View Full Version : Which Air Bypass Valve should I buy for my Subaru?

01-22-2008, 09:39 PM
I am buying a cold air intake from AEM that fits my 05 Subaru Impreza Outback Sport RS. I am going to buy a bypass valve from AEM so I don't stuck water into the intake. On aempower.com they list 4 different sizes, a 2.25", 2.5", 2.75", and a 3". I can't find anyone that can tell me which size I need to buy to correctly fit my intake. If it helps, I am buying the intake from autopartswarehouse.com and it is part number A1821472P. Thanks for your help!

01-24-2008, 02:06 AM
Call the company and ask them for the size or get the intake and measure it before buying the valve. Looks like 2.5 inch but i could be wrong.

01-25-2008, 06:33 AM
The car has to be in pretty deep water and the filter has to be submurged for water to get in the engine. At this piont you have other problems. Rain or heavy splashing on the filter will not hurt your engine. I had a cold air intake on my WRX in Oregon where it rains a lot and had no problems.

01-26-2008, 10:59 AM
i would go on to the website that you are buying it from and do the online chatting and they should be able to help you that or call them to be sure that should save you some time and problems.i wouldnt worry about water unless you are going to be drive through ponds then i would recommend a complety different intake one that reaches about 6 feet high :P