Project Sierra vs Ford F-150 5.0L

[music]

It's basic physics-type stuff, I think. I'm not a scientist. However, it should require a certain amount of energy to keep a vehicle moving at a particular speed or to accelerate. That means you have to burn so much gas to produce that energy, regardless of whether or not that energy is being expended with 4 or 8 cylinders. On the other hand, if you are idling (coasting) I would imagine that it would be slightly beneficial to only have 4 cylinders keeping the engine running as opposed to 8.

 

 

That's exactly how it works, and why things like AFM, 6-spds, and the Ecoboost have the chance for small improvements. They are able to tailor fuel delivery on the fringe when cruising. Imagine 8 cylinders running at the lowest flow rate possible for efficient burning, but that's still more power than needed. Shutting off half the cylinders and tweaking fuel delivery to the other 4 can be more efficient under light load conditions. The Ecoboost is trying for the same, only it's running as a standard V6 during low load conditions. Having more gears helps in the same way, but also on the fringe (small improvements).

 

Personally, I don't see the benefit of AFM with the 6-spds and high gears, but it does help in mine. I get about the same economy overall in this truck as I did in my '99 2wd 5.3/3.42 combo. If mine were a 6-spd/3.42, I wouldn't want AFM... since there's not enough excess power in 6th to really make use of it imho.

[MikeNH]

Modern 5.3s have VVT and almost all modern fuel injected engines shut off fuel to all cylinders while coasting at higher speeds/RPMs.

[simmons]

sharp looking truck for sure.

[Doug_Scott]

Mervz, How about ground clearance ? Every time I see a F-150 4X4 they look like they are sitting higher.

 

 

We noticed that as well, so we checked. The F-150 and Sierra sit nearly the same in the front. The F-150 is nearly 3-4 inches higher in the back. It seemed however, that the extra bed height didn't equate to more ground clearance. Both trucks looked like the differential sat around the same place. The only advantage the F-150 may have is the position of the shocks. Ford designed the shock mounts farther towards the wheels. That could potentially give an advantage depending on the situation. That said, either truck would not be my first choice for an off-road vehicle.

 

 

The differential clearance is dependant purely on tire size. If both vehicles have same size tires, the diff will be the same height from ground (assuming differential is same physical size and mounted in same location)

[Morgan1986]

So it feels like its been a month or two with nothing really happening with OUR/forums sierra truck.

[MaverickZ71]

I just got a new Truck Trend magazine in the mail yesterday. It said that GM's new truck engine will be a 5.5L direct injection V8 with 400+ horsepower but comparable fuel economy to the Ford EcoBoost V6. If it has VVT without the AFM, that'd make a great crate motor for down the road . . .

[Carder09]

I just got a new Truck Trend magazine in the mail yesterday. It said that GM's new truck engine will be a 5.5L direct injection V8 with 400+ horsepower but comparable fuel economy to the Ford EcoBoost V6. If it has VVT without the AFM, that'd make a great crate motor for down the road . . .

 

Had a gut feeling that they would go with a 5.5L for some odd reason, http://www.hiperformer.com/engines/gmc-truck-used_engines-x_601.html this website seems to have the old school gmc truck motors that were the 5.5L, wonder if it will be the same 336CID engine, not carb obviously.

[MikeNH]

I just got a new Truck Trend magazine in the mail yesterday. It said that GM's new truck engine will be a 5.5L direct injection V8 with 400+ horsepower but comparable fuel economy to the Ford EcoBoost V6. If it has VVT without the AFM, that'd make a great crate motor for down the road . . .

 

Had a gut feeling that they would go with a 5.5L for some odd reason, http://www.hiperform...ines-x_601.html this website seems to have the old school gmc truck motors that were the 5.5L, wonder if it will be the same 336CID engine, not carb obviously.

 

 

 

No way will it be the same. LSx engines share nothing with the small blocks of old.

[Morgan1986]

I just got a new Truck Trend magazine in the mail yesterday. It said that GM's new truck engine will be a 5.5L direct injection V8 with 400+ horsepower but comparable fuel economy to the Ford EcoBoost V6. If it has VVT without the AFM, that'd make a great crate motor for down the road . . .

 

how much torque you think at what rpm ?

[jro909]

do you guys think GM will retire the pushrod engines and go with OHC like everybody else? honestly the only thing i dread with OHC is the complex nature and the fact of timeing belts blaaah

[11Silvy]

do you guys think GM will retire the pushrod engines and go with OHC like everybody else? honestly the only thing i dread with OHC is the complex nature and the fact of timeing belts blaaah

 

GM experimented with dohc with the ZR1 in 90 or 91, but yea at sometime, imo they will get away from pushrod.

[MikeNH]

I doubt it. GM has had tremendous success with OHV engines. They're lighter, more compact and can be made just as powerful and efficient as the more complex DOHC engines that are used elsewhere. I mean think about it- only with the 2011 model year did Ford finally have an engine that outperformed the 5.3.

[Morgan1986]

what is the difference between a OHV engine and a DOHC engine . Like the main differance in how they operate.

[jro909]

what is the difference between a OHV engine and a DOHC engine . Like the main differance in how they operate.

 

pushrods are more simple and compact...where as OHC are bigger and more complex but more effiecient(they can rev alot higher)

[j-ten-ner]

OHV overhead valves...means the valves are in the cylinder head (unlike the flat-heads with the valves on the side of the cylinder)

 

OHC over head camshaft...the camshaft is sitting in the cylinder head and not on the side of the engine. There are no push rods needed (but most likely rockers).

 

SOHC single overhead camshaft...one camshaft in the cylinder head per cylinder bank (for both, intake and exhaust valves)

 

DOHC double overhead camshaft...two camshafts per cylinder bank (one for intake, one for exhaust)

 

so long

j-ten-ner