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John Benson
Joined: 07 Oct 2010
Posts: 150
Location: United States, Oregon, Grants pass
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 Posted: Sat Feb 09, 2013 8:04 pm Post subject: |
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Thanks Ian and Jeff for your work on this. I have never noticed that much vibration in the CR, but then, at around 11000 rpm I'm usually screaming like a little girl and holding on for dear life!   |
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Ian Harrison
Joined: 23 Nov 2006
Posts: 1671
Location: United Kingdom (Great Britain), Manchester
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| Posted: Sat Feb 09, 2013 8:29 pm Post subject: |
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Hi John
It's not a bad vibration (well as long as your teeth aren't loose ) although you tend to feel the low down period a bit more when sitting in the paddock at a fast idle.
The high end period is only slight and of course I feel it more on the dyno where I don't have more pressing distractions  , but it does actually affect engine power which you not only see on the dyno printout but also hear as a roughness in engine note.
These dyno runs only go to 10,700, but you can just pick-up the disturbance in power as the end of the run approaches.
Actually, you guys may be interested in the detail on those runs. After some questions from a US competitor ref intake systems I decided to do a controlled test. The blue curve is with a K&N mesh type filter fitted and the red one is with our regulation CIK airbox that is sealed bar breathing through 2 x 29mm internal dia. trumpets.
Top end (in fact within the normal running range) is more or less the same, although right at the bottom, up to 8,00rpm the K&N is much better. Can only be due to resonance within the airbox. Of course the airbox is much, much quieter, which has to be good.
Best Regards
Ian 
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Ian Harrison
Viper Racing UK
www.viper-racinguk.co.uk
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+44 7984 225 564
+44 161 343 2009
Championship winning Superkart race team 1997-2012 |
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John Benson
Joined: 07 Oct 2010
Posts: 150
Location: United States, Oregon, Grants pass
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| Posted: Sat Feb 09, 2013 8:56 pm Post subject: |
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| It must be a mental thing, because from about 8000 on with the air box it feels like there is a banana in the tail pipe! |
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Ian Harrison
Joined: 23 Nov 2006
Posts: 1671
Location: United Kingdom (Great Britain), Manchester
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| Posted: Sun Feb 10, 2013 4:12 am Post subject: |
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| John Benson wrote: | | It must be a mental thing, because from about 8000 on with the air box it feels like there is a banana in the tail pipe! |
Noise can have that effect of course, as you say it alters the perception, and that is why we, as a bunch of people, against the evidence, resist and hate noise restriction. The sound is all part of the experience, although personally I find induction noise unpleasant and tiring 
In fact by definition the word noise applies to something unpleasant and annoying whereas sound or note is enjoyable to the enthusiast.
Anyway, now you have no excuse, fit that CIK airbox (sorry it's proper name is an inlet silencer) and just stop shoving that banana up your tail pipe
Best Regards
Ian
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Ian Harrison
Viper Racing UK
www.viper-racinguk.co.uk
sales@viper-racinguk.co.uk
+44 7984 225 564
+44 161 343 2009
Championship winning Superkart race team 1997-2012 |
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John Benson
Joined: 07 Oct 2010
Posts: 150
Location: United States, Oregon, Grants pass
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| Posted: Sun Feb 10, 2013 8:36 am Post subject: |
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 I guess I didn't think that through before I made that analogy ! But do you think air disturbance on the track has anything to do with poor performance? I'm running the RLV 4 hole intake silencer. |
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Ian Harrison
Joined: 23 Nov 2006
Posts: 1671
Location: United Kingdom (Great Britain), Manchester
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| Posted: Sun Feb 10, 2013 5:55 pm Post subject: |
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Hi John
No, I never thought about that analagy either!! . . . until you mentioned it
So I guess this is the turkey!! 4 x 29mm trumpets, so breathing capacity is no problem. But you could be getting some sort of air turbulence or it may just be the actual resonance of the box. Without testing I can't say.
This is our CIK airbox with 2 x 29mm trumpets.
Sorry I can't be of more assistance. Only way to find out would be to buy one like ours and try it!!
