Kressieg NSX Exhaust?

If they made one for the NSX, it would probably sound like this :wink:

<iframe src="http://player.vimeo.com/video/19372585" width="400" height="300" frameborder="0"></iframe><p><a href="http://vimeo.com/19372585">Kreissieg-Type NSX Exhaust</a> from <a href="http://vimeo.com/user1744194">Dave</a> on <a href="http://vimeo.com">Vimeo</a>.</p>


It's taken 9 months and countless iterations, but I'm finally very happy with it.

- 26 lbs with catalytic convertor
- No drone with aluminum 1/4 wave resonator
- Quiet and emissions-friendly when I want it
- Loud when I want it

Now I can finish my diffusor and underbody.

Dave

Man that sounds coool nice Job

Would love to see more video! Especially a flyby :biggrin:

Sounds good

Sounds mean! I like it. The quiet mode still sounds pretty loud on there.

Man that sounds fierce - like a tiger!

You just up'ed the game. It sounds truly unique for an NSX.

I like it, sounds very different than most of the exhausts you hear on here.

Definitely a unique sound for the NSX..I would run it for sure. Too bad you can't use the rear swaybar and OEM valence. Anyone want to offer to make a version that will work with the OEM set up for sale?

Thanks for the compliments!

NetViper said:

Sounds mean! I like it. The quiet mode still sounds pretty loud on there.

Click to expand...

Yeah, it's hard to tell how quiet it really can be when I'm annoyingly revving it in the video.

The past three months alone was for fine-tuning the "Quiet Mode" because I wanted to make it quiet without adding weight. Because the Quiet Mode is still relatively straight-through, I can't cancel out the low frequencies without adding a large volume muffler (adding weight and space). I've figured out something internal to the piping to make it sound nice even when passing through cats :wink:

But, I did manage to make it very quiet at ~2700 RPM's and higher - Perfect for driving 60MPH or above. Around town, I just leave it bypassing the cats pretty much since it sounds so nasty and unique :biggrin:

This test with my cheap $10 spy cam (need to work on the mount) shows how quiet it goes to from Loud Mode to Quiet Mode at the end of the video. It really does quiet down almost to OEM levels at 2700RPM and up:

<iframe src="http://player.vimeo.com/video/19418238" width="400" height="300" frameborder="0"></iframe><p><a href="http://vimeo.com/19418238">Spy Cam</a> from <a href="http://vimeo.com/user1744194">Dave</a> on <a href="http://vimeo.com">Vimeo</a>.</p>

AdvansCPAP said:

Definitely a unique sound for the NSX..I would run it for sure. Too bad you can't use the rear swaybar and OEM valence. Anyone want to offer to make a version that will work with the OEM set up for sale?

Click to expand...

I dumped the rear sway bar a few years ago for my turbo build. At the rate I go tinkering on the occasional weekend, I'll never get the custom twin turbo's finished. Removing the rear sway and brackets opens up so many exhaust/turbo routing possibilities....

Also, some folks like me prefer the handling without the rear sway on a track :wink:

Dave

Dave, you got me thinking about my exhaust again which caused me to look back at some of the discussions on the a previous thread but it looks like the pics are gone?

This last rendition of your exhaust is awesome. Is it weird to say I like the sound in quiet mode better? haha

Thanks,

The quiet mode does sound pretty good in real life. It has some eddy-current generators internal to the piping to make a nice sound. But, it's restrictive at the higher RPM's.

When you want to be obnoxious and stinky, the wide-open mode is pretty fun too :redface:

Dave

Any chance that fellow primers can benefit from your research? :smile:

What are the odds of a production version?

It's not something I have an interest in selling - mostly because I removed my rear sway bar to open up the rear area. Keep in mind 90% of NSX drivers would never know if it was removed or not, and some of us prefer the handling that way on a track or spirited driving. If this is something you like (I'm flattered), it would probably be best to supply a sketch and pictures to your local exhaust fabricator and have them weld it up.

Before I put the final pictures up, there is just ONE MORE iteration I would like to go through. Why not, this should be a simple change and I've got all this scrap piping laying around now!

The real trick is to come up with a piping configuration where you can have the opportunity for a quiet emissions-friendly mode, and then a loud straight-through performance mode. I've gone through about 7 or 8 layouts and configurations. Each had it's benefits and drawbacks in sound and performance - and all of our tastes and requirements are different too :smile:

Then, to save weight and space from a traditional heavy muffler, you'll have to add a tuned resonator to cancel out the ~110Hz engine firing rate frequency so that it doesn't make any cabin droning noise. This process and the formulas for the simplest 1/4 wave resonator have been shown here.

It really just boils down to imagination, time, patience, fabrication skills and money to get what YOU want. All things I have very little of :biggrin:

Dave

Dave I have to say I commend your efforts and I do like the sound of the system in the video very much

Thank you Turbo, I appreciate it!

I have to admit though, it doesn't sound good enough to take you up on your $15k offer from awhile ago :wink:

To cancel out the low frequencies and let the ~400-700Hz ones shine through, you need a large volume. I just don't have the resources and money to make one from titanium such that it wouldn't weigh a ton (ala LFA). Even though my quad tailpipes do have their own natural resonance frequencies, they just don't stand out enough over all that bass coming from the engine.

Oh well, one more quick iteration planned that's more of a "refinement" to this one.

Dave