[BB_cuda]

I recently switched from conventional down pipe to a gutted DPF with the DOC in tact. I had bought an unmodded DPF from a fellow forum member and it sat for about a month after I cut it open and removed the particulate filter. I had to find a local welder to close it back up. I cut off the pressure sensor tubes too and had welder seal those over. I still have a sack full of the DPF broken pieces if someone knows what is proper thing to do with it. I've heard there are precious metals.

Anyway, last weekend I did the switchover. You think it sucks to remove the DPF. Its even more of a PITA to reinstall it. I did this on jack stands. I needed 4 hands to hold DPF in place while one of the fasteners gets connected. A combo of hydraulic jack and a 1 ft long 2x4 finally perched it in right position so that I could attach v band clamp.

My question is should I have any concern that the DOC will get sooted up and clog up since there will be no regens happening. My point is I wonder for a normally functioning DPF that sees frequent regens, does the DOC benefit from the regens in terms of it getting indirectly cleaned too. Think about it that those very hot gases go through the DOC before they get to the particulate filter that cooks the soot.

Here is why I ask. I changed over A) to see if my exhaust would quiet down and B) reduce the stink. Recall that I have a circuit werks exhaust but no mufflers on the back end.

The noise reduction was immediate. The smell seems better but I don't have a stinkometer to provide data. When I first installed and took for test drive, I saw some level of soot when I nailed it. As the days have gone by, I don't see as much soot but looking out the rear view mirror when I nail it isn't quantitative. It also seemed I wasn't hearing whistle as much. That said, when I got home last night and backed car into garage, I could hear turbo whistle better and also got a little soot when I revved it after parking.

Maybe I'm just paranoid. I only know a couple out there that are or were running this way at one time. One has run this way for more than 40,000 miles. Other ran this way while waiting for the first ecotune prototype to come across the Atlantic. This was on the order of 2-3 months I recall.

thoughts please? I've already written my tuner same question.

I'm hoping to hear all is well as I like the more quiet exhaust note.

[Mik325tds]

Good questions. I was thinking of doing something similar using a high flow DOC in the downpipe. While you should be good for those 40,000 miles you mentioned, especially if you full throttle it every now and then to push out accumulated soot, it might be worthwhile asking the tuner if he could activate a regen on request by diagnostic tools only. That way you cold run a regen whenever you feel like it.
I really like your comment about the stink-o-meter. We should ask TDIwyse if he can think of a redneck approach to this. But trusting your nose on a scale of 1 to 10 - how much better is it with the DOC in place? I'm especially annoyed by the stink while idling at a traffic light.

[TDIwyse]

Originally Posted by Mik325tds

Good questions. I was thinking of doing something similar using a high flow DOC in the downpipe. While you should be good for those 40,000 miles you mentioned, especially if you full throttle it every now and then to push out accumulated soot, it might be worthwhile asking the tuner if he could activate a regen on request by diagnostic tools only. That way you cold run a regen whenever you feel like it.
I really like your comment about the stink-o-meter. We should ask TDIwyse if he can think of a redneck approach to this. But trusting your nose on a scale of 1 to 10 - how much better is it with the DOC in place? I'm especially annoyed by the stink while idling at a traffic light.

I thought you were going to strap your girlfriend to the trunk to give us a calibrated before/after data point? :-)

"Other ran this way while waiting for the first ecotune prototype to come across the Atlantic. This was on the order of 2-3 months I recall."

That was me. And I didn't have any accumulated material on the honeycome after I pulled it and installed the downpipe (unlike the SCR ... which was plugging). And BB_Cuda, I completely agree about the pain in the backside about putting that pig back in place. I remember fighting to put it back in place (after gutting the DPF, just like you're doing now) and my thoughts and prayers are with you :-)

I also remember lower smell and less exhaust whistle. But I did not have a way to quantify the smell difference. Just noticed that it was less noticeable.

I'd encourage you to monitor your EGT's on your car during the initial warm up period. If I don't do the little "coast in neutral for ~10 seconds" trick right when the AFR sensor starts registering valid data, my car goes into a period of utilizing post injection to raise EGT's for a few minutes into the 600-700F region. I think this is part of the methodology to help initiate the DOC/DPF activity and raise coolant temps, but it may also help burn off any accumulated material in the DOC.

