Newbie Thoughts on PP1 6MT 2018

draph · May 23, 2018

I've had my '18 GT PP1 6MT for about 3 weeks 600 miles... I'm surprised to feel this car noticeably go wider in corners (eg cloverleaf on ramps) with a little application of throttle to accelerate mid corner. I presume this is a normal trait of the way GT PP1 is set up with 275/255 back/front and Torsen diff? I've always thought limited slip/locking diffs promoted oversteer, not understeer. I have the mag ride, but wouldn't think that would have anything to do with it. Perhaps when I get more spirited, a heavier application of throttle in turns will give it a more balanced feel when I get to the point of being confident enough to "steer with the gas pedal".... My last rwd contemporary car was a BMW 335i that had an open diff staggered set up (255/225 back/front), which didn't exhibit the push trait. I've got a 1970 'vette convertible with limited slip diff that kicks out the back end with just about any type of throttle application (on all season tires) - I was expecting the Mustang to be more like this but with safety nannies to keep the back in line...And my most previous contemporary car was 2010 TL-SHAWD with the torque vectoring rear end that would actually provide a little oversteer with heavy throttle.

So - normal trait? Does the push change into wild oversteer after a certain line is crossed with the gas pedal? Yeah, I need to find a safe track to find this out for myself, but appreciate the more experienced owner comments before then.

XCRN · May 23, 2018

Did you have an E90 or an F30? I had an F30 335i and one thing I noticed was that car was definitly more throwable around a corner and instilled a lot of confidance going through it. It just gripped with a 245/265 non runflat tires. Though I have a non PP 16, I do not feel as confidant without going into a spin. But that is a psycological problem not a car problem so I am not gassing through a corner like I did with the BMW. But I am running squared 235 all seasons that don't really give me the confidance to gas through either. I have this road I go down that has high visibilty ahead and is one way with great corners I use to test. Eventually I will learn to drive this like the BMW and I can feel the potential but I can't just go at it like the BMW could do without getting into a spin. I have not had my Mustang more than a week so take what I say with a grain of salt but figured I would throw my experience in.

w3rkn · May 23, 2018

draph said:
I've had my '18 GT PP1 6MT for about 3 weeks 600 miles... I'm surprised to feel this car noticeably go wider in corners (eg cloverleaf on ramps) with a little application of throttle to accelerate mid corner. I presume this is a normal trait of the way GT PP1 is set up with 275/255 back/front and Torsen diff? I've always thought limited slip/locking diffs promoted oversteer, not understeer. I have the mag ride, but wouldn't think that would have anything to do with it. Perhaps when I get more spirited, a heavier application of throttle in turns will give it a more balanced feel when I get to the point of being confident enough to "steer with the gas pedal".... My last rwd contemporary car was a BMW 335i that had an open diff staggered set up (255/225 back/front), which didn't exhibit the push trait. I've got a 1970 'vette convertible with limited slip diff that kicks out the back end with just about any type of throttle application (on all season tires) - I was expecting the Mustang to be more like this but with safety nannies to keep the back in line...And my most previous contemporary car was 2010 TL-SHAWD with the torque vectoring rear end that would actually provide a little oversteer with heavy throttle.

So - normal trait? Does the push change into wild oversteer after a certain line is crossed with the gas pedal? Yeah, I need to find a safe track to find this out for myself, but appreciate the more experienced owner comments before then.

To get what you want, can be achieved by using an aftermarket sway bar, etc. Ford has to maintain a certain "safety" cornering spec. But the understeer can be "tuned" out of the suspension, using the right parts and adjustments, etc..

Tony & many others will be along shortly, tossing knowledge all up in here and helping you with exactly what stiffness you need for the balance you are seeking, etc.

Stepping the back end out (mid corner) is part of the fun in learning the car's abilities...! :headbang:

NightmareMoon · May 23, 2018

255 tires and weight shifting to the rear as you feed it throttle. If you lift a bit the front should tuck in (once the ECU stops holding RPM and lets the revs drop) It’s called throttle steering.

The stock car is tuned to understeer because it’s the safest for most drivers.

gbgreen · May 24, 2018

There are many aspects of the car which affect handling: tire size (width, sidewall), construction, compound, and pressures; camber, caster, toe (front & rear), ride height (especially front-to-rear difference, a.k.a "rake"), spring rates (front & rear), dampers (compression & rebound, both high speed & low speed), ARBs (front & rear), chassis stiffness (front vs. rear, or "coupling"); diff settings (preload, ramp angles, and/or electronic lockup setting).

For the situation you describe (steady state, constant radius, moderate speed cornering, transitioning to gradual throttle application), the aspects that are most applicable are front low-speed rebound and rear low-speed compression on dampers, rear toe setting, and diff settings (accel ramp setting & preload). Next would be the spring split (front to rear), pressure differences (if any), different tread sizes, and ARBs (since these tend to affect a wide range of handling characteristics).

