Intercooler Efficiency???

[JJGarrett]

Hey guys and gals,



I have been around turbo charged airplanes and other assisted vehicles most of my life and the majority of those have been intercooled, obviously to counteract the effect of heated air that compression causes. Most were air to air, and some were water to air. I am not questioning which method is best, as Dodge has seen fit to use air to air, but just what temperature difference should an individual expect to see at the intake manifold verses the air being discharged directly from the compressor? I know that outside air temperature, bumper accessories and the like will most definately affect how the intercooler performs, but I have just a stock, unadorned RAM. Internet research (mine has been very limited) has yet to yield a standard answer. Obviously surface area plays the major role in the grand scheme of things, but I'm sure there are underlying idiosyncracies with the stock RAM/Cummins combo that have been researched. Anyway, I will leave the discussion to the pros as I have only been an owner for about a year and a half. I appreciate any help and information that will be offered. I have thick skin, so if my question is pointless, please let me know. Thanks again for your help.



J. Garrett IV

 

[DPellegrin]

The short answer would be temperature drop across the intercooler (sometimes called "delta T") is a function of the principles of heat transfer i. e. temperature difference, gas flow, surface area. At engine idle the temperture and pressure of the air leaving the compressor is about the same a ambient. As the engine begins to pick up load the temperature, pressure and flow of the compressor air appropriately increases and thus the delta T increases.



I hope this ar least somewhat answers your question. Why do you need to know this?



Best Regards

 

[Gary - K7GLD]

You're probably after a short, ballpark reply - someone may pop in with a reply - but I suspect the difference between "maximum efficiency percentage", and "average typical efficiency percentage" will differ significantly.



What happens cruising empty out on the freeway at 60 MPH on a 65 degree day will differ a lot from heavy towing up a steep grade in 100 degrees - at 45 MPH...

 

[THanley]

Typical turbo compressor outlet temperature is around 350F. The temperature should drop to around 150F at the intake manifold.

 

[DPellegrin]

I'm not sure I agree with THanley. This may be correct for one set of engine/vehicle operating conditions.

I guess the best analogy I can give is an intercooler is just a heat exchanger, like a radiator. It would basically operate the same as the engine's radiator if the engine did not have a thermostat. The quanity of BTUs in the radiator increases proportionally with engine load. The same same holds true as the engine load increases the boost pressure and air temperture increases so the quantity of BTUs the intercooler sees increases as well.

 

[cerberusiam]

Typical turbo compressor outlet temperature is around 350F. The temperature should drop to around 150F at the intake manifold.

That would be correct for the top of the Map on the turbo and about 30-35 psi. It drops off as the boost drops to around 100 degrees give or take. The lower the boost the more the temps are affected by the ambient.