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Adiabatic Efficiency of a Kenne Bell 3.6L LC versus the Whipple 4.0L


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#1 OFFLINE   Mr. Haney

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Posted 03 March 2013 - 08:12 AM

I've been researching blower upgrades for the 2013 5.8L engine. Unfortunately there isn't a lot of information for the KB 3.6L blower versus the Whipple 4.0L. What I do see is the KB seems to be the popular choice amongst most people. Both chargers are moving air, but which one is doing it more efficiently? The Whipple is listed as having a Volumetric Efficiency of 99% and an Adiabatic Efficiency of 78%. I can't find any listing for either the VE or the AE of the KB 3.6L LC supercharger.

What is Volumetric Efficiency? The definition I come up with on this is: The amount of air the blower draws in its inlet versus the amount of air pushed out its outlet. Any blower has a small amount of internal air leakage from the outlet side back to the inlet side of it as it pumps air. 99% efficiency means that the internal leakage back to the inlet is 1%. This internal air leakage creates heat in the air entering the engine.

What is Adiabatic Efficiency? This one is a lot harder to explain, but I'll try. As you compressor air, it gains heat. This term is a measurement of how much heat you gain. If you can compressor the air with an Adiabatic Efficiency of 100% to 8 psi, the air would only gain 75*F in temperature from the inlet of the supercharger to the outlet. As Adiabatic Efficiency decreases the air temperature will raise higher than the 75*F for the 8 psi increase in pressure at the outlet of the supercharger.

Now my research also brings to light the differences in the lobe design of the rotors. KB utilizes a 4 and 6 lobe rotor that is larger in diameter than the Whipple. This allows the blower to move more Cubic Foot of air a Minute(CFM) while turning the blower less RPM. The less RPM you have to turn the blower to gain the pressure boost you want, the less Hp it uses. This equates to more usable Hp at the flywheel for the same boost. But my real question is. Without the known VE and AE is it really the better component? Does Kenne Bell Liquid Cool this blower, because it doesn't have a good AE? Is the VE lower? If the VE is lower than the Whipple than you have to turn it faster to make up for the internal air leakage. This in turn drops the AE also, because the air is heated up higher for the same boost pressure. Is the liquid cooling being used as a crutch to bring the blower case and rotor temperatures down? Would the rotor and case grow to the point of blower lock up and damage without this feature? These are the questions in my mind about the KB 3.6L LC supercharger

Now the Whipple uses a smaller diameter rotor combo with a 3 and 5 count lobe design.This means that it will have to be spun at faster RPMs to move the same amount of air when compared to the KB 4 x 6 design. Now as the Whipple blower RPM increases to match the air flow of the KB design, so does the Hp to turn it, if the volumetric size of each blower is identical. We know they are not. KB moves 3.6 L while the Whipple moves 4.0L. Does Whipple use its larger displacement of air to counter the smaller diameter rotors? What I mean by this question, is Whipple slowing the blower down to create the same boost as the KB, which in turn would lower the Hp requirements to turn it. Would this than put the two blowers close to equal in HP requirements to turn them, for the same boost pressure on the same engine? Whipple using a larger blower for the same boost should create less heat in my mind.

Can anybody shed some light on these questions?

#2 OFFLINE   NMAv

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Posted 09 October 2013 - 03:42 PM

Have you posed your questions re the KB to Matt at KB. He is usually good with getting answers.

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#3 OFFLINE   Robert M

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Posted 14 October 2013 - 03:19 PM

I've been researching blower upgrades for the 2013 5.8L engine. Unfortunately there isn't a lot of information for the KB 3.6L blower versus the Whipple 4.0L. What I do see is the KB seems to be the popular choice amongst most people. Both chargers are moving air, but which one is doing it more efficiently? The Whipple is listed as having a Volumetric Efficiency of 99% and an Adiabatic Efficiency of 78%. I can't find any listing for either the VE or the AE of the KB 3.6L LC supercharger.

