All the same parts as V8A6’s car, built by the same guy.
http://audirevolution.net/videos/198/audi-v10-s6-w-headers-and-catback
Headers help make good power but you also need the same tune to pull out the power. Recent results have shown that the JHM CV headers really work and you can’t just try to make headers just standard longer pipes looking like headers don’t make the same power as the ones these guys had made by CV
The CV headers are the best!!
After a lot of extensive googlin’ I see that you’re (one of the few) the only person talking about putting the RS6 (reletevly affordable for brembo upgrade!!) calipers/rots on the S6. Q: Do any c7 stock calipers fit our c6s’ yet?!
So you confirm that you definitely “good practice” needed the larger master cylinder to account for the larger front pot capacity? When I did the 18zs on the C5, I calculated only about ~7% more MS would be needed, so kept it stock. I read your build prior to my purchase fyi ha… A script for what I would love to do!
Did you do the rears RS rotors and carrier also?
I’m curious to hear if you enjoy the monoblocks up front, was worth the upgrade vs the 385s (not sure if you track your car or not… cost of s6 brake parts vs rs…
Great build man!!!
Those are some good questions. I’m not too sure if V8A6 still has his S6. Last time he checked in on here, he was keen on selling it.
re: RS6 calipers and rotors, Honestly, I’ve never felt I’ve needed more braking power and from reports of the guys that’ve done extensive HPDE sessions in the S6, nowhere has anyone mentioned brake fade. The rotors themselves are .5" in diameter larger and the friction ring isn’t Steel meaning they’re WAY more expensive to replace with arguably shorter lifespans than steel. I’ve seem some front rotors for sale that had heat cycle cracks all over them - nope.
I hate to sound like a continual fanboi, but honestly the JHM lightweight rotors are about as good as you’ll ever need for an S6. I think they’re even a few pounds lighter per corner than the RS6 units as well. Replacement friction rings are exponentially cheaper than the RS6 units (that you’ll have to wait quite a while to import from EU to arrive).
Q7 swap is an interesting proposition that might make sense - 6piston calipers vs. 4, but I’ve never seen a definitive answer.
i’ve done some research on this. The C7 S6 calipers are on 400mm Rotors, and the offset is different on the caliper. I just had some used rotor from the C7 to see how they lined up.
Another option I stumbled on was the C6 A6 Brembo GT kit. That gets a 380mm rotors and is bolt on. (PRICEY OPTION HOWEVER)
I was toiling with the idea of changing my brakes because I hate the look of the stockers. I did swap Q7 18z on my B6 S4 previously on the stock 345mm rotors with no issue. Its just not that easy on our cars.
I’d like to look at swapping the stock C7 A6 calipers, they look much better.
I actually never got around to installing the 4F RS6 calipers. I used to have an old RS6 rotor, but Im not sure where it is now. If I were to look into it now, I would probably mount up the RS6 calipers with the stock S6 rotors, and see if the offset worked. There was only 5mm total diameter difference in the rotor (385mm vs 390) so the calipers should be able to accomodate the S6 rotors, if the offset matched.
If not, I would look around to see if any other rotors worked. There were some 400mm wave rotors that looked like they might work. Or, go custom.
I had the brake booster and master cylinder from a 4F RS6 at one point. It is at my friends shop, so should still have it.
The RS6 calipers are essentially the same design as the Brembo GT 6pots, btw. The Audi Brembo RS6 calipers have a bolt on brace accross the top, as opposed to the GT calipers that have the integrated.
If anyone wants the RS6 calipers, they are for sale. PM me if interested.
Just got the car back from tuning, and it is running INCREDIBLE !!!
Hope to get an update on the project thread up soon
Stay tuned 
Yes I was still curious about this!! Wondered how it ever panned out for you. And if you truly thought the MC was necessary for this upgrade. This would be one of them later retrofits I would take the plunge on however
I think it would nice to do the rear caliper carrier for the larger rs6 rotor. Doubt those rotors are cheap tho ha…
Interested in tuning feedback!!
Great to hear you have the car back up and running!
Glad to hear.
hey everyone…the S6 will be up for sale soon
It is running incredible, and pulls like a freight train
Ill have more details soon
Located in Toronto Canada
Car is up for sale…
one last exhaust video 
glorious sound
So what is the Cliff’s Notes version of the problem you had with the codes and running issues and the ultimate fixes? Wondering what we can learn.
Sure, I can sum up what I have learned about these cars…great idea.
The factory S6 design is, in my opinion, flawed. Someone got a great idea to stuff a v10 into the S6… but then some other team decided they needed to cram 4 catalytic converters in the middle of the factory headers. Restrictive cat placement caused performance issues and extreme heat soak, and created a maintenance nightmare when you have to drop the engine to get to the upper o2 sensors.
