GMC: "Let's Talk"

[Slideways]

Originally Posted by RamJet502

Why does GM tell people the new trucks get over 20mpg? In the new Truckin magazine their Silverado test truck has averaged 13.7mpg in real world driving. There is still a lot of room for improvement.

That's real-world mileage with a lot of city driving and stop-and-go freeway traffic. The trucks still idles in V-8 mode, which is wierd. Also, it's a heavy right foot that destroys the mileage numbers, I've driven gently and I got 19mpg on the highway. It could be worse, Dodge Ram and Nissan Titan for example.

[chakis24]

Originally Posted by Slideways

That's real-world mileage with a lot of city driving and stop-and-go freeway traffic. The trucks still idles in V-8 mode, which is wierd. Also, it's a heavy right foot that destroys the mileage numbers, I've driven gently and I got 19mpg on the highway. It could be worse, Dodge Ram and Nissan Titan for example.

thats also after alot of 0-60 runs. all that flooring it and breaking takes a toll too. cool website tho.

[asim]

Pretty cool, nice marketing scheme. I wonder how well the Cadillac version has been doing though.

[Robert Ryan]

You arent looking in the right place

GMC topkick 4500

My question is why? Is the 4500 used primarily as a commercial vehicle? Pretty hard to imagine it going to the Mall. Why is the bed so short?

[TimR]

Originally Posted by Smaart Aas Saabr

Alberta rocks.

BTW, 4 cylinder mode doesn't mean 2x the fuel economy. You are either running on 4 cylinders at high load or eight at lower load... so the difference between 105 km/h in 4 and 110 in 8 isn't very much though it is more.

I realize that but it make s big difference.

On the highway V4 going from level 105km/hr (9L/100km or 25US mpg) to V8 at 110km/hr (12L/100km or 20US mpg) is quite a bit in anyones book. The truck has instant readout so its hard to gauge exactly how they calculate that and what they might have in the calculations but its still a savings any way you look at it. For example with cruise set and level road turn on the a/c milege drops by 1L/100km, turn it off and it goes back. Not sure if that is real calculated fuel flow or if the a/c on/off signal has a certain input value in the software.

To really test it a guy would have to travel say 100km on the same stretch of road with same wind and barometric pressure etc and compare but who has time for that? The other thing is that level is a relative word, the road might look level but could actually be a slight grade up or down. But my real world numbers are pretty good, especially in the city with lots of stop and go driving off the lights. At 80km/hr (50mph) the truck has gone for miles at 8L/100km..that is pushing 29US mpg!! Construction zones aren't all bad...LOL

Never bought the truck for mileage (duh, its for truck stuff!) but its bonus for sure. I'm sure the guys with extended and crew cabs will never see those kinds of numbers, just enough extra weight penalty there to keep them out of the V4 mode.

Also, I'm sure it idles in V8 mode to power the alternator, a/c and keep a smooth idle....possibly also for better throttle response off the lights and/or cooling. I've noticed it switches to V8 mode when coasting down in V4 at about 30km/hr (20mph).

All these conversions are killing me, US mpg, Imp mpg, L/100km... :-)

PS/EDIT: There is a duty cycle for the V4/V8 mode. After 10 minutes of continuous V4 the engine will cycle to V8 mode for 1 minute.

[eaton53]

Originally Posted by RamJet502

Why does GM tell people the new trucks get over 20mpg? In the new Truckin magazine their Silverado test truck has averaged 13.7mpg in real world driving. There is still a lot of room for improvement.

When you drive a new truck with a tight motor like you stole it the 13.7 number should not be a surprise.

[Vette410]

Originally Posted by ollie7777

GMC and Chevy need a truck to compete witht the f450 with SFA I need to tow more then what GMC and Chevy have to offer now

I know about the F-450 truck, but what on earth is an SFA truck?

[VMax2007]

Originally Posted by Vette410

I know about the F-450 truck, but what on earth is an SFA truck?

SFA = Solid front axle

[gn4u2c]

I'm getting 21 all around average out of my ext 4x4 2500 diesel. I always wonder why they do not put it on the label. You would think its a selling point justifying the extra 5,800 it cost.