Comments by "Keit Hammleter" (@keithammleter3824) on "driving 4 answers" channel.

They got twin carbs because that was the cheapest way to get a bit more power output to keep up with the competition. the reason why straight-8's were phased out in favour of V8's was not any problem with unequal cylinder charge. it was because a V8 is shorter - less issues with crank tortional resonance and wind-up, less weight, and less friction. And no need for a great long ugly bonnet. Pre-war a long bonnet was a marketing advantage as men perceived it as a statement of power, but post war, women buyers considered it ugly and unwieldy. 8 cylinders inline or 16 in V is the limit as far as crankshaft tortional resonance and windup is concerned - that's why you never see longer engines in large industrial engines - except that Caterpillar do make a V20 gas engine (the 3520) - but its power output is limited to the same as their diesel v16 in the same range, so that the long crank is not over-stressed.
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@Dave5843-d9m That would certainly work, but would be more expensive than a V-engine, and not have the other advantages of a V. Where more power is needed than can be provided by 16 cylinders, and high speed is needed, the usual method is to just have two engines (as in electrical power generation - they parallel the electrical output), or have 2 engines side by side feeding a common gearbox with 2 input shafts. X-engines have been tried, but for various reasons were not successful.
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@davidmiller9485 Up draft, down draft, or side draft has no relevance to the issue discussed in this video.
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@ngauruhoezodiac3143 No, the Slant 6 has that manifold because of the need to keep the carby vertical, have a hot box, and retain one of the reasons for having the block tilted - to reduce the engine height. Dyno morse testing proved the long Ford manifold works just as well on these low revving engines. No doubt it would make a slight difference in performance engines. Do you really think major manufacturers would use their long integral cast manifolds if it actually made a difference? If cylinders worked unevenly you would get vibration, and you just don't.
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@mustang351c4 You mean Wärtsilä. Yes, one of their engines is the 14RT-flex96C - 14 cylinders inline. it is a very large ship propulsion engine with 80 megawatts output. There are 2 key reasons why it can have 14 cylinders inline - it is a slow speed engine limited to a maximum of 120 RPM, and for its size its power output is quite low.. However as far as crankshaft torsional resonance goes, a 2 stroke (as the 14RT-flex96C is) is worse than a 4-stroke in that resonance occurs at half the RPM. Note that the 14RT-flex96C has, in accordance with big ship propulsion practice, a maximum rated Brake Mean Effective Pressure of only 1.96 MPa. A typical heavy truck or industrial engine has a BMEP of around 8 to 9 MPa, so the Wärtsilä is in effect in comparison very seriously down rated. Big ship propulsion engines are, in comparison to truck engines, more or less run at not much more than high idle to secure long life and extreme reliability, as ships loosing power at a bad moment can cost lives and $millions. It is NOT a matter of beefing things up just a bit more.
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This video proves 2 things:- 1. The presenter is pretty smart - understands the topic and gives a clear explanation; 2. You can't rely in Wikipedia and like services.
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@ngauruhoezodiac3143 : I would like to see such an engine - it must look really strange, and wouldn't fit any car. If uneven fuel distribution is not much of a problem in an I6, it is certainly not going to be a problem in a V8 in which the ports are much closer together. On V8's, the carby is central between the banks. The induction paths are short and there is just no room to have anything like the slant-6 intake manifold. If they reversed the gas flow and had the intake ports on the outside of the banks, it still wouldn't fit any car. And that, besides requiring 2 carbies, would mandate a central exhaust manifold - no designer with a sense would accept that. The Chrysler V8's I have seen, such as the A and hemi have distinctly visible channels in the casting but were nothing like the long paths in the Slant-6 manifold. incidentally, that long path manifold on the Slant-6 had a significant disadvantage - the engine pig-rooted badly during warm-up due gasoline condensation and pooling in the manifold. One would go to take off, get the car moving, and the cold engine would appear to stall, only to surge forward again a half second or so later. All the US-designed pre-emission controlled I6 engines did this to some extent but the Slant-6 was really bad for it.
