Before you purchase an NPP exhaust system to retrofit to a Camaro that does not currently have the NPP system, what is it you intend to accomplish?
- Do you merely intend on installing the NPP exhaust system as replacement for your existing exhaust system because you like the sound of the NPP with exhaust bypass valves opens?
- Or, do you intend on installing the NPP exhaust system and have full functionality of the system as if it were installed at the factory?
In the first option, when you install the exhaust system with the dual mode mufflers, you end up with the muffler exhaust bypass valves in the always open position. You will have four exhaust tips, a nice sounding exhaust, but it is only going to be in single mode … that is, valves always open. Now, if you're happy with the NPP exhaust in the single mode, then you should be good to go.
In the second option, if you intend to be able to retrofit your car as it if were an original factory installed option … sorry, not going to happen. Why? Because you need to have a means to operate those valves and if your car was not equipped with NPP from the factory you will not have the necessary solenoid valve, accumulator tank, vacuum lines and ECU programming to make it all work.
Now, some have advocated getting a product called Mild2Wild NPP in a Box. Before you take this approach, you need to understand what is involved. NPP in a Box gives you a vacuum solenoid valve, a remote control relay, a couple of remote transmitters, some vacuum tubing and a component to tap into the engine manifold as a source for the vacuum required to operate the exhaust bypass valves on your NPP system. Missing from the NPP in a Box is a vacuum accumulator tank which stabilizes the vacuum that is otherwise quite unstable coming from the engine manifold, and your ECU is not wired in to control the valves. You will be using the remote control to manually open/close them. IMO, this is a Rube Goldberg solution.
You might think, OK, I can live with this. But, if you think that you can install the NPP in a Box in 5 minutes and you’re done, dream on. You will need to tap into a vacuum source, route vacuum lines, install the vacuum solenoid valve, tap into an electrical source for the solenoid valve and test everything. You will also probably want to acquire new rear diffuser for the 4-tailpipes. What you end with is a manual control for your exhaust bypass valve. But, remember, the vacuum will be quite unstable because you will be missing the vacuum accumulator tank. As you vary the throttle on your engine, the vacuum will rise and fall as you vary the throttle position. May not be a problem, but that is why manufacturers include the accumulator tank with vacuum actuated devices. Your total cost is going to the cost of the NPP exhaust system + about $200 for the NPP in a Box + a rear diffuser to accommodate the four tail pipes + your time to do all this. I would not be surprised if you end up spending close to, if not more than, $1000. Even more, if you install a vacuum accumulator tank.
If you want a true operable dual mode exhaust system to retrofit to your car which does not currently have his option, then the NPP route is a poor choice. You should be looking at an electrically operated dual mode system. Something like the Varex Xforce system.
(By the way, I am not in any way associated with Varex … I just like their products.) These electrically controlled units provide variable bypass valves that are remotely controlled using a small remote transmitter, do not require tapping into vacuum source and at the end of day will cost about the same as trying to retrofit the NPP system to your car. You can read more detail on Varex Xforce systems by going to their
web site. You can also do a YouTube search for
"Camaro Xforce" for various videos on installs and results.
Make sure you fully understand what is involved here and what the actual outcome and costs are going to be before retrofit your existing exhaust with a dual-mode exhaust system.
Best regards,
Steve