| Author | Message | ||
     Red_chili |
I learned something about the archives, if you post a reply to them, they don't rise to the top here! Interesting. So I will repost just out of curiosity and to get feedback. I've been asking about if anyone was running a spark arrested muffler. I have seen a couple as attempts to quiet a Special OPS pipe, but nothing built with spark arrestors in mind. So I determined to give it a go. A couple guys suggesting talking to Odie and Kevin, so I shot them some emails. Odie said he was going to call me but never did after several attempts to contact him - that man is busy. Oh well. Kevin replied to a query and was nice enough, said he would 'not help me build a Drummer', which I certainly understand, but that was not my goal. Oh well. I examined a Drummer my son's XB9S has with an inspection scope and was surprised. The head pipe basically ends about where the stocker ends internally, then the entire interior of the pipe is open. Drummer lines their can with perforated steel and permanent packing, which contributes to the good tone no doubt. Of course Drummers are TIG welded and the finish and construction are superb. The education was in how little back pressure is presented to the XB motor, though the 'Fatlet' diameter must be crucial. Of no use to me, though, since that is the part I am doing that is original. I was going to find some perf steel and do the same thing as Drummer with sound damping, but I had an afternoon and some motivation so I decided I could always add it if I didn't like the results. I cut the pipe in thirds with a recipro saw, in front of the front 'Jackpoint' marking, and behind the rear 'Jackpoint' marking, capturing the bulkheads in the center section. I then used a plasma cutter to remove the bulkheads and three internal pipes. Interestingly the XB12 can I used had the head pipe terminate in the forward chamber, with the center section pipe just meeting it. I thought they were connected. Nice bonus. Clean. I then plasma cut a rear plate out of some sheet steel more or less the same gauge as the muffler and added a bit of exhaust adapter that fit the Trapp perfectly. Then I stitch welded the whole thing together. Turned out rather well. I left the muffler valve in, though it does very little any more. Results? With 13 discs, the note is less 'blatty' than the Special OPS pipe I had, and quieter, but is a nice tone. Very nice surprise; I have had SuperTrapp systems that just didn't sound all that great. It is not quite as 'deep' as a Drummer, but not quite as loud either. The Drummer is aptly named, it has a thud quality. This (the Trapp homebuilt) is deep, but less percussive (because it is quieter). As far as power, I could immediately feel a stronger top end, like it wants to run past redline (this was after letting the ECM relearn the mixture). Not sure if the midrange is changed, but it seems quite strong. I might have to experiment with removing a couple discs - the nice side benefit of a SuperTrapp. And.... it is spark arrested. And dirt cheap. Rolloff leads to less afterfiring than the Spec OPS pipe did, which tells me the pipe has a bit more back pressure than Odie's pipe perhaps - cleaner run with the stock ECM in any event. No noticeable cruise surge either (unlike stock or the Spec OPS pipe, though admittedly this was in the 'barely noticeable' category). What's not to like? I'll have to see how it works with a race ECM when some funds free up. Maybe.  | ||
| Miamiuly |
pretty cool, looking forward to a pic of it on a bike. I sure would like a spark arrestor myself. | ||
| Windrider |
Nice post Red Chili | ||
| Adrian_8 |
Velly goood...I wish the ULY had more sound...sort of like the new Harleys do with the 07 bikes. The Buells do not need to be as quiet as they are. | ||
| Panhead_dan |
My '06 is "waking up" little by little. It has quite a ways to go before I will be able to hear it much, however. It seems like high RPM runs wake it up faster. | ||
| Growl |
Yes Yes! You have made my day! | ||
| Teeps |
Chili, Are you concerned, at all, about the exhaust that will be exiting upward? Looks like it might heat the swing arm and who knows what else... | ||
| Red_chili |
Not really. There is a LOT of airflow going on. I've run Trapps right next to fenders and such with little consequence aside from some carbon. I expect the swingarm gets more heat from the oil than it ever would from the Trapp. That said, they make a nifty (and cheap) stainless deflector that I might throw on there. | ||
| Wolfridgerider |
How did you attach the Trapp discs to the end of the pipe? I don't know that much about their exhaust so any info you can pass along would be great. I made my own pipe for my Firebolt after I bought a Drummer for my Uly. Its a little louder than the Drummer was and I want to reduce the amount of neighbor annoyance.... | ||
| Red_chili |
I used a section of muffler adapter from Checker/Kragen's that fit a weld-on SuperTrapp from Dan's Performance Products (cheapest I could find, a bit slow in shipping and I had to call to follow up, but oh well). http://www.dansperformanceparts.com/buggy/exh/exha ust%20acc.htm Weld-on Spark Arrestor The weld-on Steel spark arrestor fits most exhaust system with megaphone stingers. Comes with base, top and 12 Baffle plates. This muffler is tunable to any motor by adding or taking away baffle plates. 14-251076/2 SPARK ARRESTOR, WELD ON, 4X2 EACH $ 36.95 14-251076/2.5 SPARK ARRESTOR, WELD ON, 4X2.5 EACH $ 40.95 14-251076/3.5 SPARK ARRESTOR, WELD ON, 4X3.5 EACH $ 45.95 I used the 2.5" weld-on. I happened to have an aluminum end cap from a prior project I had laying around, and used it to dress it up a bit. (Message edited by Red_Chili on September 05, 2007) | ||
| Red_chili |
Here it is on the bike (sorry for the lousy cellphone cam pic). The Trapp does not actually hang down below the bottom plane of the muffler and is reasonably well protected. A skidplate extension would be simple to make if needed however. I do find a hard hit at about 5K that is a bunch of fun; it could be that the muffler valve is actually doing something (shortening the internal header pipe maybe?). I may try removing some disks; one of the advantages of a SuperTrapp.  | ||
| Sleez |
you do know that removing discs adds back pressure right? | ||
| Red_chili |
That would be the intended outcome, yes. Moving the optimum flow lower in the RPM range. | ||
| Bertotti |
What exactly will that do? Moving it down in the rpm range. | ||
| Red_chili |
Soften the hit at 5K a skoash, perhaps beef up the lower midrange a bit. Within the limits of the rest of the system of course. In my experience at least, going with too little backpressure causes overscavenging and loss of power except at the highest flow rates (higher RPM). Too much prevents the cam timing and lift from scavenging adequately. Kinda a balancing act. | ||
| Bertotti |
So how will you know then when you have it right? Is it all by feel when riding or do you measure exhaust gasses or what? A lot of questions but the topic is actually pretty cool. Red_chili how thick was the steel case of the muffler? I am thinking maybe of mocking up a stainless one before I send it in for ceramic coating. Thanks John |
