C5 S6 vagcom logging

A6 All/ S6 All
#1

Had some extra time today so I decided to run some logs on the S6. Car has 208k miles /334k km and no mods to the engine. The only mod to the exhaust was to replace the cats with Magnaflow high flow units.

Temperature is -8 degrees celcius. Run is from low RPM in first, full throttle through second, and up until high RPM in third.

http://ep1.pinkbike.org/p4pb10653275/p4pb10653275.jpg

For comparison, this is a 3rd gear run from my Audi A6 4.2, with ported S8 heads, S8 intake, Miltech dps, Magnaflow high flow cats, and full 2.5 Magaflow exhaust with catback. It was JHM tuned.

http://gp1.pinkbike.org/p4pb9142327/p4pb9142327.jpg

Some interesting notes:

  1. Airflow looks comparible. The S6 max of 278 g/s is higher than the A6 on this run, and close to the highest I ever logged on the A6 (285 g/s). I did cut a hole in the bottom of the A6 airbox, which may have actually been detrimental to airflow. Regardless, I would call airflow a tie.

  2. Timing. The JHM-tuned A6 is able to run about 10-15 degrees more advance at high RPM. It looks like the S6 maxes out about 20-25 degrees, where the A6 hits over 38 at 7000rpm without any retard. I have read that 1 degree of timing can equal 1% hp gain, up until a certain point. However, I guess this could not be verified unless you did dyno testing. If the estimate were accurate, then the A6 would probably have a peak HP about 35-50hp higher than the S6 (which is actually right around where I would guess it to be if I hadnt done any logging).

A couple questions…

On the A6, it looks like it can run a lot of timing. Where is the ‘sweet spot’ for these cars when adding more timing stops helping?

Could I have gained more power by upping the compression when I did the heads on the A6? The guy who ported the heads asked if I wanted to up the compression. Stock compression is 11:1. This calculator says you can gain about 2% power for every point of compression increase

http://www.bgsoflex.com/crchange.html

Any comments? Is any of my reasoning flawed?

#2

Nice info!

#3

what the fuck is going on with RPMs in the first log? Those numbers make absolutely no sense.

Also, I wouldn’t use the MAF as a performance measurement. Who knows what JHM does to the MAF in the tune.

Use RPMs per second if you want, or engine torque if the car can log it. Otherwise, I wouldn’t use logs to compare performance.

#4

Tiptronic. That log follows the car, floored in first, through 2nd, and then into 3rd. If you floor the car in third from low rpm, even in ‘manual’ gear mode, the car automatically shifts down to first, then second, etc. I wasnt able to figure out a way to lock the car in third gear for a proper log run, like I could on the 6speed A6. How do you guys get a 3rd gear log on the Tiptronic cars?

Good point. I don’t know why I keep going back and wanting to compare things to my old car. I guess I became so obsessed with that project at the time, that it is still in the back of my mind. I had to sell the damn car just provide some closure, otherwise I would still be working to perfect it. LOL

It was an invaluable learning experience for me, though. And I met some great people along the way. Next time around Ill be looking to force feed the car power, rather than trying to enhance it naturally :slight_smile:

#5

comparing is always fun. I think your old car would whip the shit out of the S6. Just the way JHM manages response destroys stock. It’s car lengths.

Enhancing power naturally is great. Just start from a better spot. i.e. RS4 or something. Stock 420 hp, exhaust, tune, downpipes and you’re gaining 30-40 whp whatever that translates to. Headwork? cams? none of this cumbersome shit is necessary. The car is so well put together out of the box.

Should you feel the need, force feeding the engine has proven incredibly succesful. You now have dozens and dozens of RS4s making 150-200whp more than stock…and they’re doing so without touching the motor. Literally just adding air and fuel.

#6

Yeah, good point. An RS4 would be an awesome place to start for an NA car project. If I had a choice, I would rather have a high horsepower NA car over a FI car. However, high HP NA cars are never cheap, and an RS4 is a bit above my budget.

