[Joey911]

Hello guys,

I have few questions to be made clear before I can go catless DP, I did google a lot, but I hope to have someone tell me the final answer..

1. For N55 guys going catless, members usually suggest getting a pair of resonators or *midpipe from N55 335xi* which has 2 small cats on it. Question is, are the midpipe on N55 335xi SAME AS the midpipe on N54 335i or 335is?

2. How many cells are those cats on the midpipe?

3. If all goes well, I will get catless DP, midpipe that fits from question 1 (with cats), and I should be in a no drone/smell zone right?

4. (Added) also, will this setup better than a high flow cat performance wise?

Thanks!

[Joey911]

Anyone?

[Dhillon92]

1. I have a n55xi, has secondary cats in the mid pipe, I'm also running the VRSF dp. Its quite subtle to me since ive had it for a while, I dont experience any smell, others may be more sensitive. Personally I dont mind the catless smell, doesn't bother me one bit. I'm considering even removing the secondary cats and replace them with resonators just to get a tad louder. I also dont like knowing there is ANY restriction in my mid pipe, although small.

2. No clue, they aren't a big deal though.

3. Refer to answer 1, again I wouldn't say NO drone and NO smell, both are still there, its just a matter of what you think is a lot of drone/smell. I can drone at a certain rpm if I'm looking for it, high gear on a highway cruise. Then again I could just close one exhaust flap with my jb4 and it almost sounds like stock. I dont smell anything unless I sit down right in front of my exhaust... I probably wouldn't last very long doing that though LOL.

4. Personally, I see no reason having a high flow cat, either have a cat that works and passes emission, or just delete it all together. I find high flow cats to be in between stock cat and catless, so what's really the point? Performance wise, catless>high flow>stock cat.

Hope my answers help you out!

[weehe126]

Not sure where you have read you need new mid pipes with a dp. As long as you dont have the performance exhaust or keep the flap permanently open, you wont get drone.

[Johnny Boost]

Originally Posted by weehe126

Not sure where you have read you need new mid pipes with a dp. As long as you dont have the performance exhaust or keep the flap permanently open, you wont get drone.

+1

I highly doubt you need mid pipes. I've only seen N54 people talk about swapping N55 mid pipes.

[Joey911]

Originally Posted by Dhillon92

1. I have a n55xi, has secondary cats in the mid pipe, I'm also running the VRSF dp. Its quite subtle to me since ive had it for a while, I dont experience any smell, others may be more sensitive. Personally I dont mind the catless smell, doesn't bother me one bit. I'm considering even removing the secondary cats and replace them with resonators just to get a tad louder. I also dont like knowing there is ANY restriction in my mid pipe, although small.

2. No clue, they aren't a big deal though.

3. Refer to answer 1, again I wouldn't say NO drone and NO smell, both are still there, its just a matter of what you think is a lot of drone/smell. I can drone at a certain rpm if I'm looking for it, high gear on a highway cruise. Then again I could just close one exhaust flap with my jb4 and it almost sounds like stock. I dont smell anything unless I sit down right in front of my exhaust... I probably wouldn't last very long doing that though LOL.

4. Personally, I see no reason having a high flow cat, either have a cat that works and passes emission, or just delete it all together. I find high flow cats to be in between stock cat and catless, so what's really the point? Performance wise, catless>high flow>stock cat.

Hope my answers help you out!

Thanks for your opinions bro!

You said once the flap activated through JB4, the exhaust sounds like stock to you? Do you also mean there is minimal drone?

I'm very sensitive to drone because I had experience with it, one N54 335i I test drove a long time ago, I don't know what exhaust setup it had, but as long as I touch the throttle, I COULD NOT talk to passenger without yelling... No kidding lol

Sounds like the secondary cat doesn't do much, I will *help* get rid of the smell and rasp right?

[Joey911]

Originally Posted by weehe126

Not sure where you have read you need new mid pipes with a dp. As long as you dont have the performance exhaust or keep the flap permanently open, you wont get drone.

I don't mean that I *need* midpipe for DP upgrade, just that with a pair of secondary cat, it helps with the smell and drone a bit.

I read some other post, people who went full catless always end up installing resonators or midpipe with cat, am I wrong here?

[Dhillon92]

Yea, I mean with the flap closed its not literally just like stock, but it is definitely not as much as it would be if it were open. Even with the flap open I have no problems having a conversation. The secondary cats do help with rasp and drone, but a mid pipe costs quite a bit of money, if smell is your main concern then it would definitely help with that, I dont smell much. If you're more concerned with drone, just buy resonators and get them in your current piping, it will cost you about 200 all said and done.

If you're picky about both, then I guess the mid pipe is worth it, its really hard to say since everyone's opinion on too raspy and too much drone are different.

[Joey911]

Originally Posted by Dhillon92

Yea, I mean with the flap closed its not literally just like stock, but it is definitely not as much as it would be if it were open. Even with the flap open I have no problems having a conversation. The secondary cats do help with rasp and drone, but a mid pipe costs quite a bit of money, if smell is your main concern then it would definitely help with that, I dont smell much. If you're more concerned with drone, just buy resonators and get them in your current piping, it will cost you about 200 all said and done.

If you're picky about both, then I guess the mid pipe is worth it, its really hard to say since everyone's opinion on too raspy and too much drone are different.

Guess I'm pretty picky about noise level not being able to control..

I just hope that DP with catted midpipe won't be noisy when windows *up* and driving on highway, had such bad experience with drone, guess I'm the sensitive kind.

Decided to get catless and catted midpipe, I'll see what's up from there.

Which catless has the best quality vs price?

[Dhillon92]

IMO, vrsf has great quality and price, well made and ceramic coated. I think you'll be good with the setup, it's literally as quiet as it can get when your pushing catless power lol. Windows up definitely no probs, I prefer to keep my windows down, love the spool up!

[Joey911]

Originally Posted by Dhillon92

IMO, vrsf has great quality and price, well made and ceramic coated. I think you'll be good with the setup, it's literally as quiet as it can get when your pushing catless power lol. Windows up definitely no probs, I prefer to keep my windows down, love the spool up!

Wait, I mean won't be noisy when window down lol how can I mix that up

[Joey911]

Originally Posted by Dhillon92

IMO, vrsf has great quality and price, well made and ceramic coated. I think you'll be good with the setup, it's literally as quiet as it can get when your pushing catless power lol. Windows up definitely no probs, I prefer to keep my windows down, love the spool up!

And they said 3.5 to 4" is probably the best diameter right?

Okay I'll look for a used one

[Dhillon92]

They're fairly cheap brand new, if you look for a used one, I would buy a new gasket kit from any of the vendors, which might just add up to the price of a new one lol. Vrsf is less than $300, 3.5" is where its at, I dont believe any size bigger would give more gains.

[Joey911]

Originally Posted by Dhillon92

They're fairly cheap brand new, if you look for a used one, I would buy a new gasket kit from any of the vendors, which might just add up to the price of a new one lol. Vrsf is less than $300, 3.5" is where its at, I dont believe any size bigger would give more gains.

Trying to pay even less so my setup would be cheaper then a high flow cat...