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In the AutoblogGreen Garage: 2008 Chevy Tahoe Two-Mode Hybrid

It became apparent that hybrids (and EVs) don't mix well with cold temperatures and the nickel metal hydride battery under the second row seat of the Tahoe. Anyone who has left a phone, camera or laptop in a car overnight during winter knows that cold batteries don't like to share any spare electrons they might have. When the Tahoe was cold, even without turning on seat heaters, defoggers or other power draining accessories, the Tahoe simply would not auto stop, or run in EV mode. Later in the day when the battery had warmed up, the behavior was very different. Coming to a stop or coasting at speeds up to 35mph, the engine would shut down and keeping a light foot on the gas pedal would allow battery-only driving for a mile or more.
 

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Re: Very interesting real world Tahoe hybrid review

And yet they got over "just shy of 20mpg" in very cold weather. That is amazing. Said they were getting 22.5 before weather turned cold. Here is a picture of the cold:



Shy of 20 mpg with snow on the ground....
 

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Re: Very interesting real world Tahoe hybrid review

During the time I drove the Tahoe hybrid it averaged just shy of 20mpg which is a remarkable achievement for such a big heavy vehicle with the capability to tow 6,000 pounds. During the first day I had it when the weather was warmer, it actually got up to 22.5 mpg but for the remainder of the week, the frigid temperatures often limited the usefulness of the electric drive. The driver information center in the instrument cluster can display whether the engine is running on four or eight cylinders while the main screen in the center stack displays the power flow between engine, battery and wheels. Even in cold temperatures, an easy gas foot can leave the engine running in four cylinder mode much of the time.
This is a pretty decent review. I don't sense any biased and think the guy was very fair. 20mpg in frigid temperatures is outstanding for a vehicle of that size and capability. What irks me is how people think that a full sized SUV hybrid or truck is stupid. Some of us not only prefer the view and capability of full sized vehicles, but also need them more than occasionally. In a recent trip to Colorado to visit my in laws (so they can see our newborn daughter) Alina, my 3 month old daughter, was given so many gifts (and my wife is not a light packer) that the back of my Suburban was completely filled (3rd row out). Here are some pics.







This is just one tiny reason that many of us prefer full sized vehicles and why GM built a full sized Hybrid.

I'd like to see someone fit all that in a Prius, or any other hybrid (excluding the GMT-900 2-mode, but even those would be hard pressed with all this stuff; mind you the second row is still positioned for seating because that is where my wife and daughter rode).
 

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Re: Very interesting real world Tahoe hybrid review

In order for the vehicle to "autostop", a number of criteria have to be met ... most notably engine temperature and transmission temperature. The latter takes longer to warm up, and the colder the ambient temperature is, the more driving it would take.

I don't think the problem had that much to do w/ the high voltage battery, since the engine starter, (really one of the motors in the transmission, powered form the high voltage battery) performed fine (read engine started) in the cold weather ...
 

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Re: Very interesting real world Tahoe hybrid review

It's slightly in error as to the cause of the engine running more often in cold weather. From the excerpt the writer seems to lay the responsibility on the battery. Actually it's on the engine.

All hybrids are primarily gassers with electro-mechanical assists. The electro-mechanical assist can help the gasser engine work less ( burn less fuel ) at the rate of 30-50% savings. However in cold weather we and our vehicles require warmth. We want to be warm and the engine's fluids need to be warmed, the catalytic converter has to be heated to a certain operating temperature and the NiMH battery probably needs a bit of a boost early on a cold day.

To accomplish all of this, especially warming up the huge cabin of the Tahoe the gasser engine has to run and run and run to generate heat. It has to do a lot of initial work to get us and the vehicle up to a comfortable operating temperature...THEN it can begin to take a break and let the electro-mechanical assist help drive the vehicle. All hybrids take a 10% hit in FE during the worst of winter simply because the gasser has to run more often and the electro-mechanical assist can't help out as much as in better weather.
 

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Re: Very interesting real world Tahoe hybrid review

I try to use the bloc-heather (2h) every cold morning when it goes below minus 12°C. On any cars, it really helps fuel economy. It should be standard in Canada, hybrid or not.
 

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Re: Very interesting real world Tahoe hybrid review

This is a pretty decent review. I don't sense any biased and think the guy was very fair. 20mpg in frigid temperatures is outstanding for a vehicle of that size and capability. What irks me is how people think that a full sized SUV hybrid or truck is stupid. Some of us not only prefer the view and capability of full sized vehicles, but also need them more than occasionally. In a recent trip to Colorado to visit my in laws (so they can see our newborn daughter) Alina, my 3 month old daughter, was given so many gifts (and my wife is not a light packer) that the back of my Suburban was completely filled (3rd row out). Here are some pics.







