Is 42mpg too low a goal?

[Istas]

aerohead: thanks again for the angle measurement. I got around to trying it myself, and I'm getting about 18 degrees too, if not a little more. Here's a better profile pic.


I didn't get much work done today on the car because of all the mosquitoes swarming me, but I did get some 1/2" thick "extra durable" foam tape that I placed along the top of the headlights and grille. I also used some "goop" to fill the large gaps at the bottom of the headlights, and caulk around the other edges of the headlights that had gaps.




Next I'll be templating the grille blocks in the ever-popular cardboard. I picked up some big hunks of it from a nearby grocery store. I asked, and they were happy to oblige.

[aerohead]

Originally Posted by Istas

aerohead: This is why I was thinking those airtabs might actually be a benefit in this situation. The two reports on airtabs that MetroMPG pointed me to were done on an '06 Camry and an '03 Prius, both smoother cars than mine. But even if I do try them (and really, given the design of the aluminum vortex generators, it shouldn't be too difficult to mock up some of my own on the cheap to get at least a rough guideline), I'm going to wait until I have my MPGuino installed and calibrated before I even think about testing VGs.

(I don't trust that picture either, even I'm not sure if it's level, and at any rate I get the feeling my camera (which is more than a few years old) warps pictures.)

Also, getting cfd software running will help too.

A rear spoiler off the edge of the trunk seems like it'd be really easy to do. Also, I get the impression that adding that sharp transition at the trailing edge of other parts of the car would help as well? like on the sides of the rear bumpers? (it's rounded there too)

Yeah,the air tabs ( turbulators ) were first offered by an aeronautical engineer.No doubt,he saw their value in supporting flow off of wings and onto flaps for wings at high angle of attack ( like flow off your roof onto the trunklid ).And the car shown in his article is a Honda Accord notchback,much like your Legacy in form.------- I do think the rear spoiler would,and should help at the gas pump.Straight back,like the E-85 Cobalt would be okay too,but it would need to extend back to intersect the 13-degree line.And softening the rear edge would help pedestrians if the inadvertedly walked into it.

[Istas]

I only got the passenger side of the lower partial grille block done so far, but I have the sheet metal cut out for the other side and the middle-and-upper grille block. Hopefully all the main one will require now is some bending and finagling to get it into place.

Here's some pics of the lower part I did get done.






The other side will look the same. I'm going to work on putting some ducting in on the sides there so there's less of a lip for the air to travel over. I don't think I'll be able to seal the whole passage from there to the radiator, but I'll do what I can.

[aerohead]

Originally Posted by skyl4rk

One of these should bump you up to the 40's mpg:

I'll be carrying this photo with me also,when I do the trailer test in September.I can talk to people 'til I'm blue in the face about aero,and they can still walk away without "getting it".------- These images really make a difference.Thanks for posting it!

[Istas]

Rain and mosquitoes holding back progress, but I have the other side on now.

Symmetrical enough for me.


Lower pic, showing one of the rear wheel skirts and the need for a short airdam off the bottom lip of the front bumper.


And a picture showing a more complete view of the area under the engine. Wide open canals letting air up into the wheel wells from under the car. Bad Subaru engineers!


The grille blocks all fit within a few millimeters of the bumper. I'll be sealing the edges with caulk if it ever dries out for a couple of days.

[Wonderboy]

I really like the bare aluminum color with that car - like someone said before it looks like a star wars fighter or something - scrappy but sleek. If you lived in a state that required 2 license plates, then I'd say you had enough grille blocked. I think you could block a bit more and leave less than a license plate-sized gap (I would isolate all the gapping to one area, not two little gaps). You could even make this piece somehow adjustable or easily swappable so you can block the whole thing off for winter. You'd be surprised at how little that radiator needs to breathe. You may also consider fully blocking the upper grille with -ahemm- plexiglass?

Nice work. BTW, do you happen to be a fan of McCartney's later solo work, or am I reading your avatar wrong?

[evolutionmovement]

Haven't been following this, but you're doing some of the things I plan for mine on my 1990 wagon. Glad to see some tuft testing done, though I'll still have to do my own because of the different rear end.

My plan is to duct the radiator exhaust air out the top front of the hood, moveable upper grille block, partial lower grille with acrylic so the blinkers show through, cover the undercarriage, and try to reduce the wake with some kind of spoiler. Don't know if I want to do wheel skirts or not as they'll have to come out pretty far to cover the Forester wheels. I'd do an airdam, like I did on my '83 sedan, but I love the ground clearance too much and am hoping cleaning up the horrible undercarriage will be enough.

There was a factory rear wing available on the sedans that you could probably find. They came on the turbos for sure, but I've seen them on N/As as well, though they could've been fitted later.

