To get ready for the
2014 SMCC Economy Run event in Montreal, I put together some coroplast mods for the 2014 Mitsubishi Mirage 5-speed I borrowed.
(See also:
http://ecomodder.com/forum/showthrea...cyl-29176.html )
I ran out of time to do a couple more mods that I would have liked: cowl fairing; rear wheel skirts; taped over the holes in the wheelcovers.
Pretty good factory "mods" ...
Mitsu hasn't left as much low-hanging fruit on this entry level car as other companies do on theirs. The Cd. is 0.28 in North America, and
comes with multiple factory aero elements like:
- drag-reducing spoiler/roof extension
- partial lower grille block off (and the size of blocked area is different for CVT vs manual)
- relatively smooth wheel covers (base model)
- narrow section LRR tires (165 mm)
- "optimized" rocker panel design
- sharp trailing edge/corner on the rear bumper cover
- plastic underbody panels
- front wheel/suspension deflectors
Here's what I added to that...
1) Grille blocks
This mod is less extensive than it looks, because Mitsu already blocked out about half of the "apparent" lower grille openings in the Mirage. I closed the upper slot plus a bit more than half of the lower openings.
2) Fog light inserts
Probably no real effect from covering these, but they looked lumpy and I had the plastic & tape out already, and so why not.
3) Air dam
Added a ~3 inch dam as far forward as I could, wrapping smoothly back to the front wheel arch on the sides. It left about 3.5 inches of clearance (and it scraped 3 or 4 times during the drive).
This mod is hard to do when you can't drill your borrowed car! Lots of tape (and later Goo-gone) used!
3) Passenger side mirror delete, driver's folded back
Replaced with a small (approx 2.5 x 3 inch convex mirror); folded the driver's mirror back and taped a convex mirror on its trailing end.
4) Passenger wiper delete
It parks unusually high and at an odd angle on this car (and on the Micra too, I noticed). Although it might also be angled so the local flow goes more from end than face-on. A quick tuft test would answer that.
5) Kammback/spoiler extension
This adds about 10 inches more to the roofline and up to 15 inches on the sides, and includes a notch to show the LED center brake light.
Testing...
I used my usual flat, straight 1.6 km test route. Conditions were perfect: 25C and dry, no wind at all. There was never any traffic ahead of me in my lane, but sometimes oncoming traffic went past on the other side.
I would have liked to do A-B-A, but didn't have time. Also, this car doesn't have cruise control, so I had to use laser focus on that speedometer needle. It's pretty easy to hold this car at a dead steady speed, but it did wander half a km/h or so up or down. So take all this with an appropriately sized grain of salt!
I did A-B-C, where...
-
A was all mods in place;
- B was all mods in place
except the air dam;
- C was all mods removed
Results ...
I removed the air dam separately because I was most curious about it. It was pretty much a given that all the other mods would help or have little effect, but the air dam had the potential to actually make things worse, and I wanted to check that.
The fuel economy improvement between unmodified (C) to modified (A) was 4.5 % @ 90 km/h / 56 mph based on these numbers.
A1 - 57.15 mpg US (average of 2-way run)
A2 - 56.8
B1 - 56.1
B2 - 56.15
C1 - 53.7
C2 - 55.0
C3 - 54.8