Just bought a 2017 Sierra Denali CCSB

[HotRodPC]

And it's stupid fast. I haven't found the bottom of the gas pedal yet. It's a little unnerving, because there are no sound effects with the acceleration. It just scoots -- quietly.

I love quiet and fast. It's like an element of surprise and so smooth.

You know one of Ford's better ideas, on the 4cyl EcoBoost Mustang.... to make it sound mean and like a V8, they have the stereo system make Vroom Vroom noises so you can hear it go fast in the cabin. Now isn't that some ****? Gotta have a Stereo system to make it SOUND fast. That's just pretty damn sad IMO.

 

[rich weyand]

One other note. There are 2WD and 4WD Sierras/Denalis. None are AWD. The Denali version 4WD does have an "Automatic" mode, in which it runs the transfer case in 4WD, and then electrically locks the front hubs if you spin the rears. You can also run it in 2WD, 4WD, 4LOW, and Neutral for dinghy towing behind a motor home. It warns against running 4WD or 4LOW on solid dry surfaces. G80 in the rear is standard on all of the Sierras and Yukons, I believe.

 

[HotRodPC]

One other note. There are 2WD and 4WD Sierras/Denalis. None are AWD. The Denali version 4WD does have an "Automatic" mode, in which it runs the transfer case in 4WD, and then electrically locks the front hubs if you spin the rears. You can also run it in 2WD, 4WD, 4LOW, and Neutral for dinghy towing behind a motor home. It warns against running 4WD or 4LOW on solid dry surfaces. G80 in the rear is standard on all of the Sierras and Yukons, I believe.

I like that much better. I almost bought a new Yukon Denali in 2002. What ran me off was that AWD. I didn't want AWD. Also why I didn't buy a Hummer H2. I wanted 4x4. I will CHOOSE what I want my Tcase to do, I didn't want the AWD to decide for me, not to mention all the wheel sensors and throttle pedal management applying brakes to certain wheels blah blah blah. In short, I want to drive my vehicle, not have it drive me.

 

[rich weyand]

I like that much better. I almost bought a new Yukon Denali in 2002. What ran me off was that AWD. I didn't want AWD. Also why I didn't buy a Hummer H2. I wanted 4x4. I will CHOOSE what I want my Tcase to do, I didn't want the AWD to decide for me, not to mention all the wheel sensors and throttle pedal management applying brakes to certain wheels blah blah blah. In short, I want to drive my vehicle, not have it drive me.

Well, it does have ABS, and traction control, and stability control, so the computer does mess around with the brakes to try to make it do what you are asking it to do -- stop, go, and go straight.

 

[HotRodPC]

Well, it does have ABS, and traction control, and stability control, so the computer does mess around with the brakes to try to make it do what you are asking it to do -- stop, go, and go straight.

That is true, but Traction Control can be turned off. I'm speaking more of when you're out wheeling, you have more control by choosing your drive options.

 

[rich weyand]

That is true, but Traction Control can be turned off. I'm speaking more of when you're out wheeling, you have more control by choosing your drive options.

That's true.

As for off-roading, it has yaw and pitch displays (angles L-R, and F-R) that can be displayed on the instrument panel.

It also has a "steep hill descent" function that acts as a slow speed cruise control for going down hills. When turned on, it will maintain a speed between 5 and 20 miles per hour down a grade. Speed it up a bit with a little gas, it will now maintain that speed. Slow it down a bit with the brakes, it will now maintain that speed.

Finally, it has hill holder. When pointed up a grade, it will hold the brakes on for up to two seconds while you move your foot from the brakes to the gas, so you don't roll backwards.

The wheel base is so long, however, that it wouldn't be a good choice for someone whose main motivations included off-roading. Too easy to high-center it.

 

[HotRodPC]

That's true.

As for off-roading, it has yaw and pitch displays (angles L-R, and F-R) that can be displayed on the instrument panel.

It also has a "steep hill descent" function that acts as a slow speed cruise control for going down hills. When turned on, it will maintain a speed between 5 and 20 miles per hour down a grade. Speed it up a bit with a little gas, it will now maintain that speed. Slow it down a bit with the brakes, it will now maintain that speed.

Finally, it has hill holder. When pointed up a grade, it will hold the brakes on for up to two seconds while you move your foot from the brakes to the gas, so you don't roll backwards.

The wheel base is so long, however, that it wouldn't be a good choice for someone whose main motivations included off-roading. Too easy to high-center it.

Geez, Sounds like it'll even hold your pecker for you while you pee.

