3rd gen Prius aeromod thread

[Vman455]

Originally Posted by secaturbo

I would Not do the air dam. it will add frontal area to the car. your under tray is designed to allow air to pass efficiently enough. Wish could find the post that said this. Air dams are good if there is a lot of under car openings. You might want an air dam at the front and rear tires like the early Insights.

Actually, the Prius has airdams on both front and rear tires too.

When Ford built the hydrogen 999 Bonneville car based on the Fusion, the engineers lowered the car to 50mm ground clearance (similar effect at the front as adding an airdam)--a modification they claimed lowered Cd by .08--and then added an entirely smooth belly pan (which reduced Cd another .01, they said). The Prius doesn't have anything near a perfectly smooth belly pan, and even if it did, based on their research, it could potentially still benefit from an airdam.

If there's anything I've learned about aerodynamics from reading this site and other research, it's that almost nothing is a hard-and-fast rule, and everything should be experimented. The Prius, for example, should have too steep an angle at the rear for attached flow, according to the ideal template, yet the flow is indeed attached and the resulting Cd is low because of it. So, the only way to find out is to try it. If it doesn't help, I can always take it off.

[KrautBurner]

Originally Posted by BrandonMods

I really like your idea to use pizza pans bolted to the hub caps. Do you know of anyway to do something similar but on aluminum rims? Thanks in advance

the Prius has aluminum wheels (with snap on wheel covers)


you could use these "Screw On" type wheel covers
MOON Disc Screw-on Type

or these weld on DSUS tabs
Dzus Tab Kit
(this is what I'm thinking of going with)

[KrautBurner]

Originally Posted by Vman455

A huge difference. Running errands around town tonight, I pulled into the driveway sitting at 81.8 mpg for the trip on the Scangauge. However, by far the majority of my driving is on the freeway, more than 250 miles per week, where the aeromods really pay off.

this is what I was wondering

my wife has a 2010 Prius II (it will become my commuter in another year or so)
she drives it like a normal car (no real regard for mpg) and averages about 46mpg

I can coax about 53-54 out of a tank if I'm careful

if I use it for my commute, I end up with abut 50mpg (55 miles each way, all highway, lots of hills (about 2,000-2,500 ft of combined elevation each way))
I'd love to squeeze another fifteen mpg out of it, but I don't know if that's possible

[aerohead]

Originally Posted by KrautBurner

this is what I was wondering

my wife has a 2010 Prius II (it will become my commuter in another year or so)
she drives it like a normal car (no real regard for mpg) and averages about 46mpg

I can coax about 53-54 out of a tank if I'm careful

if I use it for my commute, I end up with abut 50mpg (55 miles each way, all highway, lots of hills (about 2,000-2,500 ft of combined elevation each way))
I'd love to squeeze another fifteen mpg out of it, but I don't know if that's possible

Getting to 65-mpg would require your Cd to drop to around 0.10,which would have the Prius looking like this

[Vman455]

The air dam experiment has begun! I bolted some L-brackets onto the bumper cover:


Uh oh--OSHA inspectors.


Lawn edging bolted to the brackets, all stainless hardware. I took the opportunity with the bumper off to get rid of the pipe foam grill block; instead, I used one of the hatch panels I had taken off and cut it up to be a permanent grill block zip-tied behind the slats, with a center opening in the lower grill under the license plate and the inward side of both upper grills still open.


Back on the car:


Still a little more than 4" clearance, about the same as the 1st gen Volt with original air dam.

[gone-ot]

VERY nicely & cleanly done!

[Daox]

Agreed, I like it!

[redpoint5]

Originally Posted by Vman455

Since I've been moonlighting with Uber occasionally, I unfortunately can't remove the rear seats at the moment.

I'm thinking about moonlighting too since I took a massive pay cut and my wife is in a $90k medical program. How much do you average an hour?

Originally Posted by Vman455

The air dam experiment has begun!

I don't believe it will improve MPG since the underbody was already engineered to be aerodynamically efficient, but I look forward to the test results.

[Vman455]

Originally Posted by redpoint5

I'm thinking about moonlighting too since I took a massive pay cut and my wife is in a $90k medical program. How much do you average an hour?

I've been going out on Sunday afternoons and averaging $15-20/hour. Uber says the busiest times around here are weekday mornings and weekend evenings, so I imagine I could pull in more going out then, but I've been enjoying the slower Sunday afternoon crowd.

Edit: And, so far, no comments on the strange-looking car.

[MetroMPG]

Originally Posted by Vman455

The air dam experiment has begun!

You beat me to it! I haven't seen one done on a Gen 3 or 2 yet.