435d exhaust conversion to 440i twin exit

Manivxr · 03-13-2018, 06:58 AM

Hi folks I need some advice
I managed to pick up s 440i back box to convert my 435d twin pipe to dual pipes.
I note on the 440i back box there is a exhaust flap which is closed on one of the pipes.

So the question is that does my 2015 pre lci 435d have the exhaust connection and software to open the flap in sports mode?
Secondly if it doesn't how do i open the flap and keep it open?

Cheers
Mani

GEP77 · 03-13-2018, 08:23 AM

Only a actual 340/440i will have the wiring for the valve.

To open it you just have to manually move the butterfly valve to the required position, or apply 12v across the motor and it will drive open.

The valve will stay in its last position.

Manivxr · 03-13-2018, 08:45 AM

Got it. Cheers.

Manivxr · 03-13-2018, 08:51 AM

does anyone know if I move it clockwise to open the valve or anticlockwise

Steve_M_Sport · 03-13-2018, 12:24 PM

Quote:

Originally Posted by Manivxr

does anyone know if I move it clockwise to open the valve or anticlockwise

You are best to unscrew the control box and remove it. The exhaust fitter will apply a spot weld to keep the flap open. That's what mine did.

Manivxr · 03-13-2018, 01:40 PM

Quote:

Originally Posted by Steve_M_Sport

You are best to unscrew the control box and remove it. The exhaust fitter will apply a spot weld to keep the flap open. That's what mine did.

Cheers mate. relative easy to do. May just secure with a wire in mean time.

TW666 · 03-14-2018, 05:37 AM

Interested to know how easy fitting twin pipes was eg was there an existing support bracket both sides or did you have to add one ? Also where did you source 440i back box, cost etc.

leeadam · 03-14-2018, 05:50 AM

just go custom like mine...free flowing no flaps... and bigger than 440 3.5 inch tips

leeadam · 03-14-2018, 05:54 AM

....

Darth Helmut · 03-14-2018, 06:13 AM

Agree with Lee. Just go custom.

leeadam · 03-14-2018, 07:30 AM

Quote:

Originally Posted by Darth Helmut

Agree with Lee. Just go custom.

looks great

MrFiasco · 12-07-2018, 11:36 AM

Quote:

Originally Posted by leeadam

just go custom like mine...free flowing no flaps... and bigger than 440 3.5 inch tips

Hi mate,

Can I ask who did this conversion for you? I Have a 435d and am wanting to go full custom like you with required defuser to fit. I'm in the north east.

Cheers

Jack.

MrFiasco · 12-07-2018, 11:37 AM

Quote:

Originally Posted by Darth Helmut

Agree with Lee. Just go custom.

Hi mate

Same question to you..
Can I ask who did this conversion for you? I Have a 435d and am wanting to go full custom like you with required defuser to fit. I'm in the north east.*

Cheers

Jack.

kiteboardkid · 05-10-2019, 12:30 AM

What does it sound like with the back box delete please? I bought a 435i back box but I'm thinking and agreeing what you've done seems a better option :-)

Thanks

j10gtr · 02-13-2023, 07:05 AM

is the 440i backbox a direct fit for the 435D baring the flap position ?

Cheers

Steve_M_Sport · 02-13-2023, 10:23 AM

Quote:

Originally Posted by j10gtr

is the 440i backbox a direct fit for the 435D baring the flap position ?

Cheers

You will need a short reducer pipe as the diameter of the 35D pipe is different to the 40i pipe attached to backbox - it was for a 335D to 340i conversion i did so guessing similar for 435D.

j10gtr · 02-14-2023, 01:21 AM

Those that have gone the custom route ie back box delete what difference has it made to the sound ?

I don't want a noisy exhaust for a daily driver like mine is.

Stainy · 02-14-2023, 02:52 AM

Quote:

Originally Posted by j10gtr

Those that have gone the custom route ie back box delete what difference has it made to the sound ?