 

[Old77]

Sounds like a super nice truck, rich! Sounds like it's about like driving around in your living room lol

 

[bucket]

That nifty "hill hold" feature must be on all the trucks. A friend of mine has a 2014 Silverado with it. It's not a base model, but close to it.

 

[68post]

Very nice Rich ! I love the blue (my fav), I like quiet/fast too. And you definitely have done the best on the tonneau cover 'n michelins.

That's the "Caddy" of trucks !!

 

[rich weyand]

Took the new truck on a 575-mile loop last Thursday: Bloomington, IN to Naperville, IL, to Champaign, IL, to Blooomington, IN. Mostly Interstate driving at 76-77 mph indicated (figure actual is one to two mph slower, per the construction site radars), with some local driving in each location. Total mileage: 20 miles per gallon.

Interesting things: The intake runners must be a foot long. The momentum of the air in the intake runner when the intake valve closes causes a pressure against the valve that aids filling the cylinder when the valve re-opens. When cruising, it often switches seamlessly into V4 mode. It has direct injection, so it simply shuts off the gas to four cylinders. What this does is double the total air required for a given horsepower (because half is being thrown away in the un-fueled cylinders). Doubling the air required means the throttle plate has to be open much further, reducing intake manifold vacuum and increasing the density of the charge into the cylinders. It also doubles the speed of the air in the intake runners, which increases the air pressure on the intake vales when they open, from the increased momentum of the faster air in the runners.

They really played all the tricks on this thing.

 

[HotRodPC]

Can't complain about 20 mpg whatsoever for that much truck. Might even do a hair better after it's broke in real good? So it's Displacement on Demand (DOD) truck. I didn't even realize it would have that.

I had a gf that bought a Grand Prix GXP with the aluminum 5.3 V8 in it, it had DOD but they called it something else back then. It probably would have done better on mpg if I could keep my foot out of it, but feeling that torque I just didn't have the discipline to stay out of it. The DOD once on the freeway seemed to be fairly flawless and you didn't even realize you were running on 4 cylinders. Touch the gas, it was seemless back to all 8 and gone.

 

[rich weyand]

Can't complain about 20 mpg whatsoever for that much truck. Might even do a hair better after it's broke in real good? So it's Displacement on Demand (DOD) truck. I didn't even realize it would have that.

I had a gf that bought a Grand Prix GXP with the aluminum 5.3 V8 in it, it had DOD but they called it something else back then. It probably would have done better on mpg if I could keep my foot out of it, but feeling that torque I just didn't have the discipline to stay out of it. The DOD once on the freeway seemed to be fairly flawless and you didn't even realize you were running on 4 cylinders. Touch the gas, it was seemless back to all 8 and gone.

Yup. One big killer of gas mileage on the highway is that the throttle plate is almost closed, so vacuum is high, and stack velocity in the runners is down. DOD solves those issues.

And unless you have the display on, you wouldn't know.

I suspect it's noisier in V4, because the DOD has active noise cancellation built into the stereo. Quietest cabin of any vehicle I have ever driven.

 

[rich weyand]

One more addition to the truck. So far it's been replace OEM POS Goodyear Eagle LS-2 tires with Michelin Premiere LTX, install rolling tonneau cover, install USB with my tunes, and install dash cam.

Now I put in the Storage tub under the back seats. Didn't come with it, and I saved 20% buying the OEM GM part off of Amazon.

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[rich weyand]

So I'm doing a little messing around with numbers, figuring out why the 2017 Denali with the 6.2 liter has such a hole shot, even though it is a heavier (crew cab instead of regular cab) truck.

Here's the numbers on my 78 Cheyenne K-10 first:

1st gear on a TH350 is 2.5:1, and the rear axle ratio is 3.73:1. So a combined 9.325:1 in first.
Max torque: 420 ftlbs with the cam I'm running. So total torque at the wheels is 3916 ftlb.
Tires are 31" diameter, so 15.5" radius, which is 1.29 feet.
Total thrust at the wheels, assuming I can hook up, is 3035 lbs.
Truck is 4800 pounds, so maximum possible acceleration is .63g, or 20 ft/sec^2.

For the Denali the numbers are:

1st gear on the 8L90E is 4.65:1, and the rear axle ratio is 3.23:1. So a combined 15.02:1 in first.
Max torque: 460 ftlbs with 6.2 liter. So total torque at the wheels is 6908 ftlb.
Tires are 31.7" diameter, so 15.8" radius, which is 1.32 feet.
Total thrust at the wheels, assuming I can hook up, is 5233 lbs.
Truck is 5500 pounds, so maximum possible acceleration is .95g, or 30 ft/sec^2.

So half again the acceleration of the cammed 350 with 3.73:1 in the lighter vehicle.

Yowza.