Cheap manually-controllable variable mufflers?

I'm shopping for a muffler for my 'rolla to replace the ricey fart can that the donor car has on it. I can either buy a cheapo stock-ish muffler or import something.

I don't want anything too loud and obnoxious, a variable exhaust would be ideal. I'm looking at the Dynomax VT and the Xforce Varex. Both are mufflers that use a butterfly valve to bypass the muffler internals and let the muffler work like a straight pipe, on the VT it's controlled by a simple springload mechanism (opens up with higher flow), on the Varex it's servo-actuated and can be dynamically controlled with some kind of ECU or manually adjusted with a remote (therefore you can run the engine hard while staying quiet - better!).

Those electronic doodads somehow come up to a $200+ difference on the Varex. It's a difference I might be able to grudgingly tolerate if I wasn't facing massive import duties and paying for it all on a 3rd-world income.

So are there any cheaper manually-controllable variable mufflers out there?

Supertrapp springs to mind, but I'm doubtful about their ability to not be loud and obnoxious.

Supertrapps can indeed be setup to be either really annoying or not too obnoxious. At least with their motorcycle pipes.

You need one of these devices. They eliminate ricey exhaust sound, and are manually controlled by the right foot. Some people claim that they add power too.

When I said manually-controllable I meant controllable from the driver's seat, not me having to add and remove plates from the muffler I've heard Supertrapps are useful for dialing down massive noise.

High temperature, 1/4 turn, Butterfly valve with a push pull cable. Get an old dash mounted choke assembly to operate it.

RossD wrote: High temperature, 1/4 turn, Butterfly valve with a push pull cable. Get an old dash mounted choke assembly to operate it.

I was actually thinking about this, I could mod the Dynomax VT, maybe use some kind of vacuum actuator which would handle the high temps well (the butterfly's axle isn't centered on this model so some force would be required to hold it closed). I'd rather see what other options are available first though.

Servo actuated exhaust cutout?

Or find a used wastegate and actuate it with manifold vacuum.

In reply to kb58:

Oh...amazon has a 46mm (1.8") external wastegate for $68

That would probably work...

bludroptop wrote: Servo actuated exhaust cutout?

Got a product link? I'm not looking for just this, but adding this into the VT would make it just like the Varex...

Edit: found it:

http://www.summitracing.com/search/part-type/exhaust-cutouts/exhaust-cutout-installation/bolt-on

Hmm not cheap...

kb58 wrote: Or find a used wastegate and actuate it with manifold vacuum.

Vacuum isn't what actuates wastegates, though.

I don't really see a way that a wastegate would work, unless you just let it do its wastegate-y things and just open when enough exhaust flow is created to force it open.

Pretty rough without a turbo.

My next question is: Why?

Aren't you running MS? Set up the MS to switch the valve based on your inputs, such as TPS, RPM, load, dash switch if you want it disable, etc. and make it automatic. Many modern engines use this approach to improve power at high/low RPM as necessary (heavy accelerator pedal application) and still have a nice quiet ride the rest of the time.

At $120 bucks for the valve at Summit, that seems pretty cheap to me for a purpose built part. What is your idea of "cheap" and what kind of quality are you expecting?

Bryce

I will be running MS later on, I was thinking about having it controlled by the MS, but when you add up all the stuff I'd need to make something like the Varex it ends up costing almost as much, guess it's not so overpriced after all...so the question is really how much I can spend.

SRT 8 charger rear resonators have a butterfly in them that kick open only when enough pressure is presented. When they open, they're straight through. When they are closed, the exhaust gasses have to pass through the extra resonator.

While not manually controllable, you should be able to find a take off or two that might work on a budget. I paid under $50 for my pair.

OK thought about it, going with the Dynomax VT. I'd really like the Varex but I don't like it 3-4x more than the VT, and I need that money for a new rear spring setup.

yamaha wrote: SRT 8 charger rear resonators have a butterfly in them that kick open only when enough pressure is presented. When they open, they're straight through. When they are closed, the exhaust gasses have to pass through the extra resonator. While not manually controllable, you should be able to find a take off or two that might work on a budget. I paid under $50 for my pair.

Sounds like the same thing as the VT but cheaper, I'll look into this. You know what years had this setup?

http://www.racelandus.com/exhaust-systems/cut-out-exhaust-systems.html

^Huh those things are cheaper than just the valve by itself...still I think that piece + a cheapo muffler + adding in a straight pipe system would be most of the cost of the Varex but much less tidy.

Warlock muffler + GM heat riser valve + a little fab work= eggzachary what you are looking for...

Beat me to the heat riser idea...

Swank Force One wrote:

kb58 wrote: Or find a used wastegate and actuate it with manifold vacuum.

Vacuum isn't what actuates wastegates, though. I don't really see a way that a wastegate would work, unless you just let it do its wastegate-y things and just open when enough exhaust flow is created to force it open. Pretty rough without a turbo. My next question is: Why?

Yes it can. Wastegates have two ports, one above, and one below the diaphragm, so yes, engine vacuum can be used and will work well.

The heat riser thing, as he set it up there, is just like a Dynomax VT except the butterfly is controlled by intake vacuum level rather than exhaust flow. I could remove the vacuum actuator and attach a cable to it, and then have either manual control or drive the cable with a servo.

Fitting it on an AE92 in particular could be tricky because it uses a center-exit muffler jammed between the rear suspension and back bumper. Still a great way to get something very similar to a Varex for a lot less money, especially if you can junkyard-source that valve, you could probably do it all for under $200.

I think there are mufflers that have valves from the factory like the Maxima and a few others Quick google search found this

You just control it with the gas pedal

Yeah those are the same "spring door" design as the Dynomax VT, which is my fallback option and is quite affordable.