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Spencer Uzri
Joined: 18 Apr 2006
Posts: 798
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 Posted: Thu Sep 20, 2012 6:57 pm Post subject: |
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| Craig Sender wrote: | | The reason 2-strokes are prohibited at PGP from my google search (pacific grand prix conditional use permit) Indicates that during the permitting process for the kart track in 2005 it was communicated that 2-stroke karts would be phased out by late 2008. The reason for that statement was either a mistake, misinterpeted or worse an assumption. The end result was that Jan 1, 2009 2 stroke karts would be prohibited at PGP. |
I have to wonder if there was ever a specific reason why the county would even want 2-strokes removed. Pulling up a Fletcher-Munson curve, since CRF 250's & CR 125's run @ RPM's > ~10K (with 250's firing 1/2 the time but at roughly twice the dB output), both should be nearly equivalent in terms of the perceived noise sensitivity.
Last edited by Spencer Uzri on Thu Sep 20, 2012 9:57 pm, edited 1 time in total |
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Craig Sender
Joined: 20 Apr 2002
Posts: 18
Location: United States, Washington, Kent
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| Posted: Thu Sep 20, 2012 7:44 pm Post subject: |
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| I don't think this has anything to do with science or common sense. |
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Bob Francis
Joined: 19 Jul 2001
Posts: 884
Location: United States, Oregon, Salem
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| Posted: Thu Sep 20, 2012 11:36 pm Post subject: |
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Triple post
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B.Francis,
Last edited by Bob Francis on Fri Sep 21, 2012 6:45 am, edited 1 time in total |
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Bob Francis
Joined: 19 Jul 2001
Posts: 884
Location: United States, Oregon, Salem
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| Posted: Thu Sep 20, 2012 11:36 pm Post subject: |
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Triple post
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B.Francis,
Last edited by Bob Francis on Fri Sep 21, 2012 6:48 am, edited 1 time in total |
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Bob Francis
Joined: 19 Jul 2001
Posts: 884
Location: United States, Oregon, Salem
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| Posted: Thu Sep 20, 2012 11:37 pm Post subject: |
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We all over think this stuff it probably is as simple as PGP wanting to have a class that is captive to PGP. It will be the only track/series running the CRF and anyone interested or crazy enough to build one would only be driving it there. I could be wrong but having people come from rentals to clones to the CRF as they progress is a possibility. The package is a good recreational deal but really expensive for what it is. Besides racing it now would be crazy as there are no rule sets I know of. With a little research you can see the improvements year to year with the CRF as they are in competition with Yamaha, Kawasaki and Suzuki. So performance will no doubt change. And they are seeing big gains in power with internals in motocross along with programable igntions,etc. So keeping them box stock is and will be difficult unless an arrive and drive program is in the works. So we will see what happens but I see no real threat or interest from racers looking to replace the CR125 ith the CRF. The CR is a stable program with a solid rule set.
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Spencer Uzri
Joined: 18 Apr 2006
Posts: 798
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| Posted: Fri Sep 21, 2012 12:33 am Post subject: |
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We got it, Bob.  |
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Jim Derrig
Joined: 22 Apr 2008
Posts: 1015
Location: United States, Washington,
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| Posted: Fri Sep 21, 2012 7:52 am Post subject: |
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| Bob Francis wrote: | | We all over think this stuff it probably is as simple as PGP wanting to have a class that is captive to PGP. |
First, thanks to Craig for actually trying to figure out the real reason. I was wondering if its wasn't something like a misstatement during the original permitting process, because PGP not only lost the 2-stroke karts, but the drifting events and car lapping days. That source of revenue was something Paul found well after the track opened, and probably wasn't even mentioned in the original permits, so King County banned them too. The car lapping was mostly street cars with full mufflers, so noise could not have been an issue.
As for Bob's thought, I don't think its PGP wanting to start a new class as it is PGP having no choice but to start a new class, since its current permit will only allow it to use 4-strokes. No sensible track owner would turn away dozens of paying 2-stroke customers on the faint hope that an expensive 4-stroke shifter package somehow will cause new ones to come out of the woodwork.
Hate to say it, but I'll bet if you compared the revenue from rental karts, cars, and competition karts in the time before the ban, competition karts would place a weak third. We got to use PGP because Paul loves karting and creating this track was his dream, not because we were the big revenue producers. Likewise, I just can't see the 4-stroke shifter market generating more than a dozen entries in these parts. I think this is just an attempt by people who love karting to continue using the track for its originally intended purpose, despite the revenue, not because of it.
And if I'm wrong and PGP ends up being the leader for the 4-stroke shifter revolution that makes them a bazzilian dollars, well more power to 'em!
and more torque too.  |
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Bob Francis
Joined: 19 Jul 2001
Posts: 884
Location: United States, Oregon, Salem
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| Posted: Fri Sep 21, 2012 8:01 am Post subject: |
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Jim, just to be clear | Quote: | | We all over think this stuff it probably is as simple as PGP wanting to have a class that is captive to PGP |
. I don't think it is bad or wrong for PGP to do this. I was just pointing out that it puts the people that build CRF karts on an island.
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Chris Reinhardt
Joined: 29 Aug 2002
Posts: 2933
Location: United States, New York, Ossining
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| Posted: Fri Sep 21, 2012 2:18 pm Post subject: |
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| Spencer Uzri wrote: | | I have to wonder if there was ever a specific reason why the county would even want 2-strokes removed. Pulling up a Fletcher-Munson curve, since CRF 250's & CR 125's run @ RPM's > ~10K (with 250's firing 1/2 the time but at roughly twice the dB output), both should be nearly equivalent in terms of the perceived noise sensitivity. |
It's not twice the DB output, it could be twice as loud, the rule of thumb is:
~10dB = twice the perceived volume
So if you had a 125 that was 93db at track side, if something was 103db at track side, it would sound 2x louder.