I'd be curious if you or others who log parameters notice this EGT/post injection behavior as well. You might have such a warm climate that your car doesn't trigger it, but for me it's a normal acitivity that I've learned to bypass, as I don't like it wasting fuel with the post injection nonsense.

[TDIwyse]

An old example of the logged post injection behavior from a cold start. The DDE doesn't seem to initiate post injection until the AFR sensor comes online, and then it shuts it off after things are up to temp for some sufficient amount of time. Putting the car in neutral for ~10 seconds right when the AFR sensor comes online will abort the warm up procedure :-)

[BB_cuda]

I thought you were going to strap your girlfriend to the trunk to give us a calibrated before/after data point? :-)

More like she would tie me to back of truck and drag me. :-/

Actually, she does like the quiet car being back. We are set for an upstate road trip next week and I wanted to make sure to not have it mess up while doing the 600 mile round trip.

I'm actually delving into getting a carly OBD going so I can look at data.

[Mik325tds]

I think TDIwyse meant my girlfriend. We concluded on that method on some other thread.
I'm going to talk to her about that again. I think she wasn't all to thrilled the first time. Maybe we can compromise on lying in the open trunk...
About the warmup post injection nonsense:
I thought Jarek got rid of that at the same time with the post injections of the regens? What parameter are you monitoring? I'd like to take a look at that.
I'm going to pay Jarek a visit soon, so that would be a good chance to talk about that.

[TDIwyse]

Originally Posted by Mik325tds

I think TDIwyse meant my girlfriend. We concluded on that method on some other thread.

:-)

http://www.e90post.com/forums/showpo...&postcount=221

Originally Posted by Mik325tds

About the warmup post injection nonsense:
I thought Jarek got rid of that at the same time with the post injections of the regens? What parameter are you monitoring? I'd like to take a look at that.
I'm going to pay Jarek a visit soon, so that would be a good chance to talk about that.

I had asked about turning off all the post injection events, but it appears to me like the warm up phase is still calling for post injection.

I was using my Bav Tech tool for monitoring the post injection back then for that plot (~2012 time frame). I haven't specifically logged those same parameters in awhile, but I can tell by what the AFR and EGT's are doing on Torque that it's still being used during warm up. Unless I do the coast in neutral thing.

[k335d]

Yozh has been running the gutted DPF on his car for a long time now.

As far as i know he hasn't had any problems with it but ill send him a text tomorrow and he can confirm.

[BB_cuda]

Originally Posted by k335d

Yozh has been running the gutted DPF on his car for a long time now.

As far as i know he hasn't had any problems with it but ill send him a text tomorrow and he can confirm.

No need for this. He and have been talking before I started this thread. Car is down on power some but not a drastic drop off. I don't think it is clogging up on me. Mileage computer continuing to show 40-42 mpg on freeway runs.

EGT reaches 240 C under decent acceleration. Not sure I'm looking at the front one. I'm still learning the parameters for Carly.

[powellrm]

I'll be really interested to see what comes from this. I decided against buying the buzzken downpipe that included a cat.

[BB_cuda]

I finally heard back from my tuner this last weekend. He sees no issue with me doing this. He reports a few other customers doing the same thing with no issues. I put my foot into it a few times on the Thanksgiving road trip and got medium soot coming out of pipes. I put an honest 600 miles on it roundtrip and mileage was normal. I'm now watching telemetry through Carly Pro on a Carly OBD2 reader. I finally made it to the 21st century guys. Cruising at 80 mph, the EGT just before cat was reading 306-310°C.

[shortair44]

BB_Cuda,

I was just wondering how your car is holding up? I was looking into getting deletes as well, but I would really like to keep the DOC to reduce the diesel smell and came across your thread. Did you ever find out if the DOC will eventually get clogged? Also, what type of tune do you have?

Thanks!!!

[atwal187]

I got a gutted dpf with the DOC intact if anybody is in the market for one

[BB_cuda]

Originally Posted by shortair44

BB_Cuda,

I was just wondering how your car is holding up? I was looking into getting deletes as well, but I would really like to keep the DOC to reduce the diesel smell and came across your thread. Did you ever find out if the DOC will eventually get clogged? Also, what type of tune do you have?

Thanks!!!

