Undertray that didn't work

[editor at autospeed]

http://www.autospeed.com/cms/A_110872/article.html

[mtgeekman]

Interesting information was wondering about this my self.

I have a quick question for you though, or any one... has any one tested the difference with and without the panels under the engine?

I ask because I have one missing and the other is warped compared to yours... I think a previous owner bumped into some thing in a parking lot or what ever.


any tips on reforming the trays under the passenger compartment? one has a nice lip on it from getting caught on some thing ... again previous owner.
I think I just need to pull it off and heat it up, then bend it into shape right?

[editor at autospeed]

Prius front undertray worked well - http://www.autospeed.com.au/cms/A_2456/article.html

Front undertray seems more important than back (cf boundary layer thickness?)

[Dougie]

I suspect that the air is so turbulent by the time it gets back to the rear wheels that it doesn't make any difference if the bottom is smooth or not. You might be able to control it by sloping a long, smooth underbody down towards the road, but ground clearance would be a problem...

Some interesting stuff here: http://www.ferrariworld.com/images/ferr ... VATION.pdf

[mtgeekman]

Well, using my spare drivers site under tray. I made one from corroplast for the passenger side. If I get a chance this weekend I will install it and attempt to test it.

In this process though I will also be fixing the metal piece that's just behind the bumper underneath, since a previous owner banged it up pretty good. I will attempt to check the Cd using the coast down method as well.

[Dougie]

If you're really into this sort of experimentation, here are some ideas.

- It's better if there's no air under the car. Put an air dam under the bumper that goes almost all the way to the ground, and skirts on the sides that also almost touch the ground.

- The front wheels should be covered with skirts just like the back ones. Steering might be an issue.

- The underbody fairings should really be shaped so they go all the way to the tires, to isolate the underbody air from the wheel house air. Steering an issue again.

- Take off the mirrors.

- Cover the radiator air inlet at the front of the car, not at the radiator. If it's cool enough to get away with 50% airflow to the radiator, it's better to keep the excess air on the outside of the car. You would need to do two things; first block off the outside of the air inlet, then add a side panel between the radiator and the air inlet so the air can flow nicely to the radiator.

- Eliminate Kamm back by extending the car about ten feet with a long tapered tail.

[mtgeekman]

Some of those things are on my list to try. Front wheel skirts are planed out just need the time/weather to start putting things together. It's bit chilly to be working out side and no access to a garage.


I am going to do the coast down tests tomorrow to see where I am at to start with. If there is time I will do the tests with the corroplast under trays installed as well.