Let's talk about the C8 vs the GT500

[Stuntman]

That's cause of it's AWD. As far as understeer being the problem, laughable. Just watch any mid-engine running the ring.

My apologies. I thought you claimed the location of the engine, the centralized mass with low moment if inertia was the route cause of the C8's horrific oversteer, not the drivetrain layout

awd plays very little role in the rotation of a car off throttle, where mid/rear engine cars rotate quite well and can rotate quickly if told to do so. 996 Turbos can snap oversteer on entry with stability control off, despite being awd.

Im glad you finally admit to drawing your opinions from what you see in the internet rather than first hand experience.

Sponsored

 

[Cardude99]

That's cause of it's AWD. As far as understeer being the problem, laughable. Just watch any mid-engine running the ring.

Considering you fail to back up your claims, I think most of us are not going to take you at your word.

 

[WildHorse]

Wow. The Corsican brothers strike again. Just watch vids of any and all mid engine cars at the ring and then tell me with a straight face they have an understeering problem.

 

[Andy13186]

Rob Spagetti's take on the c8 crash. Hes blaming the c8

 

[Stuntman]

Wow. The Corsican brothers strike again. Just watch vids of any and all mid engine cars at the ring and then tell me with a straight face they have an understeering problem.

Because they are often pros (or even if they aren't) and have stability control turned off, and balance the car at the limit in a neutral way that FR cars may not be able to. That's the inherent advantage of MR platforms and rear weight distribution.

Stability control does it's job to prevent bad drivers from their own bad inputs that tell the car to oversteer, because unlike a nose heavy FR car that can't rotate, a MR car often will if you give it the inputs to do so, even of you don't intend it because you don't know what your doing.

0.02

 

[shogun32]

I've seen the Ford GT listed at 43/57% and it has 245/325 tires.

how much of the 'snap oversteer' is a direct consequence of running such wide tires? Say the rear was 275, it would let go sooner and before the G-forces got too high. Sure it wouldn't accelerate in a straight line as fast because less footprint. I suspect the 'snap' is more a function of drivers pushing harder and harder because the 325 can take it till the tire suddenly lets go. In motorcycles, we value tires that let go progressively (Pirelli) rather than all at once (Michelin) even though the max lateral grip is less.

In the instant case and based on scant evidence, my guess was the rear started to come around (lift on the throttle?), he steered into it which necessarily means he was going wide and collected a car in the opposing lane. In any event, do stupid things on public roads, reap stupid prizes.

 

[Stuntman]

how much of the 'snap oversteer' is a direct consequence of running such wide tires? Say the rear was 275, it would let go sooner and before the G-forces got too high. Sure it wouldn't accelerate in a straight line as fast because less footprint. I suspect the 'snap' is more a function of drivers pushing harder and harder because the 325 can take it till the tire suddenly lets go. In motorcycles, we value tires that let go progressively (Pirelli) rather than all at once (Michelin) even though the max lateral grip is less.

In the instant case and based on scant evidence, my guess was the rear started to come around (lift on the throttle?), he steered into it which necessarily means he was going wide and collected a car in the opposing lane. In any event, do stupid things on public roads, reap stupid prizes.

The severity of the 'snap' has to do with far more factors than just tire width. In fact, a larger diameter tire is better for longitudinal grip (acceleration & braking) than a wider tire because as you lower the tire pressure, the footprint on the ground becomes longer. Generally wider is better for cornering and larger diameter is better for acceleration. That's why top fuel dragsters have relatively large diameter tires that grow significantly, rather than short and wide tires.

A tire's construction, compound, and tread design can determine the break-away characteristics and grip at high slip angles. Yes width can also be a contributing factor but it's not the primary function.

The severity of the snap also has a lot to do with the car and suspension geometry. If you have a suspension setup and tire that breaks traction quickly, and you have a lot of rear weight like in a rear-engine 911, once you get that mass accelerating quickly, it's difficult to slow it back down, stop it, and then recover and bring it back in line. This is why old 911s are notorious for their tendency to spin. If you have a low moment of inertia (mid-engine car with no structure overhanging the rear tires), once traction is lost, there is no mass to accelerate or that needs to slow down, so the tire's ability to regain grip is not challenged by a big pendulum effect wanting to swing the car around.

