I have a 9 lb pulley that I just put on from science of speed and at the same time I added a front mount. I'm pretty sure that the intercooler is giving me a 3lb boost drop. All pipes are tight as I pressure tested the system. I ordered a 12lb pulley to see if that will give me the 9lbs I am looking for. The car made 320whp on the 9lb pulley only showing 6lbs of boost. Anyone have any suggestions like putting the stock aftercooler on. Appreciate the help.

 

aftercooler ftw...

FMIC looks great but takes a hit at peak hp performance on SCs.

 

Upgrading the pulley increases the rotational speed of the compressor, it does not guarantee that the compressor will push more flow into the engine when other factors are changed. Adding a front mount intercooler adds quite a bit of air restriction in between the compressor and the intake manifold. Even the the compressor is spinning faster with the new pulley, the added restriction reduces the efficiency of the pump as the pressure differential ratio across the unit is now greater at any givien amount of flow.

The pulley nomenclature is flawed. I know they are stated as 6, 9, and 12 psi pulleys, and should all other factors remain the same (stock setup, stock aftercooler, etc), the end results MIGHT be 6, 9, and 12 psi in the intake manifold. A more accurate nomenclature would state the gear ratio between the crank and the compressor. But this is my complaining...

Back to your setup, what did the system dyno before the changes and what were the exact specifications? Stock pulley and stock aftercooler?

I'm curious about the effectiveness of adding a front mount intercooler versus using the stock aftercooler. Has anyone proven that one is more efficient than the other? Without knowing anything about the internal flow performance comparison between the two systems, the only major advantage I can see with using a front mount is the constant temperature of the cold side heat exchanger fluid. I imagine a water based aftercooler would lose much of it's efficiency after a few track day laps.

I ramble.

 

The system only dynoed 240whp on 5.5lbs with the stock aftercooler. Thanks for the help guys much appreciated, I think I may go back stock aftercooler.

 

I am doing the sxact thing and have herd a 3psi lose in norm. So I was thinking of putting a 10 psi pulley on to get 7psi but we shall see.

 

seems like everyone's trying this out now. from what i've observed, the only way you don't lose boost is if you run at least 10psi, or get the UR kit. i guess UR really did their research and their combination of piping route/size along with the intercooler they include really does the trick.