[Dave2013]

I added VRSF down pipes and a PE exhaust and it sounds utter dogsh*t

When I start it from a cold start it sounds like a tractor unless I hold the revs above 1200 rpm for 30 seconds....once its warm it goes back to being a burble which is nice.

It sounds like a vauxhall corsa from cold driving normally until its warm and it makes this really annoying rasp when I change gear around 6,000rpm.

ONLY time it sounds decent is warm, in park when I give it some revs.



Someone please tell me its because its all new parts....I cant be the first to find this.

[gangzoom]

I have to say this was one of the reason's I held off buying a back box on mine for ages, and went with AR catted down pipes.

There's loads of YouTube videos of 335i's running no cats + loud backboxes...which sound great on a track, but in real life, when all your trying to do is get from A to B in a comfortable manner they sound rubbish. Some have a similar noise that your find coming out of a poorly modified/tarted up Civic Type R.

[ashmostro]

Assuming you have an n54. It's the combo of pe and Dps. Try going back to a calmer exhaust and much of the rasp should go away.

[dm2583]

I love the sound my PE exhaust makes. Admittedly, on cold start up it can be embarrassingly loud but its not obtrusive at all once warm unless you're giving it some.

Not sure how much of a difference the downpipes make though as I'v never heard a car with them

[Dann]

I've heard that the N55 centre section with normal downpipes is a good combo.

[Dave2013]

Originally Posted by ashmostro

Assuming you have an n54. It's the combo of pe and Dps. Try going back to a calmer exhaust and much of the rasp should go away.

its the Performance Exhaust from BMW so its only the last section, the mid cats stay.

I hoped it wouldnt be offensivly loud, and it isnt but it just sounds sh*t.

Looks like the standard exhaust may well be going back on

[Dave2013]

Originally Posted by dm2583

I love the sound my PE exhaust makes. Admittedly, on cold start up it can be embarrassingly loud but its not obtrusive at all once warm unless you're giving it some.

Not sure how much of a difference the downpipes make though as I'v never heard a car with them

Its great once its warm......its cold start/cold driving and on gear change at 6,000rpm it isnt to my liking

[nicktyler]

De catted downpipes can make a bit of a racket on cold start. Mine did with a stock exhaust. A bit like a loose bolt jumping around inside with the vibration. When you put that together with the PE it is going to be very loud.

Just to mention though, have you checked everything for clearance etc. It may be that something is vibrating or resonating due to being too close to the pipes/exhaust? Mine was touching a heat shield on the bottom of the engine and making a squeak over speed bumps and probably adding to the rasp. With the heat-shield removed and the downpipes heat wrapped instead it sounded lovely again.

I was thinking of getting the DP's ceramic coated but very expensive and the chainmail type heat wrap helped to suppress the rasp a bit I think.

[dest]

Don't forget that exhausts do quieten down a touch after they get some carbon on the insides

[djgandy]

I'm guessing the rasp is like what you get in limp mode. With the turbos off the exhaust is insanely loud and sounds like severe farting.

Both stock and PE are designed for more turbulent air, and taking the cats away changes the entire dynamics of the exhaust flow. The PE is louder up the top and a bit more tractory on a cold start. It's normal though, I heard a guy start up an E90 M3 the other day which sounded quite tractory too, and more like a 335i stock, I guess if you care about the driving noise, can be happy to make such trade offs.

You might get better luck with answers on the USA side of forum, they have a wider range of mods and people, so someone might have an answer to "what exhaust is best for decat"

[ashmostro]

Originally Posted by Dave2013

When I start it from a cold start it sounds like a tractor unless I hold the revs above 1200 rpm for 30 seconds....once its warm it goes back to being a burble which is nice.

Oh and another thing - you shouldn't be holding the throttle open like that under warmup because the reason the exhaust sounds so loud on cold start is because the wastegates are held open for a time to prevent the turbos from spinning, but they still get oil. Essentially they are priming while the oil is thick, perhaps too thick to adequately protect the journal bearings if the turbos are spinning. It's likely overkill but given how expensive it is to fix anything on an N54 I prefer to let the startup cycle do its thing without interruption.

As I mentioned in my other post, the combo is the what is causing the sound. I myself hated it at first but have now come to appreciate it, particularly at full throttle.

An in between option is to find an IS exhaust which still uses the CAN flap mechanism which will help to quiet the exhaust down on start up by keeping one of outlets shut off and forcing all the exhaust gases through both mufflers. The PE eliminates this feature, which adds to the noise.

Whatever you do, keep the DPs, as they really are the heart of the power adder on this platform.

[Phil99z]

As dest mentioned exhausts generally get a little bit quieter after a bit of use and the carbon builds up in them. How long have you had it on for?

Gutted that you're not happy with the sound as the youtube videos with the PE sound amazing and if I didn't want the 335 style pipes on my car I would have considered one. Maybe you can sell it and get a custom one made?

When I got a custom 335 style backbox for my 330i I asked for the quietest silencer they had since I have a little girl and don't want too much noise inside the cabin. It is a lovely noise and not loud at all, slightly more than standard but in a good way and certainly doesn't sound out of place for the car.

