has had new turbos then I could want to check oil supply before putting another set of turbos on.