Ya' know...
Every time one of these exhaust system threads comes along I have to laugh...
You get lines like:
Because "performance sytems" usually mean measurable gains. I have yet to see a documentable gain that is worth the money spent.
And:
You are not going to get much performance by changing pipes...
Now let's examine this a bit more analytically...
We have one *DOCUMENTED* source (
http://www.moto-one.com.au/performance/r1150r_brad.html) that shows a *STOCK* 1150 Oilhead makes 78 to 79 HP at the rear wheel, as evidenced by four different 1150's - both GS's and R's.
Next you will see that the addition of an exhaust system (and a re-mapped EPROM in this case) shows an increase - on *TWO* different 1150's - to minimum of 85.0 HP, and ot as much as 85.4 HP...
Now, worse case scenario - going from 79.0 HP to only 85.0 HP - is a gain of 6 HP, or about a 7% increase... Pretty impressive without cracking a case, and as the article shows, much more cost effective and less labor intensive than adding the cams, which showed a similar increase.
Before we take this to the next logical step, let's look at something from Laser's exhaust system website regarding re-mapped EPROM's... Go to there main page at:
http://www.laser-jama.nl/uk/Main.html
And navigate yourself to the "Bikes" page, and then click on the "Product Info" button on the left, then on the "FAQ" button. Scroll down to the bottom of the page where it says:
What is the purpose of using a powerchip on my BMW?
For some models of BMW motorcycles LASER offers the LASER Powerchip. This device has to be placed into the motronic unit and is build to improve drivability. It increases torque and makes the engine run smoother in the lower and middle rpm range. The increase in top performance is limited.
Here we have an exhaust system manufacturer who clearly states that a re-mapped EPROM "chip" will *NOT* significantly increase top end power, but will aid driveability, allow the engine to operate more smoothly in the low and mid range, and increase torque... So from these two sources we can draw a logical conclusion that the pipe has more to do with horsepower gain on an 1150 Oilhead engine while the chip has more to do with gains in mid-range torque and smoothing throttle response. This makes an enormous amount of sense when you consider that modern day fuel-injected motorcycle engines have to run lean in the low to mid RPM range because that's where the various government environmental regulatory agencies take their emissions readings... So "richening up" an engine, via a re-mapped EPROM, should have its greatest effect in that same RPM range.
Okay, back to HP gains from pipes...
We have one poster here who says he is going to be buying one of the new BMW K-1200 four-cylinder bikes, and states:
Oh, and it will have a pipe for sure!!!
Now this same poster previously stated that "performance systems" mean "measureable gains"...
Well, to stay current, let's take a look at a recent issue of "Sport Rider" magazine for a good example of quality exhaust systems on inline four-cylinder engines, shall we?
In the August 2005 issue, on page 86, the scribes at "Sport Rider" fitted a new Arata titanium full exhaust system - header pipes, can, the works - to a 2005 Kawasaki ZX-10R. Stock, their ZX-10 showed 160.1 HP at the rear wheel. Once they had fitted the Arata pipe (which showed a bigger HP increase than the Tsukigi exhaust they had fitted previosuly) the bike showed a horsepower gain to 167.0, or a 6.9 HP increase over stock...
It doesn't take a mathematical genius to see that is only a 4.1% HP gain, right?
Now, I ask you; which is a better percentage horsepower increase - a 4.1% one or a 7% one?
Which is going to make a bigger difference in the "real world" - a 6 HP gain on a 79 HP bike, or a 7 HP gain on a 160 HP one?
Now, for the kicker... The Arata exhaust for that Kawasaki costs a walloping $1499 !!!

Add another $100 bucks if you want air-fuel sensor bosses on the header pipes, BTW...
I bought my Staintune cat-eliminator, brand new, off e-Bay for $300, and I got my Neptune muffler right here off the "Buy, Sell & Trade" page of this board for $230, so I have $530 wrapped up in my exhaust system. I also just bought a full Laser HotCam exhaust off e-Bay for only $250, and it looks brand new (after a bit of clean up and polishing). I haven't installed the Laser rig yet, but I will one day when I have some spare time. I also sourced a re-mapped EPROM "chip" from the same "Brad Black" in the MotoOne article mentioned above (Thanks, Brad!) for only $200...
So depending on how you want to look at it, I could have as little as $450 wrapped up in a performance exhaust, or as much as $730... But let's take the more expensive option and do a cost-benefit ratio study comparing that Arata ZX-10 exhaust and the more expensive option for my R-1150-R...
The Arata on the ZX-10 gains 6.9 horsepower for a cost of $1499 - or a whopping cost of $217.24 per horsepower gained!!!
Worst case scenario my R-1150-R gains 6 HP (and maybe more), and if you take my most expensive combination shown above - the Staintune, Neptune, UltiMap chip at $730 - you get a cost per horsepower gained of only $121.66.
Now if you take the used, e-Bay Laser HotCam full system (which should show even a better HP gain, but we'll stick with 6 for comparison purposes here...) at $250 and the UltiMap UM872 chip from Aussieland, you get a total cost of $450, and the cost per horsepower drops to $75.00 per HP gained!
I'll take a 7% increase in engine output any time, any way, I can get it without cracking a case, and horsepower never comes cheap, but $75 bucks per pony is about as cheap as you will *EVER* find it...
And we won't even mention the weight loss, improved throttle response, decreased heat output to rider and gearbox from the loss of the catalytic converter, improved efficiency and fuel mileage, etc....
Oh, and BTW, 7% is certainly "measureable"... Just think, if you bench-pressed 250 lbs., and could increase your strength just 7%, you would be pumping 267.5 lbs.! Or if you ran the hundred in 12 seconds and you could go 7% faster you would be clocking an 11.16... But better yet, if you made $85,000 a year, and got a 7% raise, you'd be raking in $90,950! Not bad...
Just food for thought...
Cheers!
Dallara