[Gdiddy23]

This is literally identical to the rattles I was having with the MPE. BMW replaced it 3 times and it would always come back.

Let us know how it goes!

[possible335i2008]

Originally Posted by BarryB

Yup she's going back to the shop....

They didn't tighten down one of the clamps I bet, that shop sucks lol. I would honestly if I were you take a look myself and check that all the clamps are tighten and that the pipes aren't touching the heat shields

[placebo0311]

Originally Posted by BarryB

Listen to this 🙄 right side only seems like....

Yep, that's the same damn rattle I hear on my car too. I've checked the clamps and made sure everything was tight. No change. I've brought it back to the dealer 3 TIMES to have them check it too and they aren't finding anything loose either. When they heard the noise they said it was coming from the valves.

Also Dinan told me the same thing about how it's normal. They said you can hear it on their video on their website. I didn't. They also told me the stock does exhaust does the same thing too but I've never heard any noise like that come from the stock exhaust. I've already been to the dealership too many times now and I don't see anything wrong. Not sure what to do now. Sounds like ass on startup but seems to go away after warming up

[possible335i2008]

Originally Posted by placebo0311

Yep, that's the same damn rattle I hear on my car too. I've checked the clamps and made sure everything was tight. No change. I've brought it back to the dealer 3 TIMES to have them check it too and they aren't finding anything loose either. When they heard the noise they said it was coming from the valves.

Also Dinan told me the same thing about how it's normal. They said you can hear it on their video on their website. I didn't. They also told me the stock does exhaust does the same thing too but I've never heard any noise like that come from the stock exhaust. I've already been to the dealership too many times now and I don't see anything wrong. Not sure what to do now. Sounds like ass on startup but seems to go away after warming up

I'm not getting this problem at all, how did your shop put the valves together? There are screws that need to be tightened for the brace that holds the actuators. There is in one in particular in the middle of the brace.

[placebo0311]

Originally Posted by possible335i2008

I'm not getting this problem at all, how did your shop put the valves together? There are screws that need to be tightened for the brace that holds the actuators. There is in one in particular in the middle of the brace.

Wow not at all? Damn. I can try taking the valves off and see whether they tightened them. I don't suppose there are any pics of this anywhere just to make sure I'm looking at the right thing?

[possible335i2008]

Originally Posted by placebo0311

Wow not at all? Damn. I can try taking the valves off and see whether they tightened them. I don't suppose there are any pics of this anywhere just to make sure I'm looking at the right thing?

It's a pita once it's on bc you have to take the whole section down. I totally forgot to do and had to go back and do it, so I have plenty of experience doing it

I would just wiggle the brace and see if there is a lot of play in it to test it

[Dinan_Engineering]

Originally Posted by placebo0311

OTHER DINAN EXHAUST OWNERS:
I have a question regarding exhaust rattle. After recently installing this, I noticed rather loud rattling noises coming from the valves. It only seems to happen during a cold start, and after a minute or so they seem to dissipate under normal driving conditions (I think, as I can't hear anything on the highway and I don't hear anything when stopped but of course the vehicle isn't under load). I need to check further if I can hear them when driving at low RPM (same as cold start RPM). This just may be me being an noob to BMW and to Dinan products, but is anyone else getting this rattling noise? Either on this exhaust or other Dinan exhausts with valves? Just want to make sure I'm not going crazy. Thanks forum!!!

Originally Posted by BarryB

I just got off the phone with Andrew at Dinan. He says we will hear that "rattle" on cold start only for about 30 sec. It is normal as the valves are closed on cold start and we're hearing the air being forced past the valves. Will go check my car now after driving to work and see if it rattles after being warm. Shouldn't per Dinan.

Originally Posted by possible335i2008

They didn't tighten down one of the clamps I bet, that shop sucks lol. I would honestly if I were you take a look myself and check that all the clamps are tighten and that the pipes aren't touching the heat shields

For the cold start "rattle" -- the explanation BarryB was given is spot on. The valves are shut on cold start from the factory and what you are hearing is the air forcing its way around the valve. The valve itself is slightly smaller than the opening when cold to account for heat expansion when the system gets warm. Too tight a tolerance and the valve gets stuck. To wide a tolerance and its chattering all the time. This is only audible during cold start and will dissipate after that 30 seconds or so as the system heats up and the valves open. Even on the stock exhaust you would have heard some slight "rattle". The difference is the stock muffler has a bunch of deadening that muffles the excess force and minimizes the condition.

