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Been keeping an eye on these forums for a while now.

Bought myself a C5 RS6 78000KM's that's been meticulously maintained, DRC replaced, from history turboes replaced twice etc. etc.

The previous owner really looked after the car but the owner prior to him must have driven it HARD.

Prob is that when I got it it was 100%, after driving it for two weeks it sounds as if there is a boost leak. Take it in to Audi and they import a new ECU for it, 3 days later give me the car back and it's exactly the same.

So I take it to another guy and we VAG the car, it's getting up to 100% less boost from 2000RPM to 3800RPM then at 3800RPM it goes like it should. Audi try phone me yesterday and tell me the car is working to specification..... whatever....

With the other guy we saw that the piping for the DV's and the DV's have never been replaced so I feel there is an issue there.

I've attatched the VAG log, please tell me what you think it could be.

Really loving the RS6 and only 52 were ever bought into SA, prob is i'm not a rich person and worried this car is going to cost me an arm and a leg.

Wow. Thats alot of numbers !

Hmmm - needs someone clever with excel to sort out the data and create some graphs - way beyond my pay grade I'm afraid!

Dave

Here ya go

Steve

Clearly boost is going somewhere it shouldn't between 2000-4000 rpm. DV's are a good starting point, number of people have had leaking intercoolers. Might check those too.

Good luck, remember, it's usually something simple.

That's weird. Looks like the turbos are really slow to get the boost up. Could be a leak. I'd start by checking the intercoolers.

Do you get a sudden rush of power when you put your foot down?

It's achieving requested boost, but late. Possibly the N75 in poor shape?

Will have to get them to check again. Been into Audi twice in the past 2 weeks.

ECU Changed, Wastegate removed and re-installed, Throttle valve vacuum unit, vacume pipes, both DV's replaced, seal, screw, oil filter from the invoices so yea could be a possible intercooler leak

Cant think of anything else in the system that would cause an issue. Off the line she's a little sluggish then at 3800 goes like a bomb, strange thing as well is that it seems under full accelleration like it's holding back, pulls bettetr at half accelleration. At 170KM/h under full accelleration it seems as if it hits a wall and accelleration slows down like the turbos arnt working or all the boost is going somewhere else.

At half throttle it seems fine and will track up to 190 with ease.

I hope it's something simple, just want my car running 100% absolutely loving this beast when it goes like one.

Any strange noises? I heard of someone with an B5 RS4 having problems like this. It turned out to be a bad turbo in the end I believe, but I'm not saying that's what you've got.

Ok, audi telling me that it's within spec..... utter rubbish

Got word of another guy that's delt with a few RS6's at another dealer and going to try take it there.

One question, is it possible to disconect the N75, will there be any difference, will it damage something?

I know you can disconect the MAF's to test if those are bad but what about N75

Look at boost log

hey bud! its roland (quattrox) here from the audi sa forum. got exactly the same problem with my car.building a boost leak tester to find the leak. pm me if u wanna test yours as well.
cheers
roland

Warpath good to see you here too

I really think you may need to pop a call through to the Grizzmeister at Unit20
Go check out their website for details or PM him here. He has a lot of knowledge on these cars.

Also have you spoken to Vinny here in JHB and tried to get him to look into it? He has a good rep too.

Failing all of that, I bid ZAR100k for your car

Just joking

i think he has already spoken to vinny.
in the meantime i have managed to build a tester and u know what i found? the rubber pipe connecting the downpie from the airfilter to the turbo is not fitted on properly!!! wtf???? do we need to pull the engine out to fix it? these local audi dealers really suck!!!!

Sorry Guys only saw this now.

Still have the problem, Roland we must get this sorted I have the etka sketch Attatching now. Car is fine after it has gathered boost, tested again my only issue is just below 2000RPM to around 3800RPM. Wastegate duty cycle is @ almost 100% trying to gather up the boost so I think N75 is ok. Leak in the piping is on the right hand side of the car/ left seems fine as you say it's behind the engine between the air intake and the turbo. IMO Audi should know their cars better in SA, with all the research i've done I think i'm starting to know more about these engines than they do

VAG LOG pull