This is just one tiny reason that many of us prefer full sized vehicles and why GM built a full sized Hybrid.

I'd like to see someone fit all that in a Prius, or any other hybrid (excluding the GMT-900 2-mode, but even those would be hard pressed with all this stuff; mind you the second row is still positioned for seating because that is where my wife and daughter rode).
It's your vehicle, and it's your right to buy it and drive it. But if you only have one daughter, I submit that a smaller vehicle and the occasional SUV rental would work fine.
 

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Re: Very interesting real world Tahoe hybrid review

In order for the vehicle to "autostop", a number of criteria have to be met ... most notably engine temperature and transmission temperature. The latter takes longer to warm up, and the colder the ambient temperature is, the more driving it would take.

I don't think the problem had that much to do w/ the high voltage battery, since the engine starter, (really one of the motors in the transmission, powered form the high voltage battery) performed fine (read engine started) in the cold weather ...
Yup. The morning I test drove a Yukon Hybrid, it had been sitting out all night and it was still only 15 degrees F. at 10:30 a.m. when I drove it. I was out between 15 and 20 minutes, and the transmission temperature was still only 77 degrees, and it never auto-stopped once. I believe another article said that the transmission has to reach 140 degrees before it will auto-stop the engine, which in those temperatures will obviously take a while.
 

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Re: Very interesting real world Tahoe hybrid review

It's your vehicle, and it's your right to buy it and drive it. But if you only have one daughter, I submit that a smaller vehicle and the occasional SUV rental would work fine.
Why must I always defend owning a Suburban? I have only one daughter, yes, but I also have 4 cats and 2 rottweilers and find my self moving every 6 months (I'm in aviation contract maintenance). A capable vehicle to haul me and my family around this country, as well as tow a 3500+lbs trailer (for the move), is well needed. And by the way, my daily driver is a Saturn Ion. So why would I rent an SUV if I already own one? Why is a full sized SUV hybrid needed? Because people actually need them. It might not be people like you, but many people do need big SUVs and a hybrid SUV that saves more gas than a Camry hybrid is a worthy feat. But hey you can go ahead and buy that worthless little car and borrow your friends big ars SUV every time you buy new furniture.

P.S My Suburban costs less per month than my Ion (including gas). But, you know they are just expensive, gas guzzling, environment destroying, end of the world, war causing, plant killing, road hogging, dangerous, evil epitome of all that man kind has done to destroy gods green earth, right?

Try this on for size. A Tahoe Hybrid gets the same city fuel economy as a Honda Civic Si. The difference? One can carry 6+people and tow 6000lbs. The other is a smaller little thing that goes a little bit faster.

So, why did GM make a full sized SUV hybrid? Hmmmmmm, I wonder.:rolleyes:
 

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Re: Very interesting real world Tahoe hybrid review

Why must I always defend owning a Suburban? I have only one daughter, yes, but I also have 4 cats and 2 rottweilers and find my self moving every 6 months (I'm in aviation contract maintenance). A capable vehicle to haul me and my family around this country, as well as tow a 3500+lbs trailer (for the move), is well needed. And by the way, my daily driver is a Saturn Ion. So why would I rent an SUV if I already own one? Why is a full sized SUV hybrid needed? Because people actually need them. It might not be people like you, but many people do need big SUVs and a hybrid SUV that saves more gas than a Camry hybrid is a worthy feat. But hey you can go ahead and buy that worthless little car and borrow your friends big ars SUV every time you buy new furniture.

P.S My Suburban costs less per month than my Ion (including gas). But, you know they are just expensive, gas guzzling, environment destroying, end of the world, war causing, plant killing, road hogging, dangerous, evil epitome of all that man kind has done to destroy gods green earth, right?

Try this on for size. A Tahoe Hybrid gets the same city fuel economy as a Honda Civic Si. The difference? One can carry 6+people and tow 6000lbs. The other is a smaller little thing that goes a little bit faster.

So, why did GM make a full sized SUV hybrid? Hmmmmmm, I wonder.:rolleyes:
You don't have to defend yourself. There are plenty of people out there like yourself that legitimately need an larger SUV for space and towing. I can see a hybrid Tahoe being hugely popular for people with that need.

Personally, I did not buy an large SUV for my family because we don't need to tow anything. But believe me, if I needed it for towing, I would have bought one.
 

