Carputer

M has been talking about making a carputer or a major re-wiring project for years but hasn't had the right car or the means. When the S6 came along it was the perfect vehicle for this project. The S6's purpose is to be his daily driver and doubles as a great road trip/track car. Weight is also not an issue for this 3800 lb behemoth making the extra heft of the PC, wires, speakers, mounting parts, and screen negligible.

The system specs:

• 8" LCD touch screen
• 4 channel 2 ohm amp
• 8 Infinity speakers (rear door and shelf speakers are Infinity References chosen because they're 4 ohms per local array, wired in parallel for a 2-ohm wide array, plus the 4" 2 ohm Kappas for the front).
• AMD based PC
• Oxygen free copper (OFC) wire
• wireless, cellular, and GPS antenna
• Cell phone hookup where the stock 1995 Audi phone was for a mobile internet connection, and another cord going to an antenna for it on the trunk.
• Mounted on a two tier set of oak boards the lower of which is on a set of sliding drawer rails.

 

 

Transmission mounts that I installed:

The new stock S6+ transmission mount. It took me about half an hour to get all of the waxy mold release compound off. I filled the S6+ mount with urethane goo. No air gaps, very solid shifting, and the car does not vibrate. The 034 front engine mount (or snub mount). The bracket didn't fit as per the usual from them but we got it to work with some minor drilling. It's far better than the stock soft rubber mount and huge empty stock bracket. 034 has since corrected the design.

Update: 034 now makes these in solid shore 80 rubber for cheap, don't bother with the S6+ or stock mounts. We didn't prep the surface well enough either so the urethane got cooked under the car and started to fall out of our mount, I suggest using a dremel to get the new waxy rubber to be a rougher surface for the urethane to adhere to if you're going to fill your mounts.

Back to the carputer, the 5 1/4" Speakers and crossover that were actually 4" speakers on the car. It took some creative engineering to get them to fit with the stock speaker covers. They do sound delightful.

M put the Infinity Kappas into the front stock Bose mount. We sawed 70% of the the 2 1/5 foot long mount off also loosing the stock amp that was housed at the end of that monstrosity. That amp, housing, and the stock speaker weighted a lot more than the 4" Kappa and the crossover.

Initially we tried to install a high end inverter to power the carputer but there was a lot of interference on both the monitor and the speakers. We narrowed it down to that by moving it away from the amp and then later by plugging the computer into the garages AC power. It was determined that a ground loop had occurred but no amount of grounding eliminated 100% of the noise. You don't want this kind of noise entering things like your airbag ECU or the ignition system. The idea was scrapped but the inverter was re-installed in the third revision for non-computer use.

A DC power supply was sourced for the PC itself to fix the problem. It is ultimately a cheaper, lighter, and more elegant solution. In addition to drawing less due to efficiency losses, it has the ability to withstand a severe short-term voltage drop due to engine cranking. The inverter's only go down to about 11v before they shut off, this p/s goes down to about 8v. The DC power supply also incorporates startup and shutdown functions based on an amp-style remote input. The button on the dash to the above right of the screen trips the relay that in turn activates both the amp and power supply remotes.

Rally 

Part of the reason for this carputer project is to run rally software for a time/speed/distance (TSD) rally that M drives in every year. For the best results he needs an odometer that is as accurate as possible. The carputer is the first step in getting that odometer setup.

Revision 3.0:

The power supply crapped out and was sent back to be re flashed. This gave us an opportunity to mount everything better and install a better interface. The touch screen just doesn't cut it while you're driving and is even somewhat difficult for a passenger to navigate unless you make the OS interface huge. So we got a keypad instead.

The amp and a fused distribution block are mounted upside down on the top board. The Micro ATX and the inverter are mounted also upside down on the sliding tray. We used a simple door hook to keep it from sliding out under acceleration. Simple, clean, and easily serviceable.

M___ ditched the keypad in favor of touch screen friendly interface software. I liked the keypad but mostly in addition to the better front end. I prefer to have buttons I can find in the dark without look down from the road. Can't do that with a screen obviously. I kept it incase I ever get around to a carputer.

In my opinion this setup works great once you memorize the keypad.

The lights for the TSD rally. Four 55w lights switch on with the high beams. It's a sight to behold.

The horrible clunk over bumps turned out to be this thing, some ancient (?) meyel strut tops. You can barely make out with this photo the rubber around the center piece is completely separated. You can replace these without taking the suspension apart which is not common and a very nice design feature. With the new mounts in the car drives much quieter, and handling is improved.

The stock S6 Avus wheels suck. They're too narrow (barely), too heavy, and too ugly. M bought some 17x8" ASA AR1's in 35mm offset with some 245 40 17 tires. The difference is astounding and well worth the money, even with less than awesome tires. After the Brembo's went on the stock wheels/tires were the weakest link and this wheel tire combination has shifted that to the tired shocks/springs/anti-roll bar.

The dash in the S6 has this great little super bright display on it that lets you know if your brake pads are low or if your headlights are out. Problem is if you switch to non-stock brake pads or HID lights this glorious feature is on all of the time blinding you at night and beeping. Thanks to the wonders of the internet we found a "how to" on tricking the board in the engine bay relay box to think that your lights are still ok. It simply involves disabling two precision resistors by soldering two spots on the board and cutting some traces. Easy, free, and absolutely worth it. The how to is here.

For the brake pads simply take the harnesses going to the pads, cut the end off and splice the two wires together. Be sure to weatherproof them and stick them somewhere where they won't get sucked into the wheel or the valvetrain or something.

Driving the car after that display was out was like driving a different car. The gauge pod looks great as it was intended. No more beeps. Wish we'd known about that when we got the car!

Climate Control flap controler woes

M____s climate control flaps had not worked on the S6 since day one. This is a common problem with the chassis. Usually these symptoms mean that your servo motors that operate the flaps under the dash need to be rebuilt/cleaned/replaced. That was not the solution in our case which is nice because they cost a mint.

We cleaned ours and actuated them with the VAG-COM to no avail. Next we gave them power via some aa batteries and confirmed that they were indeed just fine. From there we got out the wiring diagram and my continuity tester to see if there was a break in the harness. Nope. Then we plugged the cc unit in and actuated the motors with the vag checking for power at the harness, nope. That lead to taking the cc box apart where we saw the voltage regulator had crumbled away presumably due to heat, circled above. That is our culprit. Now whatever your problem is a used CC unit is generally around 50-100$ so you can do that or try to fix the board itself. There are places that will rebuild them for you as well.

Our problem is the voltage regulator pictured above. You can find one here. Get that soldering iron and get ready for fun!