Your comparing apples to Giraffes!! There's no correlation from a frequency standpoint from one to the other... The 125 swings a 54mm piston, the CRF250 is swinging a 78mm piston, the strokes are different, the power pulses are different, you really can't compare frequencies.
That being said, they are very different, the 4 stroke although it's most likely louder, has a much lower pitch, and being so, it's easier on the ears.
CR
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Spencer Uzri
Joined: 18 Apr 2006
Posts: 798
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| Posted: Fri Sep 21, 2012 8:50 pm Post subject: |
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| Chris Reinhardt wrote: | | Spencer Uzri wrote: | | I have to wonder if there was ever a specific reason why the county would even want 2-strokes removed. Pulling up a Fletcher-Munson curve, since CRF 250's & CR 125's run @ RPM's > ~10K (with 250's firing 1/2 the time but at roughly twice the dB output), both should be nearly equivalent in terms of the perceived noise sensitivity. |
It's not twice the DB output, it could be twice as loud, the rule of thumb is:
~10dB = twice the perceived volume
So if you had a 125 that was 93db at track side, if something was 103db at track side, it would sound 2x louder.
Your comparing apples to Giraffes!! There's no correlation from a frequency standpoint from one to the other... The 125 swings a 54mm piston, the CRF250 is swinging a 78mm piston, the strokes are different, the power pulses are different, you really can't compare frequencies.
That being said, they are very different, the 4 stroke although it's most likely louder, has a much lower pitch, and being so, it's easier on the ears.
CR |
You're right. In fact, the dB scale is logarithmic. 
And yes, the 2's do indeed have a higher pitch than 4's, but that was the point: if they are loud enough, 4's become as annoying as the higher-Hz 2's. |
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Chris Reinhardt
Joined: 29 Aug 2002
Posts: 2933
Location: United States, New York, Ossining
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| Posted: Sat Sep 22, 2012 5:42 am Post subject: |
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| Spencer Uzri wrote: | | And yes, the 2's do indeed have a higher pitch than 4's, but that was the point: if they are loud enough, 4's become as annoying as the higher-Hz 2's. |
Now you're becoming subjective, it's kinda in the ears of beholder....
But...Higher pitch sounds tend to be more annoying and damaging to the ears than lower ones..... Generally speaking.....
Think of nails on the chalkboard (remember them) and a Escalade with the 10000 watt subwoofers......
CR
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Spencer Uzri
Joined: 18 Apr 2006
Posts: 798
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| Posted: Sat Sep 22, 2012 3:35 pm Post subject: |
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| Chris Reinhardt wrote: | | Spencer Uzri wrote: | | And yes, the 2's do indeed have a higher pitch than 4's, but that was the point: if they are loud enough, 4's become as annoying as the higher-Hz 2's. |
Now you're becoming subjective, it's kinda in the ears of beholder....
But...Higher pitch sounds tend to be more annoying and damaging to the ears than lower ones..... Generally speaking.....
Think of nails on the chalkboard (remember them) and a Escalade with the 10000 watt subwoofers......
CR |
Actually, I'm referring to the F-M curve. If a low-Hz noise is transmitted with sufficient amplitude (ie. it's loud enough), then it will be perceived similarly to higher-Hz waves.
1000-W subwoofers cranked up in the back of an Escalade can reach the annoyance level of a nail-scratched chalkboard.
Seems that the real force behind these regs are NOx emissions & such, & hands down, an EFI 4-stroke has a distinct advantage over a carburetted 2-stroke in that case. Unless the skeptics can be won over by clean-burning EFI 2-strokes - which are out there (I've heard TM even has an EFI ICC R&D example at the factory) - this is how the power-play will go down.
Like I said, it's King Co. Not surprised.
Last edited by Spencer Uzri on Sun Sep 23, 2012 1:19 am, edited 3 times in total |
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Bob Francis
Joined: 19 Jul 2001
Posts: 884
Location: United States, Oregon, Salem
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| Posted: Sat Sep 22, 2012 3:48 pm Post subject: |
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To add to the noise issue, there are a lot of tracks running super motard classes at kart tracks. It is incredible how loud the bikes are compared to the karts. The deep sound that the bikes make is very uncomfortable to be around for me at least. I try and not frequent the kart track when the bikes are around.
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paul rees
Joined: 06 May 2007
Posts: 264
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| Posted: Sun Sep 23, 2012 8:11 am Post subject: HONDA CRF250 |
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Honda CRF250R Engine $ 2,999.95
Carburetor w/ Modification $ 719.95
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Radiator w/Mounts $ 499.95
Tokyomods Radiator Hose Kit $ 235.85
Tokyomods Hi Pressure Radiator Cap $ 29.95
Tokyomods Hour Meter |
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Ken Schilling
Joined: 01 Dec 2005
Posts: 1347
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| Posted: Sun Sep 23, 2012 9:04 am Post subject: |
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And people are complaining about the current overall kart weights with two strokes...  Imagine what these four strokes will weigh, easily another 20 lbs. Good luck trying to scale your kart and getting the L to R balance anywhere close...
Plus the added cost and complexity when engine work needs to be done. I can do my CR125 top end for ~$100, myself, at the track, in less than 30 minutes. If you've got an engine problem at the track with a four stroke, you're done, unless you have a spare engine (with that much more cost...).
Also, the supposed noise issue isn't that big of a problem. For the last couple of years shifters have run at Laguna Seca with their very restrictive noise limits. An airbox & extra large silencer do the trick.
You can have my two stroke when you can pry it out of my cold, dead hands...!!!
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The opinions I express are mine alone and do not reflect those of any organization of which I am a member. |
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