Don't know what bgd73 is talking about. These cooling systems are very robust, so I wouldn't worry about blocking the grille at all. I know guys with modified turbos, one living in TX that is using a stock N/A radiator and has no problems. They're also 1000x the car the preceding ones were and I absolutely loved my two EA81's. I wouldn't touch an EA82 with it's terrible head design, maze of vacuum hoses, and stupid twin timing belt set up. At least the EA81s had the gear-driven cam. My 1990 New England outdoor car has very little rust, only the wheel arches, which can be easily seen and fixed. Tearing it down for a restoration is showing it to be in shockingly rust-free condition in all the hidden areas (I'm guessing re-undercoating it every year helped). You could watch the older Subarus rust, which is why mine both went to the junk yard with under 150k miles on them. The EJ22 is an amazing engine and if you ever tore one down, you'd know that, but it was also very advanced for its time with fully electronic ignition, MPFI, and learning software. The older engines had 3 mains, while the EJs are 5 large bearings, completely encapsulated by the block, with over an inch of journal overlap on a crank less than 18" long and using forged rods even on the non-turbos. At a quarter million miles of beating the hell out of the car (including an indicated 133 mph, many hard accelerations up to 120, long periods over 100 in the desert in summer, and low speed, high rpm sliding in the snow), the engine looked nearly new inside (except for the burnt exhaust valve on #3). The head designs aren't the best on these either, but there are later, much better heads that bolt on (single or DOHC). However, the head design as standard gives good bottom end, which I prefer anyway.

The firing order is 1-3-2-4, as all Subaru 4's are, unless the waste-spark ignition is causing some confusion. There are two coils—1 for each pair of cylinders and they fire 180* apart, so you get a spark on the ignition cycle on one side, while getting a spark on the exhaust cycle on the other. I have never had an ignition or fuel system problem since I bought the car at 107k. I wish I could say the same about the POS distributors and carbs (at least the Carter-Weber, the Hitachi was bulletproof) my EA81s had. The only thing about my EJ22 is that it ate ignition wires about every year and a half (about 40k miles) until I gave up wasting time with the Auto Zone "lifetime warranty" junk and got quality Magnecors that went 6 years until I parked the car a few years back (not an issue of reliability).

[Istas]

Wonderboy: Thank you! It's a theme I started with when patching rust holes and didn't feel like buying seventeen different cans of spray paint trying to find a matching color.

Actually, it's hot-dipped galvanized sheet steel, not aluminum. I don't recall the exact difference, but I believe the sheet aluminum was more expensive, and I'm not even sure I saw it in sheets wide enough for my needs.

Yup, my plan is one contiguous gap, not separate ones. It made logical sense to me from the start. The "PA doesn't require a front license plate" is sort of a double-edged sword though, I figure, because I imagine that, when driving through states that do require it, I draw more attention from cops by default, which is never desirable.

I will be testing on how much more of it I can block once I get a radiator fan LED set up. If/when I do block more of it, I'm going to offset it to the driver's side, as I believe that Subaru has their thermostat in the lower driver's side of the engine, which would indicate the outflow to the radiator is there as well.

Yes, I was very surprised when reading other people's posts at how little space is needed, verses what is designed by most manufacturers.

Hehe, the plexiglass is a good idea, but I'm going to be blocking the upper and middle vents with the same piece of material (sheet steel of course, gotta stick with the theme!). I'll be roughly imitating the mock-up I did in cardboard before.


I figure I might as well get some angle out of that while I'm at it, instead of leaving it blunt like Subaru did. It'll encourage using a single piece for the upper and middle blocks, too. That block you did on your Honda looks very slick though, nice job! (PaleMelanesian's too)

I am, however, considering moving the Subaru badge onto the sheet metal, buahahahaha. Haha. Ahem.

[Istas]

evo-move: I've had some envy issues looking at foresters and outbacks, what with the ground clearance, same with wagons for the utility and the AWD versions for their control in winter weather, but all that's tempered by how they decrease mileage somewhat. So I'm happy with what I have, would be happy if I had those instead.

My manual transmission envy is not that way though.

Cool idea ducting the radiator heat out the front of the hood, that will provide some nice vacuum will it not? (have you done vacuum testing on the surface of the hood?) I like the idea of clear plastic over the lights. I'm pondering doing it for my headlights (as the angle's so blunt into the wind), but I worry about (a) yellowing, (b) cleaning it off in winter, (c) scratching, (d) moisture getting inside, and linked to those others, (e) the fuzz complaining about it. Less an issue with blinkers though definitely.

Good idea with the spoiler. Going by the 12 to 13 degree estimate for spoiler placement for detached flow, though, I'm not sure it'd be high enough/far back enough to benefit me. I think even 15 degrees would skip over the turbo spoiler. Once I get the 'Guino hooked up, I'll do some VG tuft testing to see if I can curve the flow back down to the trunk without a net decrease in fuel economy. Plus I like the idea of making my own spoiler... out of sheet metal, of course. If I can get the surface of it flush to the trunk without hanging ridiculously far off the back of the car, that would be better than the stock spoiler that has airflow underneath it, I believe. Wouldn't it?

Thank you for the information about, and confidence in, Car's engine! It sounds to me like I should keep you in mind for suggestions if/when I have car trouble in the future, heh heh heh. I'll keep the spark plug wires in mind if I have problems again. I replaced them a while back, but now I'm prepared to suspect them in the case of problems.

[Istas]

Oh, and Wonderboy, I think you might be attributing more reference powers to me than I deserve. I wanted to put "is not currently covered in bees." (but it wouldn't fit) because it is silly and tends to lead people to mistakenly assume that I have been covered in bees at some point in the past, or will be in the near future. (neither of which is the case, to my knowledge)

I don't have good record-keeping, in my head, of which song titles and artists go to which songs I like. I'll ask my audiophile friend to play some of McCartney's later solo work to see if I recognize any of it. (And if there's any song about being covered in bees, I'll likely like it just for the lyrics)