DPF - hollow out instead of purchasing down pipe?

Hi all


I searched but couldn't find much for answers.


Has anyone removed their factory downpipe, gutted out the DPF and cat, then put it back on? With a custom tune of course.


I'm hoping to not spend $700 on a down pipe. I don't really care what it looks like, my car has 301K on it and is starting to have emissions issues.


I have access to all the tools to cut it open and weld it back up. Thoughts?


Car is a 2012 Sportwagen TDI DSG.

Talk with your tuner or the tuners you're considered going with. But it should be no problem.

As for the actual fabrication, I'd give it a shot if I was in your shoes. For me, it'd be a chance to sharpen my skills so I can be less of a grinder and paint makes me the welder I ain't kind of guy.

You’re not gonna find people documenting it, because of EPA fears. Here in Las Vegas, you still have to pass a visual inspection. Most truck guys swap their exhaust back to stock for smog, and then put the aftermarket exhaust back on. Not feasible for us with the amount of work it takes to swap dpf’s. All I’m gonna say is some hollowed out a dpf’s have a terrible drone. Think about fabbing a down pipe with a dpf shell.

The DPF on that car is a complex affair.



It would not be easy to cut it open, hollow it out, and weld it back up, and get all the mounting tabs squarely back in place where they need to be. But I am sure it *could* be done. Just that it is not a simple cylindrical "can" like a lot of other ones are.

This is probably the best deal I’ve seen for a downpipe - tune combo.
https://www.tunemyeuro.com/2009-2014-vw-2-0l-tdi-economy-package/
Something to think about.

The resonating drone that huge empty can would make would be terrible. Spend the extra dough and do it right (assuming you aren't in a place where the check for those types of things)

JesseTDI said:

The resonating drone that huge empty can would make would be terrible. Spend the extra dough and do it right (assuming you aren't in a place where the check for those types of things)

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Or run the pipe in the (fiberglass filled) shell

JELLOWSUBMARINE said:

Or run the pipe in the (fiberglass filled) shell

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I can not confirm, nor deny the fact that I’ve seen this done. All I’m saying is it’s a perfect shell for a homemade turbo muffler...

durbo said:

I can not confirm, nor deny the fact that I’ve seen this done. All I’m saying is it’s a perfect shell for a homemade turbo muffler...

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Not really. Did you see the photo oilhammer posted? That thing is an octopus. I'd get a downpipe or a different car that doesn't require mission impossible mods to be pleasant to own.

turbobrick240 said:

Not really. Did you see the photo oilhammer posted? That thing is an octopus. I'd get a downpipe or a different car that doesn't require mission impossible mods to be pleasant to own.

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I’ve seen em, and I’ve had my hands on them. Once you get the sensors and wires out of the way, it’s a lot less intimidating. Don’t cut it completely in half. Cut a window in it, do your business, and weld the window back in. It takes way more time to remove it from the car, than it does to cut it apart and make it race ready. Don’t forget that there’s a catalyst on top of the actual dpf inside. This is how you build a cheap exhaust for a non road compliant track car (Disclaimer). This shouldn’t be done on any vehicle registered to drive on the roads, because it violates federal law. Proceed at your own risk....

Ha. I think we all know how well suited these cars are for off road and/or track use. I think it's rather undignified to pretend folks don't intend to operate them on the road.

turbobrick240 said:

Ha. I think we all know how well suited these cars are for off road and/or track use. I think it's rather undignified to pretend folks don't intend to operate them on the road.

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I agree with you, but just because we know how well these cars work without all the spaghetti emissions, doesn’t mean other entities agree with us. I guarantee at least one agency (maybe even 2or 3) already started monitoring this thread as soon as the O.P. posted the original title (even though he’s in Canada). I’m not a conspiracy theorist, but I’ve done enough contract work for companies tied to the federal government to know that people get paid to collect data like this. Big brother may not be watching directly, but make no mistake, someone is in charge of a group of people to make graphs and pie charts about this subject for government agencies to have access to. This is how they’re able to make stricter laws, and go after particular companies facilitating illegal activity (removing federally mandated emissions).

JesseTDI said:

The resonating drone that huge empty can would make would be terrible. Spend the extra dough and do it right (assuming you aren't in a place where the check for those types of things)

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Hi

Just courious but empty cans make drone ?

I thought resonators ( basically empty cans) are designed to eliminate or reduce drone ( but then again maybe have to be a certain size to do that?).

Thanks

Andyinchville1 said:

Hi
Just courious but empty cans make drone ?
I thought resonators ( basically empty cans) are designed to eliminate or reduce drone ( but then again maybe have to be a certain size to do that?).
Thanks

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they are a specific size and shape to reduce harmonic resonance. certain ones work better for an application while others wouldnt.

if you can cut open the DPF and seal it back up why not just harvest the fittings and slap them on your own home made pipe? sure it'll take a little longer but gotta be still cheaper than an aftermarket pipe.

Others have gutted second cat from TSI downpipes while keeping the first cat and had good success.

Andyinchville1 said:

Hi
Just courious but empty cans make drone ?
I thought resonators ( basically empty cans) are designed to eliminate or reduce drone ( but then again maybe have to be a certain size to do that?).
Thanks

Click to expand...

Resonators usually have a perforated tube run through packed fiberglass to dull or augment the sound. A hollow chamber will almost certainly serve to amplify drone.

You could always get a j-tube (aka Helmholtz resonator) from a company like Synapse Engineering to cancel the drone from using a hollowed out DP.


http://synapseengineering.com/synapseusa/products/nodrone.html

Ive had 2 "aftermarket" dpf's, first was a very nice affair from a gentleman in Burlington, VT (performance diesel, no longer there) had all the sensors in place and retained the egr, cost a fair bit of lunch money installed and tuned, $2500.. second car got a buzken exhaust in my driveway, far cheaper, and new tune only required one or two sensors IIRC. think I was into that whole exhaust and tune for the retail on a dpf alone.. You can also retain the stock cat back if you want to save a few hundred dollars and make installation even quicker.. I highly recommend getting the flashzilla, the option to tune at will via obd2 port is really worth the extra $200, especially if you need to put the emissions stuff back on to drive on the street..