Does Power-to-Weight Ratio Even Matter in the Era of Increasingly Potent, Increasingly Capable Cars?
Posted by FoMoCoNutjob@reddit | cars | View on Reddit | 46 comments
Captain_Pink_Pants@reddit
Yes. No amount of power does anything about lateral g forces when you change direction. A 5,000 lbs vehicle cannot corner (or stop) like a 3500 lbs vehicle... And 3500 lbs was, up until recently, considered heavy. 5k+ is an absurd weight for a "sports" sedan.
gumol@reddit
It absolutely can. Let's compare BMW M5 (5250 lbs curb weight) to a Miata (2450 lbs curb weight).
Braking from 70 mph to 0: Miata stops in 176 feet, while the BMW stops in 157 feet.
Roadholding, 300-ft Skidpad: Miata corners at 0.90g, while the BMW corners at 0.98g.
Captain_Pink_Pants@reddit
Fair enough...
A M5 will not feel as nimble cornering and braking as a mazda miata. The feats of modern engineering can accomplish many things... but your butt can tell the difference.
ggtsu_00@reddit
No amount of engineering can beat simple physics.
gumol@reddit
Absolutely. But it can be stop and corner quicker.
gaius49@reddit
To be fair, the question wasn't if the heavier can be made to corner with a higher g limit, but rather whether it can corner "like" the lighter car. And in that sense, I think feel is very much part of what "like" means here.
Captain_Pink_Pants@reddit
The stopping part doesn't impress me as much as the cornering... I'm not looking up the numbers right this second, but I'd bet that the M5 brake discs are proportionally larger than the M5 is heavier. But the cornering capability is like magic... Really incredible engineering.
AngryScottish@reddit
Brake size doesn't improve braking distances on cold stops, just helps with pedal modulation and brake fade.
Meaning, you can have a car swapping between 300mm rotors and 350mm rotors, and the braking distance won't be better with the larger rotors until you start introducing a lot of heat (aka repeat stops).
AngryScottish@reddit
Give the Miata the same tires and it will absolutely stop quicker, assuming it has ABS
xlb250@reddit
Skid pad doesn’t measure how fast a car can change direction, which is the key differentiator for light weight cars. A Miata with wheel, tire, and suspension mods will keep up with Porsche GT cars in autocross.
ThatOneBitch02@reddit
Wow the car that costs 3-4x as much can brake and corner better, how suprising. Now compare the m5 to something in the same price range like a 911
AngryScottish@reddit
It's not the cost that's the biggest factor in the M5s performance in braking and lateral grip, it's the tires.
Miata is on Bridgestone Potenza S001 M5: Hankook Ventus S1 Evo Z
The S001 are a generation behind the Evo Z, and thus, are noticeably less grippy.
Put similar tires on both cars and watch the Miata match or better the M5 numbers.
strongmanass@reddit
False equivalence. The two design briefs and objectives are worlds apart. The comparable Porsche to the M5 for the same price is the Panamera 4 e-hybrid. Below are Car and Driver's tests for both:
Panamera 4 e-hybrid
M5
gumol@reddit
Of course it's more expensive to make a heavy car to corner and brake well. It's a tradeoff. But it's possible.
AngryScottish@reddit
Yes. Lighter cars are more fun. The end.
impossiblefork@reddit
Yes, but then you aren't focused on the ratio, but about the lightness.
randeus@reddit
A tossable, light car is fun and playful and more usable on the street, but there’s some fun in lighting up your rear tires and breaking traction with an angry v8 screaming at you and sledgehammering through corners with pure grip more so than dancing around them. Just fun in a different way.
Astramael@reddit
Correct. You can mask the physics but you can’t hide it. The lightness is very apparent, it feels different and very good.
Kaylee-X@reddit
After owning cars under 2000lbs, I really don't find anything much heavier "fun" anymore. The only time I find my Corvette (which isn't even that heavy) fun is when I have the opportunity to go to very inappropriate speeds.
cbf1232@reddit
Doesn't matter much for top speed, but still matters for acceleration.
gumol@reddit
eh, as long as your tires are big enough, it kind of cancels out.
