2019 RAV4 Hybrid Limited
 

Went for my first hybrid and I’m loving it. Hypermiling the best I can and running on 91 octane fuel with tires at 48psi, I am getting 49.5 mpg average per tank as indicated on dash. I was wondering if there would be any suggestions on what to try to improve aerodynamics? I know it’s higher in the air, which makes it easier to get in my driveway, would lowering it or putting an air dam help? I’m contemplating a partial grill block to help smooth out the front, but don’t want to hurt the a/c function as I’m in AZ and need it bad. I have taken off the roof rack that came factory. I’d really appreciate any and all ideas!

I probably wouldn't mess with a grill block in AZ, and especially in a new car. You sure it doesn't have an active shutter? Many newer cars are starting to come with them.

50 MPG is crazy good. My Prius gets that.

RAV4
 

clean up the belly,add rear wheel skirts,then 3-feet of boat tail.

What aerohead said, plus wheel spats.

I'm curious about the the rear drive. Does it have a driveshaft or an electric rear axle?

I expected it to have the active shutters, but it oddly doesn’t. The grill is blocked on the right and left sides a bit as in it’s not hollowed out and just has the grill look to it. Was thinking of at the least doing a smooth block there just for aerodynamic effect if it would have one at all. Also with the fog light cavities, I was thinking of getting some thin plexiglass and forming it to fit and siliconing it in to smooth it out too.

Any suggestions on how to add some sort of shield over the wiper blades? Thought that might help smooth it out too.

From my understanding, it is pretty smooth on the bottom with the factory belly pan. Any advise how I could help reduce drag for it being so high off the ground? Do some sort of block in front of the tires like the eco Corolla’s have? What about a short-ish airdam? Would that have the same effect as lowering it sort of?

Would taller tires help? Or smaller, low profile ones? I know I want to get the low rolling resistance ones when the factory set give out.

Thank you for the recommendations and advise. Really trying to understand and use the information.

wiper blades
 

I tested for this and found no improvement.Even adding a more streamlined windshield along with it only lowered drag 0.005.

How about partial wheel arch covers? Smoother wheel covers (maybe black inserts for the gaps in the rims).

The wipers appear to already be out of the path of the air to my eye.

With Toyota's HSD, there's no benefit in terms of gearing with larger tires, since the engine has no fixed ratios with the wheels. In theory a larger diameter tire will have lower rolling resisting but is heavier and with a higher moment of inertia. A narrower tire has better aerodynamics but requires more pressure to get the same load rating. I wouldn't go significantly different from factory size.

I would very much like to lower the wheel arch gap if I can. Been thinking of getting some ABS plastic that matches the fender flares and trying to fabricate some that would look seamless. Not too sure how to work with ABS plastic though. Thinking I can score it, bend it to match the curve, drill holes to match the existing wheel well fasteners, and go from there. Wanting to make it not stand out too much if at all.

As far as the tires go, I found out that they just have pretty standard all season tires on it. In AZ where it doesn't snow and barely rains, I'm thinking a low rolling resistance highway type tread would be the way to go. I was thinking of going with a taller, narrower tire if I could fit it on the same rim.

I saw the idea on here of sealing the panel gaps. Does that really help much? I decided to take some rubber door edge guard and put that around the gap of the hood to the front fenders/grill. Don't know if I'll see much difference though. Was thinking I could get the same stuff and wedge it in all the gaps. Use a clear or something. I'm just not sure if it would be worth doing though. Being a new car, they're pretty tight already.

With the underbody already being smoothed out with the factory belly pans, would an air dam be any benefit?

I'm also wondering how I could safely add additional battery storage to the hybrid system and add a grid charger as well. Ideally, be able to have the grid charger only charge the "extra" set of batteries so I can mitigate the risk of damaging the battery pack that came in the car. I just have no knowledge of electrical systems unfortunately.

As early as the 2nd gen Prius, people have been adding secondary packs and making them into PHEVs of sorts. I'm unsure how much the 2019 differs from other model years but that kind of conversion isn't something easily done as a one-off, even with a degree in electrical engineering. Wait a few years and kits might become available.

I did this, but in sheet metal:

If you cut a semicircular strip with the same radius as the wheelwell arch it will lay flat. If you use a straight strip and bend it it will stand out at 90°.

But if the strip is circular but with a larger radius it will form a conic sector at some arbitrary angle.