The Official Mustang Thread

[r0tor]

It seems like being all race car and stuff they would have shrunk the muffler and used the space for a functional rear diffuser

[Eye of the Tiger]

Oh my, what a big muffler you have there

That's how they got the 50/50 weight distribution

[CaminoRacer]

It seems like being all race car and stuff they would have shrunk the muffler and used the space for a functional rear diffuser

I've been around enough newer performance Mustang variants to be very grateful for a big muffler. Too many of them are ear-splitting when they nail the throttle. I think it was a GT350 that got kicked out of one of our autocross events for being over the sound limit.

[Eye of the Tiger]

I've been around enough newer performance Mustang variants to be very grateful for a big muffler. Too many of them are ear-splitting when they nail the throttle. I think it was a GT350 that got kicked out of one of our autocross events for being over the sound limit.

Stock?

[CaminoRacer]

Stock?

I think so. The dual mode exhausts are stupid.

[FoMoJo]

I think so. The dual mode exhausts are stupid.

They make sense if used under the right circumstances.  Presumably, the idea is that you get a little bit of extra bhp with the noisy mode.

[AutobahnSHO]

Yeah if it doesn't increase performance I HATE loud exhaust. But even if it does boost HP I really really don't like to hear it at loud levels on the street.

[FoMoJo]

What I don't get are cars that snap, crackle and pop when deaccelerating.  Subarus are the worst but I've seen/heard Mercedes (AMG) that do it as well.

[CaminoRacer]

What I don't get are cars that snap, crackle and pop when deaccelerating.  Subarus are the worst but I've seen/heard Mercedes (AMG) that do it as well.

My El Camino did that with my old exhaust system and carb. New carb and exhaust don't do it. (Helps that the exhaust is longer now, goes all the way to the back instead of dumping in front of the axle)

[r0tor]

My RX8 naturally does it... Outside of that all modern cars just program that into the tune for sportyness

[Laconian]

Subarus sound awful and Subaru drivers want to share that awfulness with the world.

[Morris Minor]

Subarus sound awful and Subaru drivers want to share that awfulness with the world.

Four-wheel Harleys.

[Eye of the Tiger]

Four-wheel Harleys.

LOL

[FoMoJo]

[FoMoJo]

[GoCougs]

Hmmm. That can't be right. The current 911 GT3 RS, both less expensive and with a vastly less advantageous power/weight ratio, was much quicker (which means something on such a high speed track). Also, some of the upshifts seem really soft/slow (esp. 4/5).

[r0tor]

The GT3RS has a better downforce package.

Ford's lap was also done is less than perfect conditions.  They came back a few months ago to try again but got rained out.

[GoCougs]

The GT3RS has a better downforce package.

Ford's lap was also done is less than perfect conditions.  They came back a few months ago to try again but got rained out.

At first glance I'd say no way - the GTD aero looks much more aggressive. And at least according to C&D's convo with Multimatic (the vendor that helped design the pushrod suspension), that is indeed the case. Even outside that, the stats and pertinent info remains:

Mustang GTD: $325k, 3600 lbs, 815 hp, a race car first, road car second.
911 GT3 RS: $250k, 3250 lbs, 525 hp, a road car first, race car second.

[r0tor]

At first glance I'd say no way - the GTD aero looks much more aggressive. And at least according to C&D's convo with Multimatic (the vendor that helped design the pushrod suspension), that is indeed the case. Even outside that, the stats and pertinent info remains:

Mustang GTD: $325k, 3600 lbs, 815 hp, a race car first, road car second.
911 GT3 RS: $250k, 3250 lbs, 525 hp, a road car first, race car second.

There is downforce and then there is drag.  It appears Porsche is way more efficient.

Both had a top speed ~300kph but the Porsche does it with 300 less HP.  All the GTD's power advantage is burned up by aero and then it has to deal with the extra weight

[GoCougs]

There is downforce and then there is drag.  It appears Porsche is way more efficient.

Both had a top speed ~300kph but the Porsche does it with 300 less HP.  All the GTD's power advantage is burned up by aero and then it has to deal with the extra weight

Nah. Remember, the GTD is a race car first unlike the GT3 RS, so it's going to get the balance between drag and downforce at least as good - Ford isn't going to drop the ball on that. Though to be fair, the Mustang is also a notably larger vehicle than a 911. Could indeed simply be less optimal track conditions and/or driver. But something doesn't add up - more info and/or 'Ring times to follow I'm sure.

[r0tor]

Nah. Remember, the GTD is a race car first unlike the GT3 RS, so it's going to get the balance between drag and downforce at least as good - Ford isn't going to drop the ball on that. Though to be fair, the Mustang is also a notably larger vehicle than a 911. Could indeed simply be less optimal track conditions and/or driver. But something doesn't add up - more info and/or 'Ring times to follow I'm sure.

Nothing "nah" about that, it's just simple physics.

