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.
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.
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.
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.
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.
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.
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.
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.
And we’re just getting started on the power adders for this legendary beast. Much more to come. I’ll be back…
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
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
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.
Karma bump boat. Lots of good helpful information these past few days
Yup, thanks Boatmobile!
The vibration I’d say is a shudder and feels likely you’re right on the diff service. CV boots look like they have been changed recently, so they’re sealed but no grinding sounds.
S6 in my year are permanent 4wd with Torsen T-2.
Suspension, the shocks do feel like they’re starting to go, so I was considering coilovers. I do want to get it a bit lower and stiffen it up a tad. But it is something I can definitely wait on and do wheels first. Tires are at 70-80% though so I’ll have to be patient there.
Trying to get to some other small niggling things like a detatched headliner, replacing some peeling/sticky control pieces in the interior, and trying to find a way to get an rs6 rear here from germany from ebay sellers who don’t seem to want to send to USA. (Any good samaritans in germany willing to help? =) )
Next chance I get I’m going to get it back on the lift and check that steering pump. A/C fan is making some noise too so hopefully thats an easy swap.
As part of a buy of a few other parts, I took a shot on some RS6 Hotchkis swaybars. Wasn’t sure if they’d fit my car, anyone know for sure? All I could find was that the AR was different because of the compressors being in the way. I’m hoping that the RS6/S6 is compatible except for maybe some diameter differences that can be overcome.
Thanks again for all the info!
To give you an idea of how it looks lowered, here is my old 2002 S6 sitting on H&R coilovers, on the highest setting. Note the pickup truck in the background. On the highest setting, these coilovers provide a really tasteful/slight drop. Factory sized tires are 255/40/R17 (overall diameter 25.0"). Tires in this picture are 245/40/R19 (overall diameter 26.7"). No rubbing issues, and looks great if you ask me.
http://audirevolution.net/addons/albums/images/556495044.png
http://audirevolution.net/addons/albums/images/365493366.png
Noisy HVAC fan is a really common issue on these cars. Super easy to change. Just remove the glove box. Even with zero experience, I’m sure you could swap the HVAC fan in less than two hours. It’s literally right there once the glove box is off. Might be less than an hour if you’re super handy.
Be careful when selecting a replacement climate control console (I assume this is what you’re talking about). The climate control consoles are different, depending on which factory stereo you have. When shopping for a used climate control unit in good shape, pay attention to the top left and right corners. Sharp corners are from cars with a Symphony/upgraded OEM stereo, and rounded corners are from a Concert/basic OEM stereo. Note these differences in the following picture:
http://audirevolution.net/addons/albums/images/137647091.jpg
Also, regarding the peeling buttons on the climate console: I heard somewhere that Audi changed the type of paint/coating on these consoles starting in 2002. So any climate control unit from 2001 or older that fits a C5 would be a unit that won’t be as prone to the same button paint peeling problems.
My S6 had a H&R rear sway bar installed right before I got it, courtesy of v8a6 (previous owner). You can see how much more beefy it is here (picture of OEM vs H&R side by side):
I’m not sure about compatibility, but I imagine the RS6 and S6 sway bars would be interchangeable. One of these images shows dimensions of all C5 cars, except the RS6 (from the Bentley manual, in inches). The other image of RS6 dimensions is from Google, in metric. I’m pretty sure a wide body C5 car is a wide body C5 car, but you can do an exact comparison using the following:
http://audirevolution.net/addons/albums/images/922303508.jpg
http://audirevolution.net/addons/albums/images/814211720.png
