[Crashball]

Hello all, long time listener, first time caller,

I have a 2007 E90 330i M Sport Auto (N53 272bph) which I've had for about 2 months and absolutely love (now that I've learnt how to drive it properly!).

So I thought I'd treat myself to a couple of mods and went for the BMW PE muffler/silencer as had heard v good reviews on many and varied forums.

Since the car is also my wife's daily I was drawn to the idea that it sounded great but wasn't really that noticeable under 3k revs but would let rip for the half an hour per year that I actually get to be on a quiet A-road on my own.

Anyway, I bought one from BMW, had it fitted, and I can definitely say that it's a lovely sounding exhaust. BUT, weirdly I'm having trouble hearing the thing! In the cabin it's not much louder than stock (which I guess is good) but a lot of people have written that they like to open the windows when they want to hear it, but as soon as I do, and by the time I'm getting the revs up, there's just too much wind noise to hear anything. Even when I get the revs up in and around town with the windows down it just doesn't seem THAT loud. I've had it burning through tunnels on low gear and again, though people have said it has this amazing noise I'm just not really hearing it! So I'm a bit confused. Some people say it gets louder after a thousand miles or so, but then some say it mellows out, which is a head-scratcher in itself.

I certainly didn't want some wideboy boombox type thing so that's good, but I do have a couple of questions:

- Is that a familiar experience with the OEM performance backbox?

- Is there another part of the exhaust system that I can replace relatively cheaply that will give it a little nudge?

I don't want to take large parts of the exhaust system out or mess with the car too much, I don't need it to blow my head off, but yeah, a little nudge up in decibels would be good. Not that crazy about the golf tee mod as the drone is a pain.

Any and all thoughts massively appreciated.

[D3THR]

Hi,

I share your thoughts after fitting the PE on my E90.

I have no covered around 2-3k miles when i floor it windows down you can hear lightly which has a nice raspy note to it, when driving in car parks sometimes can hear the odd pop again windows down. But with the windows up hardly anything.

The American market PE from looking at videos and reading reviews sounds more better as it comes with a center resonator delete pipe, which cannot be fitted to Euro models having additional sensor.

Golf tee mod for me hardly made any difference with the exception of A roads and motorway increase of drone.

[imy]

I cant speak for the 330i but i know for the 335i usually the better sound is attributed to fitting catless downpipes.

Also bear in mind that exhausts need a bit of mileage to bed in so you may find that the sound gets better as you drive it more.

[Thermobaric]

Hmm. What about cold starts? Is it night and day for those?

[Crashball]

Hi all, thanks for the replies, definitely having the same experience. I haven't quite done a thousand miles on it but (and I don't know if this is in my head) it does sound a little bit raspier, maybe a touch louder, a touch 'something' but yeah it hasn't quite lived up to its billing so far. Hot and cold starts haven't made much difference.

I'm a complete and utter newb to exhausts - so these catless downpipes, would they effect an emissions test? Would they add a bit of grunt to the noise? I had a remap done at the same time which I was pretty much expecting to do naff all since the engine is n/a but it's made a world of difference in 4th and 5th, but was hoping the exhaust would be the thing that brings it to life.

First-world problems though as it's a fantastic car.

[Tr1ppy]

I haven't done anything to my N53 330i apart from the golf tee mod which I find is quite nice actually; the drone isn't excessive and you get a nice throaty note especially when blipping the throttle for downshifts.

As far as I know, removing the primary cats may give emissions/MOT issues as these cats do most of the work in removing chemicals.

Maybe try removing the secondary cats? There is a Nox sensor before and after the cats so you'll have to map the ECU again to take this into account. This is something I am planning on in the near future.

Out of interest how much hp did you gain from your remap?

[Rueh]

I had exactly the same when I installed a PE on my n53 330i, couldn't really notice much difference. 2 weeks after I got it I had the secondary cats removed, huge difference! Sounds really good on a cold start and I noticed a very slight increase in performance. Not enough to bother with on performance alone but it does seem to rev a bit better. No backfire pops though unfortunately!

I'll see if I can get a video of a cold start over the weekend.

[Crashball]

Originally Posted by Rueh

I had exactly the same when I installed a PE on my n53 330i, couldn't really notice much difference. 2 weeks after I got it I had the secondary cats removed, huge difference! Sounds really good on a cold start and I noticed a very slight increase in performance. Not enough to bother with on performance alone but it does seem to rev a bit better. No backfire pops though unfortunately!

I'll see if I can get a video of a cold start over the weekend.

That would be incredible to get a video! (And thanks tr1ppy). Okay, so what's the deal with removing the secondary cats? Is that expensive? What kind of parts will I need to order? So sorry if this is on a billion different threads but they all seem to talk 'around' the issue I'm having.

Would removing the secondary cats (by whichever means) keep the the civilised grumble under the 3k revs mark then gimme more of the good stuff when I can get lively?

