any active-exhaust-ed 24vs here?

[static]

was inspired by this a while ago: http://autospeed.com/cms/title_Butte...2/article.html

always felt like shutting up the noisy s50 (drown at low rpm sometimes makes me feel like someone is drilling my skull), but don't want to choke the nice straight-through exhaust and lose the powa up high
So i splurged and bought this: http://www.summitracing.com/parts/DTE-HR212-3V/
and a pair of ebay-special solenoid valves to control the amount of vacuum feeding the actuator on the butterfly exhaust valve in hopes of brewing my own active exhaust system.
Made up a little proto controller, which allows me to control the angle of the butterfly valve as i spin a handle of potentiometer (later to be substituted with real input from the exhaust back-pressure sensor, throttle angle, rpm, etc).

It's not on the car yet, but soon hopefully.
I can post progress with videos if anyone is interested.

Alex

[hoveringuy]

I've always wondered about those.. let us know how it turns out.

Isn't it an on/off affair with the vacuum solenoid?

[static]

not on and off at all. I guess it would depend on solenoid valves one would use. They should be fast acting and not too large of an orifice (and not too small, as otherwise it wouldn't supply/purge vacuum fast enough, or too fast which, i imagine, would make it on and off) my valves are 3mm orifice.
I didn't count, but it looks like i've achieved at least 20 positions between fully closed and fully open while spinning the pot.

here are some pics. I'll try to shoot a video of the thing in action

[matt]

So wait... that thing just sits in your exhaust and adds backpressure?

Seriously?

[JGood]

Wife beater beer!!!!!

[416stroker]

Cool but why not just run two mufflers on a street car?

[static]

Wife beater beer!!!!!

no wife here :pimp:

yea, pretty much creating backpressure when cruising and driving at low rpm

got two mufflers already, they are largest straight through magnaflows i could fit. I realized that as long as it's straight-through, there always bound to be nasty drone.

this is just an experiment anyway. it worked for the guy in the article

[10Toes]

330's have this.

[evil_twin]

Brilliant! I want to see this. I was going to go with a big baffled muffler and run an e-cut out in my.

[matt]

A lot of cars have that... my 328 did until I put an M3 muffler on it.

But just for the noise?

[z31maniac]

Seems like running a chambered muffler would acheive your sound goals without all this. And I can't imagine a quality chambered muffler really costing you much HP/TQ

[schwannman]

that looks complicated.

and e-cut outs suck! at least the one that i had on my civic. we just did it for the lulz but it was one with a valve like that and it was SUPER hard, if not impossible, to get it perfectly closed so it sounded like there was a major exhaust leak whenever it was "closed" said fuck it and bolted a plate in place of it. waste of money. unless it's a mostly track car and you dont care what it sounds like.

[evil_twin]

What e-cut out did you have? The one that QTP always has problems with the motor going out or the valve not closing all the way.

[turbo325i]

I always see these in the e46's at work. I always thought they were interesting... I like the idea. Do they come in 3.5"?