Consistent-Throat130@reddit
Except that the linear formula correlating lateral force to the normal force is a crude approximation that doesn't hold up to large scale differences.
ilovestoride@reddit
In certain instances, weight helps with acceleration. But braking and cornering is where you'll definitely feel it.
Jamaican_Dynamite@reddit
Tl;dr Yep. See how people would talk about a new 4,000 lb Miata.
strongmanass@reddit
A Miata has no business being 4000 pounds. But the Aston Martin Vantage roadster does weigh 4000 pounds. I haven't driven it, but I haven't heard anyone say it's not enjoyable because of its weight.
hi_im_bored13@reddit
Thats not the TLDR at all, the TLDR is that it depends
Jamaican_Dynamite@reddit
That's the real answer. But considering how many people actively complain about vehicle bloat, I kind figured I'd aim for the heart on that one.
4r4r4real@reddit
That's not what a tl;dr is though. It's supposed to be a summary.
Jamaican_Dynamite@reddit
Oh well, lemme edit the earlier one.
hi_im_bored13@reddit
Yeah, but prefacing it as TLDR & then not reading/summarize the content of the article is a bit misleading
elon_free_hk@reddit
Yes, you can’t defeat inertia and mass. Consumables cost goes up too.
Also, you can only go so fast on a road with the same speed limit.
sirbleep@reddit
Yep, people always forget the increased cost of consumables such as tires and brakes on heavier cars.
Something like a modern Escalade or Yukon with the factory 22inch rims goes through tires every 25k-ish miles, which considering it’s a non-performance vehicle with normal all seasons, that’s a super short lifespan. Same goes for brakes, they wear quick and aren’t cheap because they need to be big to deal with the weight of the vehicle.
Another comparison is the S550 Mustang GT (manual w/Brembos/Performance Pack) I owned before my Integra Type S, the brakes at 20k miles on my Integra are fine and my Mustang was already needing front and rear pads by that mileage.
randeus@reddit
That has less to do with the weight and more to do with the fact that factory pads the car comes with are shit, tbh. Speaking from experience.
elon_free_hk@reddit
Not to mention that Coyote needed 10 qt of oil every oil change 🙄
cat_prophecy@reddit
Lighter cars handle better and are more efficient with the power they do have.
Even if you have 1000hp. Why would you want 1000hp in a 6000lb vehicle when 1000hp in a 3000lb vehicle will be more better?
strongmanass@reddit
The extra 3000 pounds isn't just dead weight; it adds features that the 3000 pound car won't have. Whether that's worth the weight penalty depends what the driver values and the purpose of the car.
SteveS117@reddit
This is possibly one of the dumbest headlines I’ve ever read. More weight always means you need more power and torque to move the vehicle. That’s just basic physics lmao
strongmanass@reddit
Basic physics only gives you numbers. Yes more weight requires more energy and power. What does that have to do with what I enjoy?
CarsAreRad@reddit
Anyone who has driven any recent boats like the S5 or M5 know that while they are fast as fuk boi but they just don’t feel engaging.
Penguinho@reddit
In the M5, how much of that is because of BMW's steering feel?
CarsAreRad@reddit
The weight hinders it heavily you can’t take corners as quick so the overall “playfulness” that was in the previous m5 is gone. I don’t think it has anything to do with the steering feel just more the size and weight of the thing. The best way I can explain it is it feels like a high speed rocket, what it lacks in cornering it makes up in straight line speed. If that’s what you find fun it’s a great car, but definitely not my segment of car.
Piney_Dude@reddit
Always. There are vehicle specific variations, but generally yes.
PurpleSausage77@reddit
My 2500lb coupe compared to my 5000lb sedan…physics and actually driving the cars side by side says overwhelmingly yes.
Nvm how much added wear comes with hauling around all that extra weight. Like an obese person carrying all that extra weight - hard on major organs, joints, etc.
ColonClenseByFire@reddit
Of course it does. I own a CTSV and make more power than a corvette but it would stomp me in every single metric besides how many people I can fit in it.
Von_Jelway@reddit
Yes.
OllieFromCairo@reddit
Paywalled.