My Chevrolet Tahoe Hybrid

So, first things first, you know that I’m biased. I own the damn thing ok? I’ve got a serious financial stake in the matter…. But here’s a review anyways.

Chevy Tahoe hybrid’s are made in Arlington, Texas, and this is what makes them special…

First, the hybrid power plant is brand new. The gas engine is a 332 hp, 6.0L V8 with active fuel management system (AFM) that’s found in most of the regular models. AFM deactivates 4 of the 8 engine cylinders when cruising on the highway, and assists with battery power. Then when you need more power, such as passing, pressing the accelerator a certain amount reactivates all 8 cylinders. It’s very seamless, and I can’t tell it happening unless I turn everything off and really pay attention. The instant MPG dash gauge gives a visual clue that you are driving on 4 cylinders, and the hybrid tab on the nav screen shows a unique color combination when on 4 cylinders with battery assist. The engine computer also has the ability to activate cam phasing and late-intake valve closure to allow for more efficient engine operation.

In addition to the gas motor there is a 288-volt nickel-metal hydride battery powering two 60-kilowatt electric motors. This setup acts very much like the more familiar Prius hybrid. The hybrid Energy Storage System (ESS) uses an Auto Stop mode to cut the gas motor at a stoplight. Then under acceleration it starts moving under battery power, and the Auto Start mode will engage the gas motor depending on accelerator position and speed to continue acceleration. The battery can power the truck up to 32 mph on its own under light acceleration before the gas motor kicks in. On my way to work I can drive around downtown totally on battery power, and that kicks ass. It’s like a silent moving death trap to blind people (sorry blind people). Reverse is totally on the electric motor, the engine runs, but it only powers the electric motor. Not sure why yet. The only thing I don’t like about this system is the battery isn’t immediately available when starting the truck from a cold start where it’s sat for ~8 hours. It’s a fairly large battery pack, and it must be programmed to charge to full before it engages any Auto Stop mode. It takes about 10 minutes of gas motor before the Auto Stop will activate at a stop light. I wish it would activate sooner, as I would expect there has to be charge left in the battery between when I park for work in the morning until when I leave in the afternoon.

The transmission is a 2 mode unit. Transmission Techno Babble (TTB) inc… In Mode One (M1), the EVT provides infinitely variable drive up to 1.70:1, while Mode Two (M2) provides ratios from 1.70:1 to 0.50:1. These two modes include all instances of electric-only (Auto Stop) and electric-gasoline hybrid operation. Depending on driving conditions and vehicle load, a fixed first-gear (G1) ratio of 3.69:1 is available (such as for pulling a large trailer) instead of the variable M1 ratios. Similarly, a second-gear (G2) fixed ratio of 1.70:1 may be selected by the HOS, if needed, before transitioning to the variable M2 ratios. As road speed increases, and depending on driving and vehicle load conditions, variable-ratio M2 operation can be switched instantly to a third-gear (G3) fixed ratio of 1.00:1, and finally to a fourth-gear (G4) fixed ratio of 0.73:1, which is used mainly for steady-state highway cruising.

Second, the designers improved the aerodynamics. The truck has been slightly lowered, and the most noticeable change to the eye is the front end. They’ve smoothed up a lot of openings, and the front air dam extends towards the ground further than the normal model. It has unique B pillars, tucked in tight side steps, window moldings, and the roof spoiler is slightly longer, all for the goal of reduced drag. Overall it really cut down the wind noise. It’s very quiet on the highway compared to the 2005 Silverado it replaced.

There would be some weight savings over standard Tahoe if it weren’t for all the extra weight of that battery and electronics. An aluminum hood, aluminum rear hatch, aluminum 18″ wheels, lighter tires, lack of vehicle jack, and thinner/lighter seats all help contribute to the weight balance. A regular Tahoe comes in at 7100lb gvw, and the hybrid is virtually the same. At least I think it does. I can’t find any information specifically about the weight of the hybrid model.

The truck also features regenerative braking to capture some lost energy back. It’s not a huge amount, but every bit helps.

The truck has a tire pressure monitor system. It’ll warn if any of the tires are low on pressure, and alert you to which one so you can fill it up. The tires are also unique to the hybrid model. They are lighter, low rolling resistance tires specifically to helps keep fuel economy as high as possible.

Inside the Tahoe is a hybrid specific instrument panel. Here you’ll find the economy gauge. Watching this gauge is where we play the fuel economy game. If you accelerate too quickly, the gauge dives to the right, and if you brake too quickly it dives to the left. You want it dead smack in the middle. There’s a compromise to everything in life and this is no different. Maximizing fuel economy per the needle will make anyone behind you during rush hour want to do you bodily harm. It’s pretty sensitive measuring the acceleration from a dead stop, and the first time the wife drove it she pegged the needle consistently during braking. There’s a learning curve.

Some things are different from a conventional vehicle and take getting used to. For instance the AC is electric and doesn’t get driven off the drive belt of the motor. You might expect that. But the power steering pump is also electric, which surprised me. It’ll go up to 30 miles per hour on the battery alone without the motor running, and since turning is required it makes sense. But the feel is very different. There’s no slop, it’s very quick reacting. I’d rate it pretty light to almost twitchy.

The bad…

I’m a little puzzled by some features. The hybrid Tahoe comes standard with damn near everything. So it’s lavish, excessive, and heavy. It’s got leather, nav, heated seats… loaded. The target market for this will include some environmental friendly folks that need the capacity that this truck can provide. I know that was some of my motivation. Most environmentalists don’t like leather in their vehicles… Couldn’t we get a cloth seating option?

Badges. Holy shit do we have badges. We’ve got enough badges to alert surrounding drivers from any angle that we’re upper class hippies driving a hybrid. There are 12 (?!?!?!) external badges/stickers to alert its hybrid-ness. On the front and back glass there are large 4″ window stickers saying “Hybrid”. On each side there are two hybrid badges, one 2 mode badge, and a huge hybrid sticker going across the bottom of the doors. On the lift gate on the back there is another hybrid badge, and another 2 mode badge. Jeezbus. The hybrid badges themselves are very cool. They look like circuit boards, but the rest are going to have to go. I plan on removing all the stickers as soon as possible.

The navigation DVD constantly spools and it’s loud, ruining all the work they did to make the truck quiet on the inside. I’ll probably remove the DVD for regular driving, but they should have done something about that. Maybe place the drive in the back of the truck or something.

So what’s this all add up to? EPA estimates for the 2 wheel drive model are 21 city / 22 highway. I’m getting slightly better than that when I’m focused on the economy gauge and use the cruise control, 23 mpg average. If I don’t focus, I’m down to about 19. I absolutely LOVE driving downtown on battery power. So quiet, it’s sneaky like a ninja in the parking garage.

Is it a perfect vehicle? Uh, no…. Do I like it? Oh yeah, I loves it. Mostly in a non-felt-up-in-the-storage-closet kind of way.

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