Cooling SystemCooling System

Cooling System Schematic

Surge Tank

Overflow Tank

Steam from Cylinder Head

Engine Block Water Pump

Fan

Ra

dia

tor

Thermostat

� Rule of thumb: 1.1 in2 radiator surface area needed per hp produced

� Therefore need approx. 66 in2

Radiator

Inlet from Engine

Modify for

bleed line to

Surge Tank

� Radiator from YFZ450R Yamaha ATV

� 7.5” H x 11.5” W x 7/8” D

� Surface Area 86.25 in2

� Inlet and Outlet ¾” ID tubing to connect to water pump

Outlet to Water

Pump

� Coolant naturally builds to approximately 16-18 psi

� Normal production cars run 16-18 psi, high performance cars run 22-24 psi , and racing systems run 29-31 psi

� Pressurizing the water allows for the water to reach a higher

Radiator Cap

� Pressurizing the water allows for the water to reach a higher temperature before boiling (therefore vaporizing)

� Part# T30R Radiator Cap 29-31 PSI

Pressure (PSI) Boiling Point (° F)

0 PSI 212° F

10 PSI 239° F

20 PSI 259° F

30 PSI 273° F

40 PSI 286° F

50 PSI 297° F

� Typically a 1 quart container

� Need to modify the part of the Radiator that currently has the cap and overflow line to run a ¼”- 3/8” bleed line from radiator to top of surge

Surge Tank

Bleed line

inlet from

radiator

and

Outlet to

overflow

tank

30 PSI

Pressurized

Radiator Cap

bleed line from radiator to top of surge tank

� ½” – ¾” Refill line from bottom of surge tank to inlet of water pump

� Benefits – de-aeration

� 2% air in the system leads to an 8% decrease in cooling efficiency

� 4% air in the system leads to a 38% decrease in cooling efficiency!

and

cylinder

head

tank

Refill line back

to water pump

� Comes stock on engine

� No internal bypass system. Thermostat will have to regulate continual water flow through engine

Water Pump

Need to test flow rate once we have the cylinder head again

� ¾” ID inlet and outlet tubing to connect to radiator

Flow Rate vs. RPM from R6 water pump

� Placed at the outlet of the engine, a thermostat allows water to circulate through the block, but doesn’t allow this water to circulate through the radiator until it has reached proper operating temperature

� This temperature (195°F) melts the “wax motor”, which forces the thermostat piston to open and allows the water to flow through.

Thermostat

thermostat piston to open and allows the water to flow through.

� If the engine’s temperature is lowered too much, the piston closes until it has reached proper operating temperature once again

� Stewart/Robert Shaw Thermostats – 302

� Augments bypass system

� $14.95

Cooling System Data

� Reviewed three sets � Reviewed three sets of autocross runs with different drivers

� Verify radiator is receiving adequate airflow at low speeds

� SPAL Axial Fan

� 11” Dia.

Fan

F19 F20

mph ft^3/m ft^3/m5

0 0 0

5 213 130

10 426 260

15 639 391� 11” Dia.

� 755.0 CFM

� Based on predicted power require minimum 450 CFM

� Based on airflow at speed available require minimum 500 CFM

� Maximum 7” Dia. to fit radiator

� Yamaha R6 Fan

� 5.5” Dia.

� Est. >500 CFM

15 639 391

20 853 521

25 1066 651

30 1279 781

35 1492 912

40 1705 1042