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Re: Very interesting real world Tahoe hybrid review

Why must I always defend owning a Suburban? I have only one daughter, yes, but I also have 4 cats and 2 rottweilers and find my self moving every 6 months (I'm in aviation contract maintenance).
In your previous post, you only said you have a wife and daughter. If you have 4 cats and 2 rotties and move every few months, then obviously you're going to use the fullsize SUV all of the time and a rental won't cut it.

P.S My Suburban costs less per month than my Ion (including gas). But, you know they are just expensive, gas guzzling, environment destroying, end of the world, war causing, plant killing, road hogging, dangerous, evil epitome of all that man kind has done to destroy gods green earth, right?
Hey, did I go on a rant? Did I call you evil? Did I demand that you sell your SUV or that the government take it away from you?

I'm just going from experience. I know 7 people who own half ton pickups, and only one uses his to tow - and he tows a little trailer that's less than two tons fully loaded. There are hundreds of thousands of people driving around 5000 pound trucks and SUVs that do not use their true space and hauling capabilities at all, or use them at most a few times per year. Be proud to be an exception, but that doesn't undercut my point - the rest are wasting their own money and needlessly contributing extra to our dependence on foreign oil.

And if your Suburban costs less per month than your Ion, how much did you pay for it? $15,000? $12,000? I want to shop where you shop, because most nicely optioned Suburbans near me run past $40,000.

Try this on for size. A Tahoe Hybrid gets the same city fuel economy as a Honda Civic Si. The difference? One can carry 6+people and tow 6000lbs. The other is a smaller little thing that goes a little bit faster.

So, why did GM make a full sized SUV hybrid? Hmmmmmm, I wonder.:rolleyes:
The Civic SI is sold as a sport coupe, and of course it's not much of one - but it will still handily outrun your Suburban and be more fun to drive around a road course. A better comparison is the regular Civic coupe, which still gets 50% better mileage than the Tahoe hybrid.

But more importantly, there's a $30,000 difference. The Tahoe hybrid is great for the environment, and I'm glad GM made it and I hope they profit from it. But $30,000 buys a lot of gas.
 

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Re: Very interesting real world Tahoe hybrid review

the rest are wasting their own money and needlessly contributing extra to our dependence on foreign oil.
What size TV do you have?
Are people going to complain that the average TV size purchased is going up?
Bigger TVs are not needed. They use more money.
HD might be considered a waste....

hm....
 

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Re: Very interesting real world Tahoe hybrid review

In your previous post, you only said you have a wife and daughter. If you have 4 cats and 2 rotties and move every few months, then obviously you're going to use the fullsize SUV all of the time and a rental won't cut it.


Hey, did I go on a rant? Did I call you evil? Did I demand that you sell your SUV or that the government take it away from you?

I'm just going from experience. I know 7 people who own half ton pickups, and only one uses his to tow - and he tows a little trailer that's less than two tons fully loaded. There are hundreds of thousands of people driving around 5000 pound trucks and SUVs that do not use their true space and hauling capabilities at all, or use them at most a few times per year. Be proud to be an exception, but that doesn't undercut my point - the rest are wasting their own money and needlessly contributing extra to our dependence on foreign oil.

And if your Suburban costs less per month than your Ion, how much did you pay for it? $15,000? $12,000? I want to shop where you shop, because most nicely optioned Suburbans near me run past $40,000.



The Civic SI is sold as a sport coupe, and of course it's not much of one - but it will still handily outrun your Suburban and be more fun to drive around a road course. A better comparison is the regular Civic coupe, which still gets 50% better mileage than the Tahoe hybrid.

But more importantly, there's a $30,000 difference. The Tahoe hybrid is great for the environment, and I'm glad GM made it and I hope they profit from it. But $30,000 buys a lot of gas.
The rant wasn't directed at you, so I'm sorry if you took it personally. I do get a lot of having to defend owning a Suburban and only from online blogs and forums.

The Civic Si was used because it is another prime example of what people don't need. If people are going to yell at others that drive a full sized vehicle, they should also look at what they are driving and how. And what they actually need to have as basic transportation. If they only need a vehicle for the daily grind and will yell at others that drive a SUV (without the knowledge of why they have one), they should first look at what they are driving and if they really need it. Otherwise, they become hypocrites.

Many people (I know this to be true especially in Hawaii) will drive very short trips then return home (like a 5min trip to McDonald's) then about 2 hours later make another short trip to the grocery store that was right next to the McDonald's they went to earlier. It doesn't matter if your in a compact car, the gas mileage will never see higher than 16. My Ion never got higher than 16 mpg when I was working in Texas and lived only 6 miles from work. The route was ridiculous really, it consisted of a speed limit of 55mph then a stop a left then a speed limit of 65 mph then a stop and a right then a speed limit of 40 mph; horrible for mileage.