Understeer is safer, so manufacturers tend to tune settings for mild understeer (after all, you don't want a sports car to plow like a dump truck).

One method a driver can use to mitigate understeer is to trail off the throttle, which will transfer weight to the front, creating more front grip, allowing the nose to tuck into the turn and pull the rear end outwards to create Trailing Throttle Oversteer, or TTO. You can then judiciously re-apply throttle to balance handling. In high-powered cars, if the understeer is not too great, another method the driver can use is to apply high amounts of throttle suddenly to make the rear tires lose traction. You then ease off the throttle to balance handling. This method is generally more difficult to balance, and ultimately slower - if more spectacular.

Adjustments you can make to the car (in the pits/garage) to mitigate understeer are to :

stiffen the rear ARB and/or soften the front ARB
stiffen the rear springs and/or soften the front springs
increase rear tire pressures and/or decrease front tire pressures
use wider front tires
change ride heights
adjust the rear toe angle (I assume the rear is set to toe-in, so decrease the toe-in)
Since you can't change the actual valving or compression/rebound settings, you can play with the Magneride settings to see how that affects this situation
Same with the diff: since you can't (or really, shouldn't) try to adjust the diff, play with the Drive Modes to see what it does.

I'd try the driver methods first. Then Magneride settings. Then Drive Mode settings. Then tire pressures. None of these require changes to the car. Next would be to adjust rear toe (very carefully and in small increments), then try disconnecting the front ARB (I would expect this to result in a significant change in handling characteristics, and not be a long-term solution). I would try those two since no extra expense is involved, just time. Next would be to try a softer front ARB, then a stiffer rear ARB. Then try the same with springs.

I would NOT test any of the above suspension changes on public roads.

You can also play with tire sizes. I would go with a wider front tire, but if you use the same aspect ratio, that would increase the front ride height, which would be an adjustment in the wrong direction. So I would go with a lower aspect ratio. But that will likely result in a stiffer sidewall, increasing the effective spring rate in the front, which again is an adjustment in the wrong direction. If there is some way to make a chassis adjustment specifically to change the front and/or rear ride heights, you can mitigate these "unintended consequences".

As you can see, dialing in handling is a complicated issue, especially with street cars, which generally do not have the ability to target specific adjustments.

Oh, yeah: the above is what I would do (just off the top of my head) : not what I suggest you should do. So if you do what I would do and bring harm to yourself, your car, or others, it's on you, not me.

Jimmy G · May 24, 2018

One of the first things discussed on an advanced driving course is physics.

To combat understeer you need to finish braking and apply throttle prior to entering the turn, thereby throwing weight rearward and restoring neutral balance. Sink the slipper too hard, and you'll of course get a little squirrelly (I miss watching Kevin Schwantz!)

.

sigintel · May 24, 2018

gbgreen said:
There are many aspects of the car which affect handling: tire size (width, sidewall), construction, compound, and pressures; camber, caster, toe (front & rear), ride height (especially front-to-rear difference, a.k.a "rake"), spring rates (front & rear), dampers (compression & rebound, both high speed & low speed), ARBs (front & rear), chassis stiffness (front vs. rear, or "coupling"); diff settings (preload, ramp angles, and/or electronic lockup setting).

For the situation you describe (steady state, constant radius, moderate speed cornering, transitioning to gradual throttle application), the aspects that are most applicable are front low-speed rebound and rear low-speed compression on dampers, rear toe setting, and diff settings (accel ramp setting & preload). Next would be the spring split (front to rear), pressure differences (if any), different tread sizes, and ARBs (since these tend to affect a wide range of handling characteristics).

Understeer is safer, so manufacturers tend to tune settings for mild understeer (after all, you don't want a sports car to plow like a dump truck).

One method a driver can use to mitigate understeer is to trail off the throttle, which will transfer weight to the front, creating more front grip, allowing the nose to tuck into the turn and pull the rear end outwards to create Trailing Throttle Oversteer, or TTO. You can then judiciously re-apply throttle to balance handling. In high-powered cars, if the understeer is not too great, another method the driver can use is to apply high amounts of throttle suddenly to make the rear tires lose traction. You then ease off the throttle to balance handling. This method is generally more difficult to balance, and ultimately slower - if more spectacular.

Adjustments you can make to the car (in the pits/garage) to mitigate understeer are to :

stiffen the rear ARB and/or soften the front ARB

stiffen the rear springs and/or soften the front springs

increase rear tire pressures and/or decrease front tire pressures

use wider front tires

change ride heights

adjust the rear toe angle (I assume the rear is set to toe-in, so decrease the toe-in)

Since you can't change the actual valving or compression/rebound settings, you can play with the Magneride settings to see how that affects this situation

Same with the diff: since you can't (or really, shouldn't) try to adjust the diff, play with the Drive Modes to see what it does.

