this post was submitted on 02 Dec 2023
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No u. Bam, same level argument right there. Are you going to explain why or just throw out contrarian comments?
Cost will not be a limiting factor. Just about every feature on a 2023 car already costs more than a 1993 car's version. Did adding a wheelspeed sensor, electronic 4-channel hydraulic brake actuator, and dedicated ecm programming cost too much to implement ABS? Did the complication of 40 sensors (100+ now) and a voodoo box of electronics cost too much to go efi instead of carbs? Did the price of disc brakes stop most cars from ditching rear drums? Did the cost of engineering and testing prevent manufacturers from implementing the following nearly-negligible aero improvements to eek out another 0.1% of fuel efficiency;
aero strakes into mirror shells (prius, escape)
relaminating roof spoilers into every hatchback/suv and even into every pickup bed
Vortex generators on the top surface of tail lights (sonata, chr)
Active grille shutters (fusion)
Full underbody trays
Chin spoilers (splitters) on just about every car to keep air out from underneath
Hood beak splitters to keep grille air off the canopy (Volvo, accord)
Short antennas/glass-embedded antennas to reduce antenna drag
Front fender outlet vents to create laminar flow over the wheels (f150 2015+)
No, it didn't.
And I'd be interested to hear why you think helical-cut gears will be "noisy". I'm guessing you don't know why reverse whines in certain cars but not the forward gears
Edit: also, seriously, go do some shopping. LSDs are on the decline. On top of never being common in the first place, manufacturers at removing to brake-based simulated LSD rather than discrete components. There are incredibly few Fwd cars that ever had LSDs and fwd obviously makes up the majority of North American sales. Even Miatas and Mustangs only get LSD with optional packages.
Yeah the amount of BS or confidently incorrect in tech articles about automotive engineering is crazy.
And while gear-sets are really efficient, adding 8 to each of the 4 wheels 32 total, in leu of 2-4 at each end of the car, plus 4 CVs (assuming it’s AWD) has to be close in efficiency. And as a DIY+ car restorer in New England. I wanna see how they seal this thing. And with steering wheels it’s either gonna have to swing the motor around or put the CV back in anyway.
NVH (noise vibration harshness) is also going to be a huge factor. That and cost and weight is why we don’t have gear driven camshafts except on a select few exotic motorcycle engines and F1 engines.
Helical gears are the cost effective way to reduce gear noise, but they impart axial loads which would be difficult to overcome in this hinged joint. Herringbone fears eliminate the axial load, but are much harder to make, unless you go with powdered metal sintering. Which I barely trust in a cordless drill, let alone a Kia.
Edit: And no accounting for wheel castor, or camber changes along the suspension travel (way more basic and important for handling than torque vectoring). This video is pure marketing wank.
Funny you mention motorcycles with gear-driven cams as being exotic. Generally correct, but I happen to own one of the cheapest out there: the Honda VFR. I sought out mine for being the last with the gears before going to a normal drive in 02. It's a glorious sound.
Anyway, that's true too, helical gear will need a beefy housing to resist that axial load. That's more weight. A pair of helicals fastened together could help bring down cost, probably, compared to herringbone, but that's added complexity. I can't claim the tech is marketing wank but the video absolutely is