DamonB

Nope because the forum hasn't been allowing pic uploads lately. You should be able to find it at a decent newstand.

Grassroots Motorsports, May 2004

7racer

thanks!

Nathan Kwok

Thermal conductivity: how quickly heat transfers, higher is more

Specific heat: how much a given amount of heat raises the temperature, high means less change in temperature

My understanding is that Evans has higher thermal conductivity but a lower specific heat, but don't quote me on that. I'm mainly pointing this out as people tend to mix these two things up and/or think they are the same thing.

turbojeff

iTrader: (30)

IIRC Evans has a lower thermal conductivity and a lower specific heat. Since specific heat includes a mass measurement it is important to mention that I think Evans has a higher density.

DamonB

The article speaks of Evans having the consistency of 2% milk, so that's probably true.

xchaos

It seems to me that the consitency is higher than than...more like whole milk.

the_glass_man

iTrader: (2)

I'll pass unless it's healthy like skim milk!

pomanferrari

iTrader: (1)

Another thing I've noticed: the voltage differential with a probe in the NPG+ and a ground probe in the block, the voltage was .05 volt over 7 mos. Much much lower than EG/water which I saw up to 0.3 volts w/in a year.

KevinK2

The sg of npg+ is only 2% higher than 50/50 egw, while the specific heat for egw is 27% higher. So npg+ still gets hotter quicker for a given heat flow. But net heat flow is slower due to lower net heat transfer rate due to higher viscosity (bad, 10X at 50F, 3X at 212F) and 25% lower thermal conductivity.

Quick warm up of fluid at cold start gives false indication of higher heat transfer rate.The fluid gets hot quick from hot spots in block, but the cold metal stays cool. At 50F, NPG+ has over 10X the visc of egw, and 25% lower thermal conductivity, both bad for heat transfer. But due to low specific heat, it does warm up quickly, but does not redistribute the heat to metal surfaces well or quickly.

Not bashing npg+, just giving the facts. Big advantages are no pressure needed, long run life, and I suspect can do better for extreme hp 13B, vs egw.

The very low vapor pressure should allow stock water pump speed without any cavitiation.

I'd run zero psi with alum ast and .08" pill in side hose, to assure lower rad hose never sees vacuum. With no ast, mabe a 7 psi cap. Fluidyne with nice big tubes would be a good match.

Just give plenty of time for warm-up, regardless of how quick gage rises.

pomanferrari

iTrader: (1)

My water temp gauge is at the water pump and I' seeing 165 degrees whereas the instrument panel idiot gauge (which senses metal temp on the rear rotor) shows half-way. This is opposite what you're saying.

In any case, I wait until my analog water temp gauge catches up before going on boost.

It's nice to thrash the hell out of the car, park it without hearing that crappy gurgling noise.

BTW, my auxiliary electric water pump is working great at keep the block cool. I need to datalog the temp drop to illustrate the difference with and without the electric pump.

KevinK2

"This is opposite what you're saying..."

may be some misleading data .......

if stock gauge, it shows 1/2 way from about 160F to 240F, iirc. The sensor is a standard water sensor probe, with sensing element in contact with flowing coolant.

unless aux gauge sensor is mounted on back side of wp hsg, it will be in stagnant coolant until t-stat opens.

A common result of NPG+ use is higher oil temps. this is due to less heat removed by cooling system, and more by the unchanged oil cooling system, with net higher metal temps for same hp load.

I think before/aft oil temp readings would tell if engine is running hotter or cooler. Or, readings from a temp sensor on the ctr housing (thermister, vdo cyl head temp gauge, etc).

RX7Wishing

omg.. i had to stop reading this. to many cry babys posting