[M5 Hayden]

Hi everyone!
I am new to diesel cars as I recently bought a UK import 2007 BMW 335d with 171000km (106k miles). The previous owner already gutted the DPF and did a stage 1 tune, it also have EGR delete, swirl flap delete, however it still has the stock exhaust so that means it still has the SCR, which I believe its the rectangle box that looks like a resonator before the rear muffler.

I am planning to delete the SCR too because I just love the turbo whistle, but I wonder if I need someone to tune it again or it does not matter. I do know that if you run DPF delete with stock tune it will limp, I'm not sure if it will limp with SCR delete.

Thanks

[335dlci]

Originally Posted by hdnjjjng

Hi everyone!
I am new to diesel cars as I recently bought a UK import 2007 BMW 335d with 171000km (106k miles). The previous owner already gutted the DPF and did a stage 1 tune, it also have EGR delete, swirl flap delete, however it still has the stock exhaust so that means it still has the SCR, which I believe its the rectangle box that looks like a resonator before the rear muffler.

I am planning to delete the SCR too because I just love the turbo whistle, but I wonder if I need someone to tune it again or it does not matter. I do know that if you run DPF delete with stock tune it will limp, I'm not sure if it will limp with SCR delete.

Thanks

Have you searched

[lnxguy]

I'd take a real close look at that SCR and make sure it hasn't been opened up, gutted and re-welded back together.

[M5 Hayden]

Originally Posted by lnxguy

I'd take a real close look at that SCR and make sure it hasn't been opened up, gutted and re-welded back together.

apparently the cat in the downpipe they left it inside too, does not sound like there is SCR delete because the turbo whistle is not that loud. Guess ill have to email the shop that did the tune...

[Tomnavigator]

Using sound to determine what is deleted is not a very good way to determine what is deleted. Many people leave the catalytic converter in place when they do deletes. There will be very little turbo whine with the factory cat in place. If the DPF was removed the SCR had to be deleted and removed also. If the SCR was left in place the SCR would plug up with soot and the vehicle would not run.
One easy way to check if the SCR was deleted is to look to see if the NOx sensors are in place and plugged in. If not then the SCR was deleted. If the NOx sensors are still plugged in, Unplug one and see if you get a code. If you get an engine code then the NOx sensor and SCR are still working. If you don't get an engine code, then the NOx sensor was not working which means the SCR was deleted.

[Tomnavigator]

Also, I did not know anyone used an SCR on diesels in 2007. I thought the first year was 2009. Where was your 335d imported from?

[M5 Hayden]

Originally Posted by Tomnavigator

Also, I did not know anyone used an SCR on diesels in 2007. I thought the first year was 2009. Where was your 335d imported from?

Thanks for your comment I will take a closer look when I can, my car is imported from UK, 2007 BMW 335d

[Tomnavigator]

I could be wrong. But, I don't think BMW used SCR earlier than 2009 anywhere.