Results of a Custom Intercooler Install on 2002 CLK55 HPS Gen1 System

 

The Eaton MP90 Supercharger is not a good fit for a CLK55 engine.  With a 2.095 inch pulley, the blower is spinning at 17,000RPM just to deliver 3.5 psi(with intercooler).  A sure sign that the blower can not flow the needed air requirements is revealed in the HP numbers.  Improvement results: 18% more Torque, 10% HP.  These are terrible numbers and show that putting the wrong supercharger on a car gives you nothing. 

 

This set-up installed on a CLK430 4.3L would probably be OK. (I did see a just a little belt rubber on the pulley, so that means the belt is slipping some.  I have no idea how much, probably 1-1.5psi loss.)

 

Some may it is the intercooler, and yes they are somewhat correct.  Testing revealed almost a 3.0 psi drop across the intercooler.  WOW, that means the cooler I selected is probably a little small!  However, that is the largest I could fit in the area.   (Even so, 6psi total max is all the Eaton can push through a CLK55)

 

Even with the boost drop, look at real improvements in intake temperature as the blower spins.  Inter-cooling allows for a safety margin to reduce possible detonation.  With these HPS kits at full timing, inter-cooling is a must as far as I am concerned.  Those Eaton roots blowers run HOT.

 

The final graph is a data collected on fuel and boost pressure during the dyno run.  See the fuel pressure drop?  That is another issue that needs to be addressed.

 

So what should you do if you have the HPS Gen1 System?  If you want to up boost a little over the factory 3-4psi to about 5,6,7psi you will need, besides a .1in smaller pulley, a larger fuel pump, water injection system, and tuned MAF signal (use Split Second PSC-001 unit).  In my case, I added a Keene Bell Boost-a-pump, which allowed me to reduce the FMU size to 4:1 from 12:1(may not be needed). 

 

 

 

Intercoolers help reduce the chance of Detonation.  I would never own a supercharger of turbo without an intercooler, be it air-to-air, water-to-air or water injection.

 

 

 

 

The fuel pressure drop as boost increased shows that the fuel pump can not flow enough fuel.  Boost reduces the flow rate of a pump because it must fight through the boost to keep flow constant.