I'm planning on fabbing an intercooler later on this summer, so I tracked this down to find out how far I can take it. I just thought you guys might be curious too...

 

Is that from Lysholm's website? I would be interested to see what the efficiency maps look like with the Whipple rotor housing.

 

yes it is.

That would be nice to see how they compare.

 

Yeah, I'm curious. I'm curious about how the hell do you read those charts. I got as far as figuring out that I'm running about a 1.8 pressure ratio, then I look across the chart along the 1.8 line, and realized that I might as well be looking at a fingerprint with numbers on it. Is it just to figure out efficiency? What do I care about efficiency, as long as it keeps making more boost the faster I turn it, and I have an effective intercooler? Please help me understand.

 

That was a serious question.

 

Yes supercharger maps are difficult to read.. and lysholm doesnt make it easy.. although they do contain alot of info on one map.

To understand boosting you must first understand basic thermodynamics.

1. Compressing air increases its temperature

2. To compress air it takes a certain amount of energy per unit mass.. i.e. kJ/kg..



Now.. first

Looking at the black lines that are labled Adiabatic Efficiency, Because air increases temperature as its compressed, there can be an "ideal" or miniumum air temperature increase. This means that if a supercharger has 100% adiabatic efficiency it will have the lowest outlet air temperature possible. HOWEVER, it will still have a high outlet temperature. Now for a given Pressure ratio, the "adiabatic efficiency" is how close the actual outlet air temp comes to the ideal inlet air temp.

In basic terms....
Adiabiatic efficiency = "Ideal Theoretical Outlet temp" / "Actual outlet temp"

points with low adiabatic efficiency will have more energy from the crankshaft being put into "heat generation"


Many of the other curves are self explanitory.. but look at the "Power "curves.. you can see exactly how much energy is being put into the supercharger.


Volumetric efficiency... A blower is specified by its displacement per revolution.. the volumetric efficincy specifies how much of that volume gets filled every revolution.

In the end, efficency matters to you in 2 ways..
1. low adiabatic efficiency takes more power from the crankshaft
2. Low adabatic efficiency has higher outlet temps and means you need a bigger and better intercooler to get rid of all the extra heat energy you placed into the air...

 

and from the looks of the map.. its hardly any more efficient than the eaton 5th gen blowers..