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@ngauruhoezodiac3143 That sounds like someone's imagination. Your imagination, presumably. Normal manifolds to fit two carbs to V8's are and always have been available - one carb in front of the other, between the cylinder heads. To do it as you suggest would mean having very long induction paths that go up then down. The engine would run extremely erratically until thoroughly warmed up, as such paths would promote considerable gasoline condensation. The Slant 6 was bad enough in this regard. There is just no reason to do it that way. Googling <chrysler "dual power'"> returned only an EV/gasoline hybrid system - a sure sign there is no such thing as you claimed.
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@ngauruhoezodiac3143 : Well, searching for <chrysler dual power> on YouTube returns nothing. Unless you can give the url, I'm not going to believe you. Neither is anybody else who has any knowledge of engines. There's plenty of room between the heads. Putting carbs outboard of the rocker covers, on the opposite side of the inlet ports, is completely stupid.
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@immikeurnot : I actually said no designer with any sense would accept a central exhaust manifold, and I was talking about carburetted car engines, though it would apply to fuel injected gasoline car engines as well. The Ford 6.7 power stroke is a turbo diesel truck engine with a single turbo. Once you have single turbo you are committed to essentially having the turbo above the block, both intake and exhaust manifolds must go to the turbo, and in a truck you have more engine bay height. Since there are no carburettors, the width of the engine is not affected, nor is long intake passages going to cause ''pig-root/surge'' problems. A central exhaust manifold is quite normal in large industrial and marine diesel engines, since the height of engines matters not a whit in such cases. Also, the exhaust manifold is usually lagged, so a lot of heat radiated at the top won't happen. F1 cars are limited to about 1 m height but the engines are quite small - 1.6 litres (formerly 2.6 L). so similar reasoning applies, plus other special factors not applicable to mass-produced car engines.
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@mrspandel5737 ; You are right1 Searching [chrysler cross ram] turns up a few videos. Apparently it is an extremely rare thing - I'm not surprised. In one video, the owner states ''what were they thinking?'" - that aspect is clear. It does have two monstrous 4-barrel carbs, seems they were trying to get as much power without a turbo as possible. But it must be a terrible engine during warm-up. Unfortunately none of the videos I checked show warm up. It would be a horrible expensive car to maintain and keep running evenly, due to the ridiculously long intakes and things like plugs covered up.
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This video is largely nonsense. I'll tell you why, but first an easy thing, from an ex Fintail Mercedes owner. The 4 cylinder 220D's were very nice smooth good handling cars with a very long range, but they were gutless. The lack of power was the biggest reason why people would buy an upmarket American car and put up with the excessive rolling and wallowing. The easiest and cheapest way for Mercedes to improve power by 20% and match the 4 cyl gasoline version was to add a 5th cylinder on, and not get the weight penalty of a six. The reason why this video is largely nonsense is as follows: When I was doing my engineering degree at university, the uni had various carburettor engines permanently mounted in dyno stands so we students could do various tests and learn how engines really work. We had a slant-six Chrysler engine with that bolt-on long path, one path for each cylinder, intake manifold, various GM inline 6's, and a Ford inline 6. The Ford engine had the usual Ford integral cast head and intake manifold, rough surface inside, a long straight pipe with 90 degree sharp bends into each valve - you would think it was the worst possible way to make an intake manifold. The path for the end 2 cylinders was MUCH longer than that for the middle 2 cylinders. Not so. We had to do Morse tests - this test lets you estimate friction by measuring the power output with all cylinders firing, and the power output with each cylinder in turn having its spark plug shorted. You add all the power drops and you get a total that is larger than the output with all cylinders firing. The difference is what's a constant power loss - that due to friction and pumping losses. The key thing here was our measurement accuracy was within 1%, and within that, the power drop for each of all cylinders was IDENTICAL - for all three makes of engine. The presenter says 5 cylinder gasoline engines ar ok if fuel injected (because presumably all 5 injectors inject the same amount of fuel). But if the air/fuel mass in a carby engine cannot be the same for all cylinders, then the air mass delivered in a fuel injected engine cannot be the same either - leading to some cylinders running rich and some lean. This problem does not arise in practice. His arguments would arise in three cylinder engines too. But Daihatsu made three cyl single carby engines that work just fine. Surely the best firing sequence for 5 cylinders would be 1-3-5-2-4.
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