DMH electric exhaust cut-outs/dump valves

[Spidercat]

O.K>
Finally got around to uploading some videos of my exhaust. I was always jealous of Fonzie's exhaust, and his custom guy wasn't up for making a second, so I did a work around. RS6Dawg gave me this idea a couple years ago (he had this done by 034 I believe, but no sound clips). Sorry in advance about some of the shaky vids. Also, traffic around here is a bitch, so most of these were a little self-indulgence on my part after getting called into work in the middle of the night...

I couldn't add the url as an attachment or upload them directly, so went through the neccessary evil of youtube and posted the links below. Mainly wanted to see if it worked, so more to follow- some of the longer ones had problems uploading due to using a civil-war era browser.

BTW, for those that don't know, I have DMH low-profile electric exhaust cutouts (aka dump valves) where my cats used to be. Had them for about a year-- no problems with the motors, leaks, or connections (other than one short early-on that was cured w/ a zip tie to keep a loose wire off the hot exhaust). I couldn't be happier--super quiet (comparatively) stock exhaust when closed, and full-bore earth-shaking hardcore when open at full howl. All at the flick of a switch:

11791

Left is cut-out rocker switch, right is laser jammer switch.


(It seems kinda muffled in the videos. Seems like I can hear all 40 valves and the turbos spool about a mile away! :revs: Well, to me anyway...)

Enjoy!

http://www.youtube.com/watch?v=PnY91N_AHwk

http://www.youtube.com/watch?v=d-8JtcWjh3s (http://www.youtube.com/watch?v=d-8JtcWjh3s)

http://www.youtube.com/watch?v=W3qop8lkeZw

http://www.youtube.com/watch?v=Lz9kAz7KfJU (http://www.youtube.com/watch?v=Lz9kAz7KfJU)

Also, as was discussed previously, opened up exhaust from a dig- it's a dog off the line initially, but up top, it's a total beast!
I'll post more vids if I can, if anyone's interested.

[Spidercat]

Here are some others:

http://www.youtube.com/watch?v=tEZ0kd9sxgw

http://www.youtube.com/watch?v=0qvpmIy9fXo

http://www.youtube.com/watch?v=y-d1jS_rhq4

http://www.youtube.com/watch?v=uU2mDAXajiA

http://www.youtube.com/watch?v=a177rqIcvhM

[speedtrapped]

I heart this mod! Awesome...

[Spidercat]

Thanks!

Last 4, if you don't mind...

http://www.youtube.com/watch?v=E6xMh44ciVs (See what I have to deal with out here! Middle of the night speed trap! You can here the laser jammer kick in at the end to save the day- He's way on the other side of the bridge)

http://www.youtube.com/watch?v=pWIC7RZNX_s How fortuitous, but neither the 5 series or M3 wanted to play : (

http://www.youtube.com/watch?v=RCGdabAJdA0 (starts out closed, then opened, then closed at the end, just to hear the diff in exhaust)

http://www.youtube.com/watch?v=-J2hgt3_mTk (Tunnels....I love tunnels...)

friggin youtube vids are slowing my computer down big time.

[Spidercat]

Or you can just skip all those and watch this one instead---I edited them together and stabilized them so you don't get a seizure or find yourself saying "Thanks for the 9 sec video, ya douchebag!"

http://www.youtube.com/watch?v=IOfpS-eEkv8

[JSRS6]

See, that's what I want. You have any under-carriage pics?

[Spidercat]

I'll get some. Not a problem. I'll do it tomorrow (I guess your today!)

[JSRS6]

Haha. Mahalo!

[aussie rs6]

I'll get some. Not a problem. I'll do it tomorrow (I guess your today!)

Hi Spidercat,

I am even further ahead of you guys in the good ole USA- right now it is saturday evening 11pm. I am planning to do the same exhaust mod - catless dps with diverter as you have, so look forward to your underside photos and any installation tips and pitfalls.

regards,
johnk

[kismetcapitan]

the car is sluggish off the line with the DVs open? I'm sure that can be mapped out; when people lose power due to reducing backpressure, it's not that you *need* backpressure, it's that the ECU map is set up for exhaust backpressure.

[aussie rs6]

thanks kismetcapitan for the advice. much appreciated. APR have advised that they will change the ECU map for the reduced back pressure when I get the catless dps or dps with 100 cell cats done. Not as good as an individual map tune for the beast, but the best i can do here.

regards,
johnk

[kismetcapitan]

looking forward to pics - I assume the exhaust exit points won't melt anything?

