Extending the Decklid (Toyota Echo) - Fuel Economy, Hypermiling, EcoModding News and Forum

CigaR007 · 08-31-2012, 05:16 PM

Hey guys !

It is time for me to concentrate my efforts and resources at some in-depth refinement of my Echo's deck-lid. Basically, I want to build an extension of some sort that is tapered, following the car's original lines. I aiming towards a deck-lid a la Ford Fusion 999. But perhaps not as pronounced length-wise. But who knows, with a little convincing, I might cave in...

See picture for reference.

I do welcome suggestions, be it concerning the decklid or any other mod leading to decent gains. You guys are the pros in this domain and I would be a fool to turn down any useful insight. However, at this moment, I do not plan on installing a boat tail. I am aware of the gains but I simply do not wish to go down that path...for the moment.

Also, I plan on providing some preliminary tuft testing videos of the airflow on the rear glass. It should help you guys decipher what is going on back there. Given that we have a 3-day weekend, I might have a video by Monday. Heck, I have to put that GoPro camera to good use..

To conlude this post, here is a pic of my car.

For some reason, I cannot find technical drawings for the first-gen Echo. It does not look good aerodynamically-speaking but the stock Cd is 0.29 so in reality, it is not that bad.

TIA for ANY feedback ! Much appreciated.

MetroMPG · 08-31-2012, 05:24 PM

Have you ever tuft-tested the decklid? It's short, and the rear glass is fairly steep, so I wonder if it's completely turbulent back there, or whether there's attachment on the trailing edge (the roof does curve down above the rear glass...)

Weather Spotter · 08-31-2012, 05:35 PM

try and see what she does

CigaR007 · 08-31-2012, 05:35 PM

Can't say I ever tuft-tested the decklid. I will do my best to capture that vital information in the coming days, as it will be key for the design of the extension. If and that is a BIG if, flow does not re-attach at the decklid, would resorting to homemade vortex generators help the air flow, especially in the roof-to-glass transition ? I know that they are very hard to tweak but could they improve the flow when combined with a decklid extension. The rear glass is steep indeed.

Anyhow, I will come up with a tuft-testing video and we will know for sure.

HyperMileQC · 08-31-2012, 05:37 PM

Nice idea! If it prove any improvement, Francis and I might try the same on the Echo-Troll as well!

MetroMPG · 08-31-2012, 10:23 PM

In the event of no re-attachment:

VG's would likely help get more flow onto the decklid, but at what cost? Don't know.

Another option is to raise the height of the decklid's upper surface to get closer to the template.

Simplest option is a NASCAR type of spoiler.

CigaR007 · 09-01-2012, 02:42 PM

Any tips on how to prepare a tuft testing ? Camera is set, just need to clean the rear glass and decklid prior to installing the wool tufts. Is there an optimal number of wool tufts, length and positioning ?

CigaR007 · 09-01-2012, 06:58 PM

Tuft testing has been done. Video will be edited this evening and posted tomorrow.

Shot at 2012-09-01

Sven7 · 09-02-2012, 01:24 PM

You can't find blueprints because in the rest of the world it was called the Platz or Yaris (first generation).

They're out there, but they're also small.

Looking forward to the tufts!

CigaR007 · 09-02-2012, 04:11 PM

Here is the video to mark my 500th post ! It is available in 720p, if desired.

http://www.youtube.com/watch?v=TpFLb...=youtu.be&hd=1

There is clearly a bubble of turbulent air in the middle of the rear glass. Whereas the sides are stabler, mainly due to vortices being generated by the C-pillar. The airflow does seem to partially re-attach on the decklid.

Awaiting your thoughts and suggestions !