OdesiTT

Hi guys! I got a NA 06 Z with bunch of bolt-on's and 3" exhaust(2.5"HFC's to 3" midpipe). I noticed that I lost some power at low rpm after installing bigger exhaust with HFC's. Mid and High is awesome but I want to get back my torque. I seen some videos with Vacuum activated exhaust cutout but I can not figure out how it's connected. I want to hang it to one of catback tips, so I'll literally fave a single exhaust until WOT.
The question is:
1) Does actuator need to be connected to the vacuum source?
2) Is it possible to install some spring loaded butterfly valve, with a very wick spring, to make it automatically open when exhaust pressure rise?
3)What is a vacuum pressure near WOT?
4) If someone was Installing this on NA Z, what is your impressions?
Thanks!
P.S.: Sorry for bad English, I hope everyone can understand me.

dcains

iTrader: (15)

Of course, you need to hook it up to a vacuum source, as that's how the valve is actuated. Hooking that thing up to one of the tailpipes isn't going to do anything. You're supposed to hook it into the single output of the Y-pipe, before the rest of the exhaust, but even there, it's not going to make more power. Just headaches for you, your passenger, and the neighbors. There are some very nice Z exhausts available, but none really make much difference in HP, and you should buy one that sounds and looks good to you. Making one yourself out of random pieces just about never works. You've already likely discovered that bolt-on's don't really do anything, either.

OdesiTT

Probably you misunderstood me. I already have a nice exhaust, but I want to make il little quieter

dcains

iTrader: (15)

That's not what an exhaust bypass valve does.

MicVelo

And maybe you misunderstood dcains.... who was saying you have the wrong exhaust system on there to begin with. I mean, what do you expect from a system that's based around HFCs, overly large pipes that do nothing on the street but make noise? Of course you're not going to have any low end.

The point is, no amount of kluge dump valves are going to make one iota of difference. You want to quiet it down and alter your torque curve, do it the right way.... resonators, better muffler(s), smaller pipes.

dcains

iTrader: (15)

Man, it's really early in CA. Get up to watch the Italian GP?

MicVelo

Nah, up and warming up for a 60 mile dawn ride on a loop alongside the PCH, North of Monterey, CA

"Ride" as in "pedal".

dcains

iTrader: (15)

Ride safely, and you're probably not missing much. Ferrari has already screwed up their tire strategy, so it looks like a Rosberg/Hamilton 1/2 finish.

OdesiTT

Then why BMW using vacuum valves for the same purpose? Even Dinan making exhausts with this valve. I'm hardly believe they don't know something that you know. Let's don't be too sceptic. The question is: how to install it and what is going to fit well.

dcains

iTrader: (15)

OK.

OdesiTT

I'm not talking about bypass, it's a chocker in one of exhaust's tips

travlee

iTrader: (8)

my corvette has those, under 3500 rpm its closed, after that it opens. it is vacuum operated, but not sure exactly how it works or what controls it

OdesiTT

How do you think, can Z benefit from this also?

travlee

iTrader: (8)

i am not sure to be honest... on my car, from my understanding, when the valve is closed it goes through the muffler baffling, when open it is essentially a straight through route. i guess with it closed you could possibly get some low end torque back.

my question would be, how much are the actuators, how much to install/wire them.... add those up to equal ... is it worth it to prob minimal torque back?

OdesiTT

Believe me or not, it's pretty cheap. Valve with actuator is about $60 + hose to vacuum line. In case of spring loaded valve it's might be even cheaper. I'm planning to install it myself

92K1500

iTrader: (1)

Gonna need a solenoid and a switch too. If you just hook it to straight vacuum it will be open all the time. Then you will have to manually switch it open or closed at which point it would be easier to just get an electric cutout and not deal with all the vacuum lines.

MicVelo

Alrighty then, I shall remain silently skeptical and admit my wrong after you post up the install and torque chart. We need pioneers here, so please prove me wrong (serious about that). No issues admitting "I learned something."

OdesiTT

There is a different type of this valves. You can get one that open at -2atm or -3 or -7. I believe that with correct valve I'll be able to make it fully open only at WOT

travlee

iTrader: (8)

one advantage of them, i know it really quiets down my car when they are closed... might run to garage to get a video

OdesiTT

I think, maybe it's will be easier to buy one exhaust tip from Corvette and weld it to Z