I’m no expert, but wouldn’t a front engine AWD layout have been better?
09-09-2019, 12:38 PM
#41
Le Mans Master
As the load goes up, the coefficient of friction slowly goes down.
A 2000 pound car on 285F and 335R will accelerate, corner, and brake faster than a 3000 pound car on the same tires.
{so far I have avoided the issue where a 2 contact patches does not make for a stable vehicle whereas 4 does (but then again 3 does, too).}
So, given the same amount of contact patch area in all cases, 4 versus 3 versus 2 is a "physics" wash.
What is not a wash is stability (both static and dynamic).
09-09-2019, 12:48 PM
#42
The coefficient of friction depends on how much weight is on per square unit of contact patch.
As the load goes up, the coefficient of friction slowly goes down.
A 2000 pound car on 285F and 335R will accelerate, corner, and brake faster than a 3000 pound car on the same tires.
{so far I have avoided the issue where a 2 contact patches does not make for a stable vehicle whereas 4 does (but then again 3 does, too).}
So, given the same amount of contact patch area in all cases, 4 versus 3 versus 2 is a "physics" wash.
What is not a wash is stability (both static and dynamic).
As the load goes up, the coefficient of friction slowly goes down.
A 2000 pound car on 285F and 335R will accelerate, corner, and brake faster than a 3000 pound car on the same tires.
{so far I have avoided the issue where a 2 contact patches does not make for a stable vehicle whereas 4 does (but then again 3 does, too).}
So, given the same amount of contact patch area in all cases, 4 versus 3 versus 2 is a "physics" wash.
What is not a wash is stability (both static and dynamic).
This is ALL basic high school physics folks. Nothing complicated. What IS complicated when it comes to tires and grip, is there are two coefficient of friction involved. Static coefficient of friction, which is the frictional coefficient involved when the tires are rotating at the same speed as the road surface, and kinetic coefficient of friction, which is the frictional coefficient involved when the tires are spinning at a different speed as the road surface, i.e. when the tires lock up due to braking or the engine overpowering the tires thus the tires are spinning faster than the road surface it's moving against.
Where WEIGHT comes in to play, is entirely based on whether the tires are experiencing static or kinetic coefficient of friction. In either case, there's actually more frictional force when there's more weight, BUT in the case of a tire, the formula changes because the contact patch deforms to create a LARGER contact patch, when pressure inside the tire remains the same, as more weight is added. Where this gets even MORE complicated, is that a car is a sprung system on top of 4 tires. A dynamic sprung system, as in weight can move and shift amongst all 4 corners as the car changes its force vector.
Contact patches are NEVER the same size unless the car's either not moving, or moving in the same predictable direction at the same speed (i.e. no changes in force vector).
Last edited by The HACK; 09-09-2019 at 12:57 PM.
09-09-2019, 01:13 PM
#43
Race Director
Member Since: Aug 2019
Location: Central Illinois
Posts: 10,093
Received 11,618 Likes
on
4,645 Posts
AWD is not the be all end all by any stretch. Porsche has offered AWD in the 911 for decades and the buyers never flocked to it because it was so much better than their 2WD only cars. At the end of the day it's a trade off, you always add weight to the car, you add complexity to the car, the handling also changes and not always for the good. A F1 car is a RME and only drives the rear wheels, the job of the fronts are to steer and if additional loads/work was asked from them they may not be as effective. Ever drive a high performance front wheel drive car that the tires are steering and driving hard at the same time, it can be interesting to say the least. There are some world class AWD sports cars, no doubt, but is it worth a bunch more $? It isn't to me.
09-09-2019, 03:14 PM
#44
Melting Slicks
Generally a fair point, but I'll play devil's advocate just for the hell of it.
There is no hard and fast rule that you have to be able to draw a straight line from one wheel hub, through the diff, and then through the other wheel hub. With halfshafts, the diff could be slightly forward (or rearward) of the hub, which could solve some of the space issues.
Again, tough on a C7, but not insurmountable on a redesign.
There is no hard and fast rule that you have to be able to draw a straight line from one wheel hub, through the diff, and then through the other wheel hub. With halfshafts, the diff could be slightly forward (or rearward) of the hub, which could solve some of the space issues.
Again, tough on a C7, but not insurmountable on a redesign.
09-09-2019, 03:14 PM
#45
Mercedes-Benz C-class, E-class, S-class, etc..
09-09-2019, 06:52 PM
#46
Le Mans Master
Coefficient of friction isn’t static. And coefficient of friction isn't determined by the weight placed on the tire. The FRICTIONAL FORCE, which is a result of coefficient of friction x weight, is. And more weight placed on the tire, the more frictional force it can generate (i.e. grip).
