Question of the Week: Would you consider a 4-cylinder Ford F150?
#49
As for the differences between a 4 and 6 cylinder engine. The 4 cylinder will have less internal losses due to the lower parts count and thereby fewer places for friction to occur. However, a 4 cylinder is inherently a little buzzy in nature and the later pistons only make this worse. A balance shaft can be used but this eliminates a lot of the efficiency that was gained. Plus the engine will be a little bit trashy because of the gaps in power pulses. Once you get more than 5 cylinders this starts to go away because the pulses are overlapping. For that reason the 6 cylinder will be much smoother to drive. That is a big reason why auto makers will use a small V6 over a big 4.
#50
The only reason V6s are smooth is because of the offset rod bearings on the crank. They are inherently the worst dynamically balance engine of all if two rods are on the same crank surface like a V8 and that is the way they were built at first. The straight 6 is the best balanced engine until you go to a v12 which is two sixes. There are a lot of sport bikes out there with straight fours turning 13k rpm. I think I remember reading that 2.5L is about the largest they can make a 4 without it being buzzy though.
#53
#55
The only reason V6s are smooth is because of the offset rod bearings on the crank. They are inherently the worst dynamically balance engine of all if two rods are on the same crank surface like a V8 and that is the way they were built at first. The straight 6 is the best balanced engine until you go to a v12 which is two sixes. There are a lot of sport bikes out there with straight fours turning 13k rpm. I think I remember reading that 2.5L is about the largest they can make a 4 without it being buzzy though.
#56
In regards to the EcoBoost
I have driven them both and I'm hard pressed to choose one or the other. The 2.7 was so impressive to me, it had so much torque. After driving the 3.5 I thought the 2.7 would be a step down and it shocked me. Technology has certainly come a long way. I can't choose here, they're both great vehicles.
#57
As of now, I'll wouldnt be buying a 150 anytime soon. If I do it'll be the 5.0. I was at the dealership and took one for a drive nice power, but dont ride like a truck. If you buy a truck its not for the milage. It'll be a 250 my next truck. I use my trucks as trucks, hunt/fish/tow my sleds/trailer with.
#58
I wouldn't have one, not in a truck that I expected to have for any length of time and expect it to do work, especially work. Generally a 4 banger fires 2 cylinders together to get the most out of the firing cycle. All of the engines pretty much work that way even a Harley fires both cylinders together or close to it. That means a working 4 cylinder engine has one pulse per rpm. That's going to be some pretty notchy power. Maybe if it was in an economiser truck, regular or extended cab configuration with zero trailer towing. There might be a market there but I keep mine too long for me to have the want to maintain all of the technology it takes to make an EB run. That's the exact reason I bought the 2014 SCrew with the 3.7. Like they always tell you, KISS, Keep It Simple Stupid. A 4 banger pulling a car with a fat chick inside down the road- no problem. A 4 banger pulling a 5000lb boat down the hiway in a truck- big problem and no, the new 11 speed automatic isn't going to help although I guess you could start out with a 4.56 rear axle ratio that will seriously effect daily driving using the 11 speed.Maybe they could take some of the notchy out with a CVT but who would want one of those? They're a pain in the but in a car.
#59
Sorta, a 90* V6 isn't very well balanced because most of the time it is a chopped down version of a V8. A 60* V6 is typically much more balanced due to its crank design. However, I was referring to the smoothness due to power delivery. A 4 cylinder has a power stroke every 180* so there is always a gap between pulses. A 6 cylinder has a power stroke every 120* so there will be a period of overlapping power delivery. This smoothes out the power delivery. Now in something as heavily dampened as a truck with a fluid coupled auto trans it won't be as prominent as say a chain driven motorcycle.
#60
What version of the V6 are you talking about? They are evenly spaced in the 60* ones used by Ford. The 90* ones GM uses they are not and therefore balance shafts are needed.