[Beastly]

oh man, the WOT in the tunnel is awesome - un real. Love this mod. ++ for some pix

[aussie rs6]

looking forward to pics - I assume the exhaust exit points won't melt anything?

wouldnt want to warm the fuel before it gets to the injectors. that would get exciting!!!

some light relief for the married men on the forum:


At a wedding party recently someone yelled, "All the married men please stand
next to the one person who has made your life worth living."

The bartender was crushed to death.

[Spidercat]

the car is sluggish off the line with the DVs open? I'm sure that can be mapped out; when people lose power due to reducing backpressure, it's not that you *need* backpressure, it's that the ECU map is set up for exhaust backpressure.

You are right on the mark there. Very succinct way of putting it!
I chose to keep my Revo tune and deal with this minor inconvenience, esp since they are closed most of the time, and so that's where I want the "tune" to be (don't want to be fiddling about with electronic gizmoes and gadgets at a stop light just to find the right program).

I just keep them open for fun, closed for business (so easy to just open them up once seriously underway anyway). You could certainly maximize the tune for when wide open, but that wasn't the route I wanted to take.

Pix will follow tonight--turning out to be a busy day for me today.

I'll also post some little tips and whatnot, aussieRS6. I actually put a lot of thought into this before doing it, and happy to pass it along...

Thx for the compliments, btw, guys! Glad you like. I'll have to get a better mic or something, because my digi camera (wife's old one) just doesn't capture the sound. I was rather disappointed in how the vids came out (hence why I never posted them before). Videography just isn't my forte, and I'm comfortable with that.

[Fonzie Audi]

sounds good bro!

[Spidercat]

Thanks, man! Good to hear that from you!
I need to get my own trunk monkey for the in-car vids! Your trunk-cam was classic! No way to top that one. That was shear dedication. :bow:



Here are a couple pix from under the passenger side. They are a little fuzzy since I was just reaching under the car. Didn't get a chance to pull it up on the ramps today. I'll try tomorrow. Maybe a vid with them opening and closing. They open/close really quickly. Maybe a second or two? You can also control how opened they are incrementally, although why would you want your car to sound like it had an exhaust leak?

Also, they are designed so that if the motor goes bad, you can just unplug, unbolt, remove and replace. Two separate cover plates are included to close the holes. They were about $450 (DMH low-profile) for both shipped, but that included some custom gaskets. I'll have to dig up where I got them.

It was about $600 I think for all the labor and extra SS pipe (to replace the cats). That was the closest place after the turbos that they would fit. Anyway, we had agreed upon a price at the outset, but the guy spent way more time on it than he thought he'd actually need. Afterward he said if he was going to do another he'd charge almost double. Extra bungs for the secondary O2 sensors were included in the price also.

Later, I also bought the O2 sensor spacers (from 42 draft design) to add to the secondary O2 sensors to reduce the secondary O2 sensor CEL from 1/month to q 6 months. I just clear them out when they come up, but I just hate seeing that stupid light come on indicating that my bank account may soon be leaking...
I posted these on another thread, but here they are:
http://store.42draftdesigns.com/O2-Sensor-Spacer_p_306.html

Initially, there were one or two small but audible leaks at the welds on the top side of the exhaust, which were quickly fixed, and the one short-out about a week later which was fixed. Since then, no probs.

I, too, was a little worried about the lines running lateral to the exhaust, so I eventually put hi-temp reflective covers on them as they pass by the exhaust cut outs, but I never had any problems.

One more thing: don't close them all the way with the engine off- they will seize closed, and they are a bitch to manually open without removing! The motor will back the butterfly valve off ever-so-slightly while the engine is running once you close them after you take your finger off the rocker switch. Otherwise, it's possible to close them too tightly. Ask me how I know.

Lastly, if your looking for these to be totally unnoticeable at idle when closed, then beware. I'd hate to mislead someone about this. There is a very slight chatter at idle (I'll capture this when I post the other video of the underside) when running in park with them closed. Once it's in gear with the brake on, however, it goes away. It probably has to do with the resonance at such low rpm, and not having enough pressure in the exhaust system at those low rpms to force the valve completely closed. If you're an idiot (like me apparently) then turn the ignition on (but don't start the engine) and close the valves completely. They won't chatter, but you will not have fun trying to get them open!
That said, it doesn't bother me in the least. Not in the least. I've been called a perfectionist (among other things), but never a prima donna, however.

I'll try to get it on the ramps tomorrow.

[speedtrapped]

Great write up, looks great

[kismetcapitan]

just had a thought - if the car is still giving you a CEL with the O2 spacers, perhaps adding a restrictor in the spacer to further reduce exhaust gas flow speed might help?