BarryB - your video is a bit different as you are obviously getting the rattle after its warm as well and only on the one side. Makes us believe its possibly a clamp/pipe touching the heat shields as mentioned above or maybe a bad valve. Easy to check the first possibility quickly enough. If it is a bad valve the system would be replaced and the old one sent in so we can inspect it and determine if there is a modification that needs to be made. At the moment though its an isolated case as far as we can tell.

[BarryB]

Originally Posted by Dinan_Engineering

For the cold start "rattle" -- the explanation BarryB was given is spot on. The valves are shut on cold start from the factory and what you are hearing is the air forcing its way around the valve. The valve itself is slightly smaller than the opening when cold to account for heat expansion when the system gets warm. Too tight a tolerance and the valve gets stuck. To wide a tolerance and its chattering all the time. This is only audible during cold start and will dissipate after that 30 seconds or so as the system heats up and the valves open. Even on the stock exhaust you would have heard some slight "rattle". The difference is the stock muffler has a bunch of deadening that muffles the excess force and minimizes the condition.

BarryB - your video is a bit different as you are obviously getting the rattle after its warm as well and only on the one side. Makes us believe its possibly a clamp/pipe touching the heat shields as mentioned above or maybe a bad valve. Easy to check the first possibility quickly enough. If it is a bad valve the system would be replaced and the old one sent in so we can inspect it and determine if there is a modification that needs to be made. At the moment though its an isolated case as far as we can tell.

Thx, going back to Carbahn next week and will report back. It does sound like the heat shield issue again (and related to pushing the tips in that far, I believe)

[Dravit_M340i]

Dang was about to pull the trigger on this set up but I don't need to hear that rattle on a $2k upgrade! Does that mean that you will hear this constantly when all 4 valves aren't open? EX. driving in comfort or eco?

[placebo0311]

Originally Posted by BarryB

Thx, going back to Carbahn next week and will report back. It does sound like the heat shield issue again (and related to pushing the tips in that far, I believe)

So is your rattle NOT during cold start? Or is this after the car has been warmed up?

[Gdiddy23]

I'm still probs gonna buy one. Was kinda waiting on AWE to compare but it's halfway through 2020 now with no updates from them

[BarryB]

Originally Posted by placebo0311

So is your rattle NOT during cold start? Or is this after the car has been warmed up?

I think I have both ie the cold start noise and the clamp rattle. I'll let her idle and listen for 30+ sec on cold start in the am

[BarryB]

Originally Posted by PETES_M340i

Dang was about to pull the trigger on this set up but I don't need to hear that rattle on a $2k upgrade! Does that mean that you will hear this constantly when all 4 valves aren't open? EX. driving in comfort or eco?

Do it. I think mine started after the install so something moved and it was quiet for a while. Again, am going back to the shop after Memorial Day. Will report back

[Dinan_Engineering]

Originally Posted by PETES_M340i

Dang was about to pull the trigger on this set up but I don't need to hear that rattle on a $2k upgrade! Does that mean that you will hear this constantly when all 4 valves aren't open? EX. driving in comfort or eco?

No. The only time you would potentially hear anything is the first 20-30 seconds of cold start. I went to a ridiculous amount of concerts in my youth and my hearing isnt the best so maybe I'm a poor evaluator on this but the only time I hear anything is when I am paying especially close attention to it and right up on the exhaust during a cold start.

Originally Posted by BarryB

Thx, going back to Carbahn next week and will report back. It does sound like the heat shield issue again (and related to pushing the tips in that far, I believe)

You got me thinking with that comment so I'm going to have them rack the M340i this morning and experiment with the pushed in tips to see if there is some variable we didnt notice with clearance and the clamp (again, we don't push them in as far as most of the market it appears). May be something we just need to add in and notate on the instructions for that instance where a clamp needs to be situated a certain way or the heat shield pressed in a certain spot or something.

[Cabby]

Originally Posted by Dinan_Engineering

You got me thinking with that comment so I'm going to have them rack the M340i this morning and experiment with the pushed in tips to see if there is some variable we didnt notice with clearance and the clamp (again, we don't push them in as far as most of the market it appears). May be something we just need to add in and notate on the instructions for that instance where a clamp needs to be situated a certain way or the heat shield pressed in a certain spot or something.

Now that's service!

[BarryB]

Thank You Dinan. They did say they had to slide the clamp forward to get the tips back how I like them. Let us know.....

[Dravit_M340i]

Originally Posted by BarryB

Do it. I think mine started after the install so something moved and it was quiet for a while. Again, am going back to the shop after Memorial Day. Will report back

Originally Posted by Dinan_Engineering

No. The only time you would potentially hear anything is the first 20-30 seconds of cold start. I went to a ridiculous amount of concerts in my youth and my hearing isnt the best so maybe I'm a poor evaluator on this but the only time I hear anything is when I am paying especially close attention to it and right up on the exhaust during a cold start.

