| Author | Message | ||
     Easyrider |
We needed to test the stacks anyway and because we will race in Bonnville with them here is the test result: http://www.twinmotorcycles.nl/artikelen.asp?aid=76 With special thanks to Pasi (-: | ||
| Westmoorenerd |
I'll be one of the first in line for the stacks! | ||
| T_man |
Then I'll be second  | ||
| Thefleshrocket |
It looks like the velocity stacks gained torque and lost horsepower compared to stock. The only point at which the stacks gained horsepower was when the bike was run with the airbox cover off, and that gain was comapared to no stacks and the airbox cover on. So I don't really think it's fair to say that the stacks gained any horsepower at all as it's likely that the stock setup would have gained power as well with the airbox cover removed. However, the midrange torque gains should be pretty noticeable, so losing 1 or 2 horsepower up top (as in 9000rpm+) probably won't be that big of a deal given the extra midrange punch. | ||
| Daniii |
It's the midrange torque I'm looking for, so I'll be interested. Wonder what the improvement is on an unmodified motor. | ||
| Torquaholic |
Easy, what kind of speed record on the 1125R are you hoping to make? Have you altered the gearing to move past the belt drive top speed of about 170mph? Is it now a chain drive 1125r? Thanks for your continued effort!! | ||
| Cowboytutt |
Somebody help me out here. I love the looks of velocity stacks but as far as I know they offer no filtration of dirt and dust? On my recent trip to Laguna Seca I met up again with a very nice man named Dennis who rides a Duc 1098. His air filter at some point did not seal resulting in dust/dirt into his motor which seriously damaged the front cylinder. Ducati tried their best to low ball him the repairs under warrenty and I must say, I WAS NOT IMPRESSED AT ALL by their customer service. Dennis is some sort of engineer who problem solves repair policies for companies around the globe and he threw Ducati's own manual repair recommendations right back into their face. Long story short, he won out eventually but it took a loooong time. Which brings me back to mention that IF ITS TRUE that velocity stacks offer no filtration, WHY would you want to take the chance of destroying you motor while running one???? Please educate me as I'm no expert on V-stacks here. -Tutt | ||
| Ridenusa4l |
Cowboy, the stacks meerly slide into the original throttle bodies and the airfilter goes in the same spot as stock, there is NO reason to run stacks without a filter, at least on hte 1125's. Jake | ||
| Cowboytutt |
Thanks Jake. As I said, I'm no expert here. A lot of people are cutting holes into their air boxes and I'm not convinced at all that this is the right thing to do for performance or reliability. Erik went to a lot of trouble to invent a good airbox. -Tutt | ||
| Easyrider |
Ridenusa4l is right, Keep airbox closed.. I did the testing because we go to bonneville and every HP i can find we will need... | ||
| Thefleshrocket |
Cowboytutt, one of the big constraints when designing an airbox is noise. The entire motorcycle has to meet noise requirements and the intake can be VERY noisy if it's opened up. (This applies to most bikes, not just the 1125. I cut the airbox on my '03 SV1000S and it was ungodly loud--as in it drowned out my Yosh "race" system when accelerating hard.) So if someone doesn't mind the additional noise, there is sometimes more power to be found my opening up or modifying the airbox. | ||
| Firemanjim |
Easy,when are you coming to Bonneville. I will be at Bubs and World of Speed this year with my Aussie partners. | ||
| Highscore |
Thank you Easy, that you give a proof for me thesis according velocity stack length for the 1125: Behind a certain length there is just a loss in peak power without any noticeable increase in peak torque in mid range. A moderate prolonged stack - and it looks like as yours, Easy, are also around +25mm or 1´´ longer - offer the best compromise by boosting mid range torque to a maximum without scarifying peak power to much. Although, with (cosmetic) cover above the stacks, there is still a shy loss in peak power past 10 grand, where the stock stacks make peak power. Circumstances with and without cover above the engine intake are completely different. This is not the question of more ore less air flow or restriction, it is a question of harmonics. Your own dyno runs, Easy, give the proof for this fact: The torque graph for "long stacks" shows with "cover on" two peaks, gut with cover off just a single one. The difference in graph shape cannot be the result of more or less air. There is happening something different: The wave action below the cover within the volume, defined by this wall, overlays the wave action inside of the stacks and intake runner. When designing new and more efficient stacks, it is necessary to be aware of this phenomenon. Riding without any cover may be possible at the salt lake, but I guess nobody likes to drive on the street with this style. | ||
| Cowboytutt |
Fleshrocket, I agree that sometimes cutting holes into the airbox can help, especially because of noise restrictions as you pointed out. I think the exception is some of the ram air intakes that are so common today. Some are better than others. My 99 'Busa didn't start making positive airbox pressure until you were going 90 mph or so if memory serves. This is because the ram air tracks were not sealed, not in the best location (although not necessarily in a poor location either) and because of the motor's enormous thirst for air. Kawasaki probably has the best ram air systems out there as they are positioned at the highest pressure zone of the bike, right at the tip of the front fairing. Obviously, when you start cutting holes into the airbox you compromise the ram air effect of the stock system. Now the Buell 1125 ram air system is most likely less than stellar as its location behind the fork tubes and in front of the engine would not seem to be ideal. It would be interesting to see at what point it starts to make positive airbox pressure or equally interesting would be to compare dyno runs on the same bike with different airbox modifications. Heck, the stock system may even suck but I'm not going to start cutting holes into my airbox until someone has good, hard data to show it helps. Erik has always been a pretty sharp guy when it comes to developing intake and exhaust systems that are quiet but also flow well because of his expertise in physics (ie Heimholtz resonators or whatever its called). I'm going to give him the benefit of the doubt until someone shows me otherwise. By the way, this is a GREAT board and I really appreciate all the expertise here and I'm willing to learn and say when I'm wrong! Thanks guys! -Tutt | ||
| Easyrider |
Torquaholic, Yes, it has a chain. Firemanjim, BuB, http://www.speedtrialsbybub.com/2010_event/index-2 010.html Highscore, It is indeed ment for Bonneville only with the open airbox. |
