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      06-17-2013, 02:31 AM   #1
Karura
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Catted Downpipes + N55 Midpipe (Catless)

Anyone got a setup like this running?

I have a E92 335is and wanted to know if this would be a good idea.

I'm already planning to go with catted downpipes somewhere down the road, and understand the pros/cons of it (more expensive, slightly less gains, but less chance of dealership/warranty issues, and most importantly less chance of blown turbo seals), and was curious as to what would be the effects of taking out the secondary cats. Discuss!

Last edited by Karura; 06-17-2013 at 02:38 AM.
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      06-17-2013, 11:48 PM   #2
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I heard the 335is with sec cat delete in person and the backfire in between shifts sounds amazing kinda like the new m5
it had the DCT
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      06-17-2013, 11:49 PM   #3
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Why do you think c@tless down pipes contribute to blown turbo seals? I've never read or heard that anywhere.
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      06-17-2013, 11:51 PM   #4
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I would keep your secondaries and go catless at the downpipes. Depending on the dealer, you can get questioned for either catted or catless, it's not OEM. Turbo seals would last longer with less backpressure.

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Originally Posted by Bimmer Barney View Post
Why do you think c@tless down pipes contribute to blown turbo seals? I've never read or heard that anywhere.
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      06-17-2013, 11:51 PM   #5
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catted or not its still not OEM so they will most likely give you problems.
get cl with dp fix
cl dp's will only expose the blown turbo seals more but in no way cause it.
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      06-18-2013, 12:13 AM   #6
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Quote:
Originally Posted by Karura View Post
Anyone got a setup like this running?

I have a E92 335is and wanted to know if this would be a good idea.

I'm already planning to go with catted downpipes somewhere down the road, and understand the pros/cons of it (more expensive, slightly less gains, but less chance of dealership/warranty issues, and most importantly less chance of blown turbo seals), and was curious as to what would be the effects of taking out the secondary cats. Discuss!
I will be running this setup, however I will be running DPs with highflow catts with them instead of cattless DPs

Replacing the N54 midpipes with the N55 midpipes will automatically delete the mid catts and exhaust = less backpressure = more flow = more gains

I do not want to go "completely cattless" cause of the following possible risks:
  1. Drone
  2. Rasp
  3. Exhaust Chimney Effect
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      06-18-2013, 02:36 PM   #7
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Quote:
Originally Posted by E90Company View Post
I would keep your secondaries and go catless at the downpipes. Depending on the dealer, you can get questioned for either catted or catless, it's not OEM. Turbo seals would last longer with less backpressure.



+1
I was always under the assumption that blown turbo seals were contributed by catless downpipes because of all those "white smoke after catless downpipes" threads; now I know better. Does that mean aside from the health and environmental damages, catless is actually better for our cars?

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Originally Posted by Bimmer Barney View Post
Why do you think c@tless down pipes contribute to blown turbo seals? I've never read or heard that anywhere.

Quote:
Originally Posted by BuraQ View Post
I will be running this setup, however I will be running DPs with highflow catts with them instead of cattless DPs

Replacing the N54 midpipes with the N55 midpipes will automatically delete the mid catts and exhaust = less backpressure = more flow = more gains

I do not want to go "completely cattless" cause of the following possible risks:
  1. Drone
  2. Rasp
  3. Exhaust Chimney Effect
I got the idea of running catted from you! I would love to hear how that setup sounds; do make another video if you got the chance.

Question about installing midpipes; from what I'm aware, our exhaust is one-piece from after DP all the way to the muffler/tips. Did you have to cut the pipes for the Dinan install? What kinda clamps/connections are best for securing the midpipe to the axle-back?
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      06-18-2013, 03:01 PM   #8
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Quote:
Originally Posted by Karura View Post
I was always under the assumption that blown turbo seals were contributed by catless downpipes because of all those "white smoke after catless downpipes" threads; now I know better. Does that mean aside from the health and environmental damages, catless is actually better for our cars?

I got the idea of running catted from you! I would love to hear how that setup sounds; do make another video if you got the chance.

