Good place to get started ? want to get at lest 40-45MPG.highway.

[Ecky]

Shamelessly stolen from Google, this is approximately what I had in mind.



Smooth wheel covers, cover as much of the rear wheels as possible, and add as much of a kamm to the rear as you feel you can get away with.

Underneath, as much smooth paneling as you can get away with.

[aerohead]

For Cd 0.10, the Tahoe will need all that and much more. Which will probably nix the project right where it is.
We're talking about a full-size SUV which would make AeroCivic faint.

[Ecky]

It won't hit 0.10, but I feel there's plenty of low hanging fruit, and room for significant improvement.

[Autobahnschleicher]

Originally Posted by aerohead

For Cd 0.10, the Tahoe will need all that and much more. Which will probably nix the project right where it is.
We're talking about a full-size SUV which would make AeroCivic faint.

Imagine the size of that boattail...

[aerohead]

Yes, 'ginormous'! Only way to go that low though.

[aerohead]

Just to keep data with this original thread, here is some dirty math for the 40+ mpg trailer:
* overall length, eleven feet
* with three-foot pull-bar
* integrator height matches Tahoe
* integrator width matches Tahoe
* boat-tailing begins on gap-filler
* total surface area of appliance 260-square-feet
* double -layer, biased, pre-preg carbon fiber epoxy, vacuum-bagged, autoclaved
* 4.321-ounce/ square-feet, monocoque, stressed skin, ovoid ( egg-shelled )
* total exterior skin, 70-pounds
* total appliance weight, 150-pounds
* bonded hard-points
* composite independent suspension
* single-wheel
* Bridgestone Ecopia EP80, 2.25- 14, Tubeless, 800 kPa ( or equivalent )
* full wheel fairing
* Road-Load horsepower, negative 22.385- hp @ 70-mph ( 115-km/h )
* Road-Load Rolling- Resistance horsepower, 0.05-hp @ 70-mph ( 115-km/h )

* Total trailer load, negative 22.335- horsepower, @ 70-mph.
* 41-mpg @ 70-mph ( assuming gear-matched, constant BSFC )

[Tahoe_Hybrid]

Originally Posted by Ecky

It won't hit 0.10, but I feel there's plenty of low hanging fruit, and room for significant improvement.

the problem is i'm not in EVT2 GEAR the engine will literally run at 1,050 rpm at 55MPH... V8 mode it reports 48-55MPG "instant mpg" with no electric assist , at 55mph in EVT2 gear.. steady speed flat land.. with a slight head breeze it will drop to EVT1... and that reading will drop to 22-27


my mpg is lost in the powertrain



this is why small changes so i only need to pick the low hanging fruit

so it's more of an engine load issue I did figure out a way to turn off DFCO which is just adding additional friction i.e pumping losses


(i.e allows longer coasting with the engine still putting gas with out allowing the engine to pump air into the exhaust )

[oil pan 4]

It's not lost in the power train, it's lost trying to ram a suv through hurricane force wind.

[Tahoe_Hybrid]

Originally Posted by oil pan 4

It's not lost in the power train, it's lost trying to ram a suv through hurricane force wind.

i t's lost because they did not put a Eco mode button so it would stay in EVT2 longer at the expense of acceleration..


eco mode just changes the shift points... which is at the expense of acceleration..

[freebeard]

Does that lack warrant pulling an eleven foot trailer?