Surprised no one has done research on swapping Cams and intake from the R8. Wonder how many things are different. I imagine the heads but maybe not that different since Both R8 and S6 are 12.5.1 Compression. HMMMMM.
Research has been done, but anything like that is always a balance of cost, risk, and reward.
Intake
First, the R8/Gallardo 5.2 intake is single plane (5.0 is dual with a very cool design, but cylinder bore spacing is different). So, youād lose a ton of torque. Not good on a 4400 pound daily driver. Second, and much more importantly, they wont fit under the hood. Third, price. For an upper plus two lowers you are looking at at least $1k. Fourth, on an NA car, variable length is usually going to be better. Unless there was a huge restriction up top with the stock manifold, which there doesnt seem to be, then why swap for one that is only optimized for peak power at a single RPM range when you can have it optimized for two.
Cams
First, $$$$$. I tried to get some and there is no such thing as cheap ones. New they are about $800 each, and youād want to do at least the two intake cams. Second, high risk. Bigger cams open the valves higher. Will the valves smack into your pistons? Donāt know. Third, powerband. As Saki pointed out, the R8/Gallardo/RS4 are optimized for high RPM engine. 8400rpm. Do you know what the S6 revs to? Heres a hintā¦it is not what your Audi S6 manual or your cars tach tells you. Donāt believe what Audi writes in the SPPs. It is half useful info and half BS marketing. The R8 cams are designed to bring more air into the engine at higher RPM. But when your engine cant rev anywhere close to that RPM, then it is a waste.
Additionally, even if your engine did rev to 8400 rpm, and you could fit the intake, and you did have $3200 to spend on R8 cams, doing the cams and intake would do relatively nothing unless you completed the other things I am about to outline.
When it comes to mods, especially on a platform that is largely unexplored, you should always keep in mind risk vs reward vs cost. I keep telling everyone this, but Ill say it againā¦ If you want to get performance out of the v10 S6, then look at the proven formula that was used on the B6 S4. Get the intake flowing better while retaining the variable intake manifold, JHM intake spacers reduce IAT, replace the exhaust manifold with headers (piggies are another option if on a tight budget), go catless or highflow cats downstream (for the S6 you want to relocate them to a place where you can access them in the future without dropping the engine) and put on an appropriately sized exhaust with a X-pipe tuned specifically for the engine. JustIncredible posted an excellent writeup for the B6/B7 S4. Study it like the bible, because the same applies hereā¦
http://audirevolution.net/forum/index.php?topic=3080.0
And top it all off with a CountVohn ECU and TCU tune.
This approach will give you greater performance, reliability, easier access to the cats and o2s, and reduce heat. It may even reduce carbon buildup, and save you money there.
Anything outside of that forumla is higher risk, more money, and with little potential reward. Sometimes it is fun to look for cheaper shortcuts, but in the end you get way more bang for the buck by sticking with the tested formula. I say, let all the other guys do the hard, expensive trial and error work, and Ill just copy them when they achieve the best combo.
BTW, I am not saying that the R8 cams wont increase performance, but you would need all the other stuff first before they made sense. And then you would still have to figure out if the price, effort, and risk were worth it to try them out. It is something I have considered if I ever have a built engine, so who knows, I may be the guinea pig one day if someone doesnt get there first.
If you are looking for the single biggest ābang for the buckā improvement you could make to this car, then I would try and see if there is anyway that you could gut all four cats without having to remove the engine. JimmyBones wrote this for the S6 Info Dumpā¦
Those stock cats are really hateful. I took off the stock Y-pipes that connect the two exhaust manifolds together to change out the transmission fluid and filter. While doing that repair it looked like the cats for the front three cylinders on each side would be easy to gut. The cats for the rear two cylinders looked like a PITA to gut but it might be possible with a good long angled striking prybar, a big 3" or 4" wire brush attachment for a drill, and a few starts of the engine to blow all the crap out.
NOTE: I think he was referring to the S8 which may be slightly different.
That will cost you practically nothing, but your time and effort. Then, you will need a CountVohn tune.
