• interdimensionalmeme
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    5 months ago

    Also all of them have locking torque converters so there is no energy loss at constant speed. Also also, unless going upward at an incline. Most of the power requirements come from aerodynamic drag, not rolling friction of the trailer.

    • barsoap@lemm.ee
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      5 months ago

      You can’t lock the converter when accelerating because that’s not a constant speed you’ll stall the motor under the torque load, and to accelerate you need to overcome momentum. Neither drag nor rolling friction are anywhere close to high torque.

      And I have no idea what the previous poster meant with a transmission cooler, I guess it’s a different thing because a torque converter very much is not a transmission, if you want to compare it to anything then to a clutch. In any case I’ve got that explanation from an actual American actual car mechanic and random lemmings aren’t going to change my mind especially while making no mechanical sense.

      • dual_sport_dork 🐧🗡️@lemmy.world
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        5 months ago

        Wow. The remaining 7,950,999,999 people on this planet now have something to be thankful for, because none of them are as wrong as you.

        You clearly did not actually understand what your mechanic told you.

        A transmission cooler is exactly what it sounds like. It is built exactly like a radiator and works the same way. It is mounted in front of or next to the radiator for the engine. On a lot of newer cars it is actually part of the main radiator. Transmission fluid flows through it and excess heat is dumped into the air. On many vehicles it’s also served by the radiator fan, i.e. for situations where the vehicle is not getting airflow because it’s not moving.

        The torque converter is part of your automatic transmission literally operates by moving the transmission fluid. There is no separation between the transmission fluid used in the torque converter and the rest of the transmission where the hydraulic valves use it to actuate the clutch bands, etc. to shift gears. The same bath of transmission fluid is circulated through the torque converter, the rest of the transmission, and the transmission cooler.

        This is not a truck thing. Even my dinkum Saturn SL I had when I was a teenager that was so pathetic it was literally made of plastic and did not crack 100 horsepower had a transmission cooler – as designed from the factory. The vast majority of passenger vehicles made in the last half century or more with automatic transmissions have transmission coolers built in. It has nothing to do with towing, either.

        Your torque converter absolutely can be locked under acceleration and in fact, nearly all vehicles equipped with a locking torque converter do so as part of their normal shifting pattern when moving up through their gears. This is observable from the driver’s seat if you know what’s happening. The locking and unlocking of the torque converter feels like an “extra gear” in between the gears. Some Japanese cars from the 80’s have a “TC Locked” light on a dash that illuminates when the converter is locked and you can watch this happen in real time. The usual pattern is 1st gear, shift to 2nd gear, lock converter, unlock converter and shift to 3rd, lock converter, unlock converter and shift to 4th, etc. A traditional automatic transmission only has 4 gear ratios, but it will feel like it has seven. Guess why.

        Think about it real hard for a minute. A locked torque converter is the same, mechanically, as a fully engaged clutch. If you could not lock the torque converter during acceleration, by the same logic you would not be able to fully release the clutch pedal during acceleration on a manual transmission car, either. It is glaringly obvious that this is not the case.

        I am not a “random lemming.” I have four decades of actual real world mechanical experience and have disassembled and rebuilt more transmissions, engines, and vehicles in general than you have probably sat in throughout your entire life.

        • barsoap@lemm.ee
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          5 months ago

          A locked torque converter is the same, mechanically, as a fully engaged clutch.

          Which stalls the motor under high torque load.

          • dual_sport_dork 🐧🗡️@lemmy.world
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            5 months ago

            Tell us you didn’t read what I just wrote without telling us you didn’t read it.

            The engine will only stall under load if it is at so low of an RPM that it is generating insufficient torque to overcome the inertia. Which if you are moving and in the correct gear for your speed is never.

            Which is why your transmission has more than one gear.

            Remember back 30 seconds ago when I told you to think? Actually try it this time. Or maybe plug some of your bullshit into Google first before continuing to make a fool of yourself in front of everybody.

            • barsoap@lemm.ee
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              5 months ago

              Which if you are moving and in the correct gear for your speed is never.

              In stop and go traffic it’s practically always. The car needs to be able to handle that, it can’t be rated higher than that situation.

              • dual_sport_dork 🐧🗡️@lemmy.world
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                5 months ago

                Which is why automatics have torque converters and manuals have clutches. It’s almost like we’ve come full circle or something!

                Millions and millions of vehicles are driving on the world’s roads right now, happily tooling along under the sound mechanical and physical principles known as “reality,” completely heedless of your apparent inability to understand it.

                • barsoap@lemm.ee
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                  5 months ago

                  Yes and a manual can slip the clutch, it’s built for that. A torque converter can’t slip the lock, it’s not build for that, it has to stay open. And that generates a fuckton of heat.

                  • dual_sport_dork 🐧🗡️@lemmy.world
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                    5 months ago

                    And? Come on, you’re almost there. Just two more neurons to put together:

                    That’s why the transmission cooler is there.

                    Wrap up: Your original claim that Americans “can’t” tow due to predominantly driving automatic transmission cars, in addition to being an uncreative and tired thinly veiled attempt at insulting Americans, is not only wrong but also prima facie absurd.

      • AlotOfReading@lemmy.world
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        5 months ago

        A torque converter is part of the whole transmission system even if it’s a separate housing. When you buy a new transmission, it comes with a torque converter.

        Torque converters also create the majority of heat in automatic transmissions and are why automatic transmissions get coolers in the first place. How many manuals have you seen with transmission coolers?

        • barsoap@lemm.ee
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          5 months ago

          You’re right, granted, it’s probably just a bad name.

          Then, though, are those cooling systems systems you find in small cars sufficient to cool the thing under sustained high torque loads? Like stop and go city traffic on flat terrain with 2.5t of fully-packed caravan behind it? How much space and weight does it take to beef them up to be able to deliver the same performance of a manual? Is it still sufficient to hook the thing up to the engine cooler, how much more radiator area do you need? Does that even fit a car? Is that why SUVs are designed to hide small kids in front of them? (ok I’ll stop now).

          • boonhet@lemm.ee
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            5 months ago

            Stop and go city traffic isn’t all that sustained, because of the stop part.

            None of my cars so far have had any issues towing ~2 tons, I’m not sure why 2.5 would be that much worse.

            Of course, they’ve each had 400 newton-meters of torque out of their dinky little diesel engines.

      • interdimensionalmeme
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        5 months ago

        No, you can accelerate and deccelerate. Only needs to unlock for gear changes.

        Only in city would the torque converter spend an appreciable amount of time unlocked but then again, in the city you won’t be moving fast either

        • barsoap@lemm.ee
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          5 months ago

          Neutral to one is a gear change and connecting gear one firmly to the motor is going to stall it when you’re accelerating from standstill. With a petrol engine just the torque needed to get going is going to stall it that’s why you slip the clutch with a manual, a trailer will also stall diesels.

          With a torque converter in between you’ll also have to let it slip as it’s serving the function of a clutch. Trying to slip the lock of the converter will kill it pretty much instantly, it’s not build for that so you have to have it unlocked.

          I was interpreting “constant speed” as “zero speed difference between motor and drive train” which was probably a bit of a brain fart. You need that slippage to not stall the motor.