I'm going to go over some lessons I've learned over the last 32 years.
Myth -- Iron heads will make more power than aluminum heads.
Fact -- With all physical characteristics being the same (chamber shape and size, port shape and size) aluminum heads will equal Iron heads in performance.
Fact -- Iron heads make their best power at a lower temperature. 160º is the optimum temperature for power but this has it's drawbacks.
1. Cylinder wall wear increases as the operating temperature is reduced. 220º is the point at which wear will be reduced the most.
2. Lubricating oil is most efficient at a 300º. With a 160º head temperature the oil will never reach this temperature. Bearing clearances in iron headed engines need to be increased to reduce the size of the wedge of oil that the crank rides on to prevent the bearing from spinning in it's bore.
3. Iron heads need to be cooled off more between rounds. The heat soak will kill the performance. This is why you see all those fancy electric water pumps.
Fact -- Aluminum cylinder heads will make the best power at 210º Every NASCAR team uses aluminum heads and make 750 horsepower with 352 cubic inches. They achieve this by running coolant temperatures of 210º - 220º. This has several advantages for a street car.
1. Less cylinder wall wear. The big three auto makers now run coolant temperatures of 195º+ and its not uncommon to see these engines last 200,000 miles or more.
2. Tighter bearing clearances. The oil gets up to the 300º and is more efficient at lubricating. Thus less wear and tear on the engine.
3. No need for those fancy electric water pumps.
Here's how you equalize the playing field using an aluminum head.
1. Use a 195º thermostat to get that motor up to temperature.
2. Use Evans NPG coolant. This coolant is designed to operate at above 190º and will not boil over until it reaches 260º and will stop any steam pockets from forming in the cooling system.
And finally here's how a rookie can be more consistant with their ET's with an aluminum headed engine. Get that motor up to temperature.
I don't know how many times I've heard this.I gotto the dragway and imediately made a pass and ran a 12.40 but all my other runs were .2 to .3 tenths slower. Why. It's because they watched a driver of an iron headed car cool down his motor between rounds and he figured he would do the same. Not a good idea. Build up that heat first and the consistancy will be there.
This is the truth and nothing but the truth. George
Myth -- Iron heads will make more power than aluminum heads.
Fact -- With all physical characteristics being the same (chamber shape and size, port shape and size) aluminum heads will equal Iron heads in performance.
Fact -- Iron heads make their best power at a lower temperature. 160º is the optimum temperature for power but this has it's drawbacks.
1. Cylinder wall wear increases as the operating temperature is reduced. 220º is the point at which wear will be reduced the most.
2. Lubricating oil is most efficient at a 300º. With a 160º head temperature the oil will never reach this temperature. Bearing clearances in iron headed engines need to be increased to reduce the size of the wedge of oil that the crank rides on to prevent the bearing from spinning in it's bore.
3. Iron heads need to be cooled off more between rounds. The heat soak will kill the performance. This is why you see all those fancy electric water pumps.
Fact -- Aluminum cylinder heads will make the best power at 210º Every NASCAR team uses aluminum heads and make 750 horsepower with 352 cubic inches. They achieve this by running coolant temperatures of 210º - 220º. This has several advantages for a street car.
1. Less cylinder wall wear. The big three auto makers now run coolant temperatures of 195º+ and its not uncommon to see these engines last 200,000 miles or more.
2. Tighter bearing clearances. The oil gets up to the 300º and is more efficient at lubricating. Thus less wear and tear on the engine.
3. No need for those fancy electric water pumps.
Here's how you equalize the playing field using an aluminum head.
1. Use a 195º thermostat to get that motor up to temperature.
2. Use Evans NPG coolant. This coolant is designed to operate at above 190º and will not boil over until it reaches 260º and will stop any steam pockets from forming in the cooling system.
And finally here's how a rookie can be more consistant with their ET's with an aluminum headed engine. Get that motor up to temperature.
I don't know how many times I've heard this.I gotto the dragway and imediately made a pass and ran a 12.40 but all my other runs were .2 to .3 tenths slower. Why. It's because they watched a driver of an iron headed car cool down his motor between rounds and he figured he would do the same. Not a good idea. Build up that heat first and the consistancy will be there.
This is the truth and nothing but the truth. George
