Randy Pobst Twitter Today

[1mic]

That's pretty laughable. The gap between a 4S and Cup 2 is pretty huge. If you don't recognize that the majority of the gap is tires, not a small fraction, you're simply wrong. If it's 5 seconds, 3-3.5s of that is Cup 2 over the 4S.

Have you driven on both? You'd know this if you have.

He doesnt know shit, just like cuckhouse.

I've been posting a long time at svtp, a lot of these guys with blown v8s buy them and the first mod they do is add more power, they dont address traction. Also they have never driven on a road course so they have no idea how big a difference better tires make.

I guess the GT4 wing doesn't make a difference. Maybe the race teams should use the base spoiler

iirc, the carbon wheels are worth about 1 second per lap.

The wing makes a difference but the biggest difference is from the tires. Also Ford could have put a bigger wing for more downforce. I dont care about the gt4 race car, the gt500 is not the same car.

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[Epiphany]

Wait, let me do that too.



Eritas, nobody said the GT4 wing doesn't work. Clearly, it gets the job done. We have numbers at specific speeds (with respect to downforce and the GT500) but we don't have access to the data along the curve at speeds well below 180mph. But we do know that the front aero is identical between the Base HP car and the CFTP car, and that the CFTP car gets more negative camber, slightly stiffer springs, and a slightly stiffer rear bar.

You do raise a good point though. The wing on a base car vs a Gurney flapped swing on a CFTP car would be another interesting combination to test.

 

[1mic]

Tires still aren’t 5 seconds or a complete majority of it. Half, yes, more than likely. Generally a track like VIR 4S-> Cup 2 have been about 2-2.5 seconds. Suspension (including unsprung mass reduction, camber, etc), and aero is the rest. Again, at VIR there’s a difference of ~5 seconds between a GT3 and an GT3RS, same tires.

Negative they dont have the same tires, where is your evidence of this? I dont even need to look it up but the gt3 has cup2 and gt3rs is cup2r. Also the 3rs has wider tires. Lol

Gm copied this formula with the zl1 and zl1 1le.
Ford did the same putting the lesser performance tire on the base model. Most owners will opt for the more comfortable tire anyways.

 

[millhouse]

For everyone that thinks just slapping sport cup 2 tires on a vehicle will shave seconds off, take a look at this video.



Cliff notes:

On this particular vehicle around this particular track, the sport cup 2 tires were worth .06 seconds over the PS4S tires. You heard that right. Not 5 seconds. Not 2 seconds. Not even 1/2 a second.

Once again, there is more to the equation than just tires.

 

[millhouse]

And for those of you that seem to forget how important the carbon wheels are, this was tested before on the 350/350R here:

https://www.caranddriver.com/news/a...ts-of-the-shelby-gt350rs-carbon-fiber-wheels/

 

[1mic]

On this particular vehicle around this particular track, the sport cup 2 tires were worth .06 seconds over the PS4S tires. You heard that right. Not 5 seconds. Not 2 seconds. Not even 1/2 a second.

Once again, there is more to the equation than just tires.

The time difference was almost half a second.
Thats good evidence, and I like how you mentioned on this particular vehicle/track.

Maybe the PS4S tires are really good on lighter fwd cars on smaller road courses? I had PS4S and love them, way better than pzero grips in virtually everything.

That said, the only thing left to do now is putting the cup2 on the base GT500 and compare it to a CFTP same day.

 

[Droopy1592]

Negative they dont have the same tires, where is your evidence of this? I dont even need to look it up but the gt3 has cup2 and gt3rs is cup2r. Also the 3rs has wider tires. Lol

Gm copied this formula with the zl1 and zl1 1le.
Ford did the same putting the lesser performance tire on the base model. Most owners will opt for the more comfortable tire anyways.

So what? 350R also has wider tires all the way around, minor suspension changes, lighter wheels, and more aero all the way around. So I guess the 3 second difference at VIR is all tires here? More like close to 2 out of the 3 seconds is tires, the rest are the differences in weight, unsprung rotational mass, aero, and minor suspension changes. I work with a few surgeons (we cover anesthesia for over 50 centers) and quite a few of them race. Same tires on a GT3 at Road Atlanta and an RS... pretty clear 2.5+ second difference in the hands of amateur racers, same day, same tires. 5 seconds is massive to attribute almost all to tires.

 

[millhouse]

The time difference was almost half a second.
Thats good evidence, and I like how you mentioned on this particular vehicle/track.

Maybe the PS4S tires are really good on lighter fwd cars on smaller road courses? I had PS4S and love them, way better than pzero grips in virtually everything.

That said, the only thing left to do now is putting the cup2 on the base GT500 and compare it to a CFTP same day.

indeed. 1/2 second. my point still stands. You aren’t slapping cup 2 tires on a base GT500 and making up even 2 seconds. People seem to forget too that these cars have specific Magneride tunes based on tire compound.

Tires are a big factor, but only a piece...and not a majority.

 

[1mic]

So what? 350R also has wider tires all the way around, minor suspension changes, lighter wheels, and more aero all the way around. So I guess the 3 second difference at VIR is all tires here? More like close to 2 out of the 3 seconds is tires, the rest are the differences in weight, unsprung rotational mass, aero, and minor suspension changes. I work with a few surgeons (we cover anesthesia for over 50 centers) and quite a few of them race. Same tires on a GT3 at Road Atlanta and an RS... pretty clear 2.5+ second difference in the hands of amateur racers, same day, same tires. 5 seconds is massive to attribute almost all to tires.

