1991 Toyota Hilux: Aerodynamic Tests and Modifications

[Vman455]

I'll use this thread to post results of testing on this vehicle. It is a 1991 Hilux, regular cab 4WD:



Starting point is stock except for slightly oversize tires; stock tires were 225/75R-15 but it's wearing 235/75R-15 now.

Test 1: Side Window Flow with Various Mirror Configurations

Mirror open:



Mirror closed:



Mirror removed:



Mirror removed, antenna removed:



I stopped by the hardware store after this to get some weatherstrip and try out small vortex generators on the A-pillars:



Final configuration, outside view:

[freebeard]

Does it have OBDII?

Each step was an improvement. How many vortex generators did you try. In all cases, the air abaft the window frame is running upward.

Do you think a continuous [smol] wickerbill might trip the airflow so that it reattaches without changing direction? That crossflow interacts with the air that flows straight back and the shear is going to create turbulence.

It might look like one of those plastic wind deflectors cut down to a fraction of an inch, with a serrated edge to quieten it.

edit: as soon as I closed the tab, the next one was this:
All new toyota Gazoo Gr DKR hilux t1+ ready for dakar 2022

You can only see it for the first few seconds, thereafter all long shots.

[redpoint5]

Would be neat to 3D print vortex generators. It's a matter of time before I finally break down and get one. Can't justify what I imagine is a lot of time learning about them at the moment.

[freebeard]

The time investment would be in learning to model the part, the slicer software is comparatively trivial. After that, leveling the bed and getting a good first layer.

I bought one with the second round of Plague Money. Eventually I filled up all the empty shelving with things I'd printed.

I like this picture for the shadow in the ditch.



Reminds me of driving North on 99W in the evening, in my first car.

[aerohead]

The lower three tiers of tufts show a marked improvement!
For the 1985 Subaru XT, the engineers moved the mirror out, 80mm from the glass, on a thin stalk. All Tesla, some Aston Martin, and Chevy VOLT are doing the same.
On the T-100, going to the SCCA race mirrors dropped the mirror drag from an indicated Cd 0.027, to Cd 0.10.
Nice testing, thanks!

[cRiPpLe_rOoStEr]

Originally Posted by aerohead

For the 1985 Subaru XT, the engineers moved the mirror out, 80mm from the glass, on a thin stalk. All Tesla, some Aston Martin, and Chevy VOLT are doing the same.

Makes me wonder why GM didn't take this very same approach for the Brazilian Chevrolet Corsa Pick-Up

Even though its mirrors were the same ones of the car range, unlike the European Opel Combo of that same generation

[Vman455]

Test 2: Bed Flow Patterns

Tailgate closed:



Tailgate open:



Test 3: Flow Through Rear Window

Side windows closed:



Side windows open:


(it's hard to see because of the sunlight angle, but the tufts are pointing into the cab)

[redpoint5]

A few more tufts and you'll end up with this

[Vman455]

Originally Posted by freebeard

Does it have OBDII?

Nope, too early. No airbags. No ABS. We die like warriors.

Originally Posted by redpoint5

A few more tufts and you'll end up with this

The worst part of tuft testing is removing the tape afterwards. I should just leave it on.

[aerohead]

On the T-100, with the slider open, I get a healthy jet of air into the cabin from the bed. A summer strategy, since the magnetic clutch on the AC compressor went south.
Also, Fem bot S's 1993 Toyota pickup, 2WD, averaged mid 26-mpg @ 65 mph, without AC.
With a cab-high, aluminum bedcover, 30.6-mpg.
She has the 5-speed manual. Wider than OEM tires.
I believe that Toyota rated these 2WD trucks at Cd 0.44.
Finally, in a road test of the Cd 0.37, 2WD, 2014 Tundra:
* with closed gate, at 65-mph, 20.8 mpg.
* with open gate, 21.0-mpg. One example where an open gate produced lower drag ( no data on rear lift ).