C5 S6 V8 power build

A6 All/ S6 All
#41

Thanks! Heres a link to the auction, feel like I got a pretty good deal:
http://www.ebay.com/itm/2003-Audi-S6-/401060107746?_trksid=p2047675.l2557&ssPageName=STRK%3AMEBIDX%3AIT&nma=true&si=Vt2W%2F0cuVnCVplbHql%2FQerssSzM%3D&orig_cvip=true&rt=nc

Mostly stock, seems to run solid so far, just a little oil leak seems like from the pan.
Got some vibration at low speed when turned to lock, not sure if it’s the CV joints or friend said maybe its the diff?

Other than that I’m really enjoying it. Sold off my 87 Carrera this week so coming off that it’s still great to drive.

Plans? Spent a few grand in my head before I had even bought the car =)
Other than the bumpers, which sounds like I might just have to be patient and keep looking, I think first things are maybe exhaust/suspension/wheels. That will probably take most of the first few months.

I’ve seen a lot of mention of JHM and checked them out, no section for the C5 S6, only the A6 thought or did I miss it?

#42

You might have to email jake or contact him on here. He is on here alot. I know they have a good amount of parts for the older 4.2 stuff like crank pulley spacers and I think even the headers will fit. But only the new midlength headers

#43

Welcome to the forum avs.

Sorry I just noticed this at the last second as I’m out the door. I’ll be back on this thread some time this week with some more info about the S6 and upgrades if you ever wanna go big.

As for the bumpers, I just wanna say before I jet that I’m almost certain that v8a6 found the C5 RS6 bumpers on eBay UK.

And if I recall correctly, they were out of Germany (but it’s been a while, so not 100% certain).

#44

Another resource would be

http://www.car-part.com/

That is, if you want a replacement S6 bumper, instead of an RS6 body kit. I just looked for the rear bumper cover on car-part.com, and it’s not showing anything at the moment, but with salvage cars, stock is constantly coming and going, so it wouldn’t hurt to check back there once in a while.

#45

Yeah seems like I have a much better shot looking at UK/Euro sources. Thanks guys! I’ll keep an eye out

#46

Today I took a look at German eBay:

www.ebay.de

I did a search for “C5 rs6 audi Stoßstange” (which is “C5 rs6 audi bumper” in German), and today at a glance, there’s at least two avant rear bumpers on there. I did not look carefully to see if they’re A6 / S6 / RS6 (since they’re interchangeable on WIDE body), but they came up in the search results for “C5 rs6 audi Stoßstange”.

And you can translate pages in another language by using a Google website translator plugin. I did this once myself.

#47

I’ll do more of an info dump on this car as the week goes on. As far as your first planned upgrades…

My suggestion for exhaust is a MagnaFlow. I had one on my S6, and it’s great bang for your buck. Sounds great too.

As far as rims go, Enkei RPF1 rims are super lightweight and cheap. I have a set of these too. Lightweight wheels combine with a few other lightweight items to make a noticeable acceleration gain (lightweight rotors and lightweight crank pulley).

I don’t really have a strong opinion about suspension, other than to tell you that I ripped the coilovers out of my A4 wagon just to re-install the factory suspension lol.

Any particular questions, then fire away, but I’ll add a little more info on adding power to this car some time this week

#48

Cool, thanks Boatmobile. suspension I felt like coilovers were overkill for me. Maybe just a straight spring/shock setup unless people have found that the ride height needs a lot of tweaking depending on the wheels?

Will check out the german ebay, hopefully they will ship to US! Thanks!

#49

So, where’s the power? Ok here comes the suggestions…

Good headers (example JHM) will have you feeling your torque start clearly pulling about 1000rpm sooner than usual. And all headers are NOT created equal.

Add to that a MagnaFlow exhaust (well priced for what you get), or, a 2.75" JHM exhaust (better). If you ever plan to build the engine for mad power, then consider a 3" exhaust.

#50

Before I forget - about you mentioning the suspension - the S6 comes stock with a sport suspension. I would highly recommend trying some low profile high performance summer tires before lowering the car any further. Low profile summer rubber truly makes a huge difference in handling, and so does rubber choice. If you like the lowered look, then consider over-sized rubber to make the car look a little lower, and still keep your factory ground clearance.

Stock S6 has 255/40/R17, which has an overall diameter of 636mm (25.0").
My S6 had 245/40/R19, which has an overall diameter of 679mm (26.7").

