[xpro]

>>Scroll to last page for final pics<<

I decided to write a little thread as it might help those wishing to do a full 340i exhaust swap.

I don't like welding nor chopping my original 335d exhaust as I prefer to keep things stock. Most of the reviews and threads are about people getting just the 340i back box or custom back section welded on..

The 340 exhausts are widely available on ebay, where I got mine for a bargain price, due to people upgrading to a Mpower exhaust system.

On my car I'm fitting the full 340i exhaust system with zero welding required,
mostly plug and play jobby using original parts.

The only modifications required are a 340i rear exhaust hangers, Left & Right. ( cost around 30£ each) Rubber mounts can be re used and are of the same part number.

Also you need the front exhaust gearbox mount ( around 40£) and thats it.

My work is still in progress as I am awaiting on parts from BMW and most importantly an exhaust reducer pipe, as 340i is 80mm and 335d is 70mm pipeing.

The exhaust valve will be completely removed and I have some carbon Akrapovic tail tips to go an aswell.

Below are some of the pictures of the current progress. Stand by for more photos and the finished product as soonest I get the rest of the parts required.

* Exhaust swap is really easy, and it takes around 10m to remove the existing exhaust. Even easier if you have a helping hand, but if not, the gearbox jacks will do the job.











Here you can see the mounts are different. Ordering a 340i mount will resolve the issue and preserve the original exhaust mounts.



The DPF downpipe is just a flexi pipe which is hanging loose in the photo.
I have ordered an exhaust reducer pipe 80mm to 73mm which will fit perfectly into both exhaust pipes allowing for a smooth connection.



More picture to follow soon when the exhaust will be complete.

thanks for watching!

[xpro]

Can mod please delete the other thread as they seem to be 2 of the same post. Regards,

[Simon89]

Very interested in this, as you I'm not too keen on chopping bits of exhaust up to make it fit.

[1 AKY]

Bit of a novice question, but can you install a 'petrol' exhaust on a diesel-engined car?

[teaston]

Originally Posted by 1 AKY

Bit of a novice question, but can you install a 'petrol' exhaust on a diesel-engined car?

I'm wondering the same thing! Can the exhaust system, especially the cats, handle the massive heat produced by the DPF when it regens!?

[DriveS]

Not heard of anyone do this before. Seems a very expensive mod to get twin pipes out the back, but each to their own.

[PaulT_M5]

On the petrol cars, the cats are in the downpipes which are before the long exhaust sections. The "boxes" in the exhaust are resonator sections to reduce the noise.

http://www.realoem.com/bmw/enUS/part...BMW-340i&mg=18

[1 AKY]

I was querying with reference to differences in fuel composition and combustion byproducts, heat output, system pressure and sound.

[adam.b]

i was about to do the same but short lived, i have got shitty ad-blue tank were will be right tail pipe, end of story

[xpro]

Originally Posted by DriveS

Not heard of anyone do this before. Seems a very expensive mod to get twin pipes out the back, but each to their own.

When you win a full 340i system on ebay for 80£, thats an excellent deal.
They mostly range 100-300£ for full exhaust. For me I budget on 150£ all in, and thats me doing the labour.
Most peeps on here pay 300/500£ just have a custom pipes welded, etc.
This is a plug & play job. If you have an access to a car lift, even better.

To answer the question on the DPF and the exhaust material, regen and heat generation.
Both exhaust systems are made out of identical stainless T304 metal and the petrol 340i exhaust is much more free flowing then a sister diesel exhaust, which in theory will make the hot DPF gases flow out quicker, and having 1 less cat in the middle should definately improve things( Only Euro 6 Lci Models apprently have a cat after the dpf). The 340i only has a non restrictive resonator in the middle.

[DriveS]

Originally Posted by xpro

When you win a full 340i system on ebay for 80£, thats an excellent deal.
They mostly range 100-300£ for full exhaust. For me I budget on 150£ all in, and thats me doing the labour.
Most peeps on here pay 300/500£ just have a custom pipes welded, etc.
This is a plug & play job. If you have an access to a car lift, even better.

To answer the question on the DPF and the exhaust material, regen and heat generation.
Both exhaust systems are made out of identical stainless T304 metal and the petrol 340i exhaust is much more free flowing then a sister diesel exhaust, which in theory will make the hot DPF gases flow out quicker, and having 1 less cat in the middle should definately improve things( Only Euro 6 Lci Models apprently have a cat after the dpf). The 340i only has a non restrictive resonator in the middle.

I think the question is - Is the CAT on a diesel car of a different design to a petrol one - Can a petrol one withstand the heat generated in the diesel regeneration cycle? AND will a petrol reduce the harmful gases in the same way?

The 340i exhaust would only improve flow rate if the 335d one was causing a restriction to the flow after the dpf. If there is any improvement in that respect it will be negligible. I noticed no difference and I have no back box.

[xpro]

Originally Posted by DriveS

I think the question is - Is the CAT on a diesel car of a different design to a petrol one - Can a petrol one withstand the heat generated in the diesel regeneration cycle? AND will a petrol reduce the harmful gases in the same way?

The 340i exhaust would only improve flow rate if the 335d one was causing a restriction to the flow after the dpf. If there is any improvement in that respect it will be negligible. I noticed no difference and I have no back box.

The 340i doesnt have a cat in the exhaust system, its built into the Turbo downpipe, as such called the PPF ( petrol particle filter) and the 335D has a DPF built in the turbo Downpipe.

Not all models 335D’s are Euro 6 emissions model, so not all are fitted with a catalytic converter post DPF, so theoretically you will downgrade a car to a Euro 5 standard. 12/13/14 plate 335D are all euro 5’s anyway.

