[Quadraria10]

I just noticed that a 2009 XT with the same metallic grey as my 2011 NA has shown up in the past couple of days at a pick-and-pull yard in my city. It's the right paint color and removal seems fairly straightforward. Basically, it can be had for $23.99 Cdn which is a tenth of the price I have seen for them in the aftermarket. I would wait until spring to install it. I am just wondering if there is any real benefit, other than looks ( and I am not completely convinced it actually looks better ). I am not so keen on drilling the two holes necessary, and I obviously would not have the template to use to position them.
Has anyone installed one themselves? I would be curious to know how it went.

 

[bman400]

I have not installed one, but I think for that price it's worth it as it creates a different air flow off the back end. You ever notice a number of 18 wheelers now have moveable flaps on the rear end of their trailers!!!

 

[TTiimm]

It probably does reduce drag a bit, maybe even significantly, by changing the way the laminar air flow over the roof separates from the vehicle at the rear.

Here's an interesting article about aerodynamics.

Aerodynamics, simulations and the Tesla Model S

The article uses the Tesla Model S as an example but the principles are the same..

 

[Quadraria10]

Without a doubt, the price is great, especially as it wouldn't need repainting. Still, it's winter and we just had more fresh snow, it may not be the easiest job to do in the conditions. We are hovering around freezing temps so the plastic won't be super brittle. I guess I will decide later as I am free this aft.
I read through some decade-old posts here about whether they work or not, and my take is that it really has no effect other than perhaps keeping the rear glass a bit cleaner. I was parked next to an SJ model with one yesterday and I kind of liked the look.

 

[DragonSubie7]

Quadraria10

I'm thinking that with the price differential, even if you decide not to install it, you could probably sell it for more than you paid provided it is in good shape and isn't damaged from the removal process.

In any case, it isn't a major investment, except perhaps for the value of your time.

From what I've heard, the best and most noticeable effect seems to be in keeping the rear window cleaner, i.e. less dust and dirt which Foresters are great at accumulating back there, so that might be worth it.

Dramatic effect... probably not so much.

 

[CO17Forester]

If you like the way it looks, then you should get it.
On my SJ it adds dirt to the back window. On very dusty roads the 3rd brake light often adds a racing stripe to the window, by adding on a layer of dirt.

 

[Quadraria10]

Good point Dragon Subie. I have thought that based on some of the pricing, it might be worth scrounging some parts and selling them on eBay, but given the time and effort involved, I am not convinced it's worthwhile.
Thanks for the feedback CO17Forester. Assuming you are right there is not much to be gained and I would be drilling holes in the roof that could be problematic down the road.

 

[CO17Forester]

Some rear-wings do deflect air, the one on my SK does not, but a spoiler from 2011 might. A spoiler that deflects air sits a little higher than the roof, and will have a path for the air to flow toward the window. The SK version is just a flat shelf that looks nice.

 

[TTiimm]

Some rear-wings do deflect air, the one on my SK does not, but a spoiler from 2011 might. A spoiler that deflects air sits a little higher than the roof, and will have a path for the air to flow toward the window. The SK version is just a flat shelf that looks nice.

The spoiler can increase downforce if pointed up but a flat spoiler can provide aerodynamic benefit in the form of reduced drag and less turbulence.

Less turbulence means greater stability at speed and less drag means better fuel efficiency.

I'm actually pondering whether the three piece spoiler setup with vertical extensions from a 2021 can be retrofitted to an earlier SJ. Subaru didn't add these just for looks.

I would do it if I knew that the bolt holes for the horizontal spoiler lined up.

.

 

[CO17Forester]

Watching the dirt patterns on my SK shows it is just for looks.
TTiimm, those might help the mpg a little, but the could also be just for the look.

 

[AZ Bill]

If you like the looks, get it. Don't fuss over "aero benefits" as there likely are none. A Forester is not exactly a track weapon.

 

[aggrex]

If holes need to be drilled (and drilled once) making a template will prevent errors.

 

[justinw2116]

I always say the same thing here. If there were true aero benefits or solid fuel economy gains these would be standard.... or at least marketed for as such by Subaru. Every manufacturer wants to get the best MPG & emissions stats as they can.

These spoilers are purely aesthetic. I think they look great! If you like it, go for it!

 

[TTiimm]

Watching the dirt patterns on my SK shows it is just for looks.
TTiimm, those might help the mpg a little, but the could also be just for the look.

The entire purpose of aerodynamics is to increase downforce and/or decrease drag.

Dirt patterns on the back of the vehicle after offroading (with a roof camper) doesn't provide objective data on whether downforce is increased or drag is decreased.

These need to be measured or we are just guessing.

 

[TTiimm]

I always say the same thing here. If there were true aero benefits or solid fuel economy gains these would be standard.... or at least marketed for as such by Subaru. Every manufacturer wants to get the best MPG & emissions stats as they can.

These spoilers are purely aesthetic. I think they look great! If you like it, go for it!

A good read on aerodynamics...

https://www.team-bhp.com/forum/technical-stuff/224530-aerodynamics-simulations-tesla-model-s.html

 

[GuusV]

I have a 2009 Forester X and a 2009 Forester XT and I DO like the looks of the spoiler.


When you go to get it, bring a couple of pieces of cardboard and after you've taken the spoiler off, hold the cardboard in place and press hard on the top edges of the carboard (or bring a knife and cut the curve of the top edge) and press hard on where the hole is. (trace it wil a pen afterwards to make it more permanent). This will help you figure out where exactly the holes are supposed to be!

I'd do it!

 

[Botnik]

perhaps keeping the rear glass a bit cleaner

The spoiler keeps the rain off the top part of the rear window. The result is that the bottom part of the rear window gets cleaned by the rain, but the top part has dirt buildup.

The stock wiper on the 2018 has problems wiping the top part of the rear window because of the curvature (reported by multiple 2018 owners) but I recently changed mine to a Bosch and it's working now.

If your rear wiper situation is like mine, the end result is that the top of your rear window will be dirtier with the spoiler. Even if you use the wiper regularly, there is more dirt up there and the dirt gets spread around.

 

[CO17Forester]

The entire purpose of aerodynamics is to increase downforce and/or decrease drag.

Dirt patterns on the back of the vehicle after offroading (with a roof camper) doesn't provide objective data on whether downforce is increased or drag is decreased.

These need to be measured or we are just guessing.

No tent or tire on this photo, I probable have others. Pattern looks the same with or without the tent to me.

 

[CrystalPistol]

Make templates when you remove it from the donor. Cardboard, sharpie, tape, and a photo with it in place to record reference points.

 

[Quadraria10]

Thank you guys for the template idea. I was not able to make it finally yesterday and it was snowing. Hopefully, in the next couple of days, I can go with my toolbag, a roll of craft paper, and some cardboard.