[Maxdog]

Just noticed on my 14 335 when eng cold first few minutes hardly any flow comes out of left tailpipe. Is that normal?

[Hernandiaz11]

Yes that's normal, there's a valve on the left tail-pipe. It closes to increase back-pressure to help the catalytic converter warm up faster.

[Maxdog]

Thx for the info

[rking117]

You might even hear it click when you start the engine. there is a golf tee mod on one of these forums if you are interested that creates quite an exhaust burble in some models. I would wonder if the F30 also has this availability.

[Hernandiaz11]

Originally Posted by rking117

You might even hear it click when you start the engine. there is a golf tee mod on one of these forums if you are interested that creates quite an exhaust burble in some models. I would wonder if the F30 also has this availability.

The golf tee mod works on the E9X models because the exhaust valve was controlled pneumatically (with an air hose). F3X models have an electric motor to control the valve so there isn't a way to keep the valve open with a golf tee. The valve can be locked in the open position other ways though. You can remove the pin that connects the motor and valve and use a modified clamp to keep the valve open.

This is difficult to explain clearly without pictures. There's a member on here who modified a hose clamp.