What is Volumetric Efficiency? The definition I come up with on this is: The amount of air the blower draws in its inlet versus the amount of air pushed out its outlet. Any blower has a small amount of internal air leakage from the outlet side back to the inlet side of it as it pumps air. 99% efficiency means that the internal leakage back to the inlet is 1%. This internal air leakage creates heat in the air entering the engine.

What is Adiabatic Efficiency? This one is a lot harder to explain, but I'll try. As you compressor air, it gains heat. This term is a measurement of how much heat you gain. If you can compressor the air with an Adiabatic Efficiency of 100% to 8 psi, the air would only gain 75*F in temperature from the inlet of the supercharger to the outlet. As Adiabatic Efficiency decreases the air temperature will raise higher than the 75*F for the 8 psi increase in pressure at the outlet of the supercharger.

Now my research also brings to light the differences in the lobe design of the rotors. KB utilizes a 4 and 6 lobe rotor that is larger in diameter than the Whipple. This allows the blower to move more Cubic Foot of air a Minute(CFM) while turning the blower less RPM. The less RPM you have to turn the blower to gain the pressure boost you want, the less Hp it uses. This equates to more usable Hp at the flywheel for the same boost. But my real question is. Without the known VE and AE is it really the better component? Does Kenne Bell Liquid Cool this blower, because it doesn't have a good AE? Is the VE lower? If the VE is lower than the Whipple than you have to turn it faster to make up for the internal air leakage. This in turn drops the AE also, because the air is heated up higher for the same boost pressure. Is the liquid cooling being used as a crutch to bring the blower case and rotor temperatures down? Would the rotor and case grow to the point of blower lock up and damage without this feature? These are the questions in my mind about the KB 3.6L LC supercharger

Now the Whipple uses a smaller diameter rotor combo with a 3 and 5 count lobe design.This means that it will have to be spun at faster RPMs to move the same amount of air when compared to the KB 4 x 6 design. Now as the Whipple blower RPM increases to match the air flow of the KB design, so does the Hp to turn it, if the volumetric size of each blower is identical. We know they are not. KB moves 3.6 L while the Whipple moves 4.0L. Does Whipple use its larger displacement of air to counter the smaller diameter rotors? What I mean by this question, is Whipple slowing the blower down to create the same boost as the KB, which in turn would lower the Hp requirements to turn it. Would this than put the two blowers close to equal in HP requirements to turn them, for the same boost pressure on the same engine? Whipple using a larger blower for the same boost should create less heat in my mind.

Can anybody shed some light on these questions?

 

 

My understanding of the LC technology is that each of these blowers is going to have cooler air coming into the inlet side of the blower and as the air is compressed it is heated. Because cooler air is coming in the inlet side, it is basically is the "air cooled" side on both of these blowers. Both of these blowers would also experience higher temps at the outlet/discharge opening because of air compression. This would leave one end of the case cooler, and one end hot on each of these blowers. LC introduces water into the equation to cool the end that is hot. By using water for cooling at the discharge end and air cooling the inlet end the temps will be more stable across the blower instead of one hot end and one cooler end. <<This is my understanding and I know of many who have placed their hand on a recently run LC KB and said that the blower case itself is much cooler to the touch which to me sounds like a positive thing?

 

S.P.E. (Seal Pressure Equalization) is another technology that is part of the 3.6LC blower and is seldom discussed.

 

Van at Revan Racing would be a good person to contribute to this discussion, he has been a vendor for both of the brands and tested both of these blowers. I will see if I can get him over here........

 

 

 

R


Edited by Robert M, 14 October 2013 - 03:20 PM.


#4 OFFLINE   cleghornm

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Posted 14 October 2013 - 04:25 PM

Has anyone ever ran a test to comparing KB against Whipple?

Edited by cleghornm, 17 October 2013 - 03:47 PM.


#5 OFFLINE   cleghornm

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Posted 23 November 2013 - 03:04 PM

KB should run a head to head test against Whippple. I have run a KB in the past and it was great, just curious is all.




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