Best Regards
Ian
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Ian Harrison
Viper Racing UK
www.viper-racinguk.co.uk
sales@viper-racinguk.co.uk
+44 7984 225 564
+44 161 343 2009
Championship winning Superkart race team 1997-2012 |
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Jeff Pickel
Joined: 14 Mar 2009
Posts: 84
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| Posted: Sun Feb 10, 2013 6:36 pm Post subject: |
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| it was done under the stuffer plate |
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Ian Harrison
Joined: 23 Nov 2006
Posts: 1671
Location: United Kingdom (Great Britain), Manchester
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| Posted: Mon Feb 11, 2013 11:48 am Post subject: |
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Hi Jeff
That makes good sense if your drilling holes, so as not to affect the aerodynamics and sealed to the stuffers so as not to increase the effective crankcase volume.
I'm presuming that you removed weight (holes) thus increasing the balance factor rather than adding weight (tungsten) and decreasing the balance factor.
Did you also correct the differences in balance of the 2 crank halves at the same time?
Do you know what balance factor your running? just interested, but feel free to tell me to *****off if you want to keep it to youself
Best Regards
Ian
_________________
Ian Harrison
Viper Racing UK
www.viper-racinguk.co.uk
sales@viper-racinguk.co.uk
+44 7984 225 564
+44 161 343 2009
Championship winning Superkart race team 1997-2012 |
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Jeff Pickel
Joined: 14 Mar 2009
Posts: 84
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| Posted: Tue Feb 12, 2013 9:21 pm Post subject: |
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Ian
I will post on this subject, really busy right now. |
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Chris Reinhardt
Joined: 29 Aug 2002
Posts: 2932
Location: United States, New York, Ossining
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| Posted: Wed Feb 13, 2013 5:41 am Post subject: |
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| John Benson wrote: | | I guess I didn't think that through before I made that analogy ! But do you think air disturbance on the track has anything to do with poor performance? I'm running the RLV 4 hole intake silencer. |
I'm not sure if an airbox takes full advantage of it, but it's called "Helmholtz Resonance" I found the same thing with the 125's, they ran better with a 2 hole air box than just an air filter alone. At that time we didn't have an air filter that flowed enough for use on an air box so we ran them without. I can tell you we lost a couple of cranks and at least one national championship that way.
Ian, do you guys run air filters inside the airbox?
CR
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East Coast Super Kart Series
"This is how we roll!"
www.eastcoastsuperkart.webs.com
CR2 Motorsports
"Home of Cobalt Superkarts"
www.CR2MotorSports.webs.com |
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Ian Harrison
Joined: 23 Nov 2006
Posts: 1671
Location: United Kingdom (Great Britain), Manchester
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| Posted: Wed Feb 13, 2013 6:47 pm Post subject: |
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Hi Chris
No they are just an empty chamber.
When I did the streets race in the Isle of Man, because of possiblilities of dust/debris we fitted a Foam filter intended for a twin choke DCOE Webber. The inlets to the filter just hooked over the backs of the inlet trumpets.
Yes that's me Isle of Man 2002. You can see the back of the Pipercross foam filter
and on a side entry box using "Ram-Air"
Best Regards
Ian
_________________
Ian Harrison
Viper Racing UK
www.viper-racinguk.co.uk
sales@viper-racinguk.co.uk
+44 7984 225 564
+44 161 343 2009
Championship winning Superkart race team 1997-2012 |
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Chris Reinhardt
Joined: 29 Aug 2002
Posts: 2932
Location: United States, New York, Ossining
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| Posted: Wed Feb 13, 2013 10:17 pm Post subject: |
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Now where completely off topic!!!! Isle of Man, it's on the bucket list!!!! I almost did it in 1997 on CBR600..
This is the filter we ended up using. The filter was actually developed for a Corvette motor... Needless to say, it did flow enough..
CR
_________________
East Coast Super Kart Series
"This is how we roll!"
www.eastcoastsuperkart.webs.com
CR2 Motorsports
"Home of Cobalt Superkarts"
www.CR2MotorSports.webs.com |
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