Then you have to look at the system as a whole. If you have a nose-heavy fwd car, with no mass over the rear axle, the car acts like a dart where the front does not want to turn, and the rear comes back in line easily. A 911 is like a backwards dart, and a mid-engine or front-midship (AMG GT), handle very well since the mass is centralized between the front and rear wheels.

It is possible for the C8 to have slid and then the driver corrected like you mentioned, then understeering in to traffic. However, stability control systems are so good these days that it would have to had been turned OFF for this to be a possibility. And even if it was turned off, there are more possibilities for the car to have understeered in to traffic than oversteered. Due to these facts, it's highly unlikely the C8 had an oversteer moment, however it's still technically possible. I'm surprised we have not heard anything more 'officially' about this accident to be sure either way.

 

[WildHorse]

Hes blaming the c8

To be fair, he thinks the driver ran outta tallent.

The severity of the snap also has a lot to do with the car and suspension geometry. If you have a suspension setup and tire that breaks traction quickly, and you have a lot of rear weight like in a rear-engine 911, once you get that mass accelerating quickly, it's difficult to slow it back down, stop it, and then recover and bring it back in line. This is why old 911s are notorious for their tendency to spin. If you have a low moment of inertia (mid-engine car with no structure overhanging the rear tires), once traction is lost, there is no mass to accelerate or that needs to slow down, so the tire's ability to regain grip is not challenged by a big pendulum effect wanting to swing the car around.

Again, with mid engine cars it's HARDER to stop the ass end from coming around. Like spinning a top, not a pendulum. front engine/RWD & rear engine/RWD cars are far easier to recover when the ass gets loose. Dunno why you find it difficult to understand that?

 

[Stuntman]

To be fair, he thinks the driver ran outta tallent.

Probably true.

Again, with mid engine cars it's HARDER to stop the ass end from coming around. Like spinning a top, not a pendulum. front engine/RWD & rear engine/RWD cars are far easier to recover when the ass gets loose.

Those two statements further show you have no clue what your'e talking about and ruin your credibility.

Dunno why you find it difficult to understand that?

Because you constantly demonstrate you don't know what you're talking about and just repeat what you watch on youtube.

 

[WildHorse]

Those two statements further show you have no clue what your'e talking about and ruin your credibility.

The reverse is true. It's grade school physics not quantum mechanics here.

 

[Stuntman]

The reverse is true. It's grade school physics not quantum mechanics here.

Exactly.

For some reason you're equating the centripetal force and gyroscopic effect of a spinning top to the way a car rotates around it's center of gravity. When in actuality, the way the mass of an engine and it's location relative to the car's Cg does have a 'pendulum effect' on the Cg. A rear-engine 911 has a lot of mass sticking out behind the rear axle, and as you accelerate that mass (laterally), it has a greater moment of inertia and 'pendulum effect' on the Cg (that's hard to stop once it starts accelerating laterally). This is racecar vehicle dynamics 101. But I guess somehow the (mis)understanding of spinning tops gives you the conclusion of unrecoverable 'snap oversteer' of mid engine cars

 

[martinjlm]

I’m going to a pre-Woodward Cruise panel discussion breakfast that will have Tim Kuniskis (Hellcat / Demon), Carl Widmann (y’all know who he is) and Ed Piatek (C8) on the panel. I expect a fun discussion.

 

[HoosierDaddy]

I’m going to a pre-Woodward Cruise panel discussion breakfast that will have Tim Kuniskis (Hellcat / Demon), Carl Widmann (y’all know who he is) and Ed Piatek (C8) on the panel. I expect a fun discussion.

How/when can we see it?

 

[martinjlm]

How/when can we see it?

I’m guessing it will show up on Autoline.tv at some point. The event is 7:30 am this Thursday. One of the moderators is John McElroy, the host of Autoline and Autoline After Hours.

[shameless plug] If you get a chance, watch Autoline After Hours episode 470, June 28, 2019. McElroy hosts, I’m the guest. [/shameless plug]

 

[HoosierDaddy]

[shameless plug] If you get a chance, watch Autoline After Hours episode 470, June 28, 2019. McElroy hosts, I’m the guest. [/shameless plug]

Already did.

Sponsored