[J_C]

The warranty of my 2020 M340i is finally over so just installed a catted downpipe with bm3 stage 2.

I'm very happy with it but the cold start is damn louder than I expected and I found a feature to turn off the cold start in the bm3 app.

What is the downside if I turn off it? Is it harmful to the engine?

Thanks for any advice.

[BingoTheClown]

Originally Posted by J_C

The warranty of my 2020 M340i is finally over so just installed a catted downpipe with bm3 stage 2.

I'm very happy with it but the cold start is damn louder than I expected and I found a feature to turn off the cold start in the bm3 app.

What is the downside if I turn off it? Is it harmful to the engine?

Thanks for any advice.

I am not a mechanic, but I have read that the cold start heats up your Catalytic Converter. In theory your C-Convert does not work properly until it's heated up.

If that is not accurate - someone else can chime in. I am not that knowledgeable, but I read a lot haha.

[Prophet26]

Originally Posted by J_C

The warranty of my 2020 M340i is finally over so just installed a catted downpipe with bm3 stage 2.

I'm very happy with it but the cold start is damn louder than I expected and I found a feature to turn off the cold start in the bm3 app.

What is the downside if I turn off it? Is it harmful to the engine?

Thanks for any advice.

The reason for the cold start is to heat up the catalytic converter quickly as it cannot do its job of decomposing exhaust gases when it is cold. Since you are not catless, I would retain the cold start.

I have mine off since I am catless. Only “downside” is the oil & coolant do not warmup as quickly for obvious reasons.

[J_C]

Originally Posted by BingoTheClown

I am not a mechanic, but I have read that the cold start heats up your Catalytic Converter. In theory your C-Convert does not work properly until it's heated up.

If that is not accurate - someone else can chime in. I am not that knowledgeable, but I read a lot haha.

Thanks!

[J_C]

Originally Posted by Prophet26

The reason for the cold start is to heat up the catalytic converter quickly as it cannot do its job of decomposing exhaust gases when it is cold. Since you are not catless, I would retain the cold start.

I have mine off since I am catless. Only “downside” is the oil & coolant do not warmup as quickly for obvious reasons.

Thank you for the input!