Heat soak causes premature part failure and inconsistency in performance. As problems started to arise in these cars, dealerships really didnt want to start replacing everything under warranty to try and figure things out. So, Audi just updated the ECU tuning to be less sensitive to the issues. So, the cars looked like they were running OK (no check engine light,) but in reality they were far from good. My car ran mid-14s at the 1/4 mile when we first got it, but had no check engine light. But when we scanned it, we could see the misfires. Just, the ECU didnt complain.
So, then what happened is the cars got driven deeper and deeper into a hole without things being fixed. Even if a few expensive things were fixed, the car still wouldnt run right because you have to fix EVERYTHING and fix the factory design flaws to make the cars reliable. Not only does the average S6 owner have no idea of all the things that have to be fixed, but even if they did, no one wants to spend the huge $$$ to fix it all.
So then, the market got flooded with a bunch of v10 S6s that dont run right. There are times when they may run OK, but will never have long term reliability in stock form. Plus, the stock car requires well functioning o2s and cats to run right, and both require an engine drop to replace (or gut the cats.)
As the newest v10 S6s are now a decade old, pretty much any one of these v10 S6s you see on the used market, are likely going to need pretty much all of the following (unless they have already been replaced)
Intake Manifold
Carbon clean
Fuel Injectors
Various seals
o2 sensors
coil packs
and likely catalytic replacement (which means either you gut them or go with aftermarket)
On my car, we also needed a new radiator, thermostat, spark plugs and battery, among other stuff. All are critical to the car functioning properly.
OK, so after you replace all that stuff, now you have to deal with the factory header/cat/o2 design problem. In my opinion, there are 2 valid ways to deal with this:
Keep the stock headers, gut the cats, and replace all o2 sensors with new ones. If you dont want to relocate the o2 sensors, then you will have to drop the engine again in the future to replace some of them. Considering the o2 sensor readings are vital to the performance of the car, I would have them relocated downstream. But note, this MAY mean you need a custom ECU tune to adjust for their relocation.
JHM headers, high flow cat, relocate the o2 to be accessible, JHM matching exhaust, and custom ECU and TCU tune to make everything work. Even though this is much more costly, my opinion is that this is the way to do it RIGHT, and the only option I would consider.
On my car, when we were troubleshooting the misfires, we pretty much replaced everything mentioned above, and every other related part that could contribute. It wasnt until all the parts were replaced that the ECU gave us a clearer picture of what had to be done to finally get it running perfectly.
For whatever reason, my car had to have a custom tune to read from only certain number of o2 sensors, not all original 8. My guess is that this had something to do with the much more efficient 5 into 1 header design, and relocation of the o2 sensors. Apparently, this was not required on the other cars that had similar mods, but on mine it was. So, I would not recommended these mods without being prepared to also do a custom JHM tune. CountVohn really saved the day, and was probably the only person on the earth who could have figured it all out and got it running right. So, a HUGE thanks to him!!!
Also, when the car finally started running amazing and making tons of power, now the transmission had no idea how to handle it…LOL. It would have huge pauses in between gear shifts, as there was way more torque then it was expecting. A custom JHM TCU tune fixed all that, and now it shifts like lightning.
To give you an idea of the torque, my car runs 275 width tires front and rear. If I leave the ESP traction control enabled, the car cuts all power under WOT going from the 1 to 2 shift. That is because it spins the 275 enough to kick in the ESP. This is in the middle of summer with lots of grip. And, if you dont disable ESP then the car doesnt allow you to really drive it fast and spirited in general. Its more subtle, but I can feel it kicking in around turns when driving spirited.
With ESP disabled, you can power-steer the car around turns and it just rips. WIth all the extra power, you can really throw it around. It is a really fun and powerful POINT N SHOOT rocket now that it is all done…But, the effort and $$$ to get there was significant.
So, to sum it all up, if your car is not running right:
Replace all the items I listed above with new. (I know you dont think they ALL need to be replaced, but they do)
Make sure the battery, radiator, thermostat, throttle bodies, HPFP are all functioning 100%, or replace.
Make sure the battery is AGM. The lead acid batteries gave me issues.
Fix the factory header design flaws with one of the two methods I outlined earlier.
After all mechanical items are addressed, get a JHM ECU and TCU tune.
Excellent post and exactly what I was looking for! What a journey—only persistence and $$$ gets the job done. Thanks.
Epic post. Really helpful.
The V10 S6 and S8 are fun great cars but your going to have to spend the money like you said… Do it right really needs to be the big statement.
V8A6. We all want to thank you for all you have done and shared. You are the original OG… I think I say we all would like to see you in another Audi project soon
Thanks Justin! …Especially for all your help along the way. I still remember driving down to Detroit in the dead of winter with my old S6 wagon, and you and CountVohn working in the freezing cold garage to install the Magnaflow exhaust and fix a bunch of other stuff on the car. You have always been so generous and helpful with everyone. This site would not be the same without you!
Thanks again !!!