Remapping and DPF

bear1

I've been thinking recently of getting a few more horsies out of the Passat.
Has 170 currently and reports suggest it can be gotten to 210 before the injectors become an issue.
So I'm closer to putting it to 190/200.
I've been reading however, that it is pointless remapping a diesel with a DPF as the DPF will restrict the power that comes out so they recommend stripping out the DPF
In some ways I suppose it makes sense, but I don't want to remove the DPF.
It works fine and I do enough KM for it not to be an issue.
Has anyone remapped a diesel with a DPF and if yes did you spot any hesitancy with the DPF?

MetzgerMeister

Thread title confusing......Adobe don't take too kindly to increasing the BHP of Acrobat Reader :P

Edited for you

bear1

MetzgerMeister wrote: »

Thread title confusing......Adobe don't take too kindly to increasing the BHP of Acrobat Reader :P

Edited for you

Weird I don't see anything edited :P I'm using a work computer maybe that's why.
thanks though

MetzgerMeister

It was the thread title rather than your post.

grogi

bear1 wrote: »

I've been thinking recently of getting a few more horsies out of the Passat.
Has 170 currently and reports suggest it can be gotten to 210 before the injectors become an issue.
So I'm closer to putting it to 190/200.
I've been reading however, that it is pointless remapping a diesel with a DPF as the DPF will restrict the power that comes out so they recommend stripping out the DPF
In some ways I suppose it makes sense, but I don't want to remove the DPF.
It works fine and I do enough KM for it not to be an issue.
Has anyone remapped a diesel with a DPF and if yes did you spot any hesitancy with the DPF?

Another Internet legend?! Don't forget to cut the silencers and oxi-cat and the as well - the car now breathzzzz!

If the power is limited by the amount of fuel the injectors can provide, than look into upgrading the injectors, not some DPF magic...

rex-x

grogi wrote: »

Another Internet legend?! Don't forget to cut the silencers and oxi-cat and the as well - the car now breathzzzz!

If the power is limited by the amount of fuel the injectors can provide, than look into upgrading the injectors, not some DPF magic...

The dpf is a huge exhaust restriction and as the engine is an air pump, if you cant get the air out, you cant get it in so limited in the power it can make!

Op you can certainly remap with the dpf in place but you wont get results as good as if it were removed.

MetzgerMeister

The question is though, when it comes to NCT and having the DPF removed how would the car fare?

bazz26

I've had two cars with DPFs remapped and there was still a noticeable different in bhp and torque.

grogi

rex-x wrote: »

The dpf is a huge exhaust restriction and as the engine is an air pump, if you cant get the air out, you cant get it in so limited in the power it can make!

Drop the exhaust competently, with the manifold... Yaaah!

Op you can certainly remap with the dpf in place but you wont get results as good as if it were removed.

You clearly never heart of wave effects in the exhaust and how existence of a certain obstacle in the exhaust pipe can help to suck the gases out. You need them out of the combustion chamber ASAP, but they might be slowed down through the exhaust without issues.

rex-x

grogi wrote: »

Drop the exhaust competently, with the manifold... Yaaah!



You clearly never heart of wave effects in the exhaust and how existence of a certain obstacle in the exhaust pipe can help to suck the gases out. You need them out of the combustion chamber ASAP, but they might be slowed down through the exhaust without issues.

First of all a dpf is always a restriction, secondly any form of fancy fluid dynamics only applies to non turbocharged engines, the turbo causes such a disruption that any and all effects are irrelevant.
All that matters post turbo is restriction. In fact an 18" length pipe of as large a diameter as possible has been proven to be the gold standard in turbocharged exhaust for power and torque purposes.

bear1

bazz26 wrote: »

I've had two cars with DPFs remapped and there was still a noticeable different in bhp and torque.

Would it have been very noticeable? If it would involve me having to remove the DPF then I won't get it done.
Bad enough driving a diesel then to have one spewing out more crap for the sake of extra power.

Special Circumstances

Compromise solution for bear1? Rather than a complete removal.

https://www.youtube.com/watch?v=_8G_q5lfcLg

grogi wrote: »

Drop the exhaust competently, with the manifold... Yaaah!



You clearly never heart of wave effects in the exhaust and how existence of a certain obstacle in the exhaust pipe can help to suck the gases out. You need them out of the combustion chamber ASAP, but they might be slowed down through the exhaust without issues.

Ah grogi grogi grogi this isn't like you at all at all. A turbo'd engine with minimal restriction after the turbo is less powerful/efficient than a turbo'd engine with a big ceramic honeycomb after it? Would 2 DPFs in series make it even better again?

grogi

rex-x wrote: »

First of all a dpf is always a restriction, secondly any form of fancy fluid dynamics only applies to non turbocharged engines, the turbo causes such a disruption that any and all effects are irrelevant.
All that matters post turbo is restriction. In fact an 18" length pipe of as large a diameter as possible has been proven to be the gold standard in turbocharged exhaust for power and torque purposes.

How much power is lost to pumping the exhaust out?

George Dalton

bear1 wrote: »

I've been reading however, that it is pointless remapping a diesel with a DPF as the DPF will restrict the power that comes out so they recommend stripping out the DPF

Obviously removing the DPF and then mapping will give you more gains than simply remapping but a remap alone will still give you a good increase.

