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

[aerohead]

A thought experiment, because it's safe, would be to draft a semitrailer at very close range on an isolated test course, at your chosen velocity, and see whether or not the engine could reach anywhere close to your target mileage.
If that didn't do it, nothing would. A Go NoGo.

[Isaac Zachary]

Originally Posted by Autobahnschleicher

Can somebody please explain me why you guys are so obsessed with absurdly large and heavy vehicles?
Also 3,99$/gallon is dirt cheap, here we're looking at the equivalent of 6-7$/gallon.
Get a normal car and you will get the fuel economy you desire.

1. You already answered your own question, partially. Fuel is cheap here. It represents a very small fraction of the total price of the vehicle. The SUV almost died in 2008 when fuel prices spiked a little while wages suffered. That killed some SUVs liked the Hummer and brought over small cars like the Smart. But the spike didn't last long and everyone went back to big vehicles. Only this time most people started buying CUVs as a happy medium.
2. As mentioned earlier, people here have been fed propaganda that large vehicles are the only safe vehicle. They have been told that anything smaller is a "death trap". So you're considered immoral if you don't buy a huge vehicle.
3. As with any fad people make up a billion reasons why they need one. Apparently everyone lives where roads are ridden with deep potholes, where the government doesn't provide enough snow removal and where if you want to be able to do any fun you have to go "off road" out in the back country, which usually means driving on a well developed dirt road.
4. You can also blame Arnold Schwarzenegger for starting the fad that oversized is cool.

[rmay635703]

0 City

[aerohead]

Originally Posted by rmay635703

0 City

Chris Payne, of 'Who Killed The Electric Car?' paid FOX $ 50,000 for a clip from 'The Simpsons' in which some of the townspeople felt that simply looking at a Prius would cause spontaneous sex change.

[Tahoe_Hybrid]

Originally Posted by aerohead

A thought experiment, because it's safe, would be to draft a semitrailer at very close range on an isolated test course, at your chosen velocity, and see whether or not the engine could reach anywhere close to your target mileage.
If that didn't do it, nothing would. A Go NoGo.

according to the meter the Best MPG zone is at 45mph which runs the engine at 1050-1070 RPM in v8 mode... it will show a consistent 40mpg on the display.meter..with the A/C on ( no change if the A/C is off ) the issue is wasting a ton getting up to speed..


it's really hard to keep it in that gear If I was able to keep it in that gear longer i would net better mpg so it seems like even slight changes would have a huge benefit.... also i noticed the hood flaps around in the wind this could potentially effect the aerodynamics

[ksa8907]

Originally Posted by Tahoe_Hybrid

according to the meter the Best MPG zone is at 45mph which runs the engine at 1050-1070 RPM in v8 mode... it will show a consistent 40mpg on the display.meter..with the A/C on ( no change if the A/C is off ) the issue is wasting a ton getting up to speed..


it's really hard to keep it in that gear If I was able to keep it in that gear longer i would net better mpg so it seems like even slight changes would have a huge benefit.... also i noticed the hood flaps around in the wind this could potentially effect the aerodynamics

In other words, it's a measurement that only gives the maximum possible outcome. Indicating that average fuel economy will be less than that.

It's not an mpg monster, it's a large SUV, ours is 4x4, that can tow 6000lbs and get 20+ mpg average. Also keeping in mind this is 15yr old technology that was originally designed for buses and large trucks.

[AeroMcAeroFace]

Originally Posted by Tahoe_Hybrid

according to the meter the Best MPG zone is at 45mph which runs the engine at 1050-1070 RPM in v8 mode... it will show a consistent 40mpg on the display.meter..with the A/C on ( no change if the A/C is off ) the issue is wasting a ton getting up to speed..


it's really hard to keep it in that gear If I was able to keep it in that gear longer i would net better mpg so it seems like even slight changes would have a huge benefit.... also i noticed the hood flaps around in the wind this could potentially effect the aerodynamics

Hood flapping in the wind is maybe 1% aero drag increase, which at those speeds is pretty low. As ksa8907 said, it is a huge frontal area, 2.5 tonne, 6.0L V8 powered vehicle and you are expecting hatchback economy from it.

At 45mph 2/3 of your drag is rolling resistance, so unless you are going to be removing the hybrid system, seats, headlining and carpet there is not much you can do about it. Play around with the numbers in the calculator, even if you half the drag coefficient, you still would only get 47mpg at 45mph

https://ecomodder.com/forum/tool-aer...ToStep=5-200-5

It is a tradeoff, you want a huge and heavy car, you get high drag. You want good economy, sell the large car and buy one that is a reasonable weight, and a reasonable size for your goals.

[oil pan 4]

I'm glad I went small. Last month I drove about 1,500 miles, cost about $30 worth of electricity normally, but the last 2 months my power bill has been $0 because of the the solar panels.
If I was driving a gas murdering suv, that would burn at least 70 gallons worth of gas. No thanks.

[aerohead]

At the time I moved away from California ( 1975 ), it was still legal to drive 45-mph on any freeway. Is this going to be your target velocity?
You know where the engine's BSFC sweet spot is. If all efficiency gain is to come at 45-mph, and only from aero drag reduction, then, after streamlining, the Tahoe's gearing must be such that is absolutely matches the load you're seeing now, keeping it on the same BSFC pounds per brake horsepower-hour island, perhaps requiring a Gear-Vendors overdrive unit if you can't find a ring and pinion tall enough.

[Isaac Zachary]

I do believe there's only one way to get +40mpg permanently out of this vehicle. An EV conversion. If it's a hybrid you apparently already have half the parts to do it. Next step would be to fill the vehicle up with more batteries. (It'll be heavier, which is what you want anyway, right?) Add a way to charge them and figure out how to cheat the system so the ICE won't turn on. And Violà! A 45mpg-e vehicle!