It's not loud at all, just a little more 'throaty'. In normal day to day driving you hardly notice. When there's a regen you know though, it goes all barritone......and when you floor it, it sounds like a hurricane

03-13-2018, 06:58 AM	#1
Manivxr Captain 203 Rep 637 Posts Drives: 435d EB Join Date: May 2017 Location: Staffordshire iTrader: (0)	435d exhaust conversion to 440i twin exit Hi folks I need some advice I managed to pick up s 440i back box to convert my 435d twin pipe to dual pipes. I note on the 440i back box there is a exhaust flap which is closed on one of the pipes. So the question is that does my 2015 pre lci 435d have the exhaust connection and software to open the flap in sports mode? Secondly if it doesn't how do i open the flap and keep it open? Cheers Mani
	Appreciate 0 Tweet Quote

03-13-2018, 08:23 AM	#2
GEP77 Major 409 Rep 1,162 Posts Drives: Tesla Model 3 Long Range. Join Date: Nov 2013 Location: South East London iTrader: (1)	Only a actual 340/440i will have the wiring for the valve. To open it you just have to manually move the butterfly valve to the required position, or apply 12v across the motor and it will drive open. The valve will stay in its last position.
	Appreciate 0 Quote

03-13-2018, 08:45 AM	#3
Manivxr Captain 203 Rep 637 Posts Drives: 435d EB Join Date: May 2017 Location: Staffordshire iTrader: (0)	Got it. Cheers.
	Appreciate 0 Quote

03-13-2018, 08:51 AM	#4
Manivxr Captain 203 Rep 637 Posts Drives: 435d EB Join Date: May 2017 Location: Staffordshire iTrader: (0)	does anyone know if I move it clockwise to open the valve or anticlockwise
	Appreciate 0 Quote

03-14-2018, 05:37 AM	#7
TW666 Private 34 Rep 52 Posts Drives: 435d M Sport+ LCI Join Date: Mar 2018 Location: North Hampshire UK iTrader: (0)	Interested to know how easy the exhaust change was. Interested to know how easy fitting twin pipes was eg was there an existing support bracket both sides or did you have to add one ? Also where did you source 440i back box, cost etc.
	Appreciate 0 Quote

03-14-2018, 05:50 AM	#8
leeadam Major 468 Rep 1,151 Posts Drives: F90 M5 Comp (Evolve Tune) Join Date: Apr 2010 Location: Buckinghamshire, England iTrader: (0)	just go custom like mine...free flowing no flaps... and bigger than 440 3.5 inch tips Attached Images
	Appreciate 2 Darth Helmut1780.00 SanMarino0.00 Quote

03-14-2018, 05:54 AM	#9
leeadam Major 468 Rep 1,151 Posts Drives: F90 M5 Comp (Evolve Tune) Join Date: Apr 2010 Location: Buckinghamshire, England iTrader: (0)	.... Attached Images
	Appreciate 1 Darth Helmut1780.00 Quote

03-14-2018, 06:13 AM	#10
Darth Helmut Banned 1780 Rep 2,029 Posts Drives: BMW F32 435d XD Join Date: Jan 2017 Location: The Penthouse, Death Star iTrader: (0)	Agree with Lee. Just go custom.
	Appreciate 3 leeadam467.50 Junebug851615.00 hudson012003168.50 Quote

05-10-2019, 12:30 AM	#14
kiteboardkid Registered 0 Rep 2 Posts Drives: 435d x f36 Join Date: May 2019 Location: Reading iTrader: (0)	What does it sound like with the back box delete please? I bought a 435i back box but I'm thinking and agreeing what you've done seems a better option :-) Thanks
	Appreciate 0 Quote

02-13-2023, 07:05 AM	#15
j10gtr New Member 0 Rep 7 Posts Drives: 435d 2017 Join Date: Feb 2023 Location: England iTrader: (0)	is the 440i backbox a direct fit for the 435D baring the flap position ? Cheers
	Appreciate 0 Quote

02-14-2023, 01:21 AM	#17
j10gtr New Member 0 Rep 7 Posts Drives: 435d 2017 Join Date: Feb 2023 Location: England iTrader: (0)	Those that have gone the custom route ie back box delete what difference has it made to the sound ? I don't want a noisy exhaust for a daily driver like mine is. Last edited by j10gtr; 02-14-2023 at 01:54 AM..
	Appreciate 0 Quote