On the remap performance front, it's hard to definitively say 'yes, there was more power available', 15bhp is the official line, but I just drove to Le Mans and back for the race on those gorgeous French toll roads and I'm telling you that in DS mode I was laying waste to all sorts, there are now no flat spots on the throttle and in triple figures the car kept asking me to do a lot more. I was very close to getting the 335i because it's such a powerful machine, amazing in its own way, but with the 330i remap I didn't feel much performance difference with the stock 335i and had the pleasure of actually having to work with the car to get it to perform, I personally enjoy that relationship with the car but I know it's not for everyone. (Haha, but of course a remapped 335i would be something else!!).

[Rueh]

Originally Posted by Crashball

That would be incredible to get a video! (And thanks tr1ppy). Okay, so what's the deal with removing the secondary cats? Is that expensive? What kind of parts will I need to order? So sorry if this is on a billion different threads but they all seem to talk 'around' the issue I'm having.

Would removing the secondary cats (by whichever means) keep the the civilised grumble under the 3k revs mark then gimme more of the good stuff when I can get lively?

It's quite a simple job, cut the 2 secondary cats out and weld 2 pipes in place. The pipes do need bending to shape but a decent exhaust shop will have no trouble doing it, mine was done in about 30 minutes. Cost for me was £200 which was quite steep but they done a very good job so wasn't too bad. No errors have been thrown on mine but I'm yet to MOT it so can't guarantee anything there. It does smell a bit petroly on start up. Secondary cats are only there until the main cats in the header are up to temperature I believe.

[Raahil]

quite interesting this thread as i was in two minds myself whether to install the PE or not. I still have not decided but looking at Crashball's and other members response im baffled even more.

I do like the way the car sounds on its original but just want a bit more of a throatier sound, especially in the higher rev range.

Has anyone tried removing secondary cats on a standard exhaust system?

[richk84]

I would give it a couple of hundred miles if not more to allow it to burn in. I'm happy with mine even when I have the roof up. I would maybe want more sound on the downshifts but I think that might be more to do with the auto gear box

[Crashball]

Originally Posted by Raahil

quite interesting this thread as i was in two minds myself whether to install the PE or not. I still have not decided but looking at Crashball's and other members response im baffled even more.

I do like the way the car sounds on its original but just want a bit more of a throatier sound, especially in the higher rev range.

Has anyone tried removing secondary cats on a standard exhaust system?

Hi Raahil, well it gets stranger still. I drove it tonight through horrible traffic in London and for the first few miles (i.e. from cold) it suddenly sounded amazing, when I upped the revs it went from a smooth subtle rumble to sounding like a jet engine with a smoker's cough, it was beautiful, not crazy loud at all but really raspy, scratchy, punchy. I thought 'hell yes, THIS is what they were talking about'. I had to crawl through town for an hour or so before I hit an A road, dropped a gear, gunned the engine, then....er..the same thing as before as described in my OP. Maybe it's still burning in but I want to bottle that sound I had at the beginning of the journey, made the hairs stand up. Perhaps removing 2nd cats would guarantee that, would love to know.

[Rueh]

https://youtu.be/SGj8lfMl4xc

Unfortunately not a proper cold start (had to take wife to tesco earlier) revved to about 2000rpm. Tone completely different higher up the rev range but I didn't want to sit on my driveway red lining my car from cold! Neighbours already think I'm weird! I'll have to get a tunnel video sometime, I was lucky enough to have a tunnel on my way home from the exhaust shop. Fun times!

And that is an exhaust pop after each rev, suprised myself with them.

[Crashball]

Hi Rueh, thanks so much for the vid! Can really hear the difference, louder and deeper. Really useful to have that. Can I ask if you've had it MoT'd since you removed the second cat? And is the sound borderline anti-social or is it still okay at low revs? Also, at high revs does it still have a good 'scream'? if you know what I mean ;-)

Thanks again!

[Rueh]

Originally Posted by Crashball

Hi Rueh, thanks so much for the vid! Can really hear the difference, louder and deeper. Really useful to have that. Can I ask if you've had it MoT'd since you removed the second cat? And is the sound borderline anti-social or is it still okay at low revs? Also, at high revs does it still have a good 'scream'? if you know what I mean ;-)

Thanks again!

No problem! The noise is not intrusive at all, it's my daily driver and you would never know about the modifications while cruising at normal engine speeds, no drone at all. I found the golf tee mod created more drone than removing the cats, so I've plugged the vacuum pipe back in. I've not yet had it MOT'd since removing the cats. The sound is not anti-social, just nice bit of burble when not pressing on. Cold start is quite loud but only for a split second. Definitely has a proper scream towards the red line too, I'll try and capture that in a video sometime. Can't really see any drawbacks as long as it passes the MOT! Make sure you keep the old cats and the exhaust shop doesn't 'lose' them if you have it done!

[jamherber]

Removing the secondary cats on the N53 will throw up NOx errors (these won't illuminate the engine warning light). In practice it will stop the engine running in stratified mode which gives this engine the ability to be very frugal. It won't give any MOT problems though as NOx levels aren't checked.

I fitted a PE to our N53 330i about 8 months ago and find the same as the OP - sounds lovely when you hear it drive away but barely noticeable in the car. With hindsight, I won't have bothered fitting it to be honest.