[caspertraberg]

Hey! My 2015 N55 M235i has been tuned to MHD stage 1!
Specs: BMS CP, Eisenmann sport exhaust. OEM dp with cat!

I've enabled the "soft" burble tune for 1.2 seconds in sport mode. Is this bad for my car?

Video clip: https://drive.google.com/file/d/1TYs...w?usp=drivesdk

[H2O_Doc]

I'd say what I heard were pops and not so much burbles, unless I have my taxonomy of exhaust notes wrong.

[caspertraberg]

Originally Posted by H2O_Doc

I'd say what I heard were pops and not so much burbles, unless I have my taxonomy of exhaust notes wrong.

Pops then. Are they bad?

[mike@x-ph.com]

I do not recommend burbles on stock cats.

[subzero05]

yes it can cause damage to your car

[Sail Boat]

Originally Posted by mike@x-ph.com

I do not recommend burbles on stock cats.

You're literally the pro here so I'm not attempting to disagree with you...

... But I have a stock M235i that only has an axle back delete. Stock tune, stock down pipe. On hot days driving in sport mode, if I hold a gear on deceleration I can trigger massively loud gunshot noises at around 2500-3000 rpm. As far as I am aware, this is par for the course along the entire BMW M/Msport range, meaning this is considered normal operation.

If that is the case, why would "burbles" be bad for the stock catalytic converter which I believe utilizes the same core material as high-performance aftermarket street-legal down pipes?

[mike@x-ph.com]

Originally Posted by Sail Boat

You're literally the pro here so I'm not attempting to disagree with you...

... But I have a stock M235i that only has an axle back delete. Stock tune, stock down pipe. On hot days driving in sport mode, if I hold a gear on deceleration I can trigger massively loud gunshot noises at around 2500-3000 rpm. As far as I am aware, this is par for the course along the entire BMW M/Msport range, meaning this is considered normal operation.

If that is the case, why would "burbles" be bad for the stock catalytic converter which I believe utilizes the same core material as high-performance aftermarket street-legal down pipes?

the stock burble are very light and short. With a tune you can increase the duration and the aggressiveness. The more aggressive/long it is, the more stress it will cause on the cats.

You are probably fine with mild burble, of course whats considered mild is subjective and thats where it gets tricky

[The_otherM235i]

I mean, i use to have my shit firing gun shots and flames out the back so i'd say it's fine. It will wear out the cat faster but if you remove that and set it light you'll be fine.

[Aoxpr]

Originally Posted by mike@x-ph.com

the stock burble are very light and short. With a tune you can increase the duration and the aggressiveness. The more aggressive/long it is, the more stress it will cause on the cats.

You are probably fine with mild burble, of course whats considered mild is subjective and thats where it gets tricky

So what is a safe timing/aggression with an MHD burble on completely stock DPs and Turbos?
Also, is it possible to only have the burble tune on Sport Mode? Is this safer?

[mike@x-ph.com]

Originally Posted by Aoxpr

So what is a safe timing/aggression with an MHD burble on completely stock DPs and Turbos?
Also, is it possible to only have the burble tune on Sport Mode? Is this safer?

Since I have not seen any cat failures due to the burble, it's safe to say you can use any burble level on any downpipe safely.

[kevinbahnz]

I just picked up a 2015 yesterday and it has an afe intake and a p3 digital vent gauge on the driver side vent. The exhaust looks and sounds stock but it does have low gurgles on deceleration. How can I find out of it has and what tune it has.

[wantam235i]

Originally Posted by mike@x-ph.com

Since I have not seen any cat failures due to the burble, it's safe to say you can use any burble level on any downpipe safely.

Hey Mike, I saw this thread where someone melted an ER high flow down pipe within a month, you commented "Im sorry to hear that OP. We always recommend keeping burbles conservative unless you are running a fully catless pipe"

A bit confused as I have seen you on other threads say you run max burbles on your shop's m4.

Appreciate if you could clarify!

[wantam235i]

Originally Posted by kevinbahnz

I just picked up a 2015 yesterday and it has an afe intake and a p3 digital vent gauge on the driver side vent. The exhaust looks and sounds stock but it does have low gurgles on deceleration. How can I find out of it has and what tune it has.

This sounds like stock behavior, you could email protuningfreaks or MHD with your VIN and ask if they have your car on file, although I believe protuningfreaks might be limited with customer information.

You can try holding the resume button, this is the map switcher for BM3 would see the rpm gauge go to 1000 (or any other x000).

[mike@x-ph.com]

Originally Posted by wantam235i

Hey Mike, I saw this thread where someone melted an ER high flow down pipe within a month, you commented "Im sorry to hear that OP. We always recommend keeping burbles conservative unless you are running a fully catless pipe"

A bit confused as I have seen you on other threads say you run max burbles on your shop's m4.

Appreciate if you could clarify!

The shop's M4 has an aftermarket downpipe.

I always recommended to not max out the burble on stock downpipes. But with all the data we have now, I don't see enough data showing cat failures due to the bubble tune.

I cannot remember a single failure, but you say it happened at least once. Even then, 1 out of tens of thousands is not enough. It also could be due to a defective cat and not the burble.

[wantam235i]

Originally Posted by mike@x-ph.com

The shop's M4 has an aftermarket downpipe.

I always recommended to not max out the burble on stock downpipes. But with all the data we have now, I don't see enough data showing cat failures due to the bubble tune.

I cannot remember a single failure, but you say it happened at least once. Even then, 1 out of tens of thousands is not enough. It also could be due to a defective cat and not the burble.

Yea I think its probably a defective cat as well, some people were arguing on if the welds broke first then it melted.

Heres the thread btw, thought I originally linked it
https://f30.bimmerpost.com/forums/sh....php?t=1693551

[wantam235i]

Heres the other one thread where it happened. N55 as well
https://f87.bimmerpost.com/forums/sh...0#post27017700

[mike@x-ph.com]

Originally Posted by wantam235i

Yea I think its probably a defective cat as well, some people were arguing on if the welds broke first then it melted.

Heres the thread btw, thought I originally linked it
https://f30.bimmerpost.com/forums/sh....php?t=1693551

Originally Posted by wantam235i

Heres the other one thread where it happened. N55 as well
https://f87.bimmerpost.com/forums/sh...0#post27017700

Got it, the numbers of claims are so low, I don't think it's enough to advise everyone to stay away from burble.

Like everything else in life, there is a risk but in this case from the data we have its very low.