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Old 06-10-2022, 06:31 PM   #45 (permalink)
Talos Woten
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Join Date: Jun 2022
Location: Aliquippa PA
Posts: 107

Champrius v3.2 - '09 Toyota Prius
90 day: 58.73 mpg (US)
Thanks: 7
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Thumbs up On Skirts and Sailing Wax

Quote:
Originally Posted by Phase View Post
how do you keep the under belly pan from roasting from the muffler? im trying to do a belly pan and diffuser for my ioniq and my muffler is right in the middle! also why didnt you do a full rear wheel skirt?
In version 1.0 I didn't. I covered everything with coroplast. Consequently, the car cabin overheated, it charred the belly pan, and I had to scrap the whole thing and start over.

In 4.0, I'm using two cat shields made out of aluminum to cover the catalytic converter and resonator, which are also in the center of my underbelly. I'm leaving the muffler exposed, because it's off to the right. If I were to cover it, it would be with a metal sheet, and I'd make sure that it had an opening in the rear for hot air to eject. Not just the tailpipe, I mean an opening the size of the muffler itself. (This assumes there's some way for air to also get into the same channel. On my car, the muffler is right behind the rear sway bar, so that's not an issue.)

I originally tried out full wheel skirts, and they definitely work. But a) the front wheels had too much flutter, negating the aero benefit, and b) they were a pain for servicing. I eventually moved to the slim fairings I have on Champrius now. They gave me 75% of the benefit of the skirt in the rear, and actually performed better than a skirt in the front. So ultimately I choose the lighter, easier to service, less hassle option that had equivalent fuel economy.

By the way, I also tried a half dozen different variants of side skirts, catamarans, wheel tails, etc. and concluded they are all crap. They don't improve mpg, and in some cases interfere with subtle aero-shaping that's already in play on the Prius (in particular near the rear wheel spats).

Last but not least, I believe that air curtains are the way to handle the front wheels, rather than a skirt of any kind. That's from multiple perspectives: performance, safety, and serviceability. That's what I plan on putting on 4.0.
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Currently building Champrius 4.0! Follow starting here:
https://www.instagram.com/p/CeeL6xyFp-k/

and ask in depth questions here:
https://ecomodder.com/forum/showthre...tml#post669277

The goal is 70 mpg this time around.

Stats from Champrius v3.2:
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