The Fluid MotorUnion Audi RS6 Build Thread (pic-heavy thread)
Before I begin the build thread, lots of things have happened at Fluid since we’ve received this car. We’ve changed locations, changed multiple members of the team, and upgraded a lot of hardware. As a result, not all the pictures are going to be the same resolution or in the same style, and pictures of things like the intercoolers are, sadly, nowhere to be found. That being said, this is the best collection of RS6 pictures that many days worth of searching could find. Enjoy!
http://www.fluidmotorunion.com/wp-co...s6_build_1.jpg
The car came into the garage with just a tune and downpipes, but big things were on everybody’s mind. After all, the RS6 is not just a standard Audi; it represents the culmination of years of engineering know-how and an ever-present quest for a more powerful yet refined vehicle. Not since the legendary Quattro has an Audi inspired both awe and fear at the same time. In keeping with this knowledge, Fluid MotorUnion set out to build a car that would command both respect and applause at every angle, and so far, that’s what it’s been doing.
http://www.fluidmotorunion.com/wp-co...s6_build_2.jpg
http://www.fluidmotorunion.com/wp-co...s6_build_3.jpg
The first round of modifications were geared towards more a “behind-the-scenes” aspect, with larger intercoolers for the turbos and upgraded charge pipes, intake and exhaust manifolds. The manifolds and charge pipes were treated with the Extrude Hone process, which is a powerful polishing treatment that allows air and other gases to flow as smoothly as possible, increasing power and reducing parasitic loss. In keeping with the notion of reducing horsepower loss to outside factors, Fluid chose to coat both the intake and exhaust manifolds with Swain Tech’s thermal coating, keeping the heat in places it should be and away from the places it shouldn’t. Adding some extra power was the next step, so we decided to port and clip the stock twin turbos, allowing the turbine wheels to spool faster and produce boost more efficiently. We also got some pretty nice wheels for it, 19” Rennen R10 concaves, with our shop name on the wheel itself, and the owner’s last name initial on the center caps.
http://www.fluidmotorunion.com/wp-co...s6_build_4.jpg
http://www.fluidmotorunion.com/wp-co...s6_build_5.jpg
And then, sadly, the stock RS6 block decided to bite the big one and depart to engine heaven. So we ended up sourcing a much stronger short block. The new block featured forged internals (rods and pistons), with a compression ratio of 8.5:1 (down from the stock numbers of 9.5:1). From this excellent starting point, we added a Cometic head gasket and a relatively large collection of ARP parts (head studs, rod caps, everything we could get to fit). At this point, the goal we had was to ensure the longevity of this vehicle by creating an engine capable of withstanding power well beyond its current capacities. For the rest of the RS6’s build, this has been the mantra – if we build it to ridiculous capacities, then all parts should function normally at power levels well below capacity.
http://www.fluidmotorunion.com/wp-co...s6_build_6.jpg
http://www.fluidmotorunion.com/wp-co...s6_build_7.jpg
http://www.fluidmotorunion.com/wp-co...s6_build_8.jpg
http://www.fluidmotorunion.com/wp-co...s6_build_9.jpg
http://www.fluidmotorunion.com/wp-co...6_build_10.jpg
http://www.fluidmotorunion.com/wp-co...6_build_11.jpg
http://www.fluidmotorunion.com/wp-co...6_build_12.jpg
http://www.fluidmotorunion.com/wp-co...6_build_13.jpg
http://www.fluidmotorunion.com/wp-co...6_build_14.jpg
From this point, OJ went to the Middle East for a couple months. Almost immediately upon his return, the RS6’s ECU had shorted and fried part of the wiring harness, which were replaced by the dealer. In terms of setting up the tune on the new ECU, we went through three tuners that promised results but failed to deliver those results. Once the tune finally stuck and things were going well, we worked on managing the boost from the twin turbos, as both turbos would drop out of peak boost well before redline. The solution to this problem was to add a boost controller, which would hold the pressures steady up until redline. This worked, but the high boost started eating up valve covers; we went through three valve covers until we realized the problem lied in the crankcase ventilation. This meant the solution was as easy as fabricating a new oil catch can, which sat atop the valve covers and added a nice aesthetic touch to the otherwise utility-driven engine bay.
