Scion xA aero mods

[SentraSE-R]

Neil,

Are you doing anything different this Summer to account for your recent excellent fuel economy? Is the reason just your hot weather?

[NeilBlanchard]

Hi Darrell,

I'm sure it is a combination of several things: better smooth wheel covers, more EOC'ing, the rear wheels strakes, the hotter weather, different driving patterns (I'm commuting this summer), tires wearing down, and more accurate distance correction, too. Here's my entire fuel record:



You can see the seasons, and when I started to ecodrive.

[SentraSE-R]

Hi Neil,

Yes, I can see how your Winter fuel economy suffers, although 40 mpg in the Winter isn't what anyone would call terrible. My xB shares your xA's drivetrain, with worse aerodynamics, so you'd clean my clock if you had my Winter weather.

I've seen on the Yaris forums where someone swapped ring gears and bolts from an xA/xB into a Yaris for quicker acceleration. Seems like we should be able to do the opposite.

[theuglyone]

I don't know why this hasn't been discussed on this thread, but why don't you remove the rear seats and remove the rear spare for added weight reduction? Also I know, by reading this thread, that you seem to keep regular maintenance on your car. I am curious as to what Intake (Stock or aftermarket) you are using? Further, Do you regularly clean out your MAF on your car?


This thread is awesome btw..I wouldn't do all the mods (for cosmetic purposes) but some of these mods are definitely on my to-do list. Very interesting indeed.

[NeilBlanchard]

Thanks for your interest. The most important mechanical mod I could make in the xA is change out the 4.31:1 final drive with the 3.56:1 unit -- the revs are way too high at highway speeds. This would be about 17% drop in revs, at least, and the fuel savings could be 10%? If I can afford it, when/if it needs a new clutch...

I need the backseat because my 2 kids and sometimes all 4 of us drive in my car. And I've had several punctures, so I couldn't go without the spare, either.

I would love to be able to redo all the Coroplast and tape mods with fiberglass, so they both looked better and worked better, without the maintenance. They have survived several years now, and in the winter aero mods are even more important, because the air is denser.

But, I am hoping to get started building my CarBEN EV5 electric car:

http://ecomodder.com/forum/showthrea...ter-11969.html

Also, see my blog linked in my signature.

[theuglyone]

Yeah I think a little of fiberglass would be good but kind of expensive. But do you still run the stock intake on your XA? I'm also wondering if you know anything I can do because I have an automatic....

[NeilBlanchard]

Sorry, I forgot your question about the intake -- I do have the so-called cold-air intake, but I don't think it matters very much.

Fiberglass is not very expensive, really; though it takes a bit of time. Check out the Insight boattail that 3Wheeler made; and there are other outstanding fiberglass mods.

Your automatic has the 3.56:1 final drive, I think?

Do you have a ScanGauge or the UltraGauge? If not, you will really get a lot of value from them. Coasting in neutral is a fine way to get 100-350MPG while you can. A grill block and smooth wheel covers would give a lot of benefit, and rear wheel skirts can be done "properly" with screw mounts and finished looking panels.

[adorable]

www dot mediafire dot com/?ek4tbm1b8iim3xs
3 PNG car models for use with Wind Tunnel app.

itunes dot apple dot com/us/app/wind-tunnel-pro-hd/id450980034?mt=8

Wind Tunnel Pro HD for iPhone 3GS, iPhone 4, iPhone 4S, iPod touch (3rd generation), iPod touch (4th generation) and iPad on the iTunes App Store

Something for aero modders to play with.
While the models and program is very, very simplistic, it does show the difference in airflow over the Prius vs xA vs iQ using the 3 models I've linked to.

The turbulent swirls behind the xA is quite dramatic at speed (lower Friction, increase Speed) vs the Prius and even the iQ! These non-smooth/turbulent airflows create a suction behind the car and slow it down.

While the resolution of the program is nowhere good enough to showcase the difference vs. real life, it's rather fun.

You'd need a 3D program with very high detail to start showing you the difference between moon caps and non, for example. This 2D program will only give you a 'very basic' idea of how the air flows over the xA and other cars you draw/import due to the very small size of the grid used.

[noahmckinnon]

Hi Neil. Reading through this thread many months ago convinced me to get moon style hubcaps and try a grille-block. I saw some modest gains though admittedly I still push 75-80 mph up and down I-5 (San Francisco/Portland) which keeps me in the mid to high 30's mpg. I now have an Ultragauge and a renewed desire to increase my efficiency, so I returned couple of nights ago to check your progress. 50+ mpg is inspiring!

I've got a a few questions – and please forgive me if the pertinent details have already been mentioned. I read the entire thread at 1a.

1) I was thinking of getting some alloy wheels until I read that you noticed no loss of efficiency when you switched to steel. Are you still rolling on steels?

2) What thickness of Coroplast are you using?

3) IIRC, you removed one face (plus corrugations I assume) of some of the pieces of Coroplast. Which pieces were those? I'm assuming not the wheel skirts because of the need to insert the metal rod, but perhaps you stripped away some of the back of the wheel skirts?

In any case, thanks for detailing your efforts. I hope to emulate some of them and save a little gas Hope your EV project is going well

[NeilBlanchard]

Hi Noah,

The steel wheels allow you to have smooth wheel covers much more easily than alloy, and yes, there was no discernible change when I used the steel wheels. My alloys are not particularly lightweight, in fact they may weigh more than the steel wheels I am using. I may be buying a second set of steel wheels so I can leave my winter tires and regular tires mounted, and do the swap myself. If you use two sets for two years, you will break even, or so on the cost.

I bought the 4mm Coroplast which is the most common thickness. I don't think that 10mm would be as practical for most uses.

I thinned down the curved edges of the rear wheel skirts so they lay close to flush. I left the corrugation everywhere except from about 3/4" from the curved edge. The rod is an 1/8" diameter steel rod and the rust on it keeps it in place. I have it slightly bowed, though that was to clear the domed wheel covers. I now have flat aluminum (16" pizza pan) covers riveted to the plastic wheel covers.

This summer was a big jump forward in FE for me, and I think a lot of it came from the flat wheel covers, much more EOC, and a few tweaks on the rear wheel strakes. My best tank average was over 55MPG!

CarBEN EV5 is actually starting construction, only just started. I'll proceed more as I find the time to run sheets through the PhlatPrinter 3 -- it takes 2-3 hours to complete cutting one 2'x8' sheet which yields a bit less than two 2" thick sections. There are about eighty five 2" thick sections, so one at a time will get it done.