Scion xA aero mods

[NeilBlanchard]

Greetings,

I've been testing some aero mods -- using good old duct tape, for the moment.





Simple stuff so far, and it seems to be quite effective: my best tankful average last year was 41.8mpg, and with some improved driving techniques, I got 43.5mpg on a tank. After covering the upper grill, I've got a new best of 45.5mpg. Then I covered the fog light recesses, and it's looking much better still!

The 45.5mpg tank was ~239 miles at the half tank -- and this tank is sitting at ~275 miles at a half a tank left! So if I do only 200 miles on the second half tank, that could be ~47.5mpg! Heck -- I might be on course to do almost 50mpg?! Incredible, if that's how it turns out.

[Edit: I ended up with 46.4mpg, partly because my last commute up Route 3/93/95 and on Route 117 was pretty clogged with stop and go traffic...]

So, I'm going to be trying to construct an even sleeker nose -- if I can form some planes to kick the air flow out and around the front wheels, and keep the required cooling (today was very hot -- near 100F and it worked fine!), then I could be exceeding what I thought this car was capable of.

[millenniumtree]

The truth will come out in 4-5 tanks.

My mileage swings up and down by almost 10mpg on each tank, depending on when the bloody pump shuts off the nozzle. I don't take the risk of topping off repeatedly like some. I do slow the pump down when I know it's nearing the top though - makes for a little more consistency.

I'm quite interested to see what sort of improvements you can make. I've got an xB and may be in the market for a replacement car for my aging civic.

[Daox]

Can't wait to hear what the next tank is Neil. Looks like its comming along well.

Thats some huge variance millenniumtree! My tanks in my Matrix vary about 3 mpg (40-43) and there are two different people driving it.

[MetroMPG]

Neil: that's encouraging. A 1.7 mpg gain works out to a 3.9% increase.

I did a number of non-rigorous "A" (5 controls) - "B" (2 grille block) runs and saw an average 2.9% gain @ highway speeds.

[digitaldissent]

looking good, I think I will just tape over my fog light spots like you for now.

I got a little bump with the upper grill block too, wonder if it will last

[pawilkes]

I didn't see much improvement on my grill block but that could be for many reasons. One questions I have is this, is it better to block the upper grill or lower grill? I have a Subaru Outback with the lower grill blocked and the upper grill open. I chose to do the lower one cause it was a bigger opening but it may be at the stagnant point anyhow so the blocking the upper grill may be better for smoothing flow over the hood. any thoughts?

[Daox]

Thats the general consensus. If your going to block one, the upper helps more with aero.

[MetroMPG]

You're right on: all else being equal, better to block the upper opening and send air that's already above the stagnation point over/around the car where there's less drag. Feed air that's below the stagnation point through the radiator, since it was going to end up in the turbulence underneath the car anyway.

[pawilkes]

sweet, i'll have to try that. I think it will make for a prettier mod too.

[NeilBlanchard]

Hi,

I blocked the upper one because it is flush (the lower one is recessed) and it helps the air flow up over the hood. Also, the standard upper grill is more closed than mine is, so I felt more confident going without the cooling air. And there is the slot just above the bumper, too.

It worked perfectly well today in very slow/stopped traffic on Route 128 with the temps in the upper 90's.

[NeilBlanchard]

Hi,

A quick update: I added a bit more duct tape to seal the hood joint with the top of the headlights. This tank is looking very good: ~370 miles with ~1/4 tank left = ~490 miles on the tank (!!!) = ~49mpg! Woohooo! That is simply amazing...these front end aero mods have added ~65-70 miles per tank, and they will have added ~5mpg to my pre-mod best!

[Edit: This is on my regular commute, so it is a round trip -- all the downhills are uphills in the other direction; and traffic is hardly ideal. There is no way I could do any pulse + glide...]

My lifetime average is 37+mpg -- and this tank looks like it will be 10-12mpg better than that. I'm still flabbergasted...

My working theory is that covering the fog lights has smoothed the air flow coming off the sides of the chin spoiler; possibly helping air to flow out an around the front wheels?