They both had pretty much the same top speed on the back stretch where everything hits terminal velocity.  If 2 cars have the same top speed but a 50% difference in power, the more powerful one has more drag.

[565]

It's got a mustang in it.

[GoCougs]

Nothing "nah" about that, it's just simple physics.

They both had pretty much the same top speed on the back stretch where everything hits terminal velocity.  If 2 cars have the same top speed but a 50% difference in power, the more powerful one has more drag.

Oh, my sweet, sweet, r0tor. "Physics" you say? Let's once again examine facts and data - the constituents of physics! Let's do so WRT each vehicle's 'Ring time: Mustang GTD vs. 911 GT3 RS. TBH, the most relevant stretch is the big straight at the end of the course. Let's look at each vehicle's average acceleration:

Mustang GTD:
Start: 6:03.6 and 148 kph
End: 6:42.1 and 300 kph
Accel: 152 kph in 38.5 sec = 3.94 kph/sec




911 GT3 RS:
Start: 5:54.8 and 158 kph
End: 6:33.9 and 286 kph
128 kph in 39.1 sec = 3.27 kph/sec




As one can plainly see, the Mustang GTD accelerates at a significantly (+ 20%) greater rate at high speeds in addition to achieving a notably higher speed, yet had a materially slower 'Ring time. IOW, excess drag, or at least materially/proportionally more drag than the 911 GT3 RS, is not in any way a factor in the GTD's underperformance this time around. How do we know this? "Physics!"

[r0tor]

     Now tell me what a top speed of a 800hp 911 looks like  

[FoMoJo]

Porsche, as a rear engine car, has always had significantly better braking (physics) than a front engine car. As noted, it came out of the corner 10 mph faster than the Mustang and likely accelerated to top speed quicker.  Lots of curves on the track, so lots of opportunity for the Porsche to pick up a few 10nths.  Not so many longish straights.

[GoCougs]

Porsche, as a rear engine car, has always had significantly better braking (physics) than a front engine car. As noted, it came out of the corner 10 mph faster than the Mustang and likely accelerated to top speed quicker.  Lots of curves on the track, so lots of opportunity for the Porsche to pick up a few 10nths.  Not so many longish straights.

Actually, in terms of raw stopping power (= traction/weight transfer), it's usually the opposite. Historically, at least in recent times, the Corvette has the been the consistent best at any price level. Per C&D as of 2021, the Corvette holds 5 of the top 15 spots for all-time leaders, including tying twice over the for the top spot.

In fact, here's a stub from C&D's 0-150-0 test. The Mustang GT Darkhorse out braked FROM 150 mph both the C8 Z06 an 911 Turbo S. And mind you, the GTD version of the Mustang is a race car first and 400 lbs lighter than the Darkhorse.

Could be conditions. Could be the driver. Could be brakes (not stopping power but maybe fade?)/handling/traction/tires/etc. The jury appears to be out. But it's mos def NOT drag. My bet is the GTD is inherently quicker than the 911 GT3 RS however given the stats (plus of course, race car vs. road car after all).

[FoMoJo]

Brakes and tires make a difference of course but, with a rear-engined car (weight behind the rear wheels) the rear tires can contribute more stopping force than on a front-engined car where the front tires do most of the stopping.  Porsche has proven this over many decades of racing.

[GoCougs]

Brakes and tires make a difference of course but, with a rear-engined car (weight behind the rear wheels) the rear tires can contribute more stopping force than on a front-engined car where the front tires do most of the stopping.  Porsche has proven this over many decades of racing.

Performance braking is much more about handling heat over the course of a race. There's pretty much no race series that requires 100% braking from 150 mph to a standstill. Porsche of course has one of the richest legacies in all of racing but I don't necessarily see how that is due to braking (plus, most of what Porsche competes in are series with bespoke race cars and most/all of them are rear/mid engine along with all the other cars).

[FoMoJo]

Performance braking is much more about handling heat over the course of a race. There's pretty much no race series that requires 100% braking from 150 mph to a standstill. Just in general Porsche hasn't done anything special with brakes.

Comparison...

991 GT3 RS Porsche Ceramic Composite Brake (PCCB) is a proven motorsport solution. Boasting particularly large brake disc diameters of 410 mm at the front and 390 mm at the rear, it offers an even more formidable braking performance.

The 2025 Ford Mustang GTD has 345 mm rear brake rotors. The GTD also has 325 mm front brake rotors and Brembo carbon ceramic brakes.

Odd that the Mustang has larger rear brakes.  Tire size maybe?

With the Porsche being a lighter car, it can go longer approaching the curve before having to apply the brakes.  A few milliseconds there.  Also the lighter weight makes a difference and with the nose being lighter (39% front and 61% rear) it would be easier to get the nose to change direction. 

[r0tor]

    Now tell me what a top speed of a 800hp 911 looks like  

Looks like someone doesn't want to answer .. it's ok

The GT2RS MR hit 312kph with only 700hp and no active aero during it's record lap