BSM Down-Under Exhaust System for R1150R, Rockster, GS etc

[tommy]

Hi Guys,

Couldn't see any posts discussing this exhaust system so thought i'd throw it out to discussion.

a company named BSM have made this 'Down-Under' exhaust system and i LOVE it
only problem is.. installing this great looking system causes a loss in power, and with slip-on cans (half the price) that increase power available, it makes justifying this system a difficult job

the system has a removable baffle (great for the UK market) and the website boasts it meets noise regulations, so should be MOT'able




manufacturer's website: http://www.bsm-exhausts.com/

tell me what you guys think

Tommy

[NoRRmad]

I think they need a site redesign right away.

[boxermania]

tommy

That's an interesting approach as it mimics the Buel muffler and it keeps the weight low, helping the bikes CG. Unfortunately if there is a hp loss it has to do with the fact that the design adds more restriction to the exhaust than the OEM muffler.....I'm sure that if BSM had gutted their muffler there would not have been an hp loss. Here is a sample where novel approach missed the mark.

Actually the cat converter is a very good muffler and the DJ conversion, adding a small turndown at the cat exhaust, is the cleanest and less expensive mod to the bike.

[Boxerpunk]

I mentioned this one in an earlier topic: viewtopic.php?f=3&t=6104&p=56354#p56354

I.m.h.o. it's a very expensive way to loose weight ánd power

[sweatmark]

I like the idea of an under-slung muffler that replaces the OE catalytic converter y-pipe (and OE cannister muffler)... plus the notion of weight savings over the OE exhaust system is great. Wish there was an aftermaerket option that -like this BSM design- provided a simplified exhaust system via unified y-pipe/lambda probe mount/muffler, but -unlike the BSM Down Under- did not suffer power loss.

As for the BSM power loss, noticed on the company's product PDF bulletin that the y-pipe collecting exhaust gasses from boxer motor headers is more like a "U-pipe", with flow making sharp 90-degree turn from left/right side into a collector stub, and then into the muffler can. That sharp turn is not friendly to higher-RPM gas flows, which might explain power loss per BSM's dyno chart.

Since R1150R/GS y-pipes appear to be unobtainium these days, I'd like to pursue local fabricator who can whip up a simple 2-into-1 collector, and then use old school SuperTrapp as muffler.