Question about installing midpipes; from what I'm aware, our exhaust is one-piece from after DP all the way to the muffler/tips. Did you have to cut the pipes for the Dinan install? What kinda clamps/connections are best for securing the midpipe to the axle-back?
Yes. Going catless on a turbo car will always be better. You want the least amount of restriction possible post-turbine. This helps reduce heat, backpressure, lowers EGT's, and will allow for quicker spool. Nothing but benefits obviously. The question you need to ask yourself is trading some of this efficiency, for exhaust sound quality on this car. Being an I6 with small turbos, catless exhausts will cause lots of rasp, it's the nature of the motor. This is the only reason I still have my mid-cats.

Midpipes: Yes, it's welded to the x-pipe/axle-back sections of this car. He cut his mufflers off and clamped the Dinan mufflers to the existing piping. About the clamps, I know Magnaflow makes nice stainless ones, but as long as it's SS304 metal you should be fine if it's the right size.

PS: Catless DP's and stock catted mids create less backpressure than catted DP's and catless mids would, because the "restriction" is further downstream from the turbos.
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      06-18-2013, 06:19 PM   #9
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Devil's Advocate: rasp can always be addressed with large resonators if catless. Less backpressure than a cat.
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      06-18-2013, 06:23 PM   #10
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Quote:
Originally Posted by ashmostro View Post
Devil's Advocate: rasp can always be addressed with large resonators if catless. Less backpressure than a cat.
This is true, but it will also reduce exhaust volume a bit more in my experience. I'm also not too much of a fan of the smell, as people can easily tell if you are burning race gas
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      06-18-2013, 06:24 PM   #11
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I too am not a fan of the smell and won't run catless. Just putting it out there for the guys and gals that do, but hate rasp
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      06-18-2013, 08:25 PM   #12
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Quote:
Originally Posted by Karura View Post

Question about installing midpipes; from what I'm aware, our exhaust is one-piece from after DP all the way to the muffler/tips. Did you have to cut the pipes for the Dinan install? What kinda clamps/connections are best for securing the midpipe to the axle-back?
Yes from the factory it is one piece. Whoever is doing the install will have to cut the axle back exhaust and then use an exhaust clamping kit, perhaps from BMW, to connect to the N55 midpipes

Mine were cut when I had my Dinan axle back exhaust installed, so install of the N55 midpipes will require less labor
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      06-18-2013, 11:21 PM   #13
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Quote:
Originally Posted by ashmostro View Post
I too am not a fan of the smell and won't run catless. Just putting it out there for the guys and gals that do, but hate rasp
Rasp is probably gonna be a huge problem for me if I go catless, since I have the 335is exhaust, good point.

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Originally Posted by BuraQ View Post
Yes from the factory it is one piece. Whoever is doing the install will have to cut the axle back exhaust and then use an exhaust clamping kit, perhaps from BMW, to connect to the N55 midpipes

Mine were cut when I had my Dinan axle back exhaust installed, so install of the N55 midpipes will require less labor
Thanks for sharing; does anyone know where I can source the BMW exhaust clamping kit (part number?)? I am making a conscious effort to not do any permanent to the car such as installing intercoolers that require cutting (will probably go with ETS and install myself), but if it's a BMW kit, then I feel less bad about it.
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      06-19-2013, 12:41 AM   #14
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Quote:
Originally Posted by Karura View Post

Thanks for sharing; does anyone know where I can source the BMW exhaust clamping kit (part number?)? I am making a conscious effort to not do any permanent to the car such as installing intercoolers that require cutting (will probably go with ETS and install myself), but if it's a BMW kit, then I feel less bad about it.
Part # - 18307560778 ; 18201742073; 18307525639
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      06-19-2013, 12:46 AM   #15
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Keep your mid pipes and just get catless downpipes. Finding a set of N55 mid pipes isn't the easiest thing unless you're willing to pay full price for new ones.
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      06-19-2013, 07:57 AM   #16
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Keep your mid pipes and just get catless downpipes. Finding a set of N55 mid pipes isn't the easiest thing unless you're willing to pay full price for new ones.
They are very easy to come by, and not that expensive. They are going for $571.74 online and the price can be matched by a local BMW dealer.

