Grimmspeed Air/Oil Separator | 2002-2014 Subaru WRX and 2004-2021 Subaru WRX STI (078006/16)

I've only had the AOS installed for a few weeks on my '05 OBXT (185K miles), but so far so good after rechecking all hoses and connections. I had to take off a star because when I opened the box, there were no instructions included. I had to watch a few YouTube videos and download their instructions from the Grimmspeed website. The paper instructions had the better details. A few install issues along the way but no 'show stoppers'. Because of the AC line, the AOS had to be pointed towards the battery. It could not be pointed towards the firewall because the hoses would interfere with each other. Also, when installing the short hose to the PCV 'tee', the hose nipple from the tee angles towards the intake so you have to try to get the short hose onto it at a bad angle. I had to heat it up and use oil to get it on there. After some wrestling with it, I was able to get it on. Otherwise, everything else went smoothly. It's too early to tell if the AOS is effective but I'm confident based on what I've seen online.

Easy instal. Didn’t use barbs had plenty of hose left. Looks good. Bought the anodized red one.

MAP always has parts ready to ship. They shipped this item to me so fast. I love MAP customer service and the part works great. I’m not going to write a full on review since I’m no professional, but this definitely helps with oil consumption just like all the other A/O separators, but this is priced pretty fairly and the brand never disappoints. Great product and great customer service.

Great entry level AoS. If you are looking for a good AoS for a lightly modded daily driver, this is it. If you are going for more power then you may want to look at the IAG street/comp series. My car is a stage 2 and this works great for the minor bolt ons. Helped cleanup Knock and Fine Knock readings as well. Make sure the air going into the car is clean buy an AoS immediately.

I’m gonna give this part a 5 star review with a few small asterisks. First, the good. It’s super easy to install, much easier than most AOS. Also, it looks great under the hood. It works mostly as stated. You’re gonna see a lot of people making an unnecessarily big deal about the foamy frozen sludge stuff in the winter. It really is only an issue if you’re going on very short drives. This is moisture from cold hoses being in your lines. If your oil is getting up to temp on your drives in the winter it’s gonna evaporate that moisture anyway. No biggie. But if you’re going on short drives and not warming your car up, it could be an issue, but probably still wouldn’t be. Another asterisk is the install directions. They are for a pre 2018 STI. You’re gonna have to do some real digging on youtube for proper install instructions for an 18+. I had to watch a spanish language YouTube video myself lol. So that’s kind of annoying. Also, the cheap zip ties. Zip ties are gonna be fine to put on the joined up sections of hose. But for the three connections that go to the actual 3 metal nipples on the body of the A.O.S. you’re gonna want to grab yourself 3 small worm-gear screw clamps at the hardware store for the connections to the body of the AOS or you’re gonna have leaks. This is verifiable by many youtube videos showing leaks during smoke tests. Just use worm gears there, and warn your oil up before you drive and you’ll be fine. Lets be honest here, if you are driving around with cold oil in your Subie it won’t be long for this world anyhow. Warm your subies up folks. Or you’re gonna have an excuse to buy a built block real fast. We should all know this by now.