The S6 I have is not a bad place to start for an FI kit car, I would think. It already has the nice heads/cams, along with the same forged rods as the C5 RS6 and D2 S8. With the proper kit and tuning it should be able to pull some good numbers. My only issue is that if I do the engine, then Ill also want to do the 6speed and a repaint. In the end, I’m looking at $20k. Crazy, but these things add up fast.

Yeah, you are right, my old A6 would have destroyed the S6. I happen to run into a buddy of mine on the road just yesterday. He has an 03 A6 4.2 (stock 300hp) with some JHM goodies, exhaust, 6speed, , stock heads and cams and intake, and JHM tune. He took off at one point, and I floored it to keep up. I caught up to relatively the same speed, and then we were about even. It surprised me because I thought the TIP S6 would be faster. Conclusion, JHM tuned 4.2 A6 6-speed = S6 TIP with high flow cats and 94 octane fuel. The best performance upgrade you can do for a C5 car is convert it to manual and get the JHM tune. That is 80%-90% of your performance gains right there. Plus you have the huge added bonus of ditching the ticking time bomb Tip transmission for the 01E, and it makes the car a blast to drive. I am kicking myself now for not doing the conversion when I bought the S6 with a blown transmission. It would have been the perfect time.

I just emailed the guy I sold my old A6 to, asking him how the car was doing. I was kinda hoping he would say, “crap” and want to sell it. Of course, it was the opposite. He cleaned up the interior and did some bodywork, and says the car is running like new and is doing great! LOL. No hope of buying it back cheaply anytime soon.

#7

damn that’s a brave call to make after selling someone your 10 year old German car. You could hear him say

“YOU’RE JUST THE MOTHERFUCKER I’M LOOKING FOR!”

:smiley:

S6 with a blower would be really cool. Such a niche car though that I think something custom will be necessary. To that end, it will likely end up being a single turbo project or something. Tough.

#8

Hahahahaaa. I was willing to take that chance :slight_smile: LOL. I figured worst case scenario, I could take a verbal beating and then buy the car back cheap. But really, the car was rock solid mechanically when I sold it. I replaced almost everything on the car in the year before I sold it to him. Timing belt, waterpump, rebuilt heads, intake manifold, leaky oil cooler, clutch, MAF, spark plugs, driveshaft, control arms, brakes, etc… the list goes on and on. I just didnt have the endurance to take the project to the end with the cosmetic stuff.

Anyway, Mike (the new owner) and I just made plans for him to come by on Saturday with the car. Ill try and snap some pics, and maybe video a brief comparison to the S6. Should be fun to see the car completed.

If I go FI on the S6, it will be custom for sure. Likely, a roots type supercharger. I can’t really talk about it much on the forums, but the work would be done by the guys who have already successfully done it before. And no, not PES. LOL.

#9

race him! would be funny to see. Funnier still if he has like 22" wheels that weigh 38 lbs each

#10

haha… yeah, those old peelers I had were about 38 pounds each. However, when I sold the car to him, he insisted I sell him it with the OZ Superleggeras (18x8), which come in at 17.6 pounds each. Over two pounds lighter than my Enkeis! With the LWFW, LW crank pulley, and the LW wheels, no wonder that car felt so agile and quick to rev.

Anyone who wants a free cappucino or espresso is welcome to drop by on Sat morning. I live in the West end of Toronto. Just PM me if interested.

#11

Just a heads up…sit in your s6 with it off. Slowly push down your gas peddle until it feels your at the bottom. But right before you hit the floor you will feel almost like your pressing a button. Well you are. Right before the gas pedal is maxed out to the floor theres a downshift switch.

So in order to do it correctly you need to go in tip mode, shift to third, and then floor it all the way, but not enough to hit the downshift switch. flooring it right before the switch is 100% WOT.

#12

Thanks for the tip. Ill try it out