[Brav]

awesome.. i think i will do this mod down the line! Ive always wanted a way more loud exhaust, but being able to quiet it down for neighbors etc is perfect.

[JSRS6]

Exactly!

[Spidercat]

I may look into the restrictor idea if it gets to be more of a problem. Great suggestion.
Seems that right now I've got bigger fish to fry...
Long story short, I went to pull up onto the ramps today. It would idle fine, but then ran horribly rough as soon as I put it into gear. RPMs dropped and stuttered at like 500-650, no response to throttle input. Would start up fine, idle well, but if I give it any throttle at all it goes into the above spiral. WTF?! Right out of the blue.
I obviously can't drive it. Luckily I could nurse it back into to garage. I have to have it towed to the dealer tomorrow, I guess.

Also, no CEL, no codes on a quick scan. I did smell a lot of raw fuel, but no puddles on the ground.
I have the fuel filter changed regularly, same gas, ACEsIV, and has been running fine up to this point.

Except: had my suction jet pump replaced last month by the dealer (requires service position and removal of quite a few parts to get to it)-- separate story but I admit I was a little concerned when I found that little things like the foglight wasn't plugged in properly (I almost bought a new bulb, but didn't need to) and the venair intercooler hoses kept popping off despite using T-bolt clamps- I finally just did it myself (turns out I just had to wipe the grease off- wtf!). Their solution was that it shouldn't be tuned with so much boost- so it was my fault, despite the fact that I've had the same hoses and tune for several years without a problem! What I'm saying is that my confidence level isn't the highest right now in how everything was connected. That may have nothing at all to do with it, however. Guess I'll find out. I'm really pissed at myself for not getting the platinum warranty instead of gold plus, since a herd of little parts aren't covered (including the suction jet pump- so that was a few thousand $ out of pocket.

Any bets? Hoping it's something simple like a coil pack. They happen to be all original and I have about 71K miles right now.

[JSRS6]

Check your venairs, and your airbox seal to inlets.

[Elevens]

+1 on what JSRS6 said. Definitely looks like the Air filter housing is not seated correctly and would result in the above symptoms. Remove and Re seat. Hope its as simple as that. Good luck......................

[kismetcapitan]

those are the symptoms I see when I pop an intercooler pipe on my Skyline. Reseat pipe, reclamp with screwdriver, five minutes (if it's accessible). Could be anything between the MAFs and intake plenum, but air that's getting measured at the MAFs isn't getting to the engine someway somehow (hence the rich running/smell of fuel).

[Spidercat]

And Bingo was his name-O!!! Thanks guys! Airbox not seated correctly it is!

Or, rather, airbox cover screw missing at the back side of the plenum assembly. Really, dude? Come on!

So I removed the cover, cleaned the seal (just in case), replaced the remaining screws, found a similar screw w/same diameter/pitch, Dremeled to proper length, and replaced (as well as several apparently forgotten washers), and double-checked the remaining hoses that I could see topside. Fired it up, blipped the throttle several times... just like a kitten...

It was getting late, so I'll pull up on the ramps tomorrow, check the other hoses from the bottom, and get those vids!

Again, thanks for the quick and accurate dx! :thumb:

Incidentally, got in a little hot water w/ the wife for taking time posting when we should have been leaving for dinner. After we got back, she was like, "Oh, somebody actually replied that fast? Sorry for getting mad. You were right."
Man that's a nice phrase!

[JSRS6]

Glad to help. :thumb:

[aussie rs6]

"Except: had my suction jet pump replaced last month by the dealer (requires service position and removal of quite a few parts to get to it)-- separate story but I admit I was a little concerned when I found that little things like the foglight wasn't plugged in properly (I almost bought a new bulb, but didn't need to) and the venair intercooler hoses kept popping off despite using T-bolt clamps- I finally just did it myself (turns out I just had to wipe the grease off- wtf!). Their solution was that it shouldn't be tuned with so much boost- so it was my fault, despite the fact that I've had the same hoses and tune for several years without a problem! What I'm saying is that my confidence level isn't the highest right now in how everything was connected. That may have nothing at all to do with it, however. Guess I'll find out. I'm really pissed at myself for not getting the platinum warranty instead of gold plus, since a herd of little parts aren't covered (including the suction jet pump- so that was a few thousand $ out of pocket.

Any bets? Hoping it's something simple like a coil pack. They happen to be all original and I have about 71K miles right now."

I had similar engine performance problem- Incorrectly seated airbox seal/MAFS is, i would wager, particularly after disturbance by inexperienced RS6 'mechanics', the most common cause of subsequent engine performance ailments!!

