Butterfly Exhaust valves

[Paintwerks]

Originally Posted by XY GTHO Ph III

Does anyone have Exhaust Butterfly Valves on there Cobra. I ask as I want to drive my Cobra to work but I leave around 5:30am so with the Cobra being so loud I will become know to my neighbours as that prick that starts his car at 5:30am in the morning guy. I saw a product that Harley's have on there bikes where a butterfly valve is placed in the exhaust and when closed 90% off it quietens the exhaust sound dramatically and when you get out on the freeway you can open it up 100% and you have the sound and performance like it was not there. Anyway I want to put those on my Cobra to lessen the noise when I start up and get around the neighbourhood, Thanks

The system is referred to as 'Bimodal'. The Xforce 'Varex' servo-adjustable bimodal mufflers are what you want. That said, with the Cobra's limited undercar space, I am not sure which of their units would fit?

Varex Mufflers

There is also the issue of legality. Despite HSV and Aston Martin (that I know of) having factory fitted, ADR approved bimodal exhaust systems, apparently to add a bimodal muffler to a vehicle that never had it from new is illegal. I guess you could get the car engineered with it after fitting and that would comply?

[gjkrv8]

Originally Posted by Paintwerks

The system is referred to as 'Bimodal'. The Xforce 'Varex' servo-adjustable bimodal mufflers are what you want. That said, with the Cobra's limited undercar space, I am not sure which of their units would fit?

Varex Mufflers

There is also the issue of legality. Despite HSV and Aston Martin (that I know of) having factory fitted, ADR approved bimodal exhaust systems, apparently to add a bimodal muffler to a vehicle that never had it from new is illegal. I guess you could get the car engineered with it after fitting and that would comply?

I had a look at the Varex a while ago too. The problem is their servo mechanism protrudes out the top a fair bit and where I wanted to put them under the Cobra floor, there just wasn't enough room.

I've seen a cobra at the Nationals that has the valve only option and diverts between a "loud" side non-mufflered exit and a "not so loud" rear mufflered exit.

cheers Gregg