I'd try the driver methods first. Then Magneride settings. Then Drive Mode settings. Then tire pressures. None of these require changes to the car. Next would be to adjust rear toe (very carefully and in small increments), then try disconnecting the front ARB (I would expect this to result in a significant change in handling characteristics, and not be a long-term solution). I would try those two since no extra expense is involved, just time. Next would be to try a softer front ARB, then a stiffer rear ARB. Then try the same with springs.

I would NOT test any of the above suspension changes on public roads.

You can also play with tire sizes. I would go with a wider front tire, but if you use the same aspect ratio, that would increase the front ride height, which would be an adjustment in the wrong direction. So I would go with a lower aspect ratio. But that will likely result in a stiffer sidewall, increasing the effective spring rate in the front, which again is an adjustment in the wrong direction. If there is some way to make a chassis adjustment specifically to change the front and/or rear ride heights, you can mitigate these "unintended consequences".

As you can see, dialing in handling is a complicated issue, especially with street cars, which generally do not have the ability to target specific adjustments.

Oh, yeah: the above is what I would do (just off the top of my head) : not what I suggest you should do. So if you do what I would do and bring harm to yourself, your car, or others, it's on you, not me.

As a former test driver having worked in Japan and US: excellent post!
Especially the “not on public roads part. “
Op, check out the “what is your next event” thread in track section. You are gonna love autoX and hpde. The S550 chassis is very tweakable to get as much oversteer balance as you want. Since the op mentioned private roads and large empty parking lots without light poles, he could try swapping front to rear, and running 25psi front and 45psi rear for some ‘hoonage’

Chad11491 · May 24, 2018

I found a square setup took away most of the understeer in my car.

Kansas GT · May 24, 2018

Chad11491 said:
I found a square setup took away most of the understeer in my car.

Agreed. I'm very pleased with a square setup on these cars and find it more predictable than the staggered setup that comes with the PP.

wildcatgoal · May 24, 2018

These cars are understeering dogs. Square wheel setup helps a lot.

gbgreen · May 24, 2018

Jimmy G said:
One of the first things discussed on an advanced driving course is physics.

To combat understeer you need to finish braking and apply throttle prior to entering the turn, thereby throwing weight rearward and restoring neutral balance. Sink the slipper too hard, and you'll of course get a little squirrelly (I miss watching Kevin Schwantz!) .

Actually, the method you describe is used to combat oversteer from trail braking into a corner. Trail braking allows you to brake later into a corner. But doing so can induce oversteer. It may seem counter-intuitive, given my discussion of TTO, but in this case, it starts by asking too much of the front tires by having them handle both (up to max) braking and (up to max) cornering forces at the same time (by braking into the corner), therefore exceeding the total traction available from the tire, causing a loss of traction. When you trail off the brake pedal, it reduces the braking load requested from the front tires to a point just below the maximum total traction available (from both braking and cornering), allowing them to grip better, tucking (pulling) the nose inward and therefore pulling the tail outwards, creating Trailing Brake Oversteer, or TBO.

Many times I have used data ac to help drivers with this issue. I remember one in particular. I was working as Strategist/Race Engineer/Data Ac Engineer for a team called Falcon Racing at a Grand-Am event at Mid-Ohio. The team owner and gentleman driver was having a hard time getting loose in Turn 1, costing him a lot of time compared to the pro driver in the car (a Ferrari 360 GT). He was trail braking into this medium-to-high speed corner, causing TBO on entry, making the car unstable. I suggested he tap the brakes lightly (eventually working up to just a lift of the throttle) much earlier, and add just maintenance throttle on turn-in to stabilize the car (too much throttle would induce understeer), then gradually and gently add throttle through the turn. He did this and gained over 1/2 sec from corner entry until the braking point for the next corner (because his mid corner and corner exit speeds were much higher, gaining him time all the way down the next straight). His name? Lawrence Stroll. He had a couple of cute kids. His son's name? Lance.

Trackaholic · May 24, 2018

gbgreen said:
Actually, the method you describe is used to combat oversteer from trail braking into a corner. Trail braking allows you to brake later into a corner. But doing so can induce oversteer. It may seem counter-intuitive, given my discussion of TTO, but in this case, it starts by asking too much of the front tires by having them handle both (up to max) braking and (up to max) cornering forces at the same time (by braking into the corner), therefore exceeding the total traction available from the tire, causing a loss of traction. When you trail off the brake pedal, it reduces the braking load requested from the front tires to a point just below the maximum total traction available (from both braking and cornering), allowing them to grip better, tucking (pulling) the nose inward and therefore pulling the tail outwards, creating Trailing Brake Oversteer, or TBO.

