[Yoxall]

my 335d e91 was remapped by AMD prior to me buying it ! Cars running 348bhp /502lb of torque car has now got a ITG panel filter and a full cat back exhaust.

When I spoke to AMD tthey said when they remap the 335d they gut the dpf and put it back in and remap it so it does not overspool the turbos ie back pressure differences post remap.

I've heard that this can cause turbo issues contrary to what AMD have told me.

Then you have eco tune in Scotland as a example who put a dpf delete pipe in which is a piece of exhaust pipe that fully removes the existing dpf and remapped to take this into account.

does any1 on here have any experience or expert knowledge when it comes to this. I have tried to do my own research and not found anything.


Thanks

Alex

[Vish8895]

Unless I'm missing something, the turbo shouldn't "over spool" with less back pressure thanks to the wastegate...? The reason high-flow cats exist is to reduce back pressure on turbo cars as the general consensus is that less back pressure is good on turbo cars?

Happy to be corrected however

[IceMan007]

If 2 335Ds are identical and one then has the DPF replacement pipe and the other DPF gut and reweld, would they sound the same?

Not a trick question, just curious.

[Aragorn30d]

The turbo wont overspool if its mapped properly. Some might argue that its MORE likely to overspeed with the deleted DPF/Filter as the turbo will spool up faster. Either way, if its tuned properly it doesnt matter.

IceMan: probably sound a bit different

DPF replacement pipe will give you MOT issues, whereas a gutted box shouldnt.

[IceMan007]

Originally Posted by Aragorn30d

IceMan: probably sound a bit different

DPF replacement pipe will give you MOT issues, whereas a gutted box shouldnt.

Thanks, which one would be louder without less whistle?

I thought the DPF was hidden under the undertray hence, if a replacement pipe went in, cannot be seen?

[Aragorn30d]

the undertray is open around the exhaust along the whole length of the car. Where the exhaust goes up into the engine bay theres a semi-circular cutout in the tray, thru which the DPF and Turbocharger are easily visible.

I'm not really sure which would whistle less. My brothers 320d has a decat pipe and a 330d system, and it whistles like a goodun.

[Yoxall]

There is a video of a 335d e91 lci that's been remapped by ecotune in Scotland so has the dpf delete pipe ! And has full cat back exhaust ! It's louder than mine ! I've got dpf delete /gutted dpf and cat back exhaust and does not have the loud turbo whistle which in my opinion is not a nice sound !

Both sound similar when on it tho ! Sounds fantastic with a cat back exhaust wakes the car up ! More responsive I was shocked by how much when I first drove it after it getting fitted !

The original exhaust really strangles the car !

[hakim20]

Very late to this thread and if it's still being read, my question to Yoxall you mentioned your dpf gutted 335d didn't make the annoying whistling sound, what type of exhaust work was done on your car? Every other video on YouTube showing gutted or deleted dpf makes that annoying whistling sound.

[nomiS330d]

My 330d exhaust is completely stock except for a gutted DPF (done by previous owner along with a remap). Compared to my sons completely stock 330d there is noticeably more turbo whistle on mine. I don’t really notice it until I get in his car and notice it’s not there!

[rasa bmw]

gutted dpf can have probs,ie can make a vortex effect,ive deffo read about it, and has been mentioned on facebook 335d forums wen i was a member,