Muffler valve open/close logic

[noogie]

How does the logic work on the muffler valve? Based on what I can tell, it seems to work like this:

Sport mode: valve is always open no matter the load on the engine
Normal mode: valve is closed under idle and low load

What about other scenarios such as:
Normal mode mid load?
Normal mode high load?

Sponsored

 

[J29DB03]

Normal mode closed all the time, Sport mode opened all the time once it reaches a particular temperature (couple minutes after cold start). And that’s more specifically attached to the engine setting in Sport Individual. If you have that set to Normal then the valve will be closed when in Sport mode.

 

[FuzzyRev]

Here's one for ya on the 2023 MT..

SPORT: always open

NORMAL: closed under 3500 RPM* unless heavy throttle

*Valve opens automatically regardless of load at 3500 RPM in gears 1-4, then opens at 3250 RPM in 5th gear, and 3000 RPM in 6th.

Not making this up

 

[noogie]

So it sounds like we have conflicting information unless MT gets its own muffler flap logic.

 

[ColonelAdama]

Here's one for ya on the 2023 MT..

SPORT: always open

NORMAL: closed under 3500 RPM* unless heavy throttle

*Valve opens automatically regardless of load at 3500 RPM in gears 1-4, then opens at 3250 RPM in 5th gear, and 3000 RPM in 6th.

Not making this up

Will report back, never driven my MT in normal mode ?

 

[Pizza]

I've always heard that in standard mode it will crack open the valve on deceleration for the burbles/pops

 

[FuzzyRev]

unless MT gets its own muffler flap logic.

I'm almost positive it does, having owned an AT prior to this

 

[alan7467]

Old post, but swapping to an aftermarket catback made the valve behavior in normal mode VERY apparent. I honestly didn't notice it before. Now It's huge bump in sound when I hit 3,500 RPM in gears 1-4.

Honestly not a fan. I drive my auto in normal/manual mode fairly often, and it's really easy to hit 3,500 RPM and go into loud mode unintentionally now.

 

[Loco38SUP]

Here's one for ya on the 2023 MT..

SPORT: always open

NORMAL: closed under 3500 RPM* unless heavy throttle

*Valve opens automatically regardless of load at 3500 RPM in gears 1-4, then opens at 3250 RPM in 5th gear, and 3000 RPM in 6th.

Not making this up

Mine is the same way but I’m AT.

-RJM

 

[FuzzyRev]

Mine is the same way but I’m AT.

-RJM

You got two more gears homie, what's happening with those? I never tested it with my 21. Granted, you'll have to be scootin right along to hit 3,000+ RPM in 8th if I remember correctly..

 

[razorlab]

If only people could see the calibration tables in the DME for this.

 

[Loco38SUP]

You got two more gears homie, what's happening with those? I never tested it with my 21. Granted, you'll have to be scootin right along to hit 3,000+ RPM in 8th if I remember correctly..

Mine doesn’t necessarily open at a certain RPM. When I mash the gas it opens, see 5th gear log. I didn’t capture when the RPMs came back down to see when it closes again.

I will mess around with it once I pull the car out of hibernation.

-RJM

Sponsored