Here is the email that I got from Kerry today...damn they are fast! If anyone is interested, just contact Kerry and his gang via the email and/or phone listed at the bottom. Thanks for everyones interest or not, this was pretty fun to do either way
All done with prototyping, testing, etc. Results are basically as expected. I have attached a zip file with pictures, dyno graph & data, sound byte.
Essentially, because of the termination point on the oem collector spigot, the length and angle options of the megaphone placement are somewhat limited for a Slip-On. Two pictures show it with a Slashcut megaphone. Two others show it with a shorter Straightcut megaphone. The advantage of the Slashcut is that it will help keep heat and/or exhaust soot off the swingarm area. I think it looks better as well. The primary core is set fairly deep into the megaphone (3" on the shorter front side, 6" on the longer back side, 45 degree angle), so basically if someone wanted to cut the megaphone down and/or change the Slash-cut angle, you have a lot of room to work with. We manufacture these out of 304 series stainless steel. So a hacksaw might be a pain to cut through it. But a chop saw or cut-off wheel would make it easier.
It is secured with a stainless steel T-bolt clamp on the inlet. We also incorporate a spring/spring tab on the back side to secure it to the oem collector (in the slight chance the clamp was not tightened securely). This would help prevent the megaphone from sliding back. The other end of the spring attaches to the exhaust butterfly valve boss. With it being so short, lightweight, and with full depth engagement onto the collector spigot, as well as swedging on the inlet side protruding into the megaphone, we don't feel an additional mounting bracket is required. It does not move.
The Slashcut Megaphone weighs 24 ounces without the core. The core weighs 6 ounces.
The short Straightcut Megaphone weighs 15 ounces without the core.
The sound data is provided on the "Data" file taken during Dyno runs. Readings taken at Idle and 5000 rpm. Measured statically at 20", 45 degrees. The quality of sound is much nicer with the core installed. The sound byte is 1st through 6th gear to the soft limiter, with the Slashcut megaphone and primary core installed. Essentially at 5000 rpm, the open header is 112 dbA, the open megaphone is 116 dbA, the megaphone with primary core installed is 110 dbA. Please make no mistake, this is not a quiet Slip-On
. For comparison sake, "Most" Slip-Ons with racing type cores will range in the 98 - 105 dbA area. The small size of the megaphone limits what can be done to help attenuate sound. There is simply no volume to work with. The only other option is to start restricting flow, which of course will decrease power over the oem muffler and somewhat defeats the purpose.
Power gain is very small which is to be expected on this design. Run 6 is no muffler on the OEM header. Run 4 is the Slash-cut megaphone without core. Run 3 is with the core installed. Basically dealing with the abbreivated length and minimal volume, there's simply not much to work with on this particular design, with a stock state-of-tune engine. All while trying to keep the fuel curve specs within acceptable tolerances. With the primary core installed, (which is the way we would recommend it be run), the fuel curve goes a little lean in some areas, but nothing too drastic. No changes should be required.
There are probably an infinete number of ideas that can be debated on design. Simply put, these are two options that would be within reason to manufacture at a lower price point. Personally, the Slashcut Meg looks pretty good. But of course everyone will have and is entilted to their opinions. The other pictures you sent to me of the "tubing design" is also doable. But this would require more development, vectoring, and core designs to consider. When considering a "MotoGP" type exhaust, there really are only a few limits. Some go with a muffler design, some with a slashcut megaphone, some with a reverse cone type megaphone, etc, etc. These designs are based on motor state-of-tune, and fitment limitations. MotoGP does not have a sound limit and currently the Ducatis can exceed 130 dbA. Even the Yamaha with a very short muffler and 78mm core, is still in the 122 dbA range.
We can make tooling/fixtures and consider going into production with it depending on the demand. We can sell this at a price point of $149.95
, provided there is a volume demand. To implement this into our production schedule, we would probably be looking at late June for them to be boxed and ready to ship. It would come with the brushed finished stainless steel megaphone, primary core packed with Silent Sport Premium, hardware kit consisting of stainless steel T-bolt clamp and a retaining spring. For someone looking for a less costly alternative and something different, perhaps this example would be considered.
I look forward to hearing from you.
President - Area P, Inc.
Silent Sport N.A., Inc.
1240 Simon Circle, G/H
Anaheim, CA 92806
Ph - 714-630-2386
Fx - 714-630-2422