Is this unrealted to the 02 issue… Depending on where they connected the pipes most of the OEM audi exhausts have production smoosh points.
Completely unrelated. The O2 fault has not returned in 2 weeks. Assume it was just the stars aligning (in a bad way), and not necessarily an imminent failure.
As for the smoosh point (love that term by the way), it was very unfortunate to be EXACTLY where I needed to connect the H-pipe. And I didn’t know how bad it was until after I had started cutting.
I wrestled the muffler off the car and went to a local midas shop (my usual connections all being closed on Saturday afternoon). I can tell you that the RS4 sounded like a cannon firing without the silencer or muffler. BOOM! That air pump really pushes some air!
I was taking a chance with the shop, but I needed them to round out my muffler’s inlet. They did so for free… but then the connector clamp was hard to get on, so they opened that up as well. At this time, I had a football game to go to, and didn’t think I had anymore time to screw around… so I asked the guy just to finish the job for me.
By the way - the shop mechanic was awesome. He let me in the shop while he worked, and finished up the car in about 30 minutes. He runs a LS1 website for nitrous, and showed me his vette with a 125 shot. Cost me $59, and I gave him some cash.
I love the hotrodders helping hotrodders stories.
^ X many.
It’s great when you get a guy who actually gives a shit about cars. Makes you feel good.
Quick update on the ECS H-pipe.
Problem: I’ve been having a rattling sound since installation.
Symptoms:
- high pitched rattling sound when decelerating in any gear
- lower pitched rattling/grinding sound when decelerating in 1st/2nd gear
- scraping sound when turning at very low speed (in or out of gear)
- all sounds go away when car is warmed up
Problem Solving:
- double checked all clamps. Repositioned, tightened, no leaks.
- removed aluminum cross brace - this eliminated the high pitched sound. There was contact with the cross brace and the flanged edge of the clamp.
- observed that passenger side JHM DP had very little clearance to subframe. Whacked it with my palm, and it would contact subframe. This was the source of the low pitched sound, and the scraping.
Corrective Actions:
- reindexed the clamps under the cross brace, and added a washer to space the cross brace. Full correction.
- took the RS4 back to my indy who installed the DPs. He fiddled with the DP and entire exhaust for a while, and was able to achieve more clearance to the subframe, although still tight. Driver side has a full finger of clearance, but passenger side only a few millimeters. He took off the DP and “flattened” the top area very slightly. Test drive demonstrates all exhaust/frame contact has been eliminated.
Discussion:
- the ECS H-pipe “cut and clamp” installation was a massive PITA. First, my stock CBE was incompatible with the ECS part due to smoosh points (to steal the term from justinincredible) that had to be re-rounded at a muffler shop. Second, when combined with the JHM DPs, the ECS H-pipe caused the passenger side DP to lose already tight clearance from the subframe.
- perhaps the engine itself has tired mounts that cause the DPs to lose clearance? No, my indy believed the mounts are still in good condition.
- perhaps the JHM DP was designed incorrectly or defective? No, it worked fine when combined with the stock CBE. He said the clearance is just very tight on the passenger side, and clamping to the ECS H-pipe moves it slightly in the wrong direction.
- perhaps the ECS H-pipe was designed incorrectly or defective? No, it worked fine for the original owner.
Commentary:
My take on the root cause is simply that the different aftermarket parts used up the tolerances available. In mechanical engineering, we call this a tolerance stack-up. Sometimes they work in your favor… sometimes not. There is no fault, it is just the risk you take when combining different company’s aftermarket parts.
The good news is that the car has no more rattle. The combination of the JHM DP and ECS H-pipe sounds pretty good. I agree with the comments that it doesn’t sound sexy (euro), but does sound muscular ('merica). I dig the burble, and the valves make a huge difference in sound volume.
Two problems with the ecs Have pipe. One it’s not ideal for a higher revving V8. The X design is much better at helping the exhaust pulse collection and creating a good balance between the banks. Sound wise is changes things a bit but he wise it’s meeehh not really helpful.
The second issue is the cut and clamp. The H pipe doesn’t perfectly fit and depending on how you cut it or the previous owner had it that’s when it creates issues.
Latest Blackstone results. Looks good!
http://tapatalk.imageshack.com/v2/14/09/26/76a8f6d0b14b73725533335dce9f3323.jpg
Carbon cleaning pics from a few thousand miles ago…
http://tapatalk.imageshack.com/v2/14/09/26/c9fba75d51b488f410e62b8e3f1de7de.jpg
http://tapatalk.imageshack.com/v2/14/09/26/85fffe7441ddbc4145e641aa8e724efe.jpg
http://tapatalk.imageshack.com/v2/14/09/26/b78b97bb1a612a5329b7c7624b2b1229.jpg
http://tapatalk.imageshack.com/v2/14/09/26/e3065ab23e95e5b0270067799eb62361.jpg
http://tapatalk.imageshack.com/v2/14/09/26/4bc0cc78ee8f2178c94222f7619bb75d.jpg
http://tapatalk.imageshack.com/v2/14/09/26/c73ab024b3eaa54ca77ba64c0164201e.jpg
http://tapatalk.imageshack.com/v2/14/09/26/1c2fa29bebff6a37f0c3d3cf940812a4.jpg
Carbon is one of those things that’s always making a impact on performance. Looks great how did you do it. Did you notice the car ran better.
Yes, although I did DPs at the same time, so I can’t differentiate.
Well the over all results look good and both those mods are good to improve the cars health.
What chemical did you use to break down the carbon.
Had an independent mechanic do the work. I don’t recall what they used. They had done many Porsche, Audi and BMW cc’s, as well as another RS4. Highly recommend the shop: Technical Dimensions in Jax, FL.
Looks well done! Time to get port meth to keep those valves clean
Thanks mec! I thought it looked good as well. I got the port separators back in a baggy, and those look nasty. LOL
Not planning on meth anytime soon, but would be very interested in seeing results from anyone else that does use it!
This thread delivers!
^ LOL, glad this thread could help you get over 150 posts. 
Haha…I think this was 151. I still love the wealth of info on here.
Thanks - I’ve enjoyed your JHM supercharger build thread. Looking forward to hearing more about your driving impressions when you return from overseas. 
Just checked fuelly for the first time since my driving trip up to DC…
It really screwed up my Fuelly average. I am no longer the lowest mileage RS4 listed. Lost a lot of ground with all that highway mileage.
In order, from my long distance trip…
15 AUG – 19.09
15 AUG – 18.90
15 AUG – 20.23
18 AUG – 19.20
18 AUG – 19.54
21 AUG – 17.71
Finally got back to my normal driving habits with the next fillup (all city):
30 AUG – 09.92 mpg
http://badges.fuelly.com/images/sig-us/222772.png
Lowest RS4 is some dude in South Africa who sold his car 3 years ago. His average is 0.1 mpg worse than mine.