Ianmtx

iTrader: (4)

Hey everyone, since I'm thinking about going all out with my exhaust, testpipes/ypipe/topspeed catback, I found this Apex Exhaust Control Valve to help control the sound on the fly if I ever needed to (cops etc.) My question is, with the ECV opened all the way, would it distort the exhaust too much and do you think it would sound different? (Putting it in between the catback and the ypipe)



Apex ECV: http://www.nipponpower.com/product.phtml?p=171

I'm looking at the 80mm one.

davidv

iTrader: (2)

That's an interesting mod. It opens and closes the exhaust system, but you have no outlet for the exhaust. When the valve is closed where does the exhaust go? You have no cut-out that is open to the outside.

Ianmtx

iTrader: (4)

See that's the thing that worries me, if it closes, wouldn't that cause serious backpressure and the engine would have nowhere for the exhaust gases to go! I wouldn't close it all the way, but I'm sure that might cause some problems. Maybe if I drilled holes in the disc?

Wired 24/7

iTrader: (2)

This is meant to be used with a direct cut-out of your exhaust. NOT to be used without adding a cut-out section of your exhaust.

I would not recommend it especially for N/A.

The idea is, you would weld a new section near the test pipes. The new section would act as an open port to the atmosphere. This is a bad idea for your sensors and it won't exactly do much for power if you're N/A.


If you completely block your exhaust, ANYTHING inside there will break.

Shove a potato into an exhaust pipe, and start up the car. Potato cannon.

If you're worried about cops and sound, your only viable option is to install an exhaust that is not too loud.

for example, if you check out tanabe-usa's website, they offer a wide variety of great sounding exhausts that are rated "under 93dB" which is supposedly below the limit of most states sound threshold for legality.

mynismo.com sells some of these exhaust such as tanabe medalion touring

davidv

iTrader: (2)

What he said. A cut-out (or dump) looks likes this. Essentially you are running straight headers.

Wired 24/7

iTrader: (2)

Just to add to what I was saying about the sensors...

your O2 sensors are HEATED sensors. They are also meant to run with hot air. Guess what happens when cold air hits a hot sensor. Same thing that happens when you take a hot dinner plate and dunk it into ice water, it breaks.

When you come to a stop, with your exhaust wide open, cold air can hit the sensors.

Ianmtx

iTrader: (4)

Well is there anything out there that might kind of be like what I'm looking for?

davidv

iTrader: (2)

Yes. I posted a mechanical dump above. You want one that is solenoid operated. When installing a dump on a street legal Z, you have a problem. How do you tune the car? With the dump OPEN or CLOSED?

Wired 24/7

iTrader: (2)

Just as david posted basically.

If you go to a tuner, or any event where people race their cars, I guarantee you will find someone who is knowledgable about so-called open dumps.

Again, this is mostly for F/I applications, but if you want to do it for N/A go for it.

Ianmtx

iTrader: (4)

Did you guys go to the link and read about it? I don't think it closes all the way. It's NOT a dump, it's made to control the dB of the exhaust system.

davidv

iTrader: (2)

Thanks. Maybe I jumped to conclusions. Adjusting the exhaust flow rate will change the noise level, but I still don't like the concept. An easier way to control noise is to keep your foot off the gas.

Hydrazine

iTrader: (53)

I have used a similar device for back pressure testing on the dyno. Its basically a valve that even when closed all the way, its still not fully blocked because the butterfly valve is undersized. (It can never fully block the flow.)

The one shown in the picture may or may not fully block the flow but if it does, you could drill holes like you said.

If you use it, put it as far back as possible and preferably after a muffler or resonator for more effective sound reduction.

Ianmtx

iTrader: (4)

Alright thanks for the input guys. Because I wanted to get an exhaust that was super loud, but obviously there's some times that you don't want your exhaust to be loud, but it will be even if you aren't accelerating that hard. That's why I was interested in this part.

davidv

iTrader: (2)

The Exhaust Control Valve can be placed anywhere you have a 2-bolt connectors. Depending on you set-up, you may need 2 valves. Go for it!

first350

iTrader: (24)

Hey, I've just gone through the past few months trying this out...I have Headers, AAM TPs/Y-pipe/3" single, needless to say it's loud; I was looking to quite it down for the street, but be able to open it up for autoX (I had AAM flash my ECU for the open exhaust)

what I tried: I messed around w/ my silencer and reduced the hole size to aroun 1/2"-3/4" diameter...this was the area at the tailpipe that reduced the exhaust sound to near stock (I wake up early, and don't want to bother my neighbors).
-I then got a simlar electric valve, drilled the same size hole and installed it just after the Y-pipe.
-when it's open, it's like normal (YEAH!...I love the sound of AAM's 3")
-when it's closed (only allowed the 1/2"-3/4" hole), the exhaust sounded like crap...the electric valve would rattle and would even cause the engine to go all wierd under WOT (it didn't do this when I had the silencer modified)

in the end, I tried a few different things, but the rattling of the valve drove me crazy...I loved the idea of how this would work, but I think to get it to sound right, you'll need to spend lots of time for trail and error-->$$

**IIRC, the new Vette has some kind of exhaust bypass for the mid-pipe/muffler...so that under WOT, something opens up to allow a less-restrictive for the exhaust gases. I'm guessing the only way to get an electric bypass valve to work is to have the open area not be a drilled portion in the middle of the valve, but to have the whole circumfrance cut away...that way there's nothing to rattle. I still like the idea, but don't have the Time or $$ to get it to sound right.

Ianmtx

iTrader: (4)

So are you talking about like cutting around the edge of the whole circle to make it smaller inside of the pipe when it's fully closed so the gases can pass around the edges of it instead of like a hole through the middle?

first350

iTrader: (24)

exactly...then there shouldn't be any rattling. I don't think it'd be too hard to try, but it's going to take time to figure out the diameters that make the car quite enough on the street and still perform (if the gap is too small, the exhuast will be low enough, but performance would greatly suffer...and the oppsite goes if there's too much open area)

Wired 24/7

iTrader: (2)

Well looks like I was wrong about my assumptions here. Maybe you should give it a try.

Ianmtx

iTrader: (4)

I don't think I'll have too much of a problem with the performance aspect. I plan on keeping it open more than closed.

But thanks for the good advice guys.