is 4wd not a better alternative to 2wd in the front or back. 4wd has more traction so it would make acceleration faster would it not? if so why do nascars, drag cars, etc not use it as opposed to rear/front wheel drive?
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There’s a couple different ways to make all 4 wheels go.
Well, way more than a couple. Let’s stick with 4wd (not awd) vs 2wd, and placement.
Old cars were mostly rear wheel drive, live axle. That’s the car backend with the pumpkin, when you’re driving behind a truck.
That pumpkin has gears to put power to at least one of the tires, coming from a driveshaft from the transmission. Pretty rugged, not very flexible and heavy.
4wd is two of those pumpkin axles, one in front and one in back. Theres a thing stuck to the back of the transmission called a transfer case that sends power to the front wheels in vehicles with 4wd.
Heavy, clumsy, but strong. Not good for speed racing.
Rear vs front wheel drive in racing:
If youre drag racing, all the weight of the car pulls the front up when you take off. If your power wheels are in the front, they lift up. If your power wheels are in the back, they push down, giving more traction. 1 point to rwd.
If you’re turning a lot, having your turning tires be able to drag you out of corners versus push you through them from the rear is great! 1 point for fwd… Sort of.
Powerful fwd cars end up with problems steering because of engine torque. Half a point deduction!
The transmissions that are able to take the most power are big long things that work well sending power to the back. Another point for rwd.
Rwd = strong transmission and big engine sending power to the wheels that don’t do turning and are located where all the weight transfers to. Turning isn’t great, but good drivers make up for that.
Fwd = more agile and makes more sense but when weight transfer and torque steer get figured in, sort of loses its edge.
That doesn’t stop fwd 1500hp Honda CRX racecars from existing. Lots of the old ways of thinking for race vehicles is falling apart, as fwd and awd are becoming better and better. Big, dumb rwd still is the top dog in high end speed though.
But what about awd? It’s a really cool way to make all wheel spin that either use electronic, mechanical or fluid dynamics to make the back wheels go. The whole thing is a little more delicate than full on race applications need, and can be heavy. They’re getting stronger and stronger though, and more cars have good awd systems.
Also a note on Nascar.
It’s a sort of formula race. that being that all the cars have to be built very very similar to each other. It’s a tube chassis, a big v8 from a couple different builders, a strong transmission and a beefy rear wheel drive. It has been this way for decades and will probably never change. There are European and Australian racing leagues that use more realistically built cars, but Nascars are very purpose built.
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