I’ve lost the advert/link for a gadget I need some advice on!!!. So does it make sense if I say- electric exhaust cut-out/port devices?, ie the things that are fitted on the Z06 exhaust to bypass the mufflers?

If anyone understands my drivel, I’d like to fit these things to a C4 with a magnaflow cat-back. I want to retain the magnaflow mufflers (so I can come home late at night) and I guess it’s an easy enough job to fit these cut-outs forward of the mufflers.

Problem is- I don’t like the idea of having the exhaust gases pumping out under the car, so I’m wondering if I could put extensions on the loud side of these cut-outs so that the gases exit somewhere near the normal exhaust tips.

If anyone has a clue what I’m talking about (I don’t!), any advice/thoughts?. How could I make it not look horrible with a couple of spare tips?

I get what you are saying.

I haven't done it, but I have pondered it and am in a similar boat. I love how my exhaust sounds most of the time, but there are times, where I'd like to quiet it down a bit. (Say leaving at the butt crack of dawn for a day of racing...as I do like my neighbors and for the time being they still seem to like me!)

My thoughts on this are:
1) Buy a spare set of the mufflers off of a C6 (2.5" inlet, I think) or Z06 (3" inlet, I think). As long as they fit, which is another question altogether as the tips are mounted at the bottom of the oval.

Not mine btw:

http://cgi.ebay.com/ebaymotors/2007-Z ... uckQ5fPartsQ5fAccessories

http://cgi.ebay.com/ebaymotors/09-Cor ... uckQ5fPartsQ5fAccessories


2) The second option I've been thinking of, is getting my brother (brilliant w/ electronics) to wire up a simple dial switch running off of the tach signal that at the dialed in RPM sends 12v to a motorized butterfly valve that you install in one of the tips of the mufflers. Therefore you set the RPM they open at, 0 RPM always open, 3500RPM opening, or say 7000RPM open (aka closed/quiet.) However besides talking about it, we haven't pursued this.

In yours and my case, the other tip of the muffler would need to probably be plugged somewhat, but who knows, maybe knocking out half of the tips on the magnaflow would quiet it down enough.

You would have to bastardize you beautiful magnaflows and weld something like this in between the end of the muffler and the end of the tip.

These are 3" I don't know what size you would need for the magnaflow tips.
http://cgi.ebay.com/ebaymotors/QTP-DU ... uckQ5fPartsQ5fAccessories

Is that what you were thinking?

Well done RedGut86, you grasped it much better than I explained.

I see where your going with C6/Z06 muffler option with the devices already fitted. I’ve never looked close at these mufflers but my first thought is they are really big and would be a heck of a job to install on a C4 (if at all possible!). Am I right in thinking the C6/Z06’s mufflers automatically open the valves at a given rpm?.

That link you posted to the electric butterfly valves is exactly what I was thinking of. The problem I see is these need to be installed forward of the muffler and without some kind of extra pipework would leave the exhaust gases coming out under the car which is not a good option. ‘I think’ the ideal solution would be specially constructed mufflers with dual in’s as well as dual out’s, one half being muffled the other half straight through, but this would be another hack of a fabrication job.

My thought was if I could possibly run another pipe from the loud side of the cut-out valve, around the outside of the mufflers to exit near the existing tips!. I don’t even think that is practical. My latest idea is a pair of ‘stinger’ type mufflers each side and gut the innards of two of them, but then I’m losing the magnaflows.

I don’t really need any electronics, I think I’d like to be able to just flip a switch.

This is probably a project that will bite the dust, I can’t see a solution.

There's a bunch of those butterflys available, saw a setup on Stacey David's Gearz (Speed) that opened up a hotrod's headers right after the collectors.

Assuming you're doing this for the sound increase, using dual stingers won't be that much louder unless one's straignt thru.

Dumping the exhaust under the car wouldn't give me any concerns. Hotrods have been doing it forever. Ever see a 57 Chev. with pipes that stop at the pumpkin? If you open the b/fly at idle, you probably won't be sitting in that spot for very long and whe you're at speed, the exhaust is blown away.

If you want to keep the Magnaflows, the easiest is to puy the b/fly and a tee in front of them.

Interesting idea, good luck.

I went a different route on my LT1, chambered cat backs with muffler elims. The chambered sections (ala 67 sidepipes) sit where the resonator use to be, then straight thru to the tips. The whole system from the cats is straight thru.

It's quiet enough when you short shift and lug (under 2000) that the cops don't don't even look when you go by. It really starts to bark at 2500 to 3000 and gets quite loud. At cruise, 70mph in 6th, you can barely notice it and no resonance.

How do you plan on tuning your car?

Exhaust open and just live with the results when it's closed?

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Bill, yes it’s just for sound, but I do need to keep it quiet at times. It’s uphill to my home and late nights/early mornings would make me very unpopular otherwise I’d go straight through from the cats too. Yep, the idea was to gut the innards of one stinger each side.

Where the exhaust exiting under the car comes in is because I had one of the standard mufflers blow a small hole in the front, perhaps its me but the fumes in the cabin were terrible (eye watering) even when moving. I also don’t really like the idea of additional heat under the car, I can already keep a Big-Mac cooking in the center consol!

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I hadn’t even thought of that Brian. Would it be a big issue with fuel mixture and timing etc?

I don't recall who makes the ones I've seen, but they were built into a flange and could easily have pipe bolted on after them.

Exhaust cutouts make sense if you have a quiet (stock) system in place that you're bypassing.

Otherwise it's just a choice between loud and louder, which seems pointless.

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Not to push what I'm running but, I too live in a residential area where people would freek if the car was loud. Speed limit's 25 & I just cruise along in third, it's not loud at all.

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typically a higher flowing exhaust leans it out.

I don't know how the C6Z06 deals with it.

The computer may receive a signal, or the open at set rpm so it's built into the map.

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You just nailed Nelson V's Chevelle. He has a built 454 with all the goodies... killer stout motor, really. but the exhaust is loud... and the cutouts are insanely loud.

The again, he is losing performance to a non-locking torque converter, but that's another issue.