Dream Prius (aerodynamic mod exercise for 2nd gen.) - Page 3 - Fuel Economy, Hypermiling, EcoModding News and Forum

AndrewJ · 02-10-2008, 10:29 PM

bestmapman - I don't think that the front "boattail" is really neccessary in your situation. If the ideal aerodynamic shape is a teardrop, then you'd want the front of your car to, basically, be blunt. I think that something like Autospeed's front undertray and wheel spoilers would be a great starting place for the front.

As for the rear, your photoshopped version looks excellent! No complaints there

bestmapman · 02-10-2008, 10:58 PM

Quote:

Originally Posted by AndrewJ

bestmapman - I don't think that the front "boattail" is really neccessary in your situation. If the ideal aerodynamic shape is a teardrop, then you'd want the front of your car to, basically, be blunt. I think that something like Autospeed's front undertray and wheel spoilers would be a great starting place for the front.

As for the rear, your photoshopped version looks excellent! No complaints there

I really wasn't aiming for a point in the front. rather just to smooth things out and make the front more streamlined. The front currently has several openings for air intake to the radiator and resesses for the lights and hood. This needs to be smoothed out as much as possible. As of now, I have all of the grill blocked for winter. It will need to have some kind of adjustable opening for the summer months.

AndrewJ · 02-11-2008, 12:29 AM

cool, the adjustable grill seems like a good idea, I might go that way this summer if required. Spotted a nice choke cable in the auto parts store that would make a nice control system.

MetroMPG · 02-11-2008, 01:31 AM

Mapman: someone at Prius Chat is looking for volunteers to work with to build free prototype products (e.g. body kits) for a Prius owner.

http://priuschat.com/forums/prius-mo...roducts-2.html

bestmapman · 02-11-2008, 09:53 AM

Quote:

Originally Posted by MetroMPG

Mapman: someone at Prius Chat is looking for volunteers to work with to build free prototype products (e.g. body kits) for a Prius owner.

http://priuschat.com/forums/prius-mo...roducts-2.html

I saw that. The problem is he is a long way away from me. Being in Virginia and me in KY near Cincinnati. Still I sent him a PM to see if we could get together. My first project will be the rear wheel skirts.

MetroMPG · 02-11-2008, 10:11 AM

I wasn't sure where you were located.

I think rear skirts are a good place to start. If you're going to undertake them yourself, I bet if you made them off a mold you could sell knock-offs to other Prius owners. The interest seems to be there.

Be a pioneer! I've been waiting for several years for a Prius owner to lead the charge.

MetroMPG · 02-11-2008, 10:25 AM

By the way: the idea of taking a vehicle like the Prius, with an already "better than average" Cd, and modifying it to make it even more aerodynamically efficient isn't unprecedented.

GM did the same thing with its Cd 0.19 Impact/EV1 for a record speed run:

(source)

Note the ...

extended boat tail,
lowered ride height,
smooth wheel discs,
rear wheel skirts (stock on the production EV1)
full grille block (the EV1 ultimately had no grille, but some versions of the Impact prototype had stylistic openings, as well as openings for electronics cooling)
external mirror delete,
improved deflectors ahead of the front tires,
... and lots and LOTS of speed tape!

krousdb · 02-11-2008, 01:30 PM

Quote:

Originally Posted by donee

Hi Metro,

Here is a link to it over on Prius Chat ... http://priuschat.com/forums/prius-mo...rim-rings.html

Which describes how I made them. Here is a picture:

Attachment 313

Have you quantified any FE gain with these?

donee · 02-11-2008, 07:03 PM

Quote:

Originally Posted by krousdb

Have you quantified any FE gain with these?

Hi Krousdb,

Do not know and have not tried to evaluate the hub caps yet either. I did them at the start of the winter, and good conditions really have not existed yet for testing. Coming up with a method to see as small a difference as I expect will be difficult as well. One of the reasons I made them out of about the lightests metal that might work is to avoid the effects of rotational momentum and extra unsprung weight.

The secondary reason for doing the hub caps is the rust spots on the brake disks when they were warm, and the snow would blow in and melt on the disks. As you know the Prius does like 85 % of its braking electrically, and so the friction brakes do not get hot enough to evaporate out the surface moisture on many trips. So, this seemed a good way to keep the surface moisture down. Which the flat hub caps do help with.

Big Dave · 02-11-2008, 08:43 PM

I'm not saying: "Don't do it!" I love seeing guys take their ideas as far as they can. Gives me more ideas to steal.

Basjoos started out with a brick and took it to the max and got fabulous results.

Just that starting with an already slick Prius means you start closer to the point of diminishing returns.

Like I could ever see that point with my full-size pickup.