NSX Valvetronic Exhaust System (first ever?)

[RYU]

Not sure where you are with the control method of this project but I have an idea that may work well for you.

You will need one of these:
http://www.oreillyauto.com/site/c/d...eyword=egr+vacuum+solenoid&pt=02144&ppt=C0018

a three possition switch and for the purpose of testing and easy programming a ZAVT-1 added to your ZT2 wideband.
http://www.zeitronix.com/Products/zavt/zavt.shtml

If you ever decide to sell this thing then the ZT2 and the ZAVT-1 would be replaced with a Zublin Engineering RPM window switch.
http://www.zublin.com/nosrpmswitch/model_ns-300.jpg

Here is how it would work, the three possition switch will allow for a valve open, closed, or auto setting from the dash. The switch in open mode would activate the solonoid and the vacuum would open the valve. the switch in the closed possition would disable the solonoid and prevent the valve from opening, the auto mode would allow the programmable RPM switch to open and close the valve at any RPM setting on the controller.

For the purpose of testing and easy programming your ZT2 can be used to trigger the solinoid at any RPM you choose and can be changed easily from a laptop connected to the ZT2 using the alarm trigger feature in the software.

I can draw up a system design and generate a parts list if you want but this will give you a good control option to run with that we can refine more with testing.

Dave

Thanks always for your valuable and helpful posts Dave. I have a hobbs switching device very similar to the one you posted and also the zublin rpm switch but what I did not consider was using the ZT2 - THAT IS BRILLIANT! It will give me full control of the valves either way which is something i'm limited to the 4800rpm VVIS cutoff at the moment. I'm wondering if the Oreilly unit you posted is normally closed or normally open. We can probably do it either way by removing the foam filter but not sure...

There's only one thing I need to consider in your setup. My vacuum valves are normally open at boost or 0 vacuum. Therefore to keep it closed it needs to see a least 3 inches of constant vacuum. I went with this style vacuum actuated (not boost actuated) valves so I can use this application for either NA or FI setup. I'm experimenting using a one-way check valve to hold vacuum and I think that should work. It will even be better if I can find constant vacuum in the NSX. I know there's a reservoir somewhere but haven't been able to tap into yet. In any event, you've definitely introduced some great control options here!

------------------------------------------------------------------
Just some feedback on the technology... I'm loving this setup so much that i've used the car almost everyday of this week. I get home from a long commute (in the DD) and switch to the NSX to go out to dinner, the gym, etc. It's really really brought back driving enjoyment once again. (Not a sales pitch because I have no plans to duplicate this exhaust).

I've left it in the RPM dependent "VVIS" mode for all street driving. The valves stay closed until 4800rpm. I found this a good compromise because it allows the car to build boost down low w/o having the valves open up. Makes it much more street friendly but on the occassion I want to screw around I just rev it into VTEC and it's grins all around - it's all very seamless. The adrenaline is fantastic and it sounds beautiful (well at least from in the cabin, no idea what it sounds like from the outside).

If anyone plans to build an 2-stage exhaust like this I recommend using the RPM as a control parameter for the street and use boost as the control parameter for the track (to squeeze out all out performance). As Dave eluded to a switch can easily be made to toggle between the two settings.

 

[racer9x]

nnnnnniceeeeee,would love to hear in person.:smile:

 

[DDozier]

There's only one thing I need to consider in your setup. My vacuum valves are normally open at boost or 0 vacuum. Therefore to keep it closed it needs to see a least 3 inches of constant vacuum. I went with this style vacuum actuated (not boost actuated) valves so I can use this application for either NA or FI setup. I'm experimenting using a one-way check valve to hold vacuum and I think that should work. It will even be better if I can find constant vacuum in the NSX. I know there's a reservoir somewhere but haven't been able to tap into yet. In any event, you've definitely introduced some great control options here!

If you pick up your vac line from the 4 lines above the throttle body on the CTSC you will have a constant vac source, take it from the manifold after the CTSC and you have both vac and boost.

