Just for the fun of it:
April 15, 2003. The second run of the GS took place to verify what the differences are.
Mileage reading: 23603.
First things first, however: Between the two dyno runs I rode the bike for about 185 km, and it really MADE a difference. However, things can be deceiving at times, as we will see in a second! What do I mean? On the very first day, and everyday after that, my "seat of the pants" impression was that there is "something" different at around 5000-5500rpm. Something like a "hike" in power, which also resulted in the bike behaving also differently: It started smoking its rear tire more easily when I was in the mood and the rpm was around there!
So, lets have a look at the charts now. What I present this time, are the new power/torque ratings, on the same graph alongside the old ones, for comparison purposes.
So, Boxer-design.de is almost true in their statement, that the bike would be different at around 5-7 HP, only, there's a small catch: The actual HP gain on MY BIKE were 3.5 and it all occured at the highest range of 6700-7700rpm; which is a range seldom used in everyday or travelling pace, let's admit it!
In all the rest of the rpm range I see (but, honestly I cannot feel it!) a LOSS of power ranging from 4 to 9 HP!!!! Isn't it amazing?!
Coming back to the "seat of the pants" feeling of that sweet spot at 5-5500rpm, when viewed on the graph, it can be seen that actually in that range the engine gains 17 HP, while pre-modification it would gain "only" 11 HP!
Coming to the lower two graphs: The left one shows how power increases in the context of time. There too, we can clearly see the loss all across the rev range, as well as the noticeable "lag" in achieving this performance in comparison with the stock setup. On the right hand graph, we can see the gear roll on power, starting with 2nd gear (on the left) and advancing to top gear at right. There are two "hot" spikes there, showing 78 and 87.9 HP respectively, but these are really that: spikes, and not repeatable.
So, was all the fuss worth the expenses? Oh, talking of expenses, it cost me 75 Euros per dyno run, (totalling 150 Euros) plus the 312 Euros for having the kit bought and installed.
Am I happy with all this? I have mixed emotions, as I write this a few hours after the second dyno run, and I admit I am in a bit of confused state of mind too. Let me explain myself: There is a very SLIGHT change in the incoming roar, when I accelerate the bike, which is quite pleasing to the ear, and not at all noticeable by other traffic. This, plus that sweet spot at 5000-5500 rpm, give one the illusion that "something happens". Alas, this is what prompted me to have the modification made, the word-of-mouth of the service personnel, who have performed the mod to lots of other GS's, and all those users coming back happily reporting "good things". Only I was the FIRST to try and verify the truth of the claims! In the end, this is what every magazine and technician in the world advises: Do a modification? Dyno the bike before AND after to see the changes. Simple.
Do I consider it money and time wasted? Not really, considering I'm a smoker, which means I would have smoked the same amount of money in roughly 2 or 3 months!
Finally, its only money! What the heck!!!
I was just curious, that's all!
Clicking on every image here will open the original graph scanned, at a size of approx. 55 to 66kb each.
What the Greek magazines dyno tested since 1994.