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tallspawn

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tallspawn Enthusiast

tallspawn

Posted
Posted

I was doing a little reading during my "vacation" and came across some information about the XFE:

 

The aero enhancements make Silverado XFE and Sierra XFE models the most aerodynamic full-size pickups in the industry, with a “Best in Class” 0.412 coefficient of drag (cd). The pickups join the Tahoe Hybrid and Yukon Hybrid as the most aerodynamic full-size SUVs at 0.349 (cd).

 

 

The only real difference is they lowered the suspension a mere 10mm, lowered the front air dam and added the bed cover. My main question is if it's so easy to reduce drag on these trucks, why don't they do it on non-XFE models. I would think a lot of people wouldn't mind having a more aerodynamic truck, even if they didn't want the other features of the XFE. Just a thought... :cool:

66nova Senior Enthusiast

66nova

Posted
Posted
I was doing a little reading during my "vacation" and came across some information about the XFE:

 

The aero enhancements make Silverado XFE and Sierra XFE models the most aerodynamic full-size pickups in the industry, with a "Best in Class" 0.412 coefficient of drag (cd). The pickups join the Tahoe Hybrid and Yukon Hybrid as the most aerodynamic full-size SUVs at 0.349 (cd).

 

 

The only real difference is they lowered the suspension a mere 10mm, lowered the front air dam and added the bed cover. My main question is if it's so easy to reduce drag on these trucks, why don't they do it on non-XFE models. I would think a lot of people wouldn't mind having a more aerodynamic truck, even if they didn't want the other features of the XFE. Just a thought... :cool:

 

They did all of this AND then some. They also have a slightly different tune, low rolling resistance tires and CAI. This all adds up to 1 more mpg according to the EPA.

 

I see the main reason they don't make those changes to all the trucks is those are things most people atleast on this website, don't want. A lot are taking the front air dam off, lifting their trucks and don't want a bed cover or want to pick their own.

 

Did that article say what the normal drag was on one of these trucks? Did it really improve it that much. I am guessing by the mileage improvement, it did not.

tallspawn Enthusiast

tallspawn

Posted
  • Author
Posted
They did all of this AND then some. They also have a slightly different tune, low rolling resistance tires and CAI. This all adds up to 1 more mpg according to the EPA.

 

I see the main reason they don't make those changes to all the trucks is those are things most people atleast on this website, don't want. A lot are taking the front air dam off, lifting their trucks and don't want a bed cover or want to pick their own.

 

Did that article say what the normal drag was on one of these trucks? Did it really improve it that much. I am guessing by the mileage improvement, it did not.

 

It didn't say what the drag was on the standard models, and couldn't really find anywhere that has it yet. That would be interesting to see though. You are right about a lot of people lifting trucks and taking the air dam off. But for the thousands that don't modify their trucks you would think the lower drag would be better, even on the non-XFE trucks. I'm not saying they should do all the weight saving and have 3.08s in everything or even market it as fuel savings, just figure the more streamlined you are and the less drag you have would also equal less wind noise and more power for pulling instead of fighting the wind. :cool:

 

 

Daddy's right about the marketing piece of course, I didn't get mine for the mpg but for the bed cover, aluminum motor and the $4500 cash back at the time. :( Oh, and the badge is coming off this weekend BTW....

 

Here's the list of the differences:

 

XFE efficiencies

 

GM's more efficient full-size pickups and SUVs are powered by a 5.3L FlexFuel V-8 (LC9) engine that's built with a mass-reducing aluminum cylinder block and heads. It is rated at 320 horsepower (238 kW)* and 340 lb.-ft. of torque (461 Nm)* in Tahoe and Yukon and 315 hp/235 kW and 338 lb-ft/458 Nm in Silverado and Sierra. The engine is backed by a Hydra-Matic 6L80 six-speed automatic transmission (with high-capacity cooling on Silverado and Sierra).

 

A rear axle equipped with a fuel-saving 3.08 ratio is also standard on all XFE models. Lightweight aluminum wheels and low rolling resistance tires (with higher tire pressure) also are included on all models.

 

Other unique content and features for Silverado XFE and Sierra XFE include:

 

Soft tonneau cover (improves aerodynamics)

 

Extended front lower air dam (improves aerodynamics)

 

Lowered suspension and revised chassis tuning (improve aerodynamics)

 

Aluminum lower control arms (reduce mass)

 

Aluminum spare wheel (reduces mass)

 

Seventeen-inch aluminum wheels (reduce mass)

 

Automatic locking rear differential

 

Trailering package

 

Low rolling resistance tires ar axle equipped with a fuel-saving 3.08 ratio is also standard on all XFE models. Lightweight aluminum wheels and low rolling resistance tires (with higher tire pressure) also are included on all models. Other unique content and features for Silverado XFE and Sierra XFE include: m (improves aerodynam

 

Oh, and here's a test I found on the improvements a bed cover can make...