Forgive my ingnorance, but I am not familar with the term "suction jet pump", but should be if costs $$$'s to replace.

johnk

ps. Good to see you took your wife to dinner.

Sensitive new age guy that I am, I did this:

My wife and I walked past a swanky new restaurant last night.

"Did you smell that food, it smelt incredible?" she said.

Being the nice guy I am, I thought "Stuff it, I'll treat her!"


So we walked past it again!

:lovl::lovl::lovl:

[Brav]

Glad you got it sorted! I just found a missing screw on the top of my airbox cover (hex head)... would this cause me some problems? Seems to run smooth, but sometimes down on power. I do get an O2 code every few thousand miles however.

So your airbox was seated on the intake (round hole) ok? just a missing screw on top?

[Spidercat]

Yeah, it appeared to be seated correctly, just a missing screw. It was at the back, so only 2 back there on each half, as well as ends- 3 run across the front for each half. Thing is, last time the engine was pulled for tq I noticed the same thing, and replaced it! Same mechanic (only 1 does the RS6s at the dealer), too. Jeez!
I would replace the screw, if I were you. Or at least rob one from the front to put around back for now.
Suction jet pump is actually a pretty cheap plastic part (not really a pump, per say just google if interested) just really hard to get to on these cars. Dealer charged 11 hrs. Plus my time (and I guess all you time, too) to do the mop-up afterward. Whatever happened to pride in one's work?

[Spidercat]

Couple more vids, this time from below:

http://www.youtube.com/watch?v=n6HYQrR22yo

http://www.youtube.com/watch?v=qVg_l7rLDO0

[kismetcapitan]

if I were to have one gripe about owning an RS6, it's the engine bay. Not only is it a rat's nest under those bling carbon fiber airboxes, it's packed in so tight, the labor to get at anything is far too extensive for casual mechanics. Understandably, the packaging is part of the engineering of the car itself. Just am nostalgic about working on my own engine with nothing more than a set of wrenches, and where pulling two turbos could be done with a box wrench and an beer-fueled afternoon...

[speedtrapped]

i can wrench the cts-v easier then the beast....swapping connectors on the firewall required 40 minutes of my labor, and those connectors were on the firewall. has anyone tried to replace the relativly accessable water temp sensor...hahaha
Spidercat, as soon as I find my gremlin, I am doing this mod, as I love a car that sounds just as intimidating as its speed

[Spidercat]

Spidercat, as soon as I find my gremlin, I am doing this mod, as I love a car that sounds just as intimidating as its speed

Yeah, it ain't subtle with them open!

Speaking of gremlins and wrenching on your own cars...
After I made that last vid, I went to work, ran some errands, drove home, and as I'm approaching my house, the sputtering started again!!!
At least it did it in my drive way both times- could have been a much bigger head ache, so I appreciate the ole girl's timing. So, I backed in, got out the ramps, but I didn't even have the power to get up on the ramps! Crap! Reseated the airbox cover (hey, it worked once), and at least had enough umpph to get it in the air. Lowe and behold, passenger lower Venair slipped off intercooler completely! Ahh, too easy- took it off entirely, cleaned off all the grease from everything in the area, a little hairspray on the lip to give some tackiness, reclamped, done and done!
FWIW, that clamp is a pain to seat properly cause it tends to watermelon-seed out from under the clamp as you tighten- I had to fasten that side first while pushing it onto the intercooler until the clamp started to really "bite," then tightened the other end.
Anyway, when I started it, it was still sputtering! It was raining pretty hard at that point and I was soaked, so before I did something I would regret later, I just said F-it, buttoned it up, and decided to have it towed first thing in the morning to the dealer.
Guess what? Worked fine in the morning. I nursed it to the dealer anyway so as not to push my luck (and I had to order some parts and vacuum hoses that I noticed were pretty worn), and it was doing it again when I arrived. They took it in right away, and I spoke with the tech directly about what was going on. Also, the CEL came on and it threw a few codes while we we looking at it. We shall see...
I was so hoping that it was just the airbox cover and the loose hose.

If keep thread-jacking myself, I'm gonna go blind!

[speedtrapped]

ALAS...POOR URICH i KNEW HIM WELL....I have know clue why i am quoting shakespeare....can this car be a PIA, yes, does it have its issues, 8 years old, massaged power...sh#t happens....u will get it figured out....I cant wait to do this mod!

[Spidercat]

Nice one! Not quite at the graveyard stage, though, I hope!
It could always be worse. There was another RS6 at the shop with engine oil in the coolant---Ouch!!!

