Author |
Message |
Blower1
| Posted on Friday, October 02, 2009 - 11:12 am: |
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Has anybody tested velocity stacks in 1125? They should increase the mid range torque. |
Tbenson
| Posted on Friday, October 02, 2009 - 11:55 am: |
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Redscuell has. http://www.badweatherbikers.com/buell/messages/290 431/495478.html |
1_mike
| Posted on Friday, October 02, 2009 - 02:14 pm: |
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Mid range torque...? Huh... More midrange vs. what? Your talking length right? From long to short... Longer = equals more low end torque Shorter = equals more high end power. Mid = mid range But theres's much more to it than JUST changing the length. There IS tuning involved to obtain the best of what you are working with. Mike |
Hootowl
| Posted on Friday, October 02, 2009 - 02:47 pm: |
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See, size does matter. |
Blake
| Posted on Friday, October 02, 2009 - 05:12 pm: |
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"Redscuell has." Not really. He tested muffler mod in conjunction with some kind of intake mod. From that, there is no way to know the effect of the intake alone that I've seen. |
Blake
| Posted on Friday, October 02, 2009 - 05:14 pm: |
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"From long to short... Longer = equals more low end torque Shorter = equals more high end power. Mid = mid range " I don't believe the issue is that simplistic. It is possible that a longer stack may also enhance top end. |
Blower1
| Posted on Saturday, October 03, 2009 - 01:21 am: |
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I have tested a different length stacks in my other bikes, but not in my 1125R. Blake is right, itīs not so simple. When having a right length stacks also high end power is better. |
Stevel
| Posted on Saturday, October 03, 2009 - 11:23 am: |
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I'm not sure that stacks would help on the 1125. The purpose of velocity stacks is to increase closed intake valve back pressure. The air column in the inlet track starts and stops flowing air following the inlet valve action. The inertia of the air column creates a cramming effect at the back side of the valve when closed. Then, upon opening, air immediately starts flowing even before the vacuum from the intake stroke develops. It's like free supercharging. In order to take advantage of the phenomena, the valve must open several degrees before TDC and sufficient back pressure must exist. On the 1125, the inlet track is enormous. Much larger than required in fact (and I believe to a fault) As an example, the throttle bodies on the Vrod, which is a very similar design, are approximately 10mm smaller in diameter. The net effect is to drastically reduce the air column speed. The magic number for speed is about 140 fps and if you do the arithmetic, it is well short of that. In point of fact, this ram effect does not work below 10,000 rpm. So unless the redline is increased to around 15,000, column inertia won't help much at the existing design size. In that light, shifting what does not exist to a lower RPM doesn't add a lot of value. If I were serious about making this engine competitive in SB competition, I would weld up these passages in the head and remachine them smaller. Steve |
Blower1
| Posted on Saturday, October 03, 2009 - 12:34 pm: |
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Itīs maybe better to try find the optimal length headers and the muffler. Does anybody know the 1125R cam specs? |
Hellgate
| Posted on Saturday, October 03, 2009 - 03:19 pm: |
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Steve is on it. There are many cases were a smaller intake track yields much better power and torque. It's all about charge velocity that determine engine performance not flow bench outcomes. |
01xjbuell
| Posted on Saturday, October 03, 2009 - 05:20 pm: |
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So my question, as I am starting to tackle intake designs (not expecting big results, just like playing) is that maybe a slightly thinner velocity stack with a pod-style filter could accelerate the intake charge? Nick |
Zac4mac
| Posted on Saturday, October 03, 2009 - 10:02 pm: |
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You probably won't really hurt the power. Looks IIRC, Baggermike was talking about stacks and neon lights with a kickash cover. No function, he just thought it would look cool. and different. Want a power increase? Go from 5000' ASL to the coast(any coast) and you get a scary wheelie machine. I kinda like Loretta behaving even when I forget to. |
Bigblock
| Posted on Sunday, October 04, 2009 - 09:35 pm: |
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hmm, I wonder if the oversize intake tract on the 1125 has anything to do with the ram-air (or it's potential in a more power inspired race airbox, ala RR)? |
Redscuell
| Posted on Monday, October 05, 2009 - 07:45 pm: |
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"Not really. He tested muffler mod in conjunction with some kind of intake mod. From that, there is no way to know the effect of the intake alone that I've seen." That's a fair comment. And in my post, I stated that I have no evidence that my velocity stacks contributed anything. I put them in because there was room. On the other hand, given that some posters have alleged that my exhaust mod did not create the power and torque increases that the dyno shows, then logically the increase came from the $10 intake stacks? Or did it actually come from the $50 muffler mod? Someday I'll test them separately. Maybe. |
Fresnobuell
| Posted on Monday, October 05, 2009 - 07:57 pm: |
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On the other hand, given that some posters have alleged that my exhaust mod did not create the power and torque increases that the dyno shows, then logically the increase came from the $10 intake stacks? Or did it actually come from the $50 muffler mod? No, logic says that there is no power/torque increase at all. All dynos are different and you cannot claim a power increase unless you have a baseline run. It's as simple as that. |
Blake
| Posted on Tuesday, October 06, 2009 - 01:56 pm: |
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I'd say that logic indicates that there may be a power improvement, but without independently run before and after dyno test results we have no way of knowing. |
Fresnobuell
| Posted on Tuesday, October 06, 2009 - 01:59 pm: |
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+1 Blake. |
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