I did apply for a patent on this last year, but it isn't S2000 specific. I wouldn't consider patenting anything related to the back section.

 

You may have a hard time selling a mid-pipe (as awesome as it may be) for $1k. Are people still spending that kind of dough on s2k's? I'd rock it if I had the cash to spare. Are you looking at other premium aftermarket targets like Porsche, Ferrari, etc?

Or, license the patent to the highest bidder. If it's as good as you say it is Walker, Borla, HKS, Greddy, OEM manufacturers, etc. will be interested. If the design can improve power delivery through tuned exhaust, it can also improve efficiency. Look at the money Mazda spent with Skyactive in the name of efficiency. After about a million years of use in aftermarket, an OE finally installed a tuned exhaust header on an economy car (in addition to all the other improvements, of course). Your tuned midpipe patent could be the next evolution. Go get'em tiger!

 

I meant a patent for the midpipe not a back portion, sorry I wasn't clearer on that. Reading your explanation above I understand you wanting to stick with the midpipe only.

 

I would only be interested in a bolt on solution for the mid-pipe. I am not willing to pay to have it welded in. With the Berk single you have it pretty easy with a standard connection to the OEM/Aftermarket header and a 3" V-Band clamp already used by Berk. The long prototype you have in the picture above looks like it would already bolt onto the Berk exhaust if it were a tad shorter.

 

I understand that many people will want a bolt-on solution. Unfortunately, many of those people will just have to live with poor performance and excessive drone.

Also, a bolt-on solution will be considerably more expensive, since I will be making each specific adapter in smaller quanities, and will have significant development cost for each one..

 

In general, would this increase/decrease the volume under load/@WOT?

 

All exhaust systems have certain frequencies (RPMs) where they will resonate, making the exhaust noise much, much louder. For the S2000, the exhaust systems available tend to resonate at about 3500-4000 RPMs. Regardless of what the load is, the exhaust sound will be louder while in that RPM range. That is "drone".

My mid-pipe alters the resonant frequency of the pipe so that it does NOT drone in that RPM range. The result is that the volume of the exhaust note winds up following the torque level. Basically, if you are at part throttle (low torque), then the volume will be low. If you are at full throttle (high torque) the volume will be louder. Since our engines produce more torque at higher RPMs, it also makes more exhaust noise at higher RPMs.

I need to post some pictures of the "drone-o-meter" application I used to analyze drone. I used a surround-sound digital recorder attached to the passenger seat head rest to record exhaust sound throughout the RPM range at WOT and PT (electronically controlled via DBW), then processed the recordings to determine sound level and dominant frequency, then plotted it across the RPM range.

 

I have a Q300 V4 Dual.
I would be interested in one of your mid-pipes as well if it were fairly easy to modify in.

As far as noise levels how does it compare to Stock cat, Berk HFC, and test pipe?
When I first put my Q300 on my car I had a Berk HFC installed as well and it was a bit too loud/raspy for my taste so I have since gone back to the stock Cat (quiter but more drone)

 

I really can't say how my mid-pipe would compare to various combinations of test pipes, HFC's, or OEM cat with various other mid-pipes. Some exhausts drone more with the OEM cat while others drone less. It just depends on how their mid-pipes were designed. Mismatches in pipe diameter also play a role. However, since I will be installing a Q300 this weekend, I'll soon find out how it sounds. I will make a "bolt-on" adapter for the Q300 V4 dual, so it will be a super easy install.

 

Interesting, pricey at around $1k though! Would this piece lead to a performance gain on the oem exhaust system? How will it sound with the OEM Mufflers?