I read everything I can about hyrids yet I have not seen an explaination about why the GM hybrids aren't. Can anyone explain this?

Aren't what? There are GM hybrids, they're just the newest ones -- for the most part, not available 'til 2007. (See HybridCars.com/cars.html)

- Shannon (Geeky, Wild Texan)

The Silverado hybrid . . . It's fuel efficiency seems to be less than impressive.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
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My big gripe with GM is that all of their 2007-2008 hybrids are HUGE vehicles. I just see it as a waste to invest $4000 in hybrid equipment into a Durango or Escalade when the boost will be 3 MPG. It would much more useful to make a hybrid Chevy Cobalt that would gain 10-15 MPG. But GM wont do that.

A 3mpg increase in a vehice that gets 15 to begin with is actually saving more fuel than a 10mpg increase in something that gets 30mpg. This is why I think gpc (gallons/100mi) would be a more straightforward measurement system in terms of calculating cost. GM basically sees those large inefficient vehicles as an easier opportunity to save fuel in terms of total dollars, and realize cost-effectiveness, than putting similarly expensive hybrid equipment into a smaller, already more efficient vehicle. I suspect they will migrate their system down to smaller vehicles in subsequent model years.

If I get 3 mpg more in my 15 mpg vehicle, then that's a 3/15 or 20% improvement and if I get 10 mpg more in my 30 mpg vehicle that's a 10/30 or 33% improvement. A much better % and...

Assuming I have a 10 gallon fuel tank, I get 30 more miles per tank in the 15 mpg vehicle with a 20% improvement, saving 2 gallons of fuel in the process.

Assuming I have a 10 gallon fuel tank, a 10 mpg improvement equals 100 more miles per tank in the 30 mpg vehicle, saving 3.3 gallons of fuel in the process.

That's a diff of 1.3 gallons of fuel saved in the 30 mpg vehicle vs the 15 mpg vehicle....So you would get a better fuel savings by improving the higher mpg vehicle not the other way around.

Maybe GM CEO needs to focus on replacing their engineers......

If I have a 15mpg vehicle, I'm using 6.66 gallons to go 100 miles.
If I move that up to 18mpg, it takes 5.55 gallons to go that same 100 miles.
That means I've saved 1.11 gallons.

If I have a 30mpg vehicle, I'm using 3.33 gallons to go 100 miles.
If I move that up to 40mpg, it takes 2.5 gallons to go 100 miles.
That means I've saved 0.83 gallons.

So Double-Trinity is right, hybridizing the guzzler will save more gas.

However, I suspect that GM's motivation is to assuage customers. "It's okay to keep driving that 7-seater SUV, single guy. We'll make it a hybrid and you can pat yourself on the back. Emissions standards? Those don't matter."

i don't think gm is thinking at all about the fuel savings (well maybe as an ancillary by-product). if you look at their marketing, they are saying that you get more power out of a hybridized suv than a standard version.

i think this article about the lexus suv applies here:
http://www.redherring.com/Article.as...onomyAndPolicy

A 15 mpg vehicle uses 6667 gal/100,000 miles.
A 18 mpg vehicle uses 5555 gal/100,000 miles.- It saves 1111 gallons.

A 30 mpg vehicle uses 3333gal/100,000 miles.
A 40 mpg vehicle uses 2500 gal/100,000 miles. It saves 833 gallons.We really should use 36 mpg instead of 40 mpg, but since 40 mpg was stated,I'll use it.

The smaller % savings on the gas guzzler is much more important. GM is making the right choice in one sense. However, a 3 mpg increase just doesn't "look" as big as a 6 mpg increase. I use 6 mpg rather than 10 mpg because the percentage improvement of different sized vehicles should be kind of close, if the same hybrid system is used.Luck,Charlie

Guess I needed to look at it on a per 100 mile basis vs my per tank basis.
However, the 1,111 gallons you saved with an 18mpg avg would only get you an extra 20K miles but the 833 gallons you saved with a 40mpg avg would get you an extra 33,320 miles. A diff of +13,320 miles of driving pleasure...and a lot less CO2/NOx per mile... You can look at it both ways, one is per 100 miles driven and the other is per 100 gal used, which is more efficient??? or cleaner??? Guzzling gas is definitely less green/less efficient for the environ cuz you're burning more hydrocarbon per mile.... IMO, GM still doesn't get it.....

My old Hummer gets 7mpg and my new one gets 8mpg.....so I use less fuel per 100miles driven but at what expense???

Can't compare an 18mpg vehicle with a 40mpg vehicle, apples and oranges again.....