What year is your Passat?

bear1

Special Circumstances wrote: »

Compromise solution for bear1? Rather than a complete removal.

https://www.youtube.com/watch?v=_8G_q5lfcLg

Ah grogi grogi grogi this isn't like you at all at all. A turbo'd engine with minimal restriction after the turbo is less powerful/efficient than a turbo'd engine with a big ceramic honeycomb after it? Would 2 DPFs in series make it even better again?

The link is simply boring out the DPF right? So the DPF stays in place but the inside has been gutted to be more free flow?

George Dalton wrote: »

Obviously removing the DPF and then mapping will give you more gains than simply remapping but a remap alone will still give you a good increase.

What year is your Passat?

It's a 2007, BMR engine.

bazz26

bear1 wrote: »

Would it have been very noticeable? If it would involve me having to remove the DPF then I won't get it done.
Bad enough driving a diesel then to have one spewing out more crap for the sake of extra power.

I certainly noticed a deal more low down torque. I suppose some folks might prefer to get every last bit of available bhp/torque by removing the DPF and other bits of tuning wizardry but I was content with the improvements of a standard remap and my DPF wasn't giving any problems so saw no need in removing it.

bear1

bazz26 wrote: »

I certainly noticed a deal more low down torque. I suppose some folks might prefer to get every last bit of available bhp/torque by removing the DPF and other bits of tuning wizardry but I was content with the improvements of a standard remap and my DPF wasn't giving any problems so saw no need in removing it.

Yes I'm in the same boat, DPF gives no issues so I don't see a need to get rid of it.
The thing with the Passat is that all it's torque is at the lower end of the scale so if you're cruising along in 5th you'd need to drop down a gear if you want to get some extra power.
Did you also get better mpg?

shietpilot

Remember that a remapped car will put out more soot so the DPF has to work harder to filter it. Better off removing it to begin with than facing issues later on.

grogi

shietpilot wrote: »

Remember that a remapped car will put out more soot so the DPF has to work harder to filter it.

That's a very good point... But the DPF will get much hotter as well - so easier for it to regenerate...

shietpilot wrote: »

Better off removing it to begin with than facing issues later on.

To sum up - you'll be producing more dangerous substances, let's just remove the device that neutralises them, so maybe in future you won't have issues...

Everyone expects social responsibility from others, but hardly ever from themselves...

bear1

shietpilot wrote: »

Remember that a remapped car will put out more soot so the DPF has to work harder to filter it. Better off removing it to begin with than facing issues later on.

Hadn't thought of that.
Just don't really want to remove something which is working and then end up causing more pollution.
Also, I'd also have to have the EGR deleted in the ECU so additional expense I imagine?

The Bishop Basher

If it's more horses you want, it's well worth removing the DPF when getting the remap.

I hollowed out the dpf a couple of weeks before having a remap done and the increase in power with dpf removal alone was significant..

Cheensbo

grogi wrote: »

...



To sum up - you'll be producing more dangerous substances, let's just remove the device that neutralises them, so maybe in future you won't have issues...

Everyone expects social responsibility from others, but hardly ever from themselves...

Eh, you forgetting how a dpf works? It basically stores up all the shíte and then spits it out in one go during a 're-generation'

Also, if social responsibility was the top of anyone's agenda, they wouldn't be driving a diesel.

grogi

Cheensbo wrote: »

Eh, you forgetting how a dpf works? It basically stores up all the shíte and then spits it out in one go during a 're-generation'

It is not how it works.

Don't worry - it is a common misunderstanding. During the regeneration the soot is burned and only CO2 emitted. It is, again contrary to the popular belief, almost harmless.

Also, if social responsibility was the top of anyone's agenda, they wouldn't be driving a diesel.

As if make the matter worse once was not enough.

Special Circumstances

grogi wrote: »

It is not how it works.

Don't worry - it is a common misunderstanding. During the regeneration the soot is burned and only CO2 emitted. It is, again contrary to the popular belief, almost harmless.



As if make the matter worse once was not enough.

ALL of the soot is converted to C02 (I hear it's awful stuff btw)?
There is no emission of even smaller particulates as part of the burnoff?

grogi

Special Circumstances wrote: »

ALL of the soot is converted to C02 (I hear it's awful stuff btw)?
There is no emission of even smaller particulates as part of the burnoff?

I see what you're doing here...

shietpilot

bear1 wrote: »

Also, I'd also have to have the EGR deleted in the ECU so additional expense I imagine?

That's probably one of the first things the mapper would do, actually! Modify the EGR table so the EGR stays closed permanently. Makes no sense not getting rid of the DPF as you see

The Bishop Basher

shietpilot wrote: »

That's probably one of the first things the mapper would do, actually! Modify the EGR table so the EGR stays closed permanently.

Or plugging the EGR with a Golf Tee will work just as well..

shietpilot

Swanner wrote: »

Or plugging the EGR with a Golf Tee will work just as well..

There's a right and a wrong way to do an EGR delete :P Disabling the EGR valve in the EGR table on the ECU is the right way as the ECU will maintain the correct air to fuel ratio when calculating how much fuel to inject.

bear1

So would the general opinion be to delete the egr and dpf and get it remapped or simply remap it with the dpf in place and live with more gain but more restriction?

grogi

bear1 wrote: »

So would the general opinion be to delete the egr and dpf and get it remapped or simply remap it with the dpf in place and live with more gain but more restriction?

Don't forget that when it comes to high performance, the majority is always wrong..

And I know it is a different kind of performance...