I want to make a pan for the rear undercarriage behind the axle -- ideally, this could be structural, and the new space would add a fair amount of volume to this car's Achilles Heel -- storage space. Both the rear bumper fascia and part of the metal frame hang down an form sharp edges across the air flow.

[echomodder]

NeilBlanchard Do you have a scangauge? Just wondering what the water temp got to? I've been thinking of doing so aero mods to my echo but am wondering if that will cause the cooling fan to kick on more taking all the saved gas from the mod?

[NeilBlanchard]

Hello,

I do not have a Scangauge -- yet. The coolant did not get too hot -- the electric fan only ever comes on when I'm stuck in traffic. The red warning light never came on.

My mileage has improved with these mods -- so, the answer to your question is the mods save gas; and the car does not overheat. It was nearly 100F yesterday, and all was fine.

Mechanically, the Echo is very similar to the xA (and the xB and the Spectrum). Are the grill openings similar? (Post some pictures.) Try blocking only the top of the grill with one strip of duct tape (and seal the edge of the hood), and see how it goes.

[NoCO2]

I did similarly to my Camry recently and have yet to see any gains from it, but my last tank was an oddball because I drove in the rain for about half of it unfortunately so less is to be expected. However, as of right now with my lower grill blocks (upper is going to be tricky to cover because of it's shape) I haven't noticed the fans kicking in more (I would hear them, one makes a sound like a frog) and my temps haven't moved at all (and I'm actually very low on coolant right now, which reminds me I need to fill it up). It will be interesting, once I put the partial belly pan in to bridge the gap from the bumper to the chassis, if the heat builds up in any exponential fashion or if there are any real aero gains made.

That should be your next move though, once you're sure everything is ok where it is with the grill blocks, made a panel to cover the underside of the front of the car to seal the gap that is usually between where the radiator is and the bottom of the bumper.

[NeilBlanchard]

Hello,

Originally Posted by NoCO2

That should be your next move though, once you're sure everything is ok where it is with the grill blocks, made a panel to cover the underside of the front of the car to seal the gap that is usually between where the radiator is and the bottom of the bumper.

Actually, on the xA there is already a couple of plastic panels extending back to below the radiator -- there are some holes in it, and the two pieces move around a bit. This would concentrate the air flow through the radiator, and if anything, it will improve the cooling.

Another aero mod I want to do is to improve the air intake for the ventilation system. It is pretty anemic and a lot of warm air leaks into it from under the hood -- but now I've got the hood taped shut!

[NeilBlanchard]

G'Day,

Well, I filled the tank today:

458.8 miles (a new high)
9.882 gallons ($4.04.9/gallon = $40.01)
46.4mpg -- a new high as well, but less than I'd hoped...there was about 15-18 miles of stop and go traffic on Rt. 3/93/95, and on Rt 117 -- very thick. There were a few accidents along the way, so I'll see how things go on the next tank. Things are trending in the right direction!

I may try (partially) covering the slot just above the bumper...

[digitaldissent]

dude 46 is great! you got me beat

don't you just hate it when you know your getting awesome MPG then you get stuck someplace and you are all "oh noes!" this is going to hurt

[NeilBlanchard]

Hello,

A further modification test; I've filled in a pretty deep inset between the A-pillar and the windshield:


I'll see how these go...

[MetroMPG]

You mean you filled the rain channels on the sides of the windshield?

The 1995+ Metro doesn't have any A pillar rain channels, or drip rails. Good for aero, bad when it rains (water streams freely into the side windows even if they're just cracked open a little).

[Cd]

Originally Posted by MetroMPG

You mean you filled the rain channels on the sides of the windshield?

The 1995+ Metro doesn't have any A pillar rain channels, or drip rails. Good for aero, bad when it rains (water streams freely into the side windows even if they're just cracked open a little).

I've wondered about that area of my Civic.

As you can see, the air slams right into those cannels causing a lot of drag ( I assume )



Now I know why they are designed like that . Thanks for clearing that up Metro !

Congratulations on your progress Neil ! You have some cool stickers BTW.