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Discussion Starter #1
I saw some photos of the "Presureized cooling system" on Hodgsons bike that was being run at Sears Point this weekend. What's up with this? Is the idea to run higher coolant temps for more power?? Or are thet trying to find a way make the tank not sprout a piss leak?


I was interested to see the schrader valve fit to the top, that would not be needed for higher temps, perhaps there is a cavitation issue?
 
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Re: High Pressure cooling system? (NC Rick)

I haven't seen the set-up but if you fill a system with coolant and then pressurize its expansion tank (with compressed air like you would a tire) you'll raise the boiling temperature of the coolant. The hottest coolant passage is in the heads so this will reduce local boiling (that occurs there first) and thereby improve heat transfer - allowing more power without fuel detonation issues. Heat transfer to a liquid is much more efficient than heat transfer to a vapor (bubble.)


Modified by Shazaam! at 3:33 AM 5/16/2005
 
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Re: High Pressure cooling system? (NC Rick)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NC Rick »</TD></TR><TR><TD CLASS="quote">I was interested to see the schrader valve fit to the top, </TD></TR></TABLE>

That's where they refill the Nos bottle that's hidden in the radiator.

 
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Re: High Pressure cooling system? (NC Rick)

Here's what one of the M.A.D. members said about the system...

"The existing street and race bike cooling systems are capable of being pressurized to 1.1 BAR (1.1 times the existing atmospheric pressure or equivalent to 16.5 PSI [1 BAR = 15 PSI]), as is evident from the pressure release cap on the plastic reservoir. However, the existing system receives its pressure from the buildup of heat through the normal process of the engine running and not from an external source.

I doubt that the current plastic expansion tank could handle much more than these pressures.

Most radiators are designed to handle 50-60 PSI and are frequently tested to these pressures.

The fabricated aluminum expansion tank with the Schrader valve present at the top would indicate the team is utilizing a compressed gas (most likely air) to pressurize the system to attain a higher boiling point for the coolant. The higher the pressure, the more heat the cooling medium can absorb from the engine and dissipate through the radiator without boiling.

Also, note the hex fitting with the clear hose on the right side of the tower where the Schrader valve is located. This is most likely a pressure release valve (tunable spring/ball action) designed to relieve the system of excess pressure to save seals/hoses from blowing.

Ever removed the radiator cap from your vehicle after a long trip?
The coolant wasn't boiling but when you suddenly lower the pressure it immediately boils and rushes out to greet you!

Just my 2 cents worth!"

Photos are here <A HREF="http://www.superbikeplanet.com/image/2005ama/searspoint/tim-04/
" TARGET="_blank">http://www.superbikeplanet.com...4/
</A>
 
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Re: High Pressure cooling system? (Tifosi)

Yea, I understand that but with a 40 PSI "cap" the pressure would build via the heat. I think Shazzam has a point in that pre-pressurizing the system may prevent localized boiling or cavitation before the system comes up to the temperature to generate the pressure that way.

Cool, i never woulda thunk!
 
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Re: High Pressure cooling system? (NC Rick)

i think the sbp article references specifically the need for the system at pikes peak.

at higher altitudes, things boil faster. I imagine this system is to combat that issue specifically, although Eric seemed to have no problems at all last season smoking everyone for the win.

This may be Ducati's first attempt at closing the suzuki gap per what you guys are saying above.
 
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Discussion Starter #7
Re: High Pressure cooling system? (Tifosi)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tifosi »</TD></TR><TR><TD CLASS="quote">Here's what one of the M.A.D. members said about the system...

"The existing street and race bike cooling systems are capable of being pressurized to 1.1 BAR (1.1 times the existing atmospheric pressure or equivalent to 16.5 PSI [1 BAR = 15 PSI]), as is evident from the pressure release cap on the plastic reservoir.
</TD></TR></TABLE>

Actually 1 BAR is 14.7 PSI therefore 1.1 BAR=16.17 PSI. Sorry if thats niggling but 15psi isnt acurate.
 
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Discussion Starter #8
The water in the cooling system won’t boil sooner at altitude in the closed system. The internal pressure would have to be the same absolute pressure (gauge pressure would change) so a slightly higher pressure cap would be needed. Other than that, I can’t see where the altitude would change the boiling point of the coolant.
 
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Discussion Starter #9
Re: High Pressure cooling system? (Ducman851)

I think if you check, 1.0 bar = 14.5 psi. Common mistake.
 
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Re: High Pressure cooling system? (Shazaam!)

OK ya got me.

actually 14.504
 
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Discussion Starter #11
Re: High Pressure cooling system? (Ducman851)

14.503774. Sorry, I couldn't resist. Respect.
 
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Discussion Starter #12
Re: High Pressure cooling system? (Shazaam!)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Shazaam! »</TD></TR><TR><TD CLASS="quote">14.503774. Sorry, I couldn't resist. Respect.</TD></TR></TABLE>



Ya know ya read the wrong chart and well
 
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Discussion Starter #13
Re: High Pressure cooling system? (Ducman851)

What I find more interesting is this:

Not the song title stamped into the engine case???? But the date that the engine will be used!! Hmmmmm.
 
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