All is fine here. I don't think anyone could ever guarantee that their CAT will not get clogged up (gasoline or diesel). As written above, another forum member is at more than 41,000 miles running this way. The design of the CAT is to let soot through so I'm not going to worry anymore. I will continue to monitor the EGT temp pre CAT to gauge if everything is flowing properly.

[OR335d]

I'm planning to do this work in the next few days. How do you advise to remove the particulate filter section of the DPF without damaging the DOC section? Where does one stop and the other start? Any help appreciated. Doing alphabet delete with help from a 2.8 JR tune. Already have the swirl flaps and EGR taken care of. Going under the car tomorrow.

[pbdm4k]

I'm running a Diesel Cat with a 3" Magnaflow resonator.

I was pure straight pipe from the turbo all the way back prior. The sound and smells were very much night and day difference.

It still smells, but it's much more bearable.

There was a noticeable drop off on acceleration immediately after putting the cat on, but the car is still plenty fast.

I used to have giant white clouds out the back when I launched it, not so much anymore, but still some smoke when pressing on it.

Similar to you having the DOC intact, I'm curious if the cat is going to get plugged up one day and I'll notice a drop off.

[TorqueAddict]

Originally Posted by pbdm4k

I'm running a Diesel Cat with a 3" Magnaflow resonator.

I was pure straight pipe from the turbo all the way back prior. The sound and smells were very much night and day difference.

It still smells, but it's much more bearable.

There was a noticeable drop off on acceleration immediately after putting the cat on, but the car is still plenty fast.

I used to have giant white clouds out the back when I launched it, not so much anymore, but still some smoke when pressing on it.

Similar to you having the DOC intact, I'm curious if the cat is going to get plugged up one day and I'll notice a drop off.

I am running a catted DP too. Its been over an year and no issues so far with it plugging up with soot. i believe it was a 300 Cell cat.

[BB_cuda]

Okay. Look where the 2nd EGT hole is. You can stick a thin wire in that hole and it is in the in between spot of DOC and DPF. I had the exact same question and a couple guys here helped me. The dead give away hint is to look at the case and notice where it changes color. That is where the DPF starts. I have a couple welded up pictures but they are on the phone and I'm not home right now. I will post later tonight.

[OR335d]

Originally Posted by BB_cuda

Okay. Look where the 2nd EGT hole is. You can stick a thin wire in that hole and it is in the in between spot of DOC and DPF. I had the exact same question and a couple guys here helped me. The dead give away hint is to look at the case and notice where it changes color. That is where the DPF starts. I have a couple welded up pictures but they are on the phone and I'm not home right now. I will post later tonight.

Thanks! Your timing couldn't be more perfect. Going back under the car in a few minutes to finish taking it out, and then to the welding shop with the SCR and DPF. My tune should be here, FedEx at 10:30. It's beginning to look a lot like Christmas!

[BB_cuda]

I used a 4" angle grinder with thin cutting wheel to cut the DPF window. I used a small hatchet to cut out segments of the filter. I hit back of hatchet with hammer and pulled out a chunk at a time. It was very simple. No clue about the SCR.

One more thing, are you cutting off the pressure sensor tubes? Thoses can spell trouble if one of the black hoses comes off and cooks things close to those tubes. I cut them off and had little welds shut off the cut ends. You can see one of them in the picture. That's my ecotune pipe as a comparison. Its tubes were "gelded" as well.

[atwal187]

As for the SCR , same process just like cuda did for his DPF, I got the welders to cut the SCR off , took it home angle grinded it. Took out all the internals ( just about the same filters in the dpf ) , brought it back to the welder he welded it back on

[OR335d]

Originally Posted by atwal187

As for the SCR , same process just like cuda did for his DPF, I got the welders to cut the SCR off , took it home angle grinded it. Took out all the internals ( just about the same filters in the dpf ) , brought it back to the welder he welded it back on

Got it all out, and off to the welders. Cut all the way around the very top of the DPF. The 2" of DOC stayed with the top section. I then used a 1" drill bit to drill a bunch of holes through the DPF section then chucked it out with a hammer and screw driver. Went very quick and clean. Will be having the two pipe ports welded shut.

Took out the whole exhaust system to get to the top of the SCR. Needed to do this to get rid of the DEF tanks any way. Cut the common hole in the top without removing from the system. I'll post pictures once the welders are done with their magic. Hope to have it back together and running before the end of the week, but with no dry asphalt in the forecast, it might be a ridiculous experience.