391–399 of 399 posts
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Scifi novel idea: A habited planet without a sun (these actually exist) with heavy elements and high gravity. The surface unevenness is the best source of energy. After millions of years of extracting energy from flattening, the planet becomes a perfect ball and all life ceases as there is no energy to be found anywhere.
Geothermal energy is the way to go for this kind of worlds.
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I think the rev matching to minimize the strain on the clutch pack. The car also had standard hill hold assist to minimize the risk of wearing out the clutch over a long period of time while living in a hilly area. The design of the VW Golf Mark VII was absolutely brilliant. The EU model got a few why-didn’t-I-think-of-that extras that the NA market didn’t get, particularly around towing. There was a hidden tow hitch…
Dang, I might take one for a spin if I get the chance. I talked to a mkVII GTI owner today at work, I asked him about his DSG. He said he liked it a lot, but mentioned that he found the shifting too fast and got a DSG tune and either paid or on his own was able to modify the shifting, but I didn't have time to ask him what he meant or for more details about the tune. He's a chemistry PhD, and is into German stuff. He…
DSG tunes are also a thing but then it becomes a rabbit hole and a money pit…
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Dang, I might take one for a spin if I get the chance. I talked to a mkVII GTI owner today at work, I asked him about his DSG. He said he liked it a lot, but mentioned that he found the shifting too fast and got a DSG tune and either paid or on his own was able to modify the shifting, but I didn't have time to ask him what he meant or for more details about the tune. He's a chemistry PhD, and is into German stuff. He…
APR is one tuner that provides chip mods for VW engines and transmissions. A base 1.8L 184 hp up engine can be wrung out to 239 hp with flash mods with practically no changes in reliability. DSG tunes are also a thing but then it becomes a rabbit hole and a money pit…
What if they had a Tesla merry-go-round where instead of charging your Tesla, you connected it to this giant horizontal ferris wheel that spun it around and charged the battery? It could be wind powered!
You said this as a joke, but I found myself (at least for a little while) wondering whether this might be more efficient than having the wind turbine generate electricity and then have that electricity power the charger. But then I remembered that there is the cost of moving the relatively heavy vehicle on the merry-go-round and realized it wouldn't actually work.
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do you know how does those volvo semis stop on a dime? are there some sort of destructive braking mechanism to perform emergency brake?
I'm not sure what you're referring to, sorry
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I'm not sure what you're referring to, sorry
There's a video I've seen of one slamming the brakes on for a kid that runs into the road, and it stops super quickly.
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There's a video I've seen of one slamming the brakes on for a kid that runs into the road, and it stops super quickly.
just saw another one, really black magic to me https://www.youtube.com/watch?v=P-giC24SxwE
Another fact that might seem counterintuitive at first is that a heavily loaded truck can stop faster than an empty one. This is because it has more weight on the wheels, which means more force before they start to skid, and the brakes themselves are not the limiting factor.
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> If you apply only rear brake, it will cause the rear wheels to pull their suspension downwards tipping the car rearward somewhat. Are you sure? I'm trying to draw a free body diagram of that, and I get a net moment tipping the car forward. Can you explain it using physics principles? > Try this on a bicycle if you have the time. You can't easily compare because the rear wheel easily skids with a fraction of the bra…
> Are you sure? Yes. It's pretty confusing, I did the same thing and came up with the same answer as you. Then I typed a sentence about "even on fully independent multi-link rear suspensions" before going off into the weeds. If the suspension were rigid, it seems like it should do the opposite, climbing upwards, but there is more going on in the car than the assumptions we typically make with a model. A rear suspensi…
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> Are you sure? Yes. It's pretty confusing, I did the same thing and came up with the same answer as you. Then I typed a sentence about "even on fully independent multi-link rear suspensions" before going off into the weeds. If the suspension were rigid, it seems like it should do the opposite, climbing upwards, but there is more going on in the car than the assumptions we typically make with a model. A rear suspensi…
I see. It's specifically an effect of the trailing arm type of suspension. Damping, the wheel's rotational inertia, the sway bar and lateral movement of the wheel aren't needed to explain this, are they?
Some vehicles don't have swaybars, or instead they might have a "solid rear" rear subframe to which both knuckles are attached, and moves as one large unit. They always have shock absorbers though. I'll just keep considering only the rear axle here.
I can tell you are away of, but do note, that even without a trailing arm configuration but something else, the wheels will still always want to go back and towards the centerline of the vehicle during braking. The suspension geometry will determine how this is controlled, usually the move is to go down. I've never seen one that goes up unless something is broken, usually the shocks. People normally call this excessive movement "nose dive". It happens because a functional shock absorber momentarily control the climb, allowing the suspension to control the wheel characteristics. Without it, the forces will yank the wheel out of configuration.
In most vehicles, without the sway bar controlling both sides of the suspension, or the shock absorber damping, you will experience many varieties of reduced braking and handling performance unless both wheels on the axle are reacting in exactly the same way, which is very unlikely.
If the spring is undamped, aside from the "nose dive", it will start to oscillate in an uncontrolled manner during braking, causing hopping. This will cause the wheels to both not brake well and also lock up. This will still affect the solid rear, causing wonky camber.
If one wheel locks up, the ABS will kick in. This is normally fine, and increases performance in all categories, but only if the wheels are in contact with the ground and exhibiting correct camber. If they aren't and are instead hopping because of the undamped spring, the ABS won't be able to control much, it will in fact suck.
If the sway bar is absent/broken/ the linkage or bushings damaged, and one wheel has different handling or braking performance than the other wheel on the axle, (such as in all the time or during hopping or ABS engagement) the ride height will change as the wheel reacts along the second circle, causing body roll which will alter camber and other factors on every other wheel, especially the opposing wheel, which will experience much worse performance in every category.
All this stuff will show up on the tire. You can often tell whats wrong just by glancing at the tire tread.