So I've been slowly putting together this little DIY intake project since I bought Kermy; casually ordering and collecting parts one at a time to make sure they all fit together. These photos were taken over a period of 2-ish months.
Kermy's a daily driver, but I still wanted an intake partially cause I just wanted to, partial to try and get a few more mpg's (theoretically), and mostly just for fun
I also love to casually tinker, I find it very relaxing. Also wanted a re-usable air filter too (but more so then just a drop-in panel filter).
BUT, I also didn't want to go broke doing so. I didn't feel like spending $200 - $300 on, again, just a daily driver, for what's essentially a curved pipe with a filter on it.
I wanted to do one myself as after looking into an aftermarket intake, the cheapest I could find was from Cosmo Racing. Even though they're in Montreal and were quite helpful, they're asking $125 for an intake, and in USD? At the time I looked into it it would've worked out to $200 CAD out of my pocket; no thanks
I started looking to the raw ingredients to put one together, and the priciest one of all was the pipe itself. Even though this was a DIY setup, I didn't want to go down the route of PVC or plastic plumbing piping, I still wanted one out of metal. The raw piping with the right curves and bends were also at a price-point where I'd end up breaking even buying an aftermarket intake as well, so I set out to find a used intake pipe. I figured there had to be someone whose done an STI swap or something and doesn't need they're old intake pipe anymore. I was willing to take one intended for pretty much any Subaru too, as looking online, they're all roughly bent/shaped the same way and figure I'd make it work. I also didn't need to be concerned about where the vacuum outlets were located as my valve covers are vented anyway I just needed that one 'centre' outlet for the PCV in roughly the same spot.
Special thanks to
@Metalmania82 for the hookup on a "used" intake intended for a 00-04 Impreza for $20! And I mean "used" as it showed up in mint shape!
Comparing it to the one Cosmo Racing has for my Forester, it looked like I could make it work.
After holding the intake pipe up in the engine bay, it looked like I would've had to trim that last curve in this pipe's case. Had I left it on, it would've only just barely cleared the, proportioning valve? its lines and the front face of the strut tower in general, leaving
maybe 5mm of clearance and no room for a filter. I cut the pipe
just as it started to bend. I'd rather cut off more later if I needed to then cut off too much off the bat. Again, I didn't need that vacuum outlet underneath at this end
I then scuffed it up...
And gave it the green touch!
So, next part down the line was a coupling from the green pipe to the MAF pipe. Found this one online for cheap, and some brand I never heard of. A bit of a gamble, but figured it's just a piece of hose that's gonna sit in an intake, so I gauged the risk as low. Only $6 and took nearly the entire 2 months of the project to arrive, but, it's also green...
Next in line was the MAF-pipe-to-filter-bracket/adapter. $10 and gave it my personal touch as well...
And then a green cone filter to top things off. $18 from Speed Daddy (from my experience they don't really sell junk) and Softie approved.
Everything came in for a total of $54 shipped! A much more DIY price range! And tonight I tackled the project of removing the stock piping and installing the setup.
Took out the stock MAF pipe and gave it and the sensor 'the touch' as well. Mounted the air-filter-MAF-adapter re-using the OEM bolts and brackets out of the airbox. I decided to re-use the OEM MAF pipe as I found the cheapest aftermarket one to still be $40 and didn't think it was worth it when I already had something. I, ironically, later found out that an aftermarket pipe/tube at this section causes voltage and therefore rich fueling issue between 1000 and 1800 rpm as they're usually not the OEM diameter, which is also hard to find in OEM diameter apparently.
This is the one part where cheapness caused of a bit of problem with this project. Despite being advertised to fit all Subarus and Mitsubishi's, the bolt holes didn't quite line up. Well, they did, but it would've staggered this bracket off-centre to where air would've ended up hitting wall. I had to drill my own holes in the bracket so that the centre hole lined up with the MAF pipe's tube. I could've gone with Vibrant's $33 bracket that was also "guaranteed" to fit? Or drill holes.
I placed everything in the engine bay and started tightening up the hose clamps, and everything landed where it should have without any extra cutting of anything. The coupler gave me a bit of adjustibility as there's space between the pipe and MAF tube. Being that the stock MAF tube's also 'angled', rotating it gave me some adjustibility there too.
Oiled up the filter and the final setup is complete!
The only "quirks" I had encountered was the hose coming from the PCV was much larger then the outlet on the pipe, but managed to cinch it tight with the right size hose clamp. This outlet also sits a bit more vertically higher then the stock airbox, but the PCV hose is hardly out of place at all.
The pipe itself runs vertically lower overall compared to where the stock pipe had run (going under and clearing the, proportioning valve?), allowing me to anchor the pipe to the power steering and A/C line area, above the rear injector. The angled OEM MAF tube also allowed me to arrange the filter itself lower, tucking it away nicely.
Engine bay's now complete. I have no further nor distant plans to do anything else to the engine.
I went for a quick, late night spin, and the gas pedal is noticeably more sensitive, so I achieved my main goal. The stock air boxes and piping were also noticeably heavier then this setup. I also noticed I can climb hills
WAAYYY better! As though I've awakened the torque curve! Before I'd had to keep the pedal floored just to maintain and eventually loose speed up hills in 5th. Now I can hold speed climbing hills at 1/2 - 3/4 throttle.
A nice bonus: when I do give him gas now, I get a nice, low and throaty WOO sound that's not too loud!