BTW--
- Make sure you get the graphite gaskets (or similar hi-quality gasket material--they may have changed it, but the gaskets that come w/the kit leave a little to be desired) P.S. You could also have some made--it's just two small rectangles w/oval hole.
- The wiring harness was about a foot too short for me. Not a big deal-- 4 spliced wires. I didn't want any holes in the floor, etc. They run up along side the trans/engine, and through existing hole in the fire wall.

[Spidercat]

I have the fuel filter changed regularly, same gas, ACEsIV, and has been running fine up to this point.

My car is apparently quite a hot mess!
After a day of diagnosis, guess what they came up with- the fuel filter was almost completely clogged. Yay!

Hey, wait a minute, why is my fuel filter clogged? I just changed it a year or 2 ago (certainly less than 35k miles that I believe Audi recommends), my gas tank was replaced a couple years ago when the roll-over valve was leaking, and I almost never run on fumes...

I asked them to give me the old fuel filter- I want to crack it open and see what's clogging it. I guess I'll see what I'll see. I can't remember ever seeing any particulate matter in the ACES IV, either.

What are the odds that I had 3 different things wrong with my car at the same time? I hit almost all the major internal combustion engine food groups-- Air, fuel, just missing spark.

I 'm hoping that that actually solves the problem once and for all. I get the car back tomorrow morning.

[Spidercat]

No dice. Fuel pump's bad. So four things now and counting.
Upside is now it's on warranty co. dime. :dig:
Downside is the part is not in stock.

[Spidercat]

Good news- Fuel pump arrived today (paid extra to have it overnighted).
Bad news- The wrong one arrived.

At least I get an Audi loner now and don't have to deal with the rental anymore.
This is really turning into a long, drawn-out headache...

[Spidercat]

Well, I got my baby back today! Running great. I had them install my KW-V3s while it was there and I had a loaner anyway. It was worth a little extra for me to have it done at the dealer, given the circumstances. I love the look!
Rubs and scrapes a tiny bit, so I may raise it a little.

[4everRS]

Great news!

[Spidercat]

It's been quite a while, but I finally removed the pre-cats a few months ago while the engine was out for the infamous oil-cooler pipe leak (replaced with Bufkin billet aluminum piece, btw). Took about an hour and 15 mins for each pre-cat with a power drill, wood-boring bits, extension, hammer, and a piece of angled aluminum to pound out the residual (and PPE of course- that platinum dust is nasty). I got the Revo Stage 2 remap, also.

I made some more in-car videos to compare. The roar still overpowers the mic, so maybe hard to tell any difference. In person it sounds even better than before. Unquestionably louder turbo spool.
I'll do a couple drive-bys at WOT when I find the tripod and call it a day w/the vids.
I got called back into work a couple times and decided to make the most of it by finally taking some vids. I edited them all into one longer video:

http://www.youtube.com/watch?v=gQiB3PygxZQ

[ben916]

It's been quite a while, but I finally removed the pre-cats a few months ago while the engine was out for the infamous oil-cooler pipe leak (replaced with Bufkin billet aluminum piece, btw). Took about an hour and 15 mins for each pre-cat with a power drill, wood-boring bits, extension, hammer, and a piece of angled aluminum to pound out the residual (and PPE of course- that platinum dust is nasty). I got the Revo Stage 2 remap, also.

I made some more in-car videos to compare. The roar still overpowers the mic, so maybe hard to tell any difference. In person it sounds even better than before. Unquestionably louder turbo spool.
I'll do a couple drive-bys at WOT when I find the tripod and call it a day w/the vids.
I got called back into work a couple times and decided to make the most of it by finally taking some vids. I edited them all into one longer video:

http://www.youtube.com/watch?v=gQiB3PygxZQ

AWESOME!!!!

How far up did you put the cut outs? Meaning where in relation to the body? Before the Mufflers? or closer up towards the cats that used to be there?

[Spidercat]

Thanks, Ben!
Correct. They are exactly where the primary cats used to be, so about 2 feet or so downstream from the flange on the downpipes.
There's a perfectly-sized bit of real estate where the primary cats were.

[kismetcapitan]

damn. that sounds incredible and a must-do. I love putting the RS6 into cruiser/camper mode with the wife and having the silence - we have our best talks and bonding time on long road trips (seeing as we have no choice but to talk with each other lol :P), but that's just perfect, to have a sound to match the Beast's power at the flip of a switch!

Decatting is also high on the priority list - really, the only thing left to do is to work on the exhaust and I'm done tuning my car. But discretionary funds...having bought two bikes this summer and pouring money into them, then discovering the Better Half is pregnant, has put a chokehold on toy spending for the time being. But I built my Skyline while starting off kid #1 so it's a doable balancing act.