 

Interesting test on bed covers...

mr_bots Enthusiast

mr_bots

Posted
Posted
I'm not saying they should do all the weight saving and have 3.08s in everything or even market it as fuel savings, just figure the more streamlined you are and the less drag you have would also equal less wind noise and more power for pulling instead of fighting the wind. :cool:

 

I bet the extremely high rear end would more than offset the pulling vs wind resistance ratio. I bet it feels fairly gutless and once the "low rolling resistance" tires wear out in 15-20k miles and normal tires are put on the mileage gain would be minimal.

tallspawn Enthusiast

tallspawn

Posted
  • Author
Posted
I'm not saying they should do all the weight saving and have 3.08s in everything or even market it as fuel savings, just figure the more streamlined you are and the less drag you have would also equal less wind noise and more power for pulling instead of fighting the wind. :smash:

 

I bet the extremely high rear end would more than offset the pulling vs wind resistance ratio. I bet it feels fairly gutless and once the "low rolling resistance" tires wear out in 15-20k miles and normal tires are put on the mileage gain would be minimal.

 

 

 

I meant having the better aerodynamics with the lower geared rear end might make things a little better. It may not make a big difference at all just saying it looks like it could.... :uhoh:

 

I've actually been quite impressed with the feel of the 3.08 rear end with the 6-spd. Actually does really well off the line and hasn't left me feeling powerless at all yet. I've always had lower gears in my previous trucks and I don't notice much of a difference. That being said, I don't use my truck for towing...I would have gone a different route if I did.

Zembonez Senior Enthusiast

Zembonez

Posted
Posted

A 1 MPG increase in RATED fuel economy is big for a couple of reasons.

 

1. It makes their overall CAFE rating look better (on paper) which is very important to GM.

2. It represents a 5% improvement in fuel economy (on paper) which is important to consumers on some level.

 

Very small things but big in the grand scheme of marketing and future development. If they had made such small improvements even 10 times in the last 30 years, we could theoretically be getting 30 MPG in our trucks today.

 

This group (GMT) does not represent the norm in any way, shape, or form. Most of us are tinkerers. I'd bet 95% of all people who buy a truck just drive it as delivered until they trade it in or wear it out.

tallspawn Enthusiast

tallspawn

Posted
  • Author
Posted
A 1 MPG increase in RATED fuel economy is big for a couple of reasons.

 

1. It makes their overall CAFE rating look better (on paper) which is very important to GM.

2. It represents a 5% improvement in fuel economy (on paper) which is important to consumers on some level.

 

Very small things but big in the grand scheme of marketing and future development. If they had made such small improvements even 10 times in the last 30 years, we could theoretically be getting 30 MPG in our trucks today.

 

This group (GMT) does not represent the norm in any way, shape, or form. Most of us are tinkerers. I'd bet 95% of all people who buy a truck just drive it as delivered until they trade it in or wear it out.

 

 

I agree, most of the ones I see running around (trust me a see tons) are stock. Maybe debadged or color matched emblems, but mostly stock otherwise.

 

I'm also with you on the mpg gains, they could have been making these kinds of improvements years ago and been way ahead of the game. I know everyone says the 1 mpg doesn't add up to much, but I have to say mine is doing quite a bit better than any of my previous trucks and when you put on a ton of miles a year every little bit helps. Especially if I'm not losing anything in the process...

Zembonez Senior Enthusiast

Zembonez

Posted
Posted
A 1 MPG increase in RATED fuel economy is big for a couple of reasons.

 

1. It makes their overall CAFE rating look better (on paper) which is very important to GM.

2. It represents a 5% improvement in fuel economy (on paper) which is important to consumers on some level.

 

Very small things but big in the grand scheme of marketing and future development. If they had made such small improvements even 10 times in the last 30 years, we could theoretically be getting 30 MPG in our trucks today.

 

This group (GMT) does not represent the norm in any way, shape, or form. Most of us are tinkerers. I'd bet 95% of all people who buy a truck just drive it as delivered until they trade it in or wear it out.

 

 

I agree, most of the ones I see running around (trust me a see tons) are stock. Maybe debadged or color matched emblems, but mostly stock otherwise.

 

I'm also with you on the mpg gains, they could have been making these kinds of improvements years ago and been way ahead of the game. I know everyone says the 1 mpg doesn't add up to much, but I have to say mine is doing quite a bit better than any of my previous trucks and when you put on a ton of miles a year every little bit helps. Especially if I'm not losing anything in the process...

 

This being Texas... I bet there are 25 trucks within a block of me. I bet 22 of them are bone stock.

2005LT Enthusiast

2005LT

Posted
Posted

I agree with Jim. Most people don't even know how their car/truck works in the first place, never mind installing aftermarket upgrades and tinkering with things.

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