Fighting understeer in high speed corners

[honeybadger]

Just wanted to follow-up. This won't be a surprise to many, but it will be informative for those looking to learn.

So tried a couple of different things this weekend:

1. Added a bit more camber going from -1.9 to -2.5 in rear ----this just induced corner-entry oversteer

2. I moved the sway bar 1 click stiff - this helped a bit with weight transfer, but overall grip felt down

3. I tried adding more rear wing to both options ---this helped settle the car in high speed direction changes, but little effect elsewhere

All this to say, we're not able to fix without springs. Sway bar helped with push, but made it a bit unstable. Camber disrupted corner exit.

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[luc]

Sounds like front end needs to lose a few hundred lbs - try an Ecoboost swap haha.

Frankly the electronics should be able to deal with it. Pretty much everyone can make a 6000 lb SUV exceed 1G with no drama.

Maybe some mods are disrupting Ford's $BN chassis engineering?

Once you reach a certain skills level, you turn off stability and traction control because you can be faster and have a better feel for the car without them

 

[JAJ]

Just wanted to follow-up. This won't be a surprise to many, but it will be informative for those looking to learn.

So tried a couple of different things this weekend:

1. Added a bit more camber going from -1.9 to -2.5 in rear ----this just induced corner-entry oversteer

2. I moved the sway bar 1 click stiff - this helped a bit with weight transfer, but overall grip felt down

3. I tried adding more rear wing to both options ---this helped settle the car in high speed direction changes, but little effect elsewhere

All this to say, we're not able to fix without springs. Sway bar helped with push, but made it a bit unstable. Camber disrupted corner exit.

When you changed the rear camber, did you reset toe as well? Going from -1.9 to -2.5 would push the rear from toe-in to toe-out if you just leave the toe setting alone. Presumably you know all that already though...

As for the springs, well, it might be worth trying the original springs just to see what difference it makes.

 

[honeybadger]

When you changed the rear camber, did you reset toe as well? Going from -1.9 to -2.5 would push the rear from toe-in to toe-out if you just leave the toe setting alone. Presumably you know all that already though...

As for the springs, well, it might be worth trying the original springs just to see what difference it makes.

Oh ya, I was super meticulous and set everything up for it properly. Toe was reset at 1/16" toe in

 

[WildHorse]

Taking grip away from one end to “create balance” is never a good thing.

Not entirely true, sometimes having a little oversteer on a RWD car is a good thing, I like having the rear rotate through a corner a little.

 

[honeybadger]

Yeah I know the top 0.0005 % of drivers can maybe extract an additional 1/1000 the of a second once in 50 laps.

The software configs are so good with so many maps and computing power it's ridiculous. Few humans can compete.

This under steer issue is best discovered by removing any mods, going back to OEM, then building them back in to identify the issue.

I cant tell if you’re trolling or serious, but I’ll take it as you’re serious in case you’re being genuine.

It’s A LOT more than that. A perfectly-tuned race system might be able to make the best drivers a little faster in something like an F1 car, but a mustang does not have a race tuned system nor is it tuned for the world best drivers. Track mode i calibrated for average people like you and me. And it’s calibrated for the stock brakes, weight, aero, tires, engine, etc. change those, and you need to recalibrate it to maximize effectiveness (and that assumes it’s optimized for lap time - which it isn’t).

the reality is even wannabe-fast-drivers like me can be faster without TCM. I keep it on most of the time because it’s safer, not because it’s faster.

At a track like cota, traction control will easily kill 1-2 seconds for a competent driver.

 

[Norm Peterson]

The software configs are so good with so many maps and computing power it's ridiculous. Few humans can compete.

As long as the car is kept close to stock, anyway. But modifications such as wider or grippier tires and brake pads with higher coefficients of friction can put you out past what the car's OE calibrations assume are present and lead to unexpected behaviors. All that computing power is capable of making a wrong decision just as fast as the right one . . .


Norm

 

[luc]

Yeah I know the top 0.0005 % of drivers can maybe extract an additional 1/1000 the of a second once in 50 laps.

The software configs are so good with so many maps and computing power it's ridiculous. Few humans can compete.

This under steer issue is best discovered by removing any mods, going back to OEM, then building them back in to identify the issue.

