I don’t know about you guys but I’ve noticed lately that my car doesn’t run quite like it should in rainy weather. When it’s dry my car runs perfect, but when it rains the boost seems to get cut a lil bit earlier. An intercooler sprayer, found on 03-04 USDM evo’s, benefits by assisting in cooling the intake charge right? Then why would my wastegates seem to cut boost a lil bit earlier when there in enormous amount of water directly linked to the intercooler? As I said, I don’t know if any of you guys notice the lack of acceleration in rainy weather, not that any of us should be driving fast in the rain, but I'm jus curios.

 

what do you mean by cut? you mean as an exapmle in dry you run 20PSI and rain it hits like 18?

Weather has alot to do with your boost and effieceny. humidity will make you boost less PSI.

 

yeah exactly, it just feels like I'm running less boost in rainy weather. Tonight it rained again and straight line acceleration does not feel the same as if it was dry.

I guess you're right, humidity will make you boost less PSI, but my question now is why would humidity do that? Is it cause of the increase in moisture to the intercoller?

 

that an easy answer, think about how a turbo works. Ok and of course a turbo is pushing hot air and the FMIC is there to cool that air well if it is humid for one the FMIC is doing its job as well as if it were cold out and the are is less dense. So when it is cold out you will gain a few PSI most likly when driving I know my car does

 

My Evo does the same thing. In colder weather my boost goes to 1.5 where as in warmer weather my boost will hover around 1.4. No big deal, just the weather.