Debunking the S650 Acceleration Timers & Track Apps

[Renntech]

There's been some contention lately on the accuracy of Ford's Sync4 performance timers built into the car's infotainment system. (See thread: "S650 is fast")
Many people know the displayed numbers are bogus, but I thought I'd compare them to GPS readouts to put the nail in the coffin.
I've even seen established personas like StangMode use these in-car timers and frankly it's embarrassing.

2024 Mustang GT Premium Non-PP, A10, 3.55:1 ratio.
275/35/20 front tires, 315/30/20 rear tires. These are within 0.4% and 1.1% total circumference delta to the 265/35/20 that came factory with my car and that my speedometer is presumably calibrated to.

• 95 degree heat even at 11:00pm
• 4,500+ density altitude
• 91 octane fuel.
• 37psi in the tires
• Arizona, yikes.

Virtually the least ideal possible scenario - every variable is pretty much a mitigating factor for performance. Yes your car will likely be quicker.
Results:

As you can see, on 0-60 tests alone, the car is claiming you're about 0.5 seconds quicker than you actually are.
I bought this Dragy unit in 2021 and have used it on 70 total 1/4mi passes at Wild Horse Pass Motorsports Park in Chandler, AZ. The Dragy readouts are within 0.02-0.05 seconds and 0.2mph to my printed track timeslips, every time. It's as feasibly accurate as you can get on your own.

What I think is happening: Ford's software is built to extract an estimated 1ft-rollout, possibly from both the 0-60mph and the quarter mile, and then display that figure. If you have aftermarket wheels and tires without recalibrating your speedo, the more inaccurate it will become.

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[Adamrx11]

How do you get the speedometer recalibrated??

 

[Upacurb]

Awesome well thought out post. Probably one of the best I have seen on here in a long time….

 

[Renntech]

How do you get the speedometer recalibrated??

I know that FORScan allows you to adjust tire circumference for the F-150. I would expect a similar capability exists for the Mustang. It would be best to let a dealership take care of it if you get new wheels/tires that are noticeably different from the original equipment.

 

[135Hoser]

@Ford Motor Company Care to show your work on how the car comes up with such optimistic numbers?

 

[Radiant]

optimistic numbers

I'm assuming Ford follows EU compliance, which has zero margin for showing a lower speed than the vehicle is traveling, but allows for it to display a higher speed.

 

[robvas]

Who's to say they aren't? The Dodge cars use the front sensor (2015+)

The 1/4 mile is pretty accurate on those but the 1/8th and especially 0-60 aren't

 

[smurfslayer]

I bought this Dragy unit in 2021 and have used it on 70 total 1/4mi passes at Wild Horse Pass Motorsports Park in Chandler, AZ. The Dragy readouts are within 0.02-0.05 seconds and 0.2mph to my printed track timeslips, every time.

The money shot there Good work

 

[Ace]

Thank you for that, these look like the numbers I know. And yes the cars themselves usally have 1ft rollout programmed into it while dragy or racebox has not.

I drove the European Dark Horse with 10AT and was quite a bit disappointed of the power output. It's rated about 50hp lower than US model. Measured was 0-100kph, so about 0-62kph, but without huge drop of elevation it was not possible to go below 5 seconds.

 

[IceGamer]

Thank you for that, these look like the numbers I know. And yes the cars themselves usally have 1ft rollout programmed into it while dragy or racebox has not.

I drove the European Dark Horse with 10AT and was quite a bit disappointed of the power output. It's rated about 50hp lower than US model. Measured was 0-100kph, so about 0-62kph, but without huge drop of elevation it was not possible to go below 5 seconds.

95er Benzin drin?

That's waaay slower than the S550 and as slow as a S550 EU manual... The A10 S650 should do ~4.6 seconds. Still somewhat slow in 2024 but not that slow.

 

[Ace]

95er Benzin drin?

That's waaay slower than the S550 and as slow as a S550 EU manual... The A10 S650 should do ~4.6 seconds. Still somewhat slow in 2024 but not that slow.

I was told Vpower was filled in. heard from another source the 100-200kph run took 10,9s in EU DH which is just not great for the horsepower it should have

 

[ArthurJGuy]

I think there is more to it than just rollout, as this was in a bone stock A10 car with less than 1,000 miles on it. It's clearly horribly inaccurate on every single metric. There was little to no wheel spin on this pass either.

For reference my 2,000 horsepower X275 car doesn't cut a sub 1.0 60 foot.

 

[Renntech]

I think there is more to it than just rollout, as this was in a bone stock A10 car with less than 1,000 miles on it. It's clearly horribly inaccurate on every single metric. There was little to no wheel spin on this pass either.

For reference my 2,000 horsepower X275 car doesn't cut a sub 1.0 60 foot.

HAHA wow, that's actually the craziest one I've seen yet... 0.94 60 foot might as well be an NHRA Pro Stock. The 10.11 is also wildly off too, by at least ~2 seconds.

 

[Zig]

I think there is more to it than just rollout, as this was in a bone stock A10 car with less than 1,000 miles on it. It's clearly horribly inaccurate on every single metric. There was little to no wheel spin on this pass either.

For reference my 2,000 horsepower X275 car doesn't cut a sub 1.0 60 foot.

Whippled? Oh wait you said bone stock , nvm

 

[Skye]

For my own insight, I was curious what Ford was using in these apps as a reference for movement.

Later, I began to consider both physical and logical inputs.

When Ford initially rolled out Track Apps in 2012, the reference source for movement was an internal accelerometer. I'm also finding posts discussing this reference as well.

https://www.motortrend.com/news/video-find-ford-shows-off-mustangs-track-apps-181097/

Interestingly, Ford began installing GPS as far back at 2007.

https://themustangsource.com/forums/f730/mustang-factory-gps-446140/

In the S550 and S650, the roof-mount shark fin antenna is the car's GPS receiver. In the S550, the receiver is connected to Accessory Protocol Interface Module (APIM), which is itself attached to the backside of the center console screen. I couldn't readily confirm if the APIM moved in the S650 to support the updated interior.

From several searches, it appears Ford never changed their reference. It seems Ford vehicles continue to use an internal accelerometer. While GPS is readily available, the received civilian signal more accurate than previous generations, Ford is not relying on it.

Edit,

For the physical part of the equation, which would have higher resolution: Ford's accelerometer or received GPS? I cannot answer that.

For the logical formulas, as others have asked, what is Ford's math? I'd be curious. But I wouldn't expect Ford to offer deeper insight.

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