Many times I have used data ac to help drivers with this issue. I remember one in particular. I was working as Strategist/Race Engineer/Data Ac Engineer for a team called Falcon Racing at a Grand-Am event at Mid-Ohio. The team owner and gentleman driver was having a hard time getting loose in Turn 1, costing him a lot of time compared to the pro driver in the car (a Ferrari 360 GT). He was trail braking into this medium-to-high speed corner, causing TBO on entry, making the car unstable. I suggested he tap the brakes lightly (eventually working up to just a lift of the throttle) much earlier, and add just maintenance throttle on turn-in to stabilize the car (too much throttle would induce understeer), then gradually and gently add throttle through the turn. He did this and gained over 1/2 sec from corner entry until the braking point for the next corner (because his mid corner and corner exit speeds were much higher, gaining him time all the way down the next straight). His name? Lawrence Stroll. He had a couple of cute kids. His son's name? Lance.

Good points. Lance had some nice races last year. Hopefully some good ones to come this year, but Williams seems to be struggling.

One thing for the OP to keep in mind (that you are mentioning but not directly), is that the front/rear weight transfer during cornering (due to brake or throttle application), will definitely affect the balance of the car. So, getting on the gas will transfer weight to the rear, reducing grip on the front, and will tend to increase understeer. Also, your speed will increase, requiring a greater corner radius, which will also cause the car to move away from the apex. Pretty much every car will tend towards understeer when the throttle is applied mid-corner. Especially those with a limited slip diff, because the torque causes the diff to start to lock, which also inhibits the car's ability to turn.

At some point enough throttle will cause the rear tires to start to spin, and then the car will transition to oversteer. If you have applied lots of steering input in an attempt to combat the understeer (which is not the way to do it) when the transition to oversteer occurs, the car will want to spin pretty quickly.

-T

Vato · May 24, 2018

GBGREEN is correct.

I never had adjustable sway bars before. I had upgraded sway bars on many previous cars but not adjustable ones. This new set I bought are adjustable and I quickly realized what is ideal for me. I installed just the rear for a couple of days and OH BOY! Major oversteer city. I loved it but definitely too dangerous. I then installed the front one and put it on the hardest setting. It still handles better than stock but now it's not as tossable. I adjusted the front to the softer setting and now it's poyfect!

Anyway, I thought I'd share that since we're talking about handling.

JohnD · May 24, 2018

wildcatgoal said:
These cars are understeering dogs. Square wheel setup helps a lot.

Mine's not. Unless I'm dumb enough to pound it into a corner way beyond what the front tires can deal with. It's up to the driver to find and respect the maximum adhesion limit at both ends of the car.

draph · May 24, 2018

Thanks all, for those fine posts. I believe most of my questions are answered. I thought of another one: My PP1 wheels are the nickel luster forged. I understand these might weigh a bit less than the black painted cast wheels...any thoughts on whether less unsprung mass of the wheels would exacerbate or reduce the understeer in my scenario?

I will be trying the "no money" experiments before I do anything else; and I probably won't do much until I get truly comfortable with the full range of the stock setup (I'm a believer that, these days, the "break in period" is more about breaking in the driver to get accustomed to the car before exploring the limits too soon and experience embarrassment and regret). My winter tires and wheels will definitely be a square setup - I have a while to determine whether I optimize for cold, dry traction (eg go with stock width of rear front and back), or snow traction (eg go with width of the stock GT non PP A/Ss all the way around)..understanding I've got to stay with 19s to fit over the Brembos up front....

The fact Ford's PP2 is essentially a square setup except for slightly narrower front wheels kind of adds credence to the recommendations of going square; and it makes me wonder how much different the PP2 magnaride and other suspension bits really are from the PP1. It seems it's all down to compromise and tradeoffs - PP2 didn't appeal to me due to extra road noise of the wider tires, higher susceptibility to tramlining and hydroplaning, and, of course, the frequency of tire replacement (or need to put the PP2 set to the side except for track days and get a separate, daily commute set).

Overall, still no regrets choosing a PP1 Mustang over a Camaro 2SS 1LE for the same money, since the daily commute is immensely more enjoyable in the Mustang, which will be 90+% of my driving in this car.

Newbie Thoughts on PP1 6MT 2018

draph

Well-Known Member

XCRN

Well-Known Member

w3rkn

Well-Known Member

NightmareMoon

Well-Known Member

gbgreen

Well-Known Member

Jimmy G

Hangin' about, waitin'..

sigintel

Well-Known Member

Chad11491

Well-Known Member

Kansas GT

Mustang Enthusiast

wildcatgoal

@sirboom_photography

gbgreen

Well-Known Member

Trackaholic

Well-Known Member

Vato

Well-Known Member

JohnD

Legend in his own mind

draph

Well-Known Member