Camaro XV

[Vince@Meanstreets]

Originally Posted by ratman67

what is heat rejection????

the removal of heat from a heat generator. Water to air cooling or the exhaust. In this case he was referring to the inner cooler or heat exchanger efficiency.

[mikels]

Originally Posted by Vince@MSperfab

the removal of heat from a heat generator. Water to air cooling or the exhaust. In this case he was referring to the inner cooler or heat exchanger efficiency.

In this case, there is 3 sources of heat - engine, supercharger and AC. Breaking that down further, engine heat in form of coolant and oil, supercharger heat in form of air and AC in form of refrigerant.

Engine heat in coolant and oil comes from the inefficiencies of an IC engine - only about 1/3 the energy released from combustion actually makes power, another 1/3 goes into cooling system (coolant & oil) and 1/3 goes out exhaust.

Since this is a SC engine, also have to take into account mechanical energy used to drive supercharger - in Red Devil and Mayhem, this worked out to ~120-140HP. So Mayhem generating an output of 878 HP is actually generating over 1000 HP already - and that also nearly equals the amount of energy we need to release from cooling system.

Complicating this further, we have the heat from the intake air charge to reduce as well - and use air-to-water heat exchanger with a stand-alone cooling system to then convert this with a water-to-air heat exchanger in front of car. Since delta-T is critical for heat exchanger effectiveness, we package the intercooler radiator in front of the cooling stack (all the heat exchangers in front of car) to get greatest delta-T for charge air cooling. This adversely effects radiator efficiency as air temp reaching front face of it is already heated above ambient. And we have 1000+ HP worth of heat to dissipate from it.

Packaged between the CAC (charge air cooler radiator) and the coolant radiator is the AC condenser. At least Mark hasn't become too much of a wimp is his old age to want to race with AC on, so while this doesn't add heat to air flowing through, it does add pressure drop of airflow through entire cooling stack.

We also have engine oil to contend with - and can either use oil-to-air heat exchanger, or oil-to-water. If oil-to-water, this is more KW to release through radiator. If oil-to-air packaging, airflow restriction and preheated cooling air have to be considered.

All this is converted to heat transfer equations and calculated to optimize the entire cooling system of heat rejection balance.

Drag racing is easy - you can get away with a whole lot if only running in <10 second bursts of WOT. Road racing makes this much more difficult as entire system reaches equilibrium.

And haven't even talked about trans and diff oil cooling yet....

Dave

[JohnC]

Wow, very cool, Dave. ...you are an awesome dude.

John

[frojoe]

Originally Posted by mikels

In this case, there is 3 sources of heat - engine, supercharger and AC. Breaking that down further, engine heat in form of coolant and oil, supercharger heat in form of air and AC in form of refrigerant.

Engine heat in coolant and oil comes from the inefficiencies of an IC engine - only about 1/3 the energy released from combustion actually makes power, another 1/3 goes into cooling system (coolant & oil) and 1/3 goes out exhaust.

Since this is a SC engine, also have to take into account mechanical energy used to drive supercharger - in Red Devil and Mayhem, this worked out to ~120-140HP. So Mayhem generating an output of 878 HP is actually generating over 1000 HP already - and that also nearly equals the amount of energy we need to release from cooling system.

Complicating this further, we have the heat from the intake air charge to reduce as well - and use air-to-water heat exchanger with a stand-alone cooling system to then convert this with a water-to-air heat exchanger in front of car. Since delta-T is critical for heat exchanger effectiveness, we package the intercooler radiator in front of the cooling stack (all the heat exchangers in front of car) to get greatest delta-T for charge air cooling. This adversely effects radiator efficiency as air temp reaching front face of it is already heated above ambient. And we have 1000+ HP worth of heat to dissipate from it.

Packaged between the CAC (charge air cooler radiator) and the coolant radiator is the AC condenser. At least Mark hasn't become too much of a wimp is his old age to want to race with AC on, so while this doesn't add heat to air flowing through, it does add pressure drop of airflow through entire cooling stack.

We also have engine oil to contend with - and can either use oil-to-air heat exchanger, or oil-to-water. If oil-to-water, this is more KW to release through radiator. If oil-to-air packaging, airflow restriction and preheated cooling air have to be considered.

All this is converted to heat transfer equations and calculated to optimize the entire cooling system of heat rejection balance.

Drag racing is easy - you can get away with a whole lot if only running in <10 second bursts of WOT. Road racing makes this much more difficult as entire system reaches equilibrium.

And haven't even talked about trans and diff oil cooling yet....

Dave

Spoken like a true engineer. Very well worded.

[Track Junky]

Thanks Dave, that was an interesting read.

Amazes me how you guys continue to raise the bar with each build.

[clill]

Don't give em a reason for even fatter heads.

[glassman]

Can fatter heads process more data?


Cause this s#\+s awesome

[Vince@Meanstreets]

Originally Posted by clill

Don't give em a reason for even fatter heads.

you can only pull so much foam out of a helmet.

[Radlark]

Originally Posted by Vince@MSperfab

you can only pull so much foam out of a helmet.

LMBO!!!!