Thanks and good to know! Curious to see if it has to do with the tips pushed in (how I would like them as well). It does seem like as soon as the camera isn't right up on the exhaust it becomes unnoticeable but hard to tell when not actually hearing it in person. I love how Dinan is extremely responsive and willing to investigate the cause on the forum. For that you have definitely earned my business!

[BarryB]

Can't say enough things about the product and the support. I don't mind dealing with some growing pains being an early'ish adopter, especially with the pushed in look.
Stay tuned and thanks Dinan.

[Dinan_Engineering]

Quick update:

In the photo below you will see a closeup of the clamp position on the passenger side outside tip using our suggested tip length. Photo isnt the best but given the small amount of daylight to capture it all its the best I could get.

When the clamp is positioned vertically with the tightening bolt at the top (where most prefer to have it so visually it looks clean) there is a 1/2" or so of clearance before the heat shield dips down and would interfere with the clamp. In this configuration (Dinan tip adjustment) this doesnt matter since the exhaust will grow away from the obstacle when its hot.

However if you move the tip in a 1/2" or more you will have to modify the heat shield to accomodate the clamp (even if you rotate it its pretty close to the outside heat shield so that would need to be modified slightly). Not a huge deal since the heat shield is pliable and can be done by anyone using some "gentle but firm" taps from a mallet or like instrument to meld the offending areas. Depending on how far you push the tips back will determine how much of the heat shield will need to be modified. In a shop environment this would be done without instruction.

The drivers side has the same hump down but it is farther back in the piping by another 3/4" or so so unless you push them really far in there would should not be any heat shield modification on that side. Even if you do it would be incredibly minor.

From a pushed in tips standpoint that's what we could determine as to potential additional sound sources. One of the guys is driving it home and rallying it with that configuration just to see if something else may come up after use but we arent expecting anything from what we saw.

So for BarryB if it is indeed something with the heat shield then maybe the clamp rotated a bit to where they didnt squish a bit of it down and its now rubbing. Or it still could be a faulty valve if its not rubbing at all. I guess we shall find out once Carbahn takes a closer look at it.

[placebo0311]

Originally Posted by Dinan_Engineering

Quick update:

In the photo below you will see a closeup of the clamp position on the passenger side outside tip using our suggested tip length. Photo isnt the best but given the small amount of daylight to capture it all its the best I could get.

When the clamp is positioned vertically with the tightening bolt at the top (where most prefer to have it so visually it looks clean) there is a 1/2" or so of clearance before the heat shield dips down and would interfere with the clamp. In this configuration (Dinan tip adjustment) this doesnt matter since the exhaust will grow away from the obstacle when its hot.

However if you move the tip in a 1/2" or more you will have to modify the heat shield to accomodate the clamp (even if you rotate it its pretty close to the outside heat shield so that would need to be modified slightly). Not a huge deal since the heat shield is pliable and can be done by anyone using some "gentle but firm" taps from a mallet or like instrument to meld the offending areas. Depending on how far you push the tips back will determine how much of the heat shield will need to be modified. In a shop environment this would be done without instruction.

The drivers side has the same hump down but it is farther back in the piping by another 3/4" or so so unless you push them really far in there would should not be any heat shield modification on that side. Even if you do it would be incredibly minor.

From a pushed in tips standpoint that's what we could determine as to potential additional sound sources. One of the guys is driving it home and rallying it with that configuration just to see if something else may come up after use but we arent expecting anything from what we saw.

So for BarryB if it is indeed something with the heat shield then maybe the clamp rotated a bit to where they didnt squish a bit of it down and its now rubbing. Or it still could be a faulty valve if its not rubbing at all. I guess we shall find out once Carbahn takes a closer look at it.

Attachment 2316287

How do you tell if it's a faulty valve? Are there any tell tale signs?

[Dinan_Engineering]

Originally Posted by placebo0311

How do you tell if it's a faulty valve? Are there any tell tale signs?

Nothing super specific but the valve essentially has one job— to open and close when it's told to so if it doesn't open or never closes either the motor is bad or the flapper is stuck for one reason or another and therefore faulty. Other then that if it chatters when the system is warm and idling or otherwise (not cold start) it's usually a sign of excessive play in the flapper mechanism. Depending on type of valve it sometimes can be resolved by a stiffer helper spring or spreading out the fixing bow for a more taut mechanism. If that doesn't resolve it it would be something out of tolerance from a production standpoint most likely. We QC the valves to a pretty stringent tolerance level so I would like to think that the chances of a faulty valve being actually used is pretty small but who knows.

[BarryB]

I will let you know next week.....