[Dave2013]

Originally Posted by 2die4

As dest mentioned exhausts generally get a little bit quieter after a bit of use and the carbon builds up in them. How long have you had it on for?

Gutted that you're not happy with the sound as the youtube videos with the PE sound amazing and if I didn't want the 335 style pipes on my car I would have considered one. Maybe you can sell it and get a custom one made?

When I got a custom 335 style backbox for my 330i I asked for the quietest silencer they had since I have a little girl and don't want too much noise inside the cabin. It is a lovely noise and not loud at all, slightly more than standard but in a good way and certainly doesn't sound out of place for the car.

less than a week so far.

they do, when its in neutral and I rev it (once its warm) the sound is EPIC but when its moving it sounds rubbish (especially cold)

No real inside cabin noise, I have been listening windows down and had a few friends text me and say it sounds like a vauxhall corsa

[Dave2013]

Originally Posted by ashmostro

Oh and another thing - you shouldn't be holding the throttle open like that under warmup because the reason the exhaust sounds so loud on cold start is because the wastegates are held open for a time to prevent the turbos from spinning, but they still get oil. Essentially they are priming while the oil is thick, perhaps too thick to adequately protect the journal bearings if the turbos are spinning. It's likely overkill but given how expensive it is to fix anything on an N54 I prefer to let the startup cycle do its thing without interruption.

As I mentioned in my other post, the combo is the what is causing the sound. I myself hated it at first but have now come to appreciate it, particularly at full throttle.

An in between option is to find an IS exhaust which still uses the CAN flap mechanism which will help to quiet the exhaust down on start up by keeping one of outlets shut off and forcing all the exhaust gases through both mufflers. The PE eliminates this feature, which adds to the noise.

Whatever you do, keep the DPs, as they really are the heart of the power adder on this platform.

Good point. Will stop doing that and wait until I go deaf and cant hear it anyway

[Phil99z]

Originally Posted by Dave2013

less than a week so far.

they do, when its in neutral and I rev it (once its warm) the sound is EPIC but when its moving it sounds rubbish (especially cold)

No real inside cabin noise, I have been listening windows down and had a few friends text me and say it sounds like a vauxhall corsa

Might be worth sticking for a bit longer to see if it settles in and reduces a little noise if you can bear it but can understand you wanting rid of it since you're just not happy with it. If you do decide to go custom give the guys at Torque Flow a bell and see what they can do but after all of this wouldn't blame you if you just went back to standard.

Hope you get it sorted mate - good luck!

[Wibbles]

I had a 135i - N54 with DP's & PE - sounded awful, proper chav. I swapped the PE for the original exhaust & the difference was night & day.

Most of the rasp was gone & cold starts were much more neighbour friendly. Give that a try.

[AWSAWS]

Downpipes do sound raspy once first installed. That reduces over time with the carbon build up as dest says. Mine sounded properly tinny but for the quicker spooling boost it's worth it.

[dy63]

i wouldnt go custom mate at all on a 335i. i dont think the exhaust is the problem tbh i get a feeling it may be something else?

[Dave2013]

Originally Posted by cupraraj

i wouldnt go custom mate at all on a 335i. i dont think the exhaust is the problem tbh i get a feeling it may be something else?

Mod list:

JB4
VRSF DCI
VRSF De-Cat Pipes
BMW Performance Exhaust

All 4 were fitted together last week so I cant narrow it down to one item.

Im not going full custom, its either PE exhaust on or off. Or change the decat pipes for another style but cant see that making some night and day difference.

[ashmostro]

As mentioned, it's the combo of catless pipes and exhaust. The DP's are actually the culprit but they are so effective that I can't recommend removing those. Just get a quieter exhaust.

[RajB]

That's a real shame as I've only heard good things about the Perf exhaust. I think as has been said you may just need to give it a little while just to be fully sure. The rasp is a more M3 noise (E46 in particular) which I think is possibly what they were going for noise wise. I think the DP's will possibly be making the biggest difference noise wise now combined with the PE.

I think also it's down to expectation. Listening to you tube vids etc can be very misleading as to what the true sound is like. I know both my 335i and X5 are no way neighbour friendly when I start them at 6am but the neighbours are used to it to an extent and I wouldn't change the noise of my catted DP's and Akra for the world (although can be a little boomy in the car at certain points).

[Dave2013]

Originally Posted by RajB

That's a real shame as I've only heard good things about the Perf exhaust. I think as has been said you may just need to give it a little while just to be fully sure. The rasp is a more M3 noise (E46 in particular) which I think is possibly what they were going for noise wise. I think the DP's will possibly be making the biggest difference noise wise now combined with the PE.

I think also it's down to expectation. Listening to you tube vids etc can be very misleading as to what the true sound is like. I know both my 335i and X5 are no way neighbour friendly when I start them at 6am but the neighbours are used to it to an extent and I wouldn't change the noise of my catted DP's and Akra for the world (although can be a little boomy in the car at certain points).

same, and it was the only reason I went for that combo.

guess I will just wait and see if it beds in....ive done probably 100 miles so far.....but it really does sound like a vauxhall corsa at some points