If the tires alone account for 2-3 seconds, thats already majority bud. Also nobody is attributing the time difference solely on tires. I said majority of that difference is the tires, they tuned the suspension, down force to those tires.
Where is this GT3 and 3RS comparison you keep talking about? No kidding the hardcore track version with better tires and wider tires will lap faster. LOL

indeed. 1/2 second. my point still stands. You aren’t slapping cup 2 tires on a base GT500 and making up even 2 seconds. People seem to forget too that these cars have specific Magneride tunes based on tire compound.
Tires are a big factor, but only a piece...and not a majority.

Only way we'd truly know is if Randy piloted a CFTP and a base with cup2's. The same guy that has already proven a time difference going from Pirelli Corsa to Pirelli Slick.

 

[Eritas]

I dont care about the gt4 race car, the gt500 is not the same car.

What's the point of this?

 

[1mic]

What's the point of this?

I guess the GT4 wing doesn't make a difference. Maybe the race teams should use the base spoiler

iirc, the carbon wheels are worth about 1 second per lap.

Nobody said the wing doesnt make a difference, the major difference is the tire. Sure Ford engineers put on that wing to help keep the car planted, but it was designed with the GT4 in mind, not a 4100lb 760hp car. Go watch a time attack, those cars have bigger wings than an ACR. My point is that wing is functional, but Ford could have put a bigger one. I prefer the looks of the base wing. Actually not sure why they didnt put a more hardcore one, maybe it'll leave room for a GT500R? Also, that 1 second per lap difference depends on the track.

@millhouse posted a video comparison on a short track, its like 1.37 miles. So that 1 second difference will not be the same. Same as shaving 2-3 seconds off, it depends on the track, which explains the massive 5 second difference the GT500 base has with the CFTP @ VIR.


For any of you who dont drive your car on a road course, go ahead and take it there, do a track day. Record your lap times.
Put on better tires and let me know what difference the tires made. Because down force alone or carbon wheels alone will not make an impact like better tires will.

 

[Eritas]

Nobody said the wing doesnt make a difference, the major difference is the tire. Sure Ford engineers put on that wing to help keep the car planted, but it was designed with the GT4 in mind, not a 4100lb 760hp car. Go watch a time attack, those cars have bigger wings than an ACR. My point is that wing is functional, but Ford could have put a bigger one. I prefer the looks of the base wing. Actually not sure why they didnt put a more hardcore one, maybe it'll leave room for a GT500R? Also, that 1 second per lap difference depends on the track.

@millhouse posted a video comparison on a short track, its like 1.37 miles. So that 1 second difference will not be the same. Same as shaving 2-3 seconds off, it depends on the track, which explains the massive 5 second difference the GT500 base has with the CFTP @ VIR.

For any of you who dont drive your car on a road course, go ahead and take it there, do a track day. Record your lap times.
Put on better tires and let me know what difference the tires made. Because down force alone or carbon wheels alone will not make an impact like better tires will.

Aerodynamics don't care how much the car weighs. The GT4 wing was designed for the S550 Mustang body shape. So it is optimized for effectiveness and efficiency whether it's on an Ecoboost, gt500 or gt4.

If you added a massive wing on the back, you would need more aero up front to balance the car out. Using a gt4 wing will likely result in a far more efficient and less drag than the base car's spoiler.

I guess it depend where that 1 second a lap was tested. If it was tested on a 1 min track, then it would be worth 2 seconds on a 2 min track. Or if it was tested on a 2 second track, then it would only be worth 0.5 seconds on a 1 min track.

 

[Droopy1592]

If the tires alone account for 2-3 seconds, thats already majority bud. Also nobody is attributing the time difference solely on tires. I said majority of that difference is the tires, they tuned the suspension, down force to those tires.
Where is this GT3 and 3RS comparison you keep talking about? No kidding the hardcore track version with better tires and wider tires will lap faster. LOL


Only way we'd truly know is if Randy piloted a CFTP and a base with cup2's. The same guy that has already proven a time difference going from Pirelli Corsa to Pirelli Slick.

I’ve already explained it. I see it here at Road Atlanta. Same fucking tires. Not R vs regular cups. They buy the same fucking tires for two cars, drive them same day. My own eyes. 2.5+ dif. Again, the 350R/350 difference is at VIR. Same track as the 500. You’re not going to get 5 whole seconds of lateral grip on a car with 40% more power just from tires when the 350R only gets about 2. 2 is not a majority of 5. Sorry your math is off. Not sure what you’re smoking but pass it around. P1 gets about 2 seconds going from a grippy street tire to a race tire at a few tracks. Not five. And it has damn near 1000 hp. We will find out soon enough.

 

[1mic]

I’ve already explained it. I see it here at Road Atlanta. Same fucking tires. Not R vs regular cups. They buy the same fucking tires for two cars, drive them same day. My own eyes. 2.5+ dif. Again, the 350R/350 difference is at VIR. Same track as the 500. You’re not going to get 5 whole seconds of lateral grip on a car with 40% more power just from tires when the 350R only gets about 2. 2 is not a majority of 5. Sorry your math is off. Not sure what you’re smoking but pass it around. P1 gets about 2 seconds going from a grippy street tire to a race tire at a few tracks. Not five. And it has damn near 1000 hp. We will find out soon enough.

Lol, where did I say 5 second difference? Maybe youre the one smoking the good stuff. All I said was majority of the difference is tires, I did not give a specific number.

Let me know when you take your GT350 to the track, I know you aint on cup2s, unless you swapped out the stock tires.

 

[BmacIL]

For everyone that thinks just slapping sport cup 2 tires on a vehicle will shave seconds off, take a look at this video.



Cliff notes:

On this particular vehicle around this particular track, the sport cup 2 tires were worth .06 seconds over the PS4S tires. You heard that right. Not 5 seconds. Not 2 seconds. Not even 1/2 a second.

Once again, there is more to the equation than just tires.

All that showed is a guy who can't take advantage of of a tremendous increase in grip.

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