You need to educate yourself, as Norm and Honeybadger have said, the Mustang system is not a race system and do not account for modifications to the car
As for your “solution” for the understeer, it’s really an asinine idea, the Mustang, Ike almost all vehicles, is designed to understeer because it’s safer for the average driver
Most of what we do on a Mustang to make it a track toy is to deal with this issue with more negative camber, wider front tires, etc

 

[ShatterPoints]

Just wanted to follow-up. This won't be a surprise to many, but it will be informative for those looking to learn.

So tried a couple of different things this weekend:

1. Added a bit more camber going from -1.9 to -2.5 in rear ----this just induced corner-entry oversteer

2. I moved the sway bar 1 click stiff - this helped a bit with weight transfer, but overall grip felt down

3. I tried adding more rear wing to both options ---this helped settle the car in high speed direction changes, but little effect elsewhere

All this to say, we're not able to fix without springs. Sway bar helped with push, but made it a bit unstable. Camber disrupted corner exit.

1. I would use toe front and rear, not just making camber adjustments. The underseteer issue is because weight is less in the front relative to the rear (considering you have not changed much beyond springs) Track alignment for US/OS first is toe, then is camber for stability in the corner. COTA does have turns which want more camber but you need to make that change more so in the front than the rear.

2. This is the subjective issue with suspensions changes, did it just "feel" down on grip, or did the stop watch show you to be slower?

3. Aero has a threshold speed, below that it has little to no effect, above it then it becomes more dominant. Changes in aero will only affect its performance where it begins to be the dominant grip provider.

***Did you make camber AND sway bar changes?

Or was it one change from baseline, then return to baseline for the next change?

You need to educate yourself, as Norm and Honeybadger have said, the Mustang system is not a race system and do not account for modifications to the car
As for your “solution” for the understeer, it’s really an asinine idea, the Mustang, Ike almost all vehicles, is designed to understeer because it’s safer for the average driver
Most of what we do on a Mustang to make it a track toy is to deal with this issue with more negative camber, wider front tires, etc

^^^ That is 100% spot on. Just about all passenger cars have terminal understeer and require quite a lot of modification to change that.

 

[honeybadger]

1. I would use toe front and rear, not just making camber adjustments. The underseteer issue is because weight is less in the front relative to the rear (considering you have not changed much beyond springs) Track alignment for US/OS first is toe, then is camber for stability in the corner. COTA does have turns which want more camber but you need to make that change more so in the front than the rear.

2. This is the subjective issue with suspensions changes, did it just "feel" down on grip, or did the stop watch show you to be slower?

3. Aero has a threshold speed, below that it has little to no effect, above it then it becomes more dominant. Changes in aero will only affect its performance where it begins to be the dominant grip provider.

***Did you make camber AND sway bar changes?

Or was it one change from baseline, then return to baseline for the next change?




^^^ That is 100% spot on. Just about all passenger cars have terminal understeer and require quite a lot of modification to change that.

See my response to JAJ. All were done individually and then reverted back. All had individual alignments.

The goal with these changes wasn't to fix it. I knew it wouldn't. I just wanted to see how it would feel and then I reported that back for others to stumble upon in their own research.

It was objectively slower - lap time proved it. Car had less lateral grip down .1-.2 in in a few places.

 

[honeybadger]

We'll see if these can help in Dec. Picked up for $143 shipped to the house. ow back to figuring out my starter issues. ha

 

[ShatterPoints]

We'll see if these can help in Dec. Picked up for $143 shipped to the house. ow back to figuring out my starter issues. ha

Rates?? I do like eibach since their published rates are the rates IRL.

 

[honeybadger]

Rates?? I do like eibach since their published rates are the rates IRL.

980 lb/in rear linear (I'm told they've tested IRL at this rate as well)

https://trackmustangsonline.com/threads/ford-performance-gt350-spring-rates.13503/

 

[NoXiDe]

We'll see if these can help in Dec. Picked up for $143 shipped to the house. ow back to figuring out my starter issues. ha

Front FP Racing (Blue) and BMR Springs in the rear?

 

[ShatterPoints]

980 lb/in rear linear (I'm told they've tested IRL at this rate as well)

https://trackmustangsonline.com/threads/ford-performance-gt350-spring-rates.13503/

With the oem spring location you'll be at a ride frequency of 1.7hz. I'm not sure if that is more or less than you're at now. I'd say raising rear spring rates would be one way to improve the understeer issue

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