[jmr0311]

I'm just a car lover and don't have a lot of mechanical aptitude for cars. I have notice lately that my M235i is being doing a "gurgling" noise coming from the exhaust when the engine is revving down or when the transmission is changing gears.

Just for your information, I have the "Race Chip" on B level.

This is actually what is doing,

Exhaust Burble on Deceleration
An exhaust burble, or throaty popping noise which could be likened to a babbling brook, is has a different cause if it only occurs when suddenly backing off on a vehicle's throttle. Essentially, the sudden easing off the throttle causes an immediate decrease in exhaust emissions to the degree that atmospheric pressure surrounding the exhaust pipe pushes cool air up into the exhaust system. This air collides with the warm exhaust gasses and creates a rumbling not unlike thunder. Normally this will only happen if the tailpipe has too wide a diameter to maintain equalized air pressure, or there is a seam in the exhaust pipes which is not air tight.

[Knightelf]

Sooo what's the question?
The burble on overrun is normal if you're wondering... a lot of us love the burble

[BMW GENIUS]

Yeah are you pointing out a problem or just merely making a statement? I'm just confused as to what you're trying to tell us

[jmr0311]

I'm looking for what could be causing the noise I'm hearing. That statement is something I found online that I thought might be what is happening to my car.

The reason why I said that this could be what is happening on my M235i is because a couple weeks ago I started noticing exhaust fumes smell when I had the windows roll down on the driver side.

[jstnstr]

Seems like all normal things to me dude. Wouldn't worry much about it.

[BMW GENIUS]

It's just electronically controlled overrun due to the MPPK that comes standard in our cars. The DME is mapped to do that.