My prediction is that no other single change (well, it is kind of two things) will give you a better performance increase for your dollar.
love that signature
again, for the NA Audis, the performance formula has been pretty simple. These are not basic chevy engines where chevy leaves the world on the table. Chevy throws a boatload of displacement at the car, and generates effortless power without extreme engineering. They generate 50-70 hp/litre of displacement.
audi does the oppositeā¦uses relatively small displacement, and stresses the shit out of everything, and then requires top fuel so the car doesnāt knock itself into oblivion. They generate 80-100 hp per litre while doing so.
The bad news is thereās not much on the table that you might find in the domestic world (cams, intake stuff). The good news is that is just a bunch less things you need to buy, because Audi has already done it for you. Thatās also one more reason these things are expensive.
As v8a6 mentioned, the formula has been pretty straightforward for all of the NA Audis Iāve been around (A6 4.2, S5 4.2, S4 4.2, RS4 4.2)
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kill the precats. and maybe even the main cats if emissions arenāt a concern. Thatās 10-15 hp/tq
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open up the exhaust because this is one area where audi skimpsā¦they keep it skinny and bendy and quiet. You want it fat and flowy and loud. Thatās another 10-15 hp/tq
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tune the car for better everything. Not a turbo tune that grabs you 50-80 hp, but it will be another 10-20 hp/tq and more importantly great driving dynamics
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cut rotating massā¦rotors, flywheel (if appropriate, but not on an S6), crank pulley, wheels, tires. this can gain you the acceleration equivalent of about 10-15 hp/tq
Add that all up and youāre picking up 30-50 hp/tq, and youāre probably shaving 5-6 tenths off your quarter mile time, and adding 4-6 MPH of trap speedā¦or vs. your car when it was stock, youāre putting 6-8 car lengths on it in a 30-130 mph race.
For those wondering about the airbox flaps, Ssicks did some testingā¦
My opinion based on the Intake from experience is leave the flaps on just make sure they are functioning properly. I took mine off and they made more noise but I also noticed my IATs never cooling off as they should. (the flaps are right next to the exhaust manifolds) When you take them off you lose the suction of the cold air from the grille and I think there is some sort of actual air pump that pumps fresh air into the intake. I replaced the filters with K&Ns and have run both flaps on flaps off and logged runs. My experience is that 0-60 20-80 speeds are improved with them installed.
And if anyone can add on about the air pumps into the air box? I know I saw the S8 had them. See belows pic, I know the design is different on our cars but ive confirmed the pumps and plumbing into the air box are there. I wonder when the pumps activate? Can they be switched on more or less? maybe higher speeds via vagcom? When get some time Iāll prob Heat wrap The boxes and Intake tubes. IATās were ridiculous (ambient temp about 48- IAT 80-90) my scanner wont tell me how much or if any timing is being pulled maybe a Vagcom would? Iāve contacted APR to see if the would at least tell me how much timing they are using so I can compare and also for when I install the N20. Ill keep you guys updated!
