Tuft testing video: Honda Insight (2000) front wheel well design

[MetroMPG]

I've always been intrigued by the effort Honda put into the bodywork around the front wheel well of the 1st generation Honda Insight.

It's definitely not conventional.

1) There's pronounced taper in the quarter panel leading back from the wheel well arch. From above:



Another view of the taper from the front, plus 2) how the tire/wheel is close to flush with the side face of the front bumper:



3) The smooth radius of the aft edge of the wheel arch - to promote flow attachment of air coming out of the well & off the wheel:



4) The sharp edge of the forward/top edge of the wheel arch to promote clean separation there:



5) ... and of course the relatively smooth/flat wheel itself. (Though it could be better ... note to self: needs a 100% smooth disc.)

All this would lead a person to think the air flow immediately aft of the wheel well is pretty good, compared to a car without these design elements.

One way to find out: To the poor man's wind tunnel, Batman!

http://www.youtube.com/watch?v=EOCV77mjm_w

The video includes a tuft testing comparison to the wheel well on my 1998 Pontiac Firefly (Geo Metro), which does not have these design features. Not surprisingly, on the Firefly you can see much more turbulence (and separation at times) in the first column of tufts immediately behind the the wheel arch. While on the Insight there's much less turbulence and no sign of separation (tufts reversing direction or lifting clear off the body).

(For a more detailed look at the Firefly wheel arch & front wheel skirt tuft test see: http://ecomodder.com/forum/showthrea...etro-5403.html )

Detail optimization for the win!

[MetroMPG]

Oh, and P.S. - the roof rack visible in the still photo in the video? It was for mounting the camera boom.

[Smurf]

Very good work. Honda put a lot of R&D into those body lines, and it shows. Really makes me wonder how difficult it would be to build your own fiberglass eco-fenders for an older slab-side vehicle, like a 1st generation S10, with the radius'd edge.

[aerohead]

Flow looks real good! Maybe a little stage fright from being on camera,but no recirculation.Tasty! Thanks! Tell your car that it will receive it's OSCAR by mail.

[Frederick]

Thank you very much for this work.

[jime57]

Thanks Darrin,

I had always wondered just how good Honda did ever since I bought my first insight. It is pretty clear that they did wonderful job with the details around the front fenders/wheels. It is so smooth that one might question whether front aero covers on an Insight would be worth the effort ;-)

I had been wondering a bit about the A pillar area also and just finished some tuft testing there. Didn't do a video, but can do so and will try that soon. The flow looks good, but I'm a bit mystified by the top half of the side window.

Thanks again for your efforts!

[MetroMPG]

Honda didn't leave a ton of room for improvement, but I still think there is some room. Without going to a full, articulated skirt, we could do:

- completely smooth wheel covers, as mentioned
- gap fillers that extend the "sharp" top & forward portion of the wheel arch a bit closer to the tire
- boat tailing aft of the front tire (on the bottom of the forward part of the rocker panel)

[WesternStarSCR]

First post here. Great site.

Oddly, this immediatly made me think of the Subaru Outback Wagon cladding.

Added to a regular car, to mimic what an Insight design has.

It seems that if the front bumper / air dam / spats end at the plane of the front wheel, it is maybe helpful to then make the body behind the front wheel, all the way to the front of the back wheel well, about 1" or so further out, and NOT in the same plane. A smooth transition from these 2 planes is what the Insight has, especially from your head on view picture.

It gives the wheel well air a nice exit path to the rest of the side for laminar flow along the body, instead of below the car, or to a side wake, or to continued turbulence in the wheel well itself?

I can't post pics yet, but maybe you can envision a outward tapered surface the height of the back of the front wheel well, going along the length of the car? It is between the front wheel well and the front door that this taper could occu.r

Continue that width increase to the back and now we have back wheels that are tucked in that same amount that body width was increased, not unlike the back wheels of the insight tucked in?

Thanks for the great site. I will be sharing my mods on my 2004 Chevy Malibu Maxx as time goes on.

[MetroMPG]

Hi - I can picture what you're talking about:



The challenge of adding material to reduce drag is you potentially increase frontal area (A). Since total drag is the product of Cd * A, the added material would have to decrease the drag coefficient enough that the net result of Cd * A is a smaller number.

Another modification approach to encourage a cleaner flow transition from the wheel well & wheel onto the quarter panel of a "conventional" design: cut a pool noodle (or equivalent) along its length to get a 1/2 round shape, and attach it to the aft part of the wheel arch. Voila - instant generous radius/transition which the air should like better.

I hope you'll post about your Malibu MAXX. Now there's a vehicle well suited to a Kammback addition!

[Tango Charlie]

The front wheel well body work on the G1 Insight has always been a favorite feature of mine. Thanks for the tuft testing!