Furthermore, to get the air into the engine more efficiently, Fluid MotorUnion used a mixture of carbon fiber intake cans and custom parts to fabricate one-off intakes for the RS6, increasing airflow while utilizing stock positions for the mass airflow sensors. Between the intakes and the catch can, the engine bay looks like a completely different beast.
http://www.fluidmotorunion.com/wp-co...6_build_15.jpg
http://www.fluidmotorunion.com/wp-co...6_build_16.jpg
There are other additions that haven’t been mentioned up to this point, as well. For starters, Craig put together a beautiful turbo-back stainless steel exhaust system, adding a larger amount of grunt for a car with plenty of it to begin with.
http://www.fluidmotorunion.com/wp-co...6_build_17.jpg
http://www.fluidmotorunion.com/wp-co...6_build_18.jpg
http://www.fluidmotorunion.com/wp-co...6_build_19.jpg
http://www.fluidmotorunion.com/wp-co...6_build_20.jpg
http://www.fluidmotorunion.com/wp-co...6_build_21.jpg
In terms of suspension, the stock setup was abandoned in favor of a KW V3 coilover setup. This eliminates the shared-hydraulics setup of the OEM design, which caused more headaches than anything else.
http://www.fluidmotorunion.com/wp-co...6_build_22.jpg
http://www.fluidmotorunion.com/wp-co...6_build_23.jpg
http://www.fluidmotorunion.com/wp-co...6_build_24.jpg
http://www.fluidmotorunion.com/wp-co...6_build_25.jpg
There were small aesthetic tweaks along the way, as well. For instance, we powdercoated the valve covers back to black, to keep everything pretty much the same color.
http://www.fluidmotorunion.com/wp-co...6_build_26.jpg
We also blacked out the front grilles, added a black vinyl wrap to the roof and added some shameless self-promotion to the window.
http://www.fluidmotorunion.com/wp-co...6_build_27.jpg
http://www.fluidmotorunion.com/wp-co...6_build_28.jpg
http://www.fluidmotorunion.com/wp-co...6_build_29.jpg
We’re almost to the end of the journey with the RS6. After the catch can helped to solve the boost issues, the fuel system began its march toward modification. The first fuel system ended up blowing the fuel pressure regulator wide-open, so we began the process of overhauling the fuel system. After building our own fuel surge tank, mating it up to two fuel pumps (capable of 1600+ horsepower), which run the fuel through custom-laid fuel lines to a new fuel pressure regulator (capable of more horsepower than the fuel pumps). After finishing the fuel system, we started work on the oil and transmission coolers.
http://www.fluidmotorunion.com/wp-co...6_build_30.jpg
http://www.fluidmotorunion.com/wp-co...6_build_31.jpg
The transmission cooler is especially important in the RS6’s build. As the power increases, the weakest link for any RS6 is the somewhat-weak ZF transmission. Heat can be a big problem with these transmissions, leading them to fail when even small amounts of power are added to the system. Therefore, our transmission cooler’s greatly increased capacity should aid cooling to a large degree, removing the notion that replacing the transmission is the only way to add serious power to an RS6.
http://www.fluidmotorunion.com/wp-co...6_build_32.jpg
http://www.fluidmotorunion.com/wp-co...6_build_33.jpg
http://www.fluidmotorunion.com/wp-co...6_build_34.jpg
http://www.fluidmotorunion.com/wp-co...6_build_35.jpg
http://www.fluidmotorunion.com/wp-co...6_build_36.jpg
http://www.fluidmotorunion.com/wp-co...6_build_37.jpg
All that’s left to do is finish rerouting the catch can lines, powdercoat the intake’s aluminum bits, slap it all back together and make sure everything runs correctly. After that, it’s back to the owner’s house (for now).
At this point, the next update to this thread should be the final pictures of the engine bay and the car itself. But if we decide to get all weird with it between now and then, that'll end up here, too.
