[GT500R]

Hi guys,

I didn't see a specific thread with Catted Downpipe options for the G01 X3 M40i and was wondering if someone could create a list for others who may want exhaust.

I know of ..

1. VRSF
2. Supersprint
3. Evolution Racewerks
4. CG precision
5. ?

Thanks

[Torinalth]

CG precision is the one I'm going to look into when I get there.

[GT500R]

Originally Posted by Torinalth

GC precision is the one I'm going to look into when I get there.

Do they make one for the X3 M40 i?

[chicagofan00]

I'm pretty new to the down pipe mod arena. Is there a particular reason why one would choose a catted versus non-catted down pipe or vice versus?

[Torinalth]

Originally Posted by GT500R

Do they make one for the X3 M40 i?

they don't specify the G01, but saw one post about it working without issues. i'd ask them before buying, but that's my plan due to the larger cat area. I'm a ways off, but if you are about to buy, shoot them a line and ask.

[Torinalth]

Originally Posted by chicagofan00

I'm pretty new to the down pipe mod arena. Is there a particular reason why one would choose a catted versus non-catted down pipe or vice versus?

traditionally the catless downpipe made more power than the catted downpipe due to the cat material slowing down the air flow. They are also cheaper to produce since the catalytic substrate costs a good deal of money, plus the fitment of a strait section of wider pipe always makes plumbing more difficult than the simple strait piping of a catless design.

why you'd want a catted pipe are a few reasons: some people don't want to swap back to stock if their location required them for emissions testing. if you remove the cat you will eventually throw a check engine light, but you can tune around that. in my case its the last 3 that make me not want to go catless: there is a distinct odor when you go catless, when you run richer you will get black accumulation that is much harder to remove that stains the car and exhaust at the back tailpipe, and its louder going catless.

so for those like me willing to give up 2-5 HP for no staining, slightly less noise (though still more than stock), and eliminating the odor while still passing emissions.... there is a catted offering. Some just don't care, and that's why they sell catless versions.

[chicagofan00]

Originally Posted by Torinalth

traditionally the catless downpipe made more power than the catted downpipe due to the cat material slowing down the air flow. They are also cheaper to produce since the catalytic substrate costs a good deal of money, plus the fitment of a strait section of wider pipe always makes plumbing more difficult than the simple strait piping of a catless design.

why you'd want a catted pipe are a few reasons: some people don't want to swap back to stock if their location required them for emissions testing. if you remove the cat you will eventually throw a check engine light, but you can tune around that. in my case its the last 3 that make me not want to go catless: there is a distinct odor when you go catless, when you run richer you will get black accumulation that is much harder to remove that stains the car and exhaust at the back tailpipe, and its louder going catless.

so for those like me willing to give up 2-5 HP for no staining, slightly less noise (though still more than stock), and eliminating the odor while still passing emissions.... there is a catted offering. Some just don't care, and that's why they sell catless versions.

Thanks for the detailed reply. I've really been considering the Bootmod3 and a downpipe lately and based on this info I think the catted downpipe would be the best choice for me.

[Alias1431]

I don't know anything about this stuff, but would like to educate myself.

https://cdn11.bigcommerce.com/s-gd6o...1544542073.jpg

I assume that picture is stock vs. aftermarket catted downpipe? If so, what's the difference? Looks like basically the same part to me.

*I have no idea what I'm talking about here.

[bm3tuning]

Originally Posted by Torinalth

so for those like me willing to give up 2-5 HP for no staining, slightly less noise (though still more than stock), and eliminating the odor while still passing emissions.... there is a catted offering. Some just don't care, and that's why they sell catless versions.

Although this use to be true, it is no longer an issue with these B58 if you keep stock muffler (X3/X4 M40i has 2 Mufflers actually).
The smell is noticeable on the V8 cars like S63TU (M5/M6, X5M, X6M) when idling and that's also due to the fact that 91/93 oct releases that smell easily fixed with E30 or something

One of my close friends @fsociety has Downpipes on his 17' M3 Comp Pkg and there's 0 smell even on idle in his car because he has stock exhaust.
In my opinion if your state doesn't require yearly inspection, the catless downpipe is better in the pocket, sound and gains!

Depends on your location I may be able to suggest a Custom Fabricator who was the first in the world to make F90 M5 (Downpipes, Midpipes, Intakes), M550, and now new M850

[Torinalth]

Originally Posted by bm3tuning

Although this use to be true, it is no longer an issue with these B58 if you keep stock muffler (X3/X4 M40i has 2 Mufflers actually).
The smell is noticeable on the V8 cars like S63TU (M5/M6, X5M, X6M) when idling and that's also due to the fact that 91/93 oct releases that smell easily fixed with E30 or something

One of my close friends @fsociety has Downpipes on his 17' M3 Comp Pkg and there's 0 smell even on idle in his car because he has stock exhaust.
In my opinion if your state doesn't require yearly inspection, the catless downpipe is better in the pocket, sound and gains!

