VF SS Series 2 Rear Muffler with Bi Modal

[Mattricho]

If I remember correctly someone else on the forum had a squeaky bimodal valve and sprayed graphite powder or silicon spray or something like that on there To stop the squeak.
As far as The operation goes I believe with the bimodals set to open it’s not actually open till 3000 RPM anything below that and the valve is shut regardless of what the setting is in mylink.

 

[myls362]

I found the post. I have asked the question. Thanks

 

[Mik 030]

Just to clarify the bimodal settings, if you have the bimodal on, the mufflers are open at idle but the close until 3000 revs when they open again. For me, this setup is good. When cruising at highway speeds, there is no dreaded drone.

 

[myls362]

Good news. Just picked up my car from the dealer. There is a service bulletin from Holden acknowledging the bi-modal squeak problem.

The fix was Loctite Silver Grade Anti-seize lubricant. This involved removing the rear mufflers to get to the bi-modal actuators. The tech then sprayed it in underneath the electrical bit as well as around the butterfly valve.

It was $360 in “warranty” labour. I will do it myself if there is a next time.

 

[PeteSS]

the factory mufflers have a spring in the valve mechanism that will open the valve once the power is removed from the electronic valve controller, when set to "quiet" or closed the controller will hold the valve shut.


you can unhook the spring and it will stop opening the valve when the vehicle is stopped

Spoiler: Picture: Spring

I want to put bi modals back on mine as its super loud on start up (due to cam and tune). Not a favorite with the neighbors at 7am every morning .
One of the reason's I haven't done it is I'm told the Holden Bi modals open on start up, even if you have them in closed position on the dash.

Does removing the spring fix this start up issue ? Also does it affect anything else in operating the bi modals ?

 

[stooge]

I want to put bi modals back on mine as its super loud on start up (due to cam and tune). Not a favorite with the neighbors at 7am every morning .
One of the reason's I haven't done it is I'm told the Holden Bi modals open on start up, even if you have them in closed position on the dash.

Does removing the spring fix this start up issue ? Also does it affect anything else in operating the bi modals ?

I dont have the ability to test the factory operation so i am not sure if the controller is sent the pwm signal to open on startup but an easy way to test it is take the controller off the muffler and plug it in and set it to closed and watch if it changes position when you start the vehicle.
Also check that the controller changes position when you open and close it on the dash and that will confirm the valve is being sent both duty cycles of the pwm to open and close.

The spring mechanism opens the valve when the pwm signal holding the controller closed is lost so unhooking the spring prevents that.
If the controller gets sent both duty cycles of the pwm to change state then unhooking the spring should not have any effect other than not opening the valve when the power to the controller is lost and if the pwm signal to open is not sent to the controller on startup then theoretically the valve should stay closed on startup with the spring unhooked.

 

[Holden17]

I want to put bi modals back on mine as its super loud on start up (due to cam and tune). Not a favorite with the neighbors at 7am every morning .
One of the reason's I haven't done it is I'm told the Holden Bi modals open on start up, even if you have them in closed position on the dash.

Does removing the spring fix this start up issue ? Also does it affect anything else in operating the bi modals ?

Alternatively, if the neighbours aren’t pre-occupied with doing life by 7am you could tell them to get a job ...unless shift workers of course.

 

[abuch47]

Everyone gets up at different times nothing to do with job or not.

I want to put bi modals back on mine as its super loud on start up (due to cam and tune). Not a favorite with the neighbors at 7am every morning .
One of the reason's I haven't done it is I'm told the Holden Bi modals open on start up, even if you have them in closed position on the dash.

Does removing the spring fix this start up issue ? Also does it affect anything else in operating the bi modals ?

Im 99.9% sure the bimodals stay closed if thats what you choose on mylink. I have mine with aftermarket relay set to permanent open or close and it definitely works. With the maloo open midsection the closed startup is still audible but no crackle, open is loud and crackles so it may not tame your open exhaust heaps but does help.

 

[clappa]

If in the closed position on the MyLink system, they are shut..ie, in idle, i have it set to closed position, and if i stick my head around the back of the car and look, its closed.

 

[Jackv8]

On this subject will an aftermarket catback system bolt up to the factory bi modal mufflers ?