No rubbing issues. And the car was sitting on H&R coilovers at highest setting. So yeah, in my opinion, a set of lightweight rims and nice summer rubber would probably be a better performance investment than an aftermarket suspension. Take it from there and see if you wanna change the suspension. Otherwise, I’d suggest you wait until the stock suspension is toast, and then consider your aftermarket options.

#51

As previously mentioned, there are three things you can do with this car to add up to a noticable acceleration boost:

(1) Lightweight crank pulley.

(2) Lightweight rims. Less than 18 pounds are definitely considered “lightweight”. Competition/crazy lightweight would be like 16 pounds. “Enkei RPF1” rims are super cheap lightweight rims.

(3) Also lightweight brake rotors. Front and back.

#52

The 2002 S6 Avant is a heat soaked disaster on a hot day. I’ve owned one and pushed the motor in July.

Intake spacers help by decreasing the transfer of heat up into the intake manifold. This helps restore power that the car holds back to prevent overheating. Basically helps maintain / restore the power felt right before the car heats up to full operating / heat soaked temperature. With a good cross flow across the intake, it still heats up, but it’s not that bad.

A cowl scoop helps with airflow and cooling, but hood cowls are not everyone’s cup of tea. I prefer the sleeper look, like, with NO power bulges in the hood.

#53

Regarding your low speed vibration, is it like you’re driving a 4x4 instead of AWD?

In 4x4 situations, if you are moving slowly, and turn to “lock” (as far as the steering wheel will go), then one of the two steering tires will kinda shudder/skip, because one steering tire is turning on an inside radius, and the other steering tire is turning on an outside turning radius, and they are both trying to turn at the same speed.

If this is the case, then a diff service will help. I had this problem with my A4, and it was in an Audi Technical Service Bulletin. It was definitely NOT “fixed” on the day I got my car back, but it worked itself out after a little while. It was a while ago but it was a few hundred kilometers or maybe a thousand before it was back to normal.

#54

You low speed vibration could also be a problem with a power steering hose or pump, so I’d suggest in your situation to consider checking with Audi for any Tech Serv Bulletins regarding your specific VIN.

And regarding your little oil leak, I thought I had a little oil leak on my S6 under the driver’s side, but it turned out to be a power steering leak. I replaced the power steering pump, and two power steering lines - one line running from the steering rack to the oil cooler on the front of the car, and one line running from the rack to the power steering pump.

I’m trying to upload an image showing the lines I replaced, but it’s not letting me upload… I’ll try again tomorrow.

#55

If it was a crappy CV joint, then you would probably hear it making a clicking noise while turning. In this case you could consider checking the CV joints.

If you’re hearing a slippage/crunch when full throttle (also known as “full lock” on drive train) - almost like hearing tire slip on some sand on a dry road - then you could check the CV joints for play.

And on a side note, if you feel a very slight vibration in drivetrain that the driver can feel under full throttle, then it’s probably from main drive shaft support bearing under the middle of the car.

#56

A lot of people babble on the internet that the C5 S6 is an upgrade dead end. Searching Google results for C5 S6 upgrades can be discouraging merely because there’s not a lot of kits and off-the-shelf parts available. It’s such a rare car that there isn’t much of a market.

Avs, you’re REALLY lucky to be in California near JHM. If you email them, then I’m sure that they can help you with whatever you need for this car.

#57

And we’re just getting started on the power adders for this legendary beast. Much more to come. I’ll be back…

#58

Good advice. JHM is a good helper in this siutaion with the S6. I think they have lots of parts and support you dont see on the web site

#59

Here is the print out from the parts counter guy that I used to help identify / trace the parts I replaced. The connection to the steering rack is in behind the driver’s side front tire, and as I mentioned earlier, the power steering fluid/oil cooler is on the front of the car.


http://audirevolution.net/addons/albums/images/180192037.jpg

#60

TSB’s (or “technical service bulletins”) are basically technician memos from Audi, which address things like part number revisions, recalls, and known issues with platform. To check TSB’s for your car from home, you can get a digital copy of the BentleyPublishers Audi A6 Service Manual (which covers S6 and RS6). Also, you get one year of free updates on any known TSB’s with the digital version (so you become aware of all known issues). If you buy the book copy for thumbing through in the garage, then you can get 50% off the digital copy by registering the book copy.

digital:
http://www.bentleypublishers.com/c/AC55