Lots of wheel spin | diff issue?

[coyote550]

So I do not know if this is normal or not, but it doesn't feel right so I thought I'd ask. When making a turn from a stop the rear tires almost always break traction even with light throttle application. Turning onto the highway is a nightmare because the wheels keep losing traction way too easily and if the road is even a little bit wet, forget about it.

Also in the wet, I can break traction at 45mph easily by simply flooring it in 2nd gear. Is this normal behavior or something to do with the LSD? Tires have only about 1k miles on them. Pilot Sport 4s. 315/30/r20 in the rear. Car is a PP1 with 3.73 gears.

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[Eyesac]

You just have too much horsepower lol, it's uncontrollable aaagh! The torsen diff you have only does limited slip type stuff if one wheel loses traction, so take it easy on the right handers from a light (or don't). Every torsen I've owned was touchy in that scenario.

 

[Paddles]

How old are those PS4S?
What PSI are you running?
What's the ambient outdoor temps?
The 3.73s definitely make it easy to burn rubber.

 

[NightmareMoon]

Are you driving around in sport mode or something?

 

[coyote550]

How old are those PS4S?
What PSI are you running?
What's the ambient outdoor temps?
The 3.73s definitely make it easy to burn rubber.

The tires are less than 6 months old. Psi is at 32. Ambient temps are in 50s now.

 

[coyote550]

Are you driving around in sport mode or something?

I do drive in sport mode but as far as I know the traction control doesn't change between normal and sport. Only track mode.

 

[NightmareMoon]

I do drive in sport mode but as far as I know the traction control doesn't change between normal and sport. Only track mode.

Well yeah, but you loose a ton of sensitivity with the throttle pedal. you said it was stepping out with a 'light' throttle application, we'll in sport mode a 'light' throttle is mapped to a medium-heavy throttle position.

Some background - Mustang is torque on demand drive by wire. Your throttle application is an 'ask' for torque, not a throttle plate setting, which generally makes the engine response more predictable. In sport mode the torque demand table is set to a pretty aggressive mapping. When you ask for 'light' throttle position in sport mode the car goes 'ok', give him the beans. Normal (and some model's track mode) are more linear, and allow you to actually control the torque better.

For comparison, you can't mash the gas at a right hand 90° corner in a 1999 RWD Miata without breaking the rear loose either, and you have about 4x as much power at the wheels. In 2nd gear, you will definitely be able to break the rear loose in the wet if you mash it. that 315 rear tire isn't helping as much as you might think it should.

I would hope you can control a 90° turn to an on-ramp in the dry, but try normal mode for a while. Sure the car will feel slow initially, but you'll get used to using your foot more.

FWIW, I love driving aggressively, but I don't drive in sport mode. Not enough sensitivity/control. I learned that from a much more experienced and better muscle car driver than I am.

The T2R Torsen in our cars are pretty awesome diffs, they don't really wear, and then handle putting torque down better than most. They aren't the best when one wheel is slipping, but they aren't bad either (as long as both wheels have some resistance). Chances are the torsen is not the problem.

 

[Paddles]

The tires are less than 6 months old. Psi is at 32. Ambient temps are in 50s now.

These tires love to be warm.
I agree with others though seems like you're just enjoying the benefits of lots of power.
What RPMs are you seeing the slipping at?

 

[CrackedHorn]

Are these pilot sport 4 all seasons or pilot sport 4 summers?

What's the manufacturing date on them?

 

[coyote550]

Are these pilot sport 4 all seasons or pilot sport 4 summers?

What's the manufacturing date on them?

They are summers. I can't tell you the exact date but I bought them new in September 2024

 

[coyote550]

These tires love to be warm.
I agree with others though seems like you're just enjoying the benefits of lots of power.
What RPMs are you seeing the slipping at?

Honestly it could be at just about any range. It's much more exacerbated when taking a turn from a stop. I think my problem might just be that I'm always in sport mode and heavy on the go pedal. I think what adds to it is that my daily is an AWD and damn quick too and the throttle is very responsive. When I get in the mustang the throttle feels kinda numb so I set sport or track mode.