http://www.getbmwparts.com/parts/201...=Center%20pipe
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      06-19-2013, 09:41 AM   #17
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Quote:
Originally Posted by BuraQ View Post
They are very easy to come by, and not that expensive. They are going for $571.74 online and the price can be matched by a local BMW dealer.

http://www.getbmwparts.com/parts/201...=Center%20pipe
What he is trying to say, is you are spending basically $600+ labor for the same thing as a secondary cat delete which costs less than $100. Waste of money when catless downpipes are cheaper than that and will give you more of a gain than Catted DP's and catless mids.
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      06-19-2013, 10:27 AM   #18
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Quote:
Originally Posted by E90Company View Post
What he is trying to say, is you are spending basically $600+ labor for the same thing as a secondary cat delete which costs less than $100. Waste of money when catless downpipes are cheaper than that and will give you more of a gain than Catted DP's and catless mids.
Yes. It just doesn't make any sense. It's counterproductive. You're paying more money for less of a gain and for no good reason. I can understand wanting N55 mid pipes instead of just cutting out the secondary cats to keep everything looking OEM under the car, but unless you can find a used set for $100, it isn't worth it.
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      06-19-2013, 11:26 AM   #19
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Originally Posted by Wesley Crusher View Post
Yes. It just doesn't make any sense. It's counterproductive. You're paying more money for less of a gain and for no good reason. I can understand wanting N55 mid pipes instead of just cutting out the secondary cats to keep everything looking OEM under the car, but unless you can find a used set for $100, it isn't worth it.
One thing about people in general they always think "NOW" and neglect the future out come of things. This is why you are unable to see the "good reasoning" behind it

No one has ever tried this setup of DPs with Highflow Catts and N55 middpipes . So your assertion is more less a theorization, following another theory", rather than facts to quickly conclude less gain results compared to the common bandwagon results

Its not just to keep everything looking OEM, it allows us to revert back to the stock without a hassle if needed.
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      06-19-2013, 11:38 AM   #20
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Quote:
Originally Posted by BuraQ View Post
One thing about people in general they always think "NOW" and neglect the future out come of things. This is why you are unable to see the "good reasoning" behind it

No one has ever tried this setup of DPs with Highflow Catts and N55 middpipes . So your assertion is more less a theorization, following another theory", rather than facts to quickly conclude less gain results compared to the common bandwagon results

Its not just to keep everything looking OEM, it allows us to revert back to the stock without a hassle if needed.
Even if catted downpipes and N55 mids yielded the same gains as catless downpipes and N54 mids, the fact is that it is still a much more expensive option for no good reason.

And if you ever need to revert back to stock, you tell me what is more of a hassle. Changing the downpipes or changing the downpipes and mids? The N54 has been out for years. If this was such a good idea, more people would have done it by now.
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      06-19-2013, 11:50 AM   #21
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Quote:
Originally Posted by Wesley Crusher View Post
Even if catted downpipes and N55 mids yielded the same gains as catless downpipes and N54 mids, the fact is that it is still a much more expensive option for no good reason.

And if you ever need to revert back to stock, you tell me what is more of a hassle. Changing the downpipes or changing the downpipes and mids? The N54 has been out for years. If this was such a good idea, more people would have done it by now.
Well said. Cutting and welding/clamping pipes isn't easier to revert back to stock either, that makes no sense BuraQ.
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      06-19-2013, 12:49 PM   #22
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Quote:
Originally Posted by Wesley Crusher View Post
Even if catted downpipes and N55 mids yielded the same gains as catless downpipes and N54 mids, the fact is that it is still a much more expensive option for no good reason.

And if you ever need to revert back to stock, you tell me what is more of a hassle. Changing the downpipes or changing the downpipes and mids? The N54 has been out for years. If this was such a good idea, more people would have done it by now.
More expensive, yes, but with added convenience

I was addressing the midcatt delete in your original post. If you add cattless DP's and do a midpipe delete it would be more of a hassle to have those things welded back on for whatever reason vs doing a swap out

The reason no one hasn't done it is because the N55 midpipes didnt exist and only recently found out that you can swap the N55 midpipes with the N54 midpipes for midcatts and mid exhaust delete.

People are only going to follow what others do, that's the trend
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