I bought my Suburban for $13,700. It was used and took a lot of digging to find, but they are out there. You'd be surprised what you can find for sale in your area if you just know where to look. I once found a 2004 Pontiac Gran Prix GXP (superchargered ) loaded minus leather and OnStar with less than 70K miles on it for only $10,988 and the carfax report came back clean. The only reason we didn't but it was because it didn't have OnStar and that is a specific my wife wants in all of her vehicles. The Gran Prix was going the be hers.

$30,000 is a lot of money for gas, I agree, but I didn't think this conversation was about money savings. A used Geo Metro will best a Toyota Prius in mileage (or so I've heard), or at least come really close, and cost significantly less. If a Prius will run you $22,000 then a Geo Metro will cost you about $21,000 less. That would give you $21,000 for gas and you would end up with only the basic requirement of transportation.
 

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Re: Very interesting real world Tahoe hybrid review

What size TV do you have?
Are people going to complain that the average TV size purchased is going up?
Bigger TVs are not needed. They use more money.
HD might be considered a waste....

hm....
And, digital is going to be required in less than 1 year.
 

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I am so impressed with this SUV U simply don't kno... It has a flaw that limits it's usefulness in the EXTREME Winter but U still are able to get it's advertised MPG. 23.5Average is EXCELLENT for a vehicle this large... and 26.5MPG combined is phenomenal. This flaw is a problem in all all hybrids thus far... and I hate to see what it will be like for TESLA owners in a cold climate.. not that they would drive a sports car in the snow, but it doesn't have to be snowing to be cold.

The great question is... will Li-Ion be better in the Cold than Nimh... and why don't the Manufacturers... GM, Toyota, Ford, etc... sell a system similar to the Engine Warmers that they do as an option in the Maine, Alaska, Minn, etc to keep the batteries warm over night?
 

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I submit that you can have a large SUV as a TV and still be responsible. I like to camp but just won't sleep in the ground at my age. I use public transportation so the Avalanche almost only goes the short drive to the train station around town with the occasional trip to the Home Depot. If not traveling I go over a month between fill ups. My fuel usage is probably less around town than full time commuters in econo-boxes. Then when I go camping I "spend" my fuel savings and enjoy every minute of it without guilt. If two-mode was available across the board in the longer vehicles and had a couple of years under it's belt to prove reliable in the boonies I'd have gone that way.
 

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Re: Very interesting real world Tahoe hybrid review

No need to justify your Suburban to the naysayers. Buy and drive what makes you happy!

I had a small SUV (Equinox) and with only one kid is was far too small for any trip beyond one day, once you load it up with pack-n-play, stroller, and much more. I also like being able to take my in-laws with me when I go out to dinner - sure beats having to take two cars! I also like being able to haul what ever I want to haul whenever I want to.

I have a 2007 Yukon XL Denali that gets only 14.5 mpg but it rides very comfortably, has gobs of passing power, and carries everything I want to carry! I don't use it for my daily commute - I have a smaller car for that. But for hauling family and stuff around, nothing beats it! I love it!

:D

The rant wasn't directed at you, so I'm sorry if you took it personally. I do get a lot of having to defend owning a Suburban and only from online blogs and forums.

The Civic Si was used because it is another prime example of what people don't need. If people are going to yell at others that drive a full sized vehicle, they should also look at what they are driving and how. And what they actually need to have as basic transportation. If they only need a vehicle for the daily grind and will yell at others that drive a SUV (without the knowledge of why they have one), they should first look at what they are driving and if they really need it. Otherwise, they become hypocrites.

Many people (I know this to be true especially in Hawaii) will drive very short trips then return home (like a 5min trip to McDonald's) then about 2 hours later make another short trip to the grocery store that was right next to the McDonald's they went to earlier. It doesn't matter if your in a compact car, the gas mileage will never see higher than 16. My Ion never got higher than 16 mpg when I was working in Texas and lived only 6 miles from work. The route was ridiculous really, it consisted of a speed limit of 55mph then a stop a left then a speed limit of 65 mph then a stop and a right then a speed limit of 40 mph; horrible for mileage.

I bought my Suburban for $13,700. It was used and took a lot of digging to find, but they are out there. You'd be surprised what you can find for sale in your area if you just know where to look. I once found a 2004 Pontiac Gran Prix GXP (superchargered ) loaded minus leather and OnStar with less than 70K miles on it for only $10,988 and the carfax report came back clean. The only reason we didn't but it was because it didn't have OnStar and that is a specific my wife wants in all of her vehicles. The Gran Prix was going the be hers.

