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bradleyland | 10 years ago

The debate over whether mid-engine is superior to rear-engine is not an open and shut case. Although proponents of either camp would have you believe otherwise. The advantages of mid-engine are en vogue, so I won't repeat them here, but here are some advantages to a rear-engine car that are often dismissed:

Under acceleration, a rear-engine car has an almost absurd traction advantage over any other engine packaging configuration. For example, under acceleration, the 911 has a 74% rear bias, where the Cayman has a 67% bias.

Under braking, a rear-engine car has better weight distribution as well. Again, the 911 has a front rear distribution of 58/42 versus 64/36 for the Cayman.

I'm not nearly well versed enough in vehicle handling dynamics to hammer out a full-blown debate, but I have read very compelling arguments from both sides of the debate. I transisioned from the "mid-engine is the only compelling packaging format" camp to the "maybe the rear-engine format isn't completely insane" camp.

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scott_karana|10 years ago

> Under acceleration, a rear-engine car has an almost absurd traction advantage over any other engine packaging configuration. For example, under acceleration, the 911 has a 74% rear bias, where the Cayman has a 67% bias.

Under acceleration, a rear engine car has an almost absurb traction disadvantage on the front wheels, too. There go your steering and braking.

Suspension design should be the main determinant of traction, not weight distribution. Hence other brands' insistence on neutral 50/50 front/rear ratios.

LoSboccacc|10 years ago

then again that's only relevant if you insist in using an absurdly sub optimal traction configuration.

longitudinal weight distribution is completely irrelevant for 4wd cars, where none of the listed advantages matter and all the disadvantages with handling do

yes, 4wd system absorb some additional power but that's largely irrelevant because: - they can be active and only engage when needed - they absorb some fixed amount of power that become marginal for a very high powered engine - you're at wheel traction limit most of the time anyway at low speed, so absorbing power doesn't really matter - at high speed power absorbed by a 4wd system is largely dwarfed by drag

andor|10 years ago

longitudinal weight distribution is completely irrelevant for 4wd cars, where none of the listed advantages matter and all the disadvantages with handling do

Four-wheel-drive doesn't help when braking. Less weight on the front wheels (and thus more braking power on the rear) should make cars less likely to understeer.