[Raahil]

Hi Guys

Have a 435d and want to do the 440i dual exhaust conversion.

Been doing some searching and although i can see many who have carried out the mods i cant seem to find much info regarding the sound aspect.

Now, i know its a diesel so im not expecting sound to be any better etc.

What i am interested to know is the following:

-With backbox deleted is there any droning sound inside the cabin at typical cruising speeds?
- With backbox deleted, would there be any problems with dpf regens etc?

Although a different car, i had someone who done a backbox delete but then fell into issues with their dpf not regenerating as the exhaust temp was not getting high enough

Any insight welcome

[Lorcan]

You won't get any drone, but I have known home-brewed solutions to introduce some annoying whistling.

Regarding DPF, it seems unlikely that deleting the back box would cause this. Alpina did it with the D4

[Stainy]

I've no idea about the 440, but a back box delete with custom pipe is perfect. Marginally louder - you can hear it's a 6 cylinder, but not massively different. No drone whatsoever. Sounds much better higher in the rev range (a sort of roar from the rush of air). No issues with regen. Highly recommended apart from the better asthetics

[StuieUK45]

Although a 335d,
https://f30.bimmerpost.com/forums/sh...postcount=3577
custom pipe with backbox delete, no MOT issues, no dpf issues, and sounds just as good as before..
Only thing i could think of is, when inside the car windows closed, and u gun it, it sounds meaty, but then, it probably sounded meaty before that!

Outside, just sounds good is all i can say

[Raahil]

Thanks for the insight guys. Much appreciated.
Need to get the rear diffuser and will soon be visiting the garage to get the duplex installed.

Was mainly after the aesthetics as i think the dual exhaust just looks
But didn't want to face any complications.

Will hopefully come back with an update once done

[APJ]

I did a complete exhaust swap a couple of years ago, managed to pick up a 340 exhaust off ebay for a very reasonable price. Sound wise, i would say it was slightly quieter than the 435d exhaust.
The only other difference that i found, was there was slightly less back pressure when gearing down, probably because the 340/440 is bigger and literally just slid over my old exhaust system. Though you might not get any of that if you are just doing a back box swap.
Cosmetically the wheelbarrow style does look so much better than the twin style and well worth the time and trouble of doing it.
Good luck and enjoy the finished product.

[Raahil]

Hey guys.
Just to update have had this done in the past week.

Have to say I'm loving to look as well as the sound!!

Thanks to All

[Beemer On The Roof]

Originally Posted by Raahil

Hey guys.
Just to update have had this done in the past week.

Have to say I'm loving to look as well as the sound!!

Thanks to All

Looks great! I know this is an old post but you dont happen to have any more pics of your spoiler do you? Im In the process of looking for one now and that looks pretty sweet from that angle.

[Rogueroyal]

Originally Posted by Raahil

Hey guys.
Just to update have had this done in the past week.

Have to say I'm loving to look as well as the sound!!

Thanks to All

Hoping you still monitor this thread.

Where did you get the splitter and the exhaust from.
Looking to do the exact same mod once ive founds a suitable garage to do the work.

[Raahil]

Originally Posted by Beemer On The Roof

Looks great! I know this is an old post but you dont happen to have any more pics of your spoiler do you? Im In the process of looking for one now and that looks pretty sweet from that angle.

Sorry buddy was inactive on the forums a while.
Have a few a pics. Have attached for your reference
Hope that helps

[Raahil]

Originally Posted by Rogueroyal

Hoping you still monitor this thread.

Where did you get the splitter and the exhaust from.
Looking to do the exact same mod once ive founds a suitable garage to do the work.

The splitter was from ebay. Widely available.
If you search f32,f36 dual exit diffuser you should find one that fit the bill for you. Will see if i can find the actual link for the one i ordered but was over a year ago so not sure it will exist.
The exhaust i had done from ‘Torqueflow exhausts’ in birmingham. Top quality guy with top quality work.
Although the tips were my own, most fabricators will give you plenty options to choose from

[Rogueroyal]

Thanks bud.
Apriciated will have a look at torqueflow