Depends on your location I may be able to suggest a Custom Fabricator who was the first in the world to make F90 M5 (Downpipes, Midpipes, Intakes), M550, and now new M850

That's interesting, but I don't see how that's possible. A muffler will not change the hydrocarbon content of the exhaust so there should be zero change to the smell or soot that comes from being catless, whether it's oem or aftermarket catback exhaust. Unless you mean there is a secondary cat (not muffler as you stated) after the downpipe. If that is the case, then I'd definitely change my direction. I'll have to get my M40i up on ramps and see.

[GT500R]

Originally Posted by bm3tuning

Although this use to be true, it is no longer an issue with these B58 if you keep stock muffler (X3/X4 M40i has 2 Mufflers actually).
The smell is noticeable on the V8 cars like S63TU (M5/M6, X5M, X6M) when idling and that's also due to the fact that 91/93 oct releases that smell easily fixed with E30 or something

One of my close friends @fsociety has Downpipes on his 17' M3 Comp Pkg and there's 0 smell even on idle in his car because he has stock exhaust.
In my opinion if your state doesn't require yearly inspection, the catless downpipe is better in the pocket, sound and gains!

Depends on your location I may be able to suggest a Custom Fabricator who was the first in the world to make F90 M5 (Downpipes, Midpipes, Intakes), M550, and now new M850

Do you have a downpipe installed on your X3 M40i?

[Alias1431]

Originally Posted by Alias1431

I don't know anything about this stuff, but would like to educate myself.

https://cdn11.bigcommerce.com/s-gd6o...1544542073.jpg

I assume that picture is stock vs. aftermarket catted downpipe? If so, what's the difference? Looks like basically the same part to me.

*I have no idea what I'm talking about here.

Ok...

[GT500R]

Originally Posted by Alias1431

I don't know anything about this stuff, but would like to educate myself.

https://cdn11.bigcommerce.com/s-gd6o...1544542073.jpg

I assume that picture is stock vs. aftermarket catted downpipe? If so, what's the difference? Looks like basically the same part to me.

*I have no idea what I'm talking about here.

The smoothness of the downpipe as it goes from the turbo to the bottom is where you will notice the most difference. The stock downpipe has that huge coke can then just goes into a smaller pipe, so all the exhaust gets shoved from that "can" down to a really small pipe within a small space, it doesn't help with flow. Aftermarket takes that flow and decreases the diameter over time where the exhaust gases don't fight as much to escape. Add in a more flowing cat converter and your gains are both of those combined.

[Alias1431]

That makes a lot of sense! Thanks.

[FSociety]

Originally Posted by Torinalth

That's interesting, but I don't see how that's possible. A muffler will not change the hydrocarbon content of the exhaust so there should be zero change to the smell or soot that comes from being catless, whether it's oem or aftermarket catback exhaust. Unless you mean there is a secondary cat (not muffler as you stated) after the downpipe. If that is the case, then I'd definitely change my direction. I'll have to get my M40i up on ramps and see.

In my testing and seeing different cars its true bm3tuning has commented.

Check this out https://www.realoem.com/bmw/enUS/sho...diagId=18_1289

Has 1 front muffler, then rear exhaust muffler which is 2.

Compare to the 340 exhaust
https://www.realoem.com/bmw/enUS/sho...diagId=18_1174

[Torinalth]

Originally Posted by FSociety

In my testing and seeing different cars its true bm3tuning has commented.

Check this out https://www.realoem.com/bmw/enUS/sho...diagId=18_1289

Has 1 front muffler, then rear exhaust muffler which is 2.

Compare to the 340 exhaust
https://www.realoem.com/bmw/enUS/sho...diagId=18_1174

My question was not to if there was two mufflers, many cars have that. My question was to how there can be no soot, and no smell if there is no secondary cat. two mufflers shouldn't be able to do that. So if that is happening there has to be something else at play. I've never heard or see that happen before and would be reluctant to go catless downpipe in that instance.

[GT500R]

BUMP....

Any other MFG's anyone can recommend?

Thank you.

[FSociety]

Originally Posted by GT500R

BUMP....

Any other MFG's anyone can recommend?

Thank you.

Catless lol CTS Turbo , especially since you have Stage 2 tune

https://www.bm3tuning.com/g30/n55-ca...downpipe-me7g5

[GT500R]

Originally Posted by FSociety

Catless lol CTS Turbo , especially since you have Stage 2 tune

https://www.bm3tuning.com/g30/n55-ca...downpipe-me7g5

Any idea if there will ever be a catted version Rob? My tuner said I’m ok with stock hardware but I’m sure a DP will open up some HP and take .2-.3 off the 1/4

[bm3tuning]

Originally Posted by GT500R

Any idea if there will ever be a catted version Rob? My tuner said I’m ok with stock hardware but I’m sure a DP will open up some HP and take .2-.3 off the 1/4

We can get Catted Downpipe option, will probably need a local X3 M40i for a day we work with LussoPerformance

[fsugatorbait]

Originally Posted by bm3tuning

We can get Catted Downpipe option, will probably need a local X3 M40i for a day we work with LussoPerformance

I'm interested in one if you're able to produce a catted DP that will last as long as the OEM one.

[i4M50Guy]

Cobra do a sports cat. It fits the M140i so I assume it will also fit the X3 M40i