On 2/1/06, Ed Anderson <eanderson@carolina.rr.com> wrote:
Thanks, Bill
Just thought it might be useful to some who might be considering it why NPG just might not be well suited to the stock rotary coolant system.
Yes, I noticed that the chart did not measure the viscosity of the NPG at the same temps as they did the 50/50 mixture. Might be a legitimate reason for that but escapes me. I suspect the viscosity goes much higher at lower temps. No problem with a running engine, but starting a really cold block might offer some problems as you suggest. Especially given the small diameters of some of the GM cores channels. Could be that Dave simply was not getting any significant cooling due to minimal flow. I recall him saying the temps went up all of a sudden and wonder if the coolant "trapped" in the block might not have reached very high temps before managing to "burst" lose and send the temp sensor soaring.
Ed
I doubt it. It's not that thick when cold. Besides, temps were well stabilized above 100 before taking off. My radiator also sees mostly pre-warmed air.
I the temp change across the rad is just not that big. I have heard numbers in the range of 5-15 deg. So after things get warm they are just not going to drop that cold in the rad.