The vac valve being closed with vac is the way you want it, the vac solonoid will be normally closed and open to vac supply with voltage across the solonoid. You should not need a check valve but for the permanent closed possition you will use a second solonoid to prevent the bleed of the first solonoid when it is released. I would have to test this but it should work and no need to store vac or check valves.

If you do not want to reinvent the wheel the product we use in the Z06 exhaust system is available here, works very well and even has a keyfob style remote so you can control the valve from outside the car. You can easily make this work for less money by making the control yourself.
http://mild2wildexhaust.com/

Dave

 

[L_RAO]

RYU - got a chance to hear your exhaust as you were leaving my house. Only got to hear the "low" phase exhaust - it sounds very throaty. Nice job.

 

[DreamPowered]

I know it's been almost a year, how is the exhaust performing.
I sent you a pm. Let me know if you recieved it.

 

[BATMANs]

Pretty cool.

My only concern would be total weight of the whole system.

Ever thought of this?

Exclusive Dynomax® Valve Technology.
DRONE-FREE Performance™.
On-demand performance & sound.
Stainless steel construction.
Straight-through welded design.
Limited Lifetime Warranty.
90 Day Performance Guarantee.
(US Patent Pending)


Dynomax Performance Exhaust: Mobile Sound Lab DynoMax® Performance Exhaust - a leading innovator in performance exhaust technologies - introduced the DynoMax VT™ muffler, a revolutionary, high-flow straight-through stainless steel performance muffler that controls irritating drone while ensuring maximum performance.

DynoMax Valve Technology Mufflers feature an exclusive, precisely calibrated internal valve that redirects exhaust flow, during cruising conditions, to provide Drone-Free Performance™. Hammer the gas and the valve automatically adjusts for maximum exhaust flow, delivering on-demand performance and a deep, throaty drone-free sound.

 

[RYU]

I know it's been almost a year, how is the exhaust performing.
I sent you a pm. Let me know if you recieved it.

Wow, seems like i've had it for longer. I guess ever since I was inspired by Mac Attack's exhaust build (2010?) it's been stewing in my brain for a while.

I'm happy to report the exhaust has been trouble free! It's actually starting to "break in" since the tone has stabilized. I've had it out on 2 track days now. The last one being really really hot (130+F track temps) but it still performed as designed.

Here's a video my brother took from his iPhone. Sorry for the quality.

As a comparison at about 3 secs in you'll hear a Open Header S2000. The volume is loud and it sounds awful imo. Then about 20 secs in you'll see Coz round the corner with his fully built, turbo charged beast! Then I follow him from behind. The valves open up about 100 ft after I round the corner. I still have to master being in VTEC before entering that corner lol.
<iframe width="560" height="315" src="//www.youtube.com/embed/Cp4ZnELSPF4" frameborder="0" allowfullscreen></iframe>

- - - Updated - - -

Yes, I did receive your PM. I've gotten a handful of request to remake these but here are my challenges every time i'm asked to do so.

1. We never made a jig because we did not expect to mass produce these. Therefore any car that wants my fabricator to build my exhaust on their car will need the car to be available for precise fitment.
2. The vacuum valves are harder to find. My supplier, Sound Performance, hasn't been responding to my emails.
3. These are header specific. Mine are mated to a 00-05 CT Headers. 97-99 are different. 91-96 are also different.

- - - Updated - - -

Pretty cool.

My only concern would be total weight of the whole system.

Ever thought of this?

Thanks Bats. I think it's pretty cool too

Total weight of the system still saved me about 40lbs from the stock system. This is when you account for the swap of the entire exhaust system (which I did). In other words, total weight of the OEM headers, OEM Cats, OEM Muffler vs. my Total Valvetronic, Smog passable, setup nets about 39.xxlbs in savings last I checked.

Yes, I thought of the spring flapper thingy that Dynomax sells. Just isn't for me for multitude of reasons I think we already discussed in this thread or in others.

- - - Updated - - -

I need to add...

It was SO HOT at the track that the VViS reservoir collapsed on itself from the heat. It was actually hysterical when we noticed it. It's #6 36361-PR7-A01 on this diagram. I've already ordered a new one and will insulate it from heat exposure. This is only a concern if you're using the OEM VViS system to actuate the exhaust valves.