However::
If you put 1000 pounds on a tire and it can produce 1000 pounds of force (1G)
If you put 1500 pounds on that same tire is produces only 1400 pounds of force,
This is the decrease I am talking about.
It comes right out of Carroll Smith "Tune to Win"
09-09-2019, 07:02 PM
#47
Team Owner
Tadge in a recent interview had said they took the front engine car as far as it could go Really? Since the front engine car had a nearly perfect balance why didn’t they do AWD? I should think it would preform much better than a mid engine layout. Certainly they didn’t gain any interior space with the mid engine design.
nose would be so heavy
09-09-2019, 07:37 PM
#48
Safety Car
Like I said I’m no expert but an awd Corvette has been discussed for decades as well as mid engine. I just think the front engine awd would have been the more logical next step with the platform. Can you imagine being able to drive your Corvettei in ice and snow without batting an eye and being able to drive it year round?
The following users liked this post:
2slow2speed (09-10-2019)
09-09-2019, 07:42 PM
#49
Team Owner
Member Since: Aug 2007
Location: I live my life by 2 rules. 1) Never share everything you know. 2)
Posts: 136,148
Received 2,402 Likes
on
1,366 Posts
St. Jude Donor '11-'12-'13, '16-'17-'18
09-09-2019, 07:43 PM
#50
Race Director
Member Since: Aug 2019
Location: Central Illinois
Posts: 10,093
Received 11,618 Likes
on
4,645 Posts
So it can get blasted by some moron in a 4x4 SUV that doesn't think there is any reason to slow down at all in the snow. Almost every vehicle I see in the winter here down in the center median of the interstate is a 4X4 SUV in one of three positions, wheels down, on side, or on roof.
09-09-2019, 07:48 PM
#52
Race Director
Member Since: Aug 2019
Location: Central Illinois
Posts: 10,093
Received 11,618 Likes
on
4,645 Posts
09-09-2019, 07:49 PM
#53
Tadge in a recent interview had said they took the front engine car as far as it could go Really? Since the front engine car had a nearly perfect balance why didn’t they do AWD? I should think it would preform much better than a mid engine layout. Certainly they didn’t gain any interior space with the mid engine design.
09-09-2019, 11:00 PM
#54
Le Mans Master
No because they designed the C8 mid-engine for the younger generation who are not interested in front engine Corvettes.
09-10-2019, 07:40 AM
#55
Race Director
09-10-2019, 08:57 AM
#56
Racer
Most X-Drive BMWs and 4-Matic Mercedes use this layout but I wouldn't recommend it for the Corvette. As others have noted a hybrid approach is a far more likely approach and is probably in the planning stages.
Last edited by BobRBob; 09-10-2019 at 09:03 AM.
09-10-2019, 09:17 AM
#57
Racer
Yeaaaa but didn’t GM just announce they are ditching hybrid cars all together?
https://www.wsj.com/articles/gm-volk...es-11565602200
https://www.wsj.com/articles/gm-volk...es-11565602200
09-10-2019, 09:44 AM
#58
Race Director
Whenever something like this comes up I look to Ferrari for guidance. 50/50 weight distribution is nice of paper....oooooh aaaaah 50/50 perfect weight distrubtion. Um ok whatever. Its B.S. Maybe Tadge is right in that the Corvettes platform has been played out but who cares. Good for GM for breaking with tradition. Change is good.
Ferrari 812 Superfast
3,800lbs
789hp
0-60 2.8s
F/W weight distribution: 47f/53r
Ferrari 812 Superfast
3,800lbs
789hp
0-60 2.8s
F/W weight distribution: 47f/53r
09-10-2019, 10:00 AM
#59
Le Mans Master
Member Since: Apr 2013
Posts: 6,657
Received 4,116 Likes
on
1,470 Posts
2020 C8 of the Year Finalist - Unmodified
490 hp Front Engine / Front wheel drive = massive torque steer.
Last edited by Sin City; 09-10-2019 at 10:01 AM.
The following users liked this post:
fzust (09-11-2019)
09-10-2019, 10:55 AM
#60
Melting Slicks
The second mod I did to my 911tt was to remove the entire awd system and install a 997 cup LSD. Saved a ton of weight, the steering was much better and way more fun to drive at the limit on the track. It had some GT2 hybrid turbos made about 530 RWHP @1.2 bar
The following users liked this post:
fzust (09-11-2019)