For me, and from my experience, I’d gladly remove all those systems, as they are chocking the car full stop.

The 340i pipe hasn’t got any restrictions in the exhaust, apart from resonators which means the gas will free flow and will not be trapped inside the exhaust.
The stainless material is the same, same tickness but wider diameter.
On the petrol turbo cars likes of 340i, etc EGT temperature will hit 400/500 celcuis on full tilt anyway, as petrol cars run much hotter then diesels.

335D runs around 300c averagely and only up to 500c for regen process which lasts up to 5/10min. So I dont see any threats at all.

When I used to tune MoteC ecus and evos back in the day, the EGT would hit 700c on full boost, to the point where the exhaust would glow red. This kind of temps are simply not achieveable on diesel cars, so I dont think the 340i exhaust will fall apart inside a diesel car.

[DriveS]

Originally Posted by xpro

The 340i doesnt have a cat in the exhaust system, its built into the Turbo downpipe, as such called the PPF ( petrol particle filter) and the 335D has a DPF built in the turbo Downpipe.

Not all models 335D’s are Euro 6 emissions model, so not all are fitted with a catalytic converter post DPF, so theoretically you will downgrade a car to a Euro 5 standard. 12/13/14 plate 335D are all euro 5’s anyway.

For me, and from my experience, I’d gladly remove all those systems, as they are chocking the car full stop.

The 340i pipe hasn’t got any restrictions in the exhaust, apart from resonators which means the gas will free flow and will not be trapped inside the exhaust.
The stainless material is the same, same tickness but wider diameter.
On the petrol turbo cars likes of 340i, etc EGT temperature will hit 400/500 celcuis on full tilt anyway, as petrol cars run much hotter them diesels.

335D runs around 300c averagely and only up to 500c for regen process which lasts up to 5/10min. So I dont see any threats at all.

When I used to tune MoteC ecus and evos back in the day, the EGT would hit 700c on full boost, to the point where the exhaust would glow red. This kind of temps are simply not achieveable on diesel cars, so I dont think the 340i will apart inside a diesel car.

Interesting thanks. Looks like you have done your homework.

Looking forward to hearing about your thoughts on what its like fitted.

[KCH1984]

That's not correct is it? I was always led to believe that all 335d's were Euro 6. It was the 330d that was Euro 5 up until c.2015 before going Euro 6.

Also, only the very recent 340i's will be PPF (July 18). Those before don't have the particulate filter, again this is why there's not an option for the MPPSK on the most recent cars.

[SkyJawa]

Correct, all 335d are Euro 6. They only came out in 2013 also.

[xpro]

Originally Posted by KCH1984

That's not correct is it? I was always led to believe that all 335d's were Euro 6. It was the 330d that was Euro 5 up until c.2015 before going Euro 6.

Also, only the very recent 340i's will be PPF (July 18). Those before don't have the particulate filter, again this is why there's not an option for the MPPSK on the most recent cars.

Yes, you're right. N57 engines in 330D were Euro 5 till LCI came out.

The exhaust I got was from a 17' 340i. Altought PPF was never a part of the full exhaust system, so I'm not sure when they first introduced it. Must be 18' as you say


And for reference 340i and 440i share the identical exhaust set up, same part numbers, etc

[xpro]

>>Mission Complete<<

Well chuffed with this job. Exhaust is fitted now. Easy enough job overall, providing you have an access to a car lift, or even easier if you pay an exhaust place to connect it all up for you.


The main advantages for me was that I still have my original 335d exhaust that can be refitted in 15 min if it needs be. No cutting, welding, connecting, and destroying your own exhaust, plus this 340i/440i exhaust guarantees OE fitment and correct alignment using original 340i mounts.

Other then that the engine sound remains the same.

[kzg1969]

Good work there!

[goodbyalfa]

Originally Posted by xpro

>>Mission Complete<<

Well chuffed with this job. Exhaust is fitted now. Easy enough job overall, providing you have an access to a car lift, or even easier if you pay an exhaust place to connect it all up for you.


The main advantages for me was that I still have my original 335d exhaust that can be refitted in 15 min if it needs be. No cutting, welding, connecting, and destroying your own exhaust, plus this 340i/440i exhaust guarantees OE fitment and correct alignment using original 340i mounts.

Other then that the engine sound remains the same.

[IMG]http://i66.tinypic.com/2eanixl.jpg[/IMG]

[IMG]http://i65.tinypic.com/2cpumaf.jpg[/IMG]

[IMG]http://i63.tinypic.com/16ay369.jpg[/IMG]

[IMG]http://i64.tinypic.com/23gzlv4.jpg[/IMG]

[IMG]http://i63.tinypic.com/2ce5hkk.jpg[/IMG]

Awesome job. Doesn't look like a dirty diesel now.

[goodbyalfa]

Originally Posted by xpro

Yes, you're right. N57 engines in 330D were Euro 5 till LCI came out.

The exhaust I got was from a 17' 340i. Altought PPF was never a part of the full exhaust system, so I'm not sure when they first introduced it. Must be 18' as you say


And for reference 340i and 440i share the identical exhaust set up, same part numbers, etc

Not strictly true. The last few months of Pre lci 330d's were euro 6. I had a May 2015 one. This period also came with the lci 5 point mounts in the suspension so all in all were almost lci I suppose...

[xpro]

something else to spruce it up a bit!!

[UKF30]

Originally Posted by teaston

I'm wondering the same thing! Can the exhaust system, especially the cats, handle the massive heat produced by the DPF when it regens!?

How are you doing mate ?

I have done same 440i backbox on 420D and works perfectly