I have been reconsidering my Water pump scheme, read below:
LS Coolant Flow:
- LS cooling system - numbered.jpg (89.97 KiB) Viewed 3669 times
I currently have on my shelf the Meziere remote mechanical pump: WP430S
Meziere makes a coolant manifold, WAM119S
https://www.summitracing.com/parts/mez- ... ?rrec=true
Unless FieroGuru releases his own manifold with t-stat sooner, I may try to order one, but I will still need to use my remote T-state housing (Moroso 63425). This makes plumbing very complex, as I need to fashion a heater bypass) and the -12 ports may be too small.
I also have this:
https://www.amazon.com/gp/product/B0BF1 ... UTF8&psc=1 and it may package better.
I also have a couple of sets of water pump spacers, to see if I can try to use a modified LS4 water pump setup with the LS3 crank pulley I have. I would love to figure out what the LS4 pump flows. I should try to test one someday.
Meziere flow graph:
- Screenshot 2023-09-06 111417.jpg (30.49 KiB) Viewed 3669 times
Pierberg:
- Screenshot 2023-09-06 120058.jpg (79.14 KiB) Viewed 3669 times
Now onto my cooling system Math:
50/50 Volume Ethylene Glycol Water Mix Specific Gravity @ 180F = 1.044
50/50 Mass Ethylene Glycol Water Mix Specific Heat @ 180F = .873 BTU/lb F
Assume 50/50 mass = 50/50 volume (Horseshoes and Hand Grenades)
Radiator Top Tank Temperature = (Thermostat Open temp + 20F) This is arbitrary ( air speed, rad size, core type, flow dependent variable)
Thermostat Temp = 160F
Top Tank Temp = 180F
Flow Rate = 55 GPM (max rating of Meziere’s Remote Electrical Pump and the mechanical at 4000RPM (The large Pierburg 7.03665.66.0 is 70L/Min or 18.5 GPM)
Heat Flux = (180F-160F)*0.873BTU/lb-F * 8.1LB/GAL * 1.044 = 8147 BTU/MIN = 192HP
How is this useful?
Two Criteria I can think of, what would the average power level be at a Track? My goal would be to take this car for a track weekend at Road America, Gingerman, or Autobahn Country Club. I don’t have data logs to use, but If there is an average power during a lap to be derived from such, we could determine what the total heat removed from the engine needs to be over time.
Second, As a rule of thumb: 1/3 of all chemical power from an engine goes to torque production, 1/3 to exhaust heat, and 1/3 to water jacket heat. Starting here we can begin sizing components when engine specific data is not known. A 400 HP engine Auto engine generally doesn’t spend all day making 400HP, especially cruising. Ideally, we have a pump control, to tailor the coolant flow to the cooling power required. That can either be a ratio of engine speed (such as an engine driven pump), an electronic pump controller, such as a PWM pump unit like BMW has been using, or just the thermostat alone, and rely on the thermostat to open and close flow to the radiator alone (SBC installs).
That is where the average power around a track may be helpful. With sufficient cooling capacity, we can absorb the 400HP when necessary and during dwell time under deceleration where engine power is very small cool the coolant to lower than operating temperatures. This works so long as the average system flow rate can cool above the average power level. This is why so many people say Electric pumps lack the flow for high performance driving outside of drag racing, they can’t flow enough for sustained power absorption outside of the drag racing duty cycle.
A more efficient radiator, be it better airflow, or a more efficient core, can improve this but we are limited to airspeed and ambient temp conditions. A 100% efficient radiator can only cool our theoretical engine from Ambient up to the maximum top tank temp, (this is the designer’s choice, and you need to base it of a criterion such as Air to Boil Temp, when Air to Boil is reached the coolant boils, and cooling performance disappears entirely).
So lets assume a summertime 85F ambient (ignoring humidity effects)
T air in = 85, T air out max = 180F (top tank temp from before)
Cp of air at 85F = .240 BTU/LB-F
Density of Air at 85F = 0.0728 lb/ft^3
Dh= 0.240 BTU/LB-F * (180F-85F) * 0.0728 lb/ft^3 = 1.67 BTU/ft^3
Radiator Area = 19.75” x 15” = 296 sq-in = 2.057 sq-ft
Air Speed 55MPH (Co Hwy or corner exit) = 4840 ft/min
Airflow = 4840 ft/min *2.057 ft^2 = 9956 ft^3/min
Heat Flux = Dh*Q = 1.67 BTU/ft^3*9956 ft^3/min = 16627 BTU/min = 392HP
That’s the maximum possible (not achievable) power absorption at traffic speeds, the capacity lowers at lower speeds, and raises at higher speeds.
We have also ignored aerodynamic effects and Turbulence, as well as radiant cooling.
Air to Boil = (BP – (Tcool in – Tair in)
Air to Boil =(225F –(180F – 85F)=130F, so probably safe for extreme hot days.
Anyways, I have yet to convince myself to run an electrical Water pump like the Peirberg unit. I will have to look at what the average power of a lap at road America could look like based on positive acceleration data vs time of similar enough car of a known weight.
Edited for clarity