http://i1348.photobucket.com/albums/p730/syncmaster347/Intakes_zpscb755667.jpg
Check out the difference in power graphs direct from Audi between the S6 and S8. Its almost like they cut fuel or timing at the peak on the S6 just so the S8 would make more power bc its their Flag ship? They do have two different engine codes would be awesome to know the differences in them. Interestingā¦ Very Interestingā¦
http://i1348.photobucket.com/albums/p730/syncmaster347/Power_zpse879a5ad.jpg
Now compare APRās Numbers Stock and with their 93 tuneā¦ S8 Tuned can make 471hp But the S6 can only make 453hp. Whats really weird is the torque comparisonā¦ S8 made 405tq stock and 427tq tuned S6 made 439tq stock and 460tq tunedā¦ (off subject but their āgraphsā lead me to believe they are most likely throwing some timing at the stock tune and charging $800 for it. At least on the v10 sedans)
http://i1348.photobucket.com/albums/p730/syncmaster347/52_fsi_v10_s8_s0_vs_s1_cc_zps99de5286.gif
http://i1348.photobucket.com/albums/p730/syncmaster347/52fsi_apr_vs_stock_93_crank_zpsc2eaee86.gif
Lots of thought went into the design of the exhaust manifolds if you read what Audi says about valves opening and closing etc. They tuned the Manifold for optimal HEATING of the Catalytic convertersā¦ Sooooo Audi also says:
āOne solution to the exhaust gas pulsation phenomenon
would be to make an exhaust manifold runner for each
cylinder ā a 5 into 1 header type system. However,
this system would be big and would create a thermal
disadvantage to the quick warming of the emission
required catalytic converters.ā
AKA Would make much more sense and Power but we have these stupid emission laws lol
Long story short Headers no cats would make power-
http://i1348.photobucket.com/albums/p730/syncmaster347/Exhaust1_zps47b0fc9d.jpg
http://i1348.photobucket.com/albums/p730/syncmaster347/Exhaust2_zpsfca53faf.jpg
Exactly! Now you are starting to see why we are focusing on the exhaust for improvements. Because, as Saki pointed out, that is where the biggest compromises were made.
I referenced the same info that you posted my project build thread, that is in the works and I hope to be posting soon. This is a short excerpt discussing the same thing
[b][i]The stock tubular 2-1-2 exhaust manifolds are pretty impressive to look at. However, reading the details in the SPP reveal the focus of their design:
One solution to the exhaust gas pulsation phenomenon
would be to make an exhaust manifold runner for each
cylinder ā a 5 into 1 header type system. However,
this system would be big and would create a thermal
disadvantage to the quick warming of the emission
required catalytic converters.
In other words, 5 into 1 headers would be ideal, but space would be tight and they wouldnāt get hot as quickly as the 2-1-2 design with the cat right up close to the engine. So, the stock headers are actually designed to heat up quick. LOL. And we wonder why you can fry an egg on the hood of the S6 at idle in the middle of January in Toronto, Canada.[/i][/b]
Air pumps? Do you mean like a simple low-power forced induction system?
I think he is talking about the SAI system. Is that what you are referring to Ssicks? If so, there is nothing there to improve power.
I guess? Ohh just notcied the air is after the MAF. So Secondary Air injection. Gotcha
I guess our cars dont have these flaps like the S8ās either
http://www.audiworld.com/forums/a8-s8-d3-platform-discussion-60/2007-audi-s8-exhaust-valve-solenoid-location-2854958/
Regarding the S6 and S8 engine differences, there really are none, except the tune. The engines themselves are the same. There is a slight difference in the intact tract before the TBs, but nothing major.
Donāt put too much faith in dynos and marketing documents. The information is quite often inaccurrate, especially when it comes to engine power. That is why you find almost everyone around here judges performance using the 1/4 mile results. Like I wrote to a buddy of mine, if you want to see how fast a car is, then you measure how fast a car is.
I canāt tell exactly what they are discussing. Seems like a flap that opens somewhere at the rear of the exahaust?
Ahh yes looks like it. Kinda cool.
On aprās graphs, Iād just ignore them ā¦they take stock dyno whp, then discount back to get to audi claimed hp and calculate drive train loss. Only problem is theyāre also including carbon buildup lossā¦ Shit maintenance lossā¦ Vac leak lossā¦ And then they apply these things to the torque curve and it always looks fucked up.
Iād just look for someoneās whp wtq data to analyze the curve.
I agree totally! I am going to dyno after my cleaning and plugs so we can maybe see a good graph. My car being a 2011 but also now having 60k miles should be a fairly good baseline.
S6 v10 short block prices
Reman 5.2 v10 short block from Audi is $8800 plus core charge
Brand new short block is $11,750 with no core charge
For some reason, I always thought that they were more expensive.
Good to know, in case things with the v10 ever go really wrong, there are options.
Thatās one of those Iām not really sure how I feel about that kinda things. Audi usually drops the price of things if they fail. There is the chance that the motors are just not in demand. Either way thatās a very reasonable price.