 

[GrabberBargeCaptain]

Well yeah, but you loose a ton of sensitivity with the throttle pedal. you said it was stepping out with a 'light' throttle application, we'll in sport mode a 'light' throttle is mapped to a medium-heavy throttle position.

Some background - Mustang is torque on demand drive by wire. Your throttle application is an 'ask' for torque, not a throttle plate setting, which generally makes the engine response more predictable. In sport mode the torque demand table is set to a pretty aggressive mapping. When you ask for 'light' throttle position in sport mode the car goes 'ok', give him the beans. Normal (and some model's track mode) are more linear, and allow you to actually control the torque better.

For comparison, you can't mash the gas at a right hand 90° corner in a 1999 RWD Miata without breaking the rear loose either, and you have about 4x as much power at the wheels. In 2nd gear, you will definitely be able to break the rear loose in the wet if you mash it. that 315 rear tire isn't helping as much as you might think it should.

I would hope you can control a 90° turn to an on-ramp in the dry, but try normal mode for a while. Sure the car will feel slow initially, but you'll get used to using your foot more.

FWIW, I love driving aggressively, but I don't drive in sport mode. Not enough sensitivity/control. I learned that from a much more experienced and better muscle car driver than I am.

The T2R Torsen in our cars are pretty awesome diffs, they don't really wear, and then handle putting torque down better than most. They aren't the best when one wheel is slipping, but they aren't bad either (as long as both wheels have some resistance). Chances are the torsen is not the problem.

I dont like sport mode much for that reason either, gives you too much pedal all at once at the start. its nice for rev match downshifting though, dont have to give it as much throttle. sometimes it is fun blasting around town in it.

 

[coyote550]

Well yeah, but you loose a ton of sensitivity with the throttle pedal. you said it was stepping out with a 'light' throttle application, we'll in sport mode a 'light' throttle is mapped to a medium-heavy throttle position.

Some background - Mustang is torque on demand drive by wire. Your throttle application is an 'ask' for torque, not a throttle plate setting, which generally makes the engine response more predictable. In sport mode the torque demand table is set to a pretty aggressive mapping. When you ask for 'light' throttle position in sport mode the car goes 'ok', give him the beans. Normal (and some model's track mode) are more linear, and allow you to actually control the torque better.

For comparison, you can't mash the gas at a right hand 90° corner in a 1999 RWD Miata without breaking the rear loose either, and you have about 4x as much power at the wheels. In 2nd gear, you will definitely be able to break the rear loose in the wet if you mash it. that 315 rear tire isn't helping as much as you might think it should.

I would hope you can control a 90° turn to an on-ramp in the dry, but try normal mode for a while. Sure the car will feel slow initially, but you'll get used to using your foot more.

FWIW, I love driving aggressively, but I don't drive in sport mode. Not enough sensitivity/control. I learned that from a much more experienced and better muscle car driver than I am.

The T2R Torsen in our cars are pretty awesome diffs, they don't really wear, and then handle putting torque down better than most. They aren't the best when one wheel is slipping, but they aren't bad either (as long as both wheels have some resistance). Chances are the torsen is not the problem.

Thank you for the detailed response. I think you are right. I'll try driving on normal. I'm just used to the very snappy throttle response in my daily bmw but traction is never an issue there cause it's AWD so I set the mustang to sport or track even to get a better response and that likely causes the wheel spin. So I guess it's my heavy foot and tail happy mustang combo. Gotta get more familiar with this car. Don't get me wrong it's fun as hell ripping it but sometimes I just want to drive normally so I guess sport mode causes the issues

 

[Paddles]

After just having a rental 330i with xDrive I can see exactly what you mean. The AWD is freakin quick from a takeoff. I don't think the Mustang can do that just by virtue of the nose heavy RWD, whereas that AWD really hooks and books.

 

[Grimreaper]

Summer tires won't grip when cold. You'll need mid 80's or higher to get full use of those unless doing a small burnout to heat them. 32 psi when cold is more than I'd run even in street tires. 28psi has always worked best for tread wear and traction.

Rear alignment matters too, bit of toe in helps.

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