Scion xA aero mods

[NeilBlanchard]

I think those improvements are not quite as good as they say they are. The stock xA is 0.31 (though I think my Release Series 2.0 model with the wide open hexagonal grill is higher than that?), and I did a coast down test with the rear wheel skirts and smooth wheel, ~80% grill block, Kamm "boards" and rear under panel - and my best estimate is ~0.26-0.27. Since then, I added the side video mirrors and the partial front wheel skirts so it might be ~0.25-0.26. A full belly pan might get it down another 0.01-0.02?

To go any lower, there would have to be a boattail or some other major reduction in shape drag. I doubt that a 0.34 Cd can be dropped to 0.21 with only detail improvements.

On the modded CRX, I think the only benefit of the front wedge is to lower the stagnant point, which could have been done with something similar to the AeroCivic - a much shorter blunt nose would have been as good or better.

[adorable]

labs . autodesk.com/utilities/falcon

Hmmm. Anyone have a free 3D xA model to try out? This Autodesk Falcon program looks interesting - free CFD simulation live, and you can easily model a tail, etc. and see what effects it will have.

Not the most accurate vs. PowerFLOW used in the prior article linked for the electric car, but free!

[adorable]

As for the big drop is cD in the prior linked articles, those were for a standard '4-door' sedan shaped car. The xA hatchback design is different and doesn't allow the air to smoothly separate off the rear as well as off the trunk lid of a 4-door sedan, so it's more difficult to improve cD as much.

[NeilBlanchard]

Until the Falcon program works more predictably, I think that trying to solve drag issues of actual cars with it is initially interesting, but a waste of time in the end.

Take a look around this Forum and see if you can find an example of a vehicle that has a Cd of less than 0.25 that "started" with a Cd of 0.30 and I think you'll find only one: the AeroCivic. It takes major shape improvements to drop the Cd by anywhere near that much.

[RandomFact314]

Hey I just bought a RS2.0 a few days ago... Saw this one recently... Just wondering what #/1700 is yours? It says it on the little plaque under your steering wheel

[NeilBlanchard]

Mine is #96 of 1700 - what number is yours?

[RandomFact314]

Originally Posted by neilblanchard

mine is #96 of 1700 - what number is yours?

283/1700

[RandomFact314]

Just to let you know... With my brand new xA RS2.0 I have set new MPG challenges for myself, and since we have the same car I started what I like to call:

"The NeilBlanchard Challenge"

I'm going to try to beat (or even get close to) your MPG, which will be quite hard since I deliver pizzas, so all my trip are 3 miles here, 3 miles back, 4 miles there, 4 miles back, all stop and go city trash.

--I do have a question for you, do you wait until your "cold oil" light goes off before you drive or do you just crank and set off immediately? I've been doing half and half.

[NeilBlanchard]

I just drive - it's gonna warm up either way and it at least goes somewhere on that gas. Short distances are tough, especially in the colder weather.

[RandomFact314]

Originally Posted by NeilBlanchard

I just drive - it's gonna warm up either way and it at least goes somewhere on that gas. Short distances are tough, especially in the colder weather.

What do you think about the EPA ratings for this car?
Was 32 city and now they say is 27 city... Doesn't 32 seem closer to right or are we just "trained" to get good mpg naturally and everyone else gets 27?