$30,000 is a lot of money for gas, I agree, but I didn't think this conversation was about money savings. A used Geo Metro will best a Toyota Prius in mileage (or so I've heard), or at least come really close, and cost significantly less. If a Prius will run you $22,000 then a Geo Metro will cost you about $21,000 less. That would give you $21,000 for gas and you would end up with only the basic requirement of transportation.
 

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Re: Very interesting real world Tahoe hybrid review

The rant wasn't directed at you, so I'm sorry if you took it personally. I do get a lot of having to defend owning a Suburban and only from online blogs and forums.
No worries. I'm sure you do get a lot of people tossing insults at you.

The Civic Si was used because it is another prime example of what people don't need. If people are going to yell at others that drive a full sized vehicle, they should also look at what they are driving and how. And what they actually need to have as basic transportation. If they only need a vehicle for the daily grind and will yell at others that drive a SUV (without the knowledge of why they have one), they should first look at what they are driving and if they really need it. Otherwise, they become hypocrites.

Many people (I know this to be true especially in Hawaii) will drive very short trips then return home (like a 5min trip to McDonald's) then about 2 hours later make another short trip to the grocery store that was right next to the McDonald's they went to earlier. It doesn't matter if your in a compact car, the gas mileage will never see higher than 16. My Ion never got higher than 16 mpg when I was working in Texas and lived only 6 miles from work. The route was ridiculous really, it consisted of a speed limit of 55mph then a stop a left then a speed limit of 65 mph then a stop and a right then a speed limit of 40 mph; horrible for mileage.
That's crazy! We had a Mercury Tracer, and it didn't matter how we drove it, we couldn't get below 30 mpg.

I bought my Suburban for $13,700. It was used and took a lot of digging to find, but they are out there. You'd be surprised what you can find for sale in your area if you just know where to look. I once found a 2004 Pontiac Gran Prix GXP (superchargered ) loaded minus leather and OnStar with less than 70K miles on it for only $10,988 and the carfax report came back clean. The only reason we didn't but it was because it didn't have OnStar and that is a specific my wife wants in all of her vehicles. The Gran Prix was going the be hers.

$30,000 is a lot of money for gas, I agree, but I didn't think this conversation was about money savings. A used Geo Metro will best a Toyota Prius in mileage (or so I've heard), or at least come really close, and cost significantly less. If a Prius will run you $22,000 then a Geo Metro will cost you about $21,000 less. That would give you $21,000 for gas and you would end up with only the basic requirement of transportation.
I was thinking in terms of comparing new cars. You got a deal on your Suburban. But somebody had to buy it new - and to me they were either very wealthy or moderately crazy. :) I think the 2007+ Suburban is a beautiful SUV, but I'm scratching my head trying to figure out how anyone with a family big enough to use most of its space can budget one.

I understand that a Prius doesn't pay for itself in fuel savings compared to a good new economy car, just like a Tahoe Hybrid doesn't pay for itself compared to, say, buying a Tahoe LTZ until you've driven them for many thousands of miles. They're bought because the high tech is a form of a luxury and prestige item - and that's fine with me.

My family has had bad luck buying used cars. We do lots of driving (I probably contribute more to air pollution and foreign oil dependence than you do) and most of the used vehicles we purchase start getting really expensive repairs.

Oh, and as an aside, I'm a stickler for safety. It's probably a waste, because your chances of dying in a car crash are relatively tiny. And if your Suburban hits an economy car, the crash ratings on the little car is irrelevant. But in many less serious crashes, the differences between a Prius (which has reasonably good crash test ratings) and a Metro are enormous. We bought a new Honda minivan instead of a perfectly good used Dodge because of the added safety doohickies on the Honda. (The 2008 Dodge minivans have the full gamut of safety doodads, but they weren't available when we bought the Odyssey.)
 

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A full size SUV that gets the same city mileage as a 4 cyl Camry blows the whole you don't need a full size SUV/PU argument out of the water.

22mpg is 22mpg no matter what you drive. Most people in N.America live in cities and their cars rarely if ever see true highway miles so saying you get 45mpg highway doesn't mean ****. If I had the cash I'd drop it on a Tahoe Hybrid in a heart beat, it beats the city mileage in my Grand Am.

Hell, you'll stop for gas less in the Tahoe due to the bigger tank, that means less impulse snacks at the convinence store, better for the environment, better for you as well.
 
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