Unstable corner transitioning

[MartinNoHo]

Take it to an autox or road course. Throwing parts at the car won't help much if the driver doesn't yet understand how the car is responding to inputs.

You can't safely learn handling on the street, you need to be able to make mistakes and the street doesn't allow for that. Even a road course will have a much wider 'lane' to play with before you get off track and into trouble.

I've seen switchbacks that were too quick for a Mustang to navigate easily, but they're pretty rare. The solution for faster transitional response is some combination of stiffer springs, shock settings, and/or swaybars, but the resulting handling is both faster to get into trouble as well as faster to recover from trouble. Better to learn those lessons on a closed course with fewer hazards. All you have to do is drop one tire off on the street and it can quickly turn into a bad day.

I wanted to learn in the canyons as I've talked to many people who seem to begin with canyon and transition to auto X or track. I think everyone enjoys canyons before going further.
I'd love to do autocross, but as a young full time student applying to med school this cycle money is tight due to apps. I budget my money well, and heavy cars + autocross, track, or road courses if I assume correctly will require me to swap many pads, tires, maybe even rotors, etc. My schedule also only permits me 3 hours in Saturday or Sunday morning to drive freely. This is also my daily driver. In addition, the front brakes of a non PP seem to be a major bottleneck, In the canyons I do not brake hard enough for them to fade. I'd like to do autoX but I'm very tight on time. This is why I want to learn on the canyons, and slowly push the car.

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[NightmareMoon]

I wanted to learn in the canyons as I've talked to many people who seem to begin with canyon and transition to auto X or track. I think everyone enjoys canyons before going further.
I'd love to do autocross, but as a young full time student applying to med school this cycle money is tight due to apps. I budget my money well, and heavy cars + autocross, track, or road courses if I assume correctly will require me to swap many pads, tires, maybe even rotors, etc. My schedule also only permits me 3 hours in Saturday or Sunday morning to drive freely. This is also my daily driver. In addition, the front brakes of a non PP seem to be a major bottleneck, In the canyons I do not brake hard enough for them to fade. I'd like to do autoX but I'm very tight on time. This is why I want to learn on the canyons, and slowly push the car.

Autox is very very cheap, most clubs have loaner helmets and the car really doesn't require any changes to participate. Definitely doesn't require any brake work whatsoever since the speeds are low and you aren't slowing much, and not from high speed. Non pp pads and rotors are completely fine. You can run your daily tires, all they need is a little extra air pressure. Autox is by far the cheapest way to start building car handling skills at the limit.

Track is another story entirely. The speeds are higher and the demands on the brakes are much much more significant. Tire wear is also a much larger factor for an hour or so of time per track days, versus 5 or 6 minutes of racing time at an autox.

Look for local clubs in your area and try to attend a handful when they get going again. At an Autox most clubs will provide experienced driver/instructors to help you on nearly every run while you're a novice. Chances are you don't have any sort of tutor if you're trying to figure things out on the street. At an autox you can really find the limit of the car at 10/10ths or even go way over the limit with some safety margin designed into all of the courses. No way to do that on the street. Take a day off your usual calendar and give it a try.

 

[SteveW]

@MartinNoHo two questions:

1. does the delayed response feel like the steering hanging for a split second? I had a condition once where the steering would kind of get stuck to the left around left hand bends.

2. what shocks do you have on the car? Shocks play a huge role in transitional response.

 

[MartinNoHo]

@MartinNoHo two questions:

1. does the delayed response feel like the steering hanging for a split second? I had a condition once where the steering would kind of get stuck to the left around left hand bends.

2. what shocks do you have on the car? Shocks play a huge role in transitional response.

St coilover shocks and struts with their respective springs, It does hang for a split second, but I wouldn't say it's biased towards left turns over right turns or vice versa.

 

[SteveW]

St coilover shocks and struts with their respective springs, It does hang for a split second, but I wouldn't say it's biased towards left turns over right turns or vice versa.

Sorry, missed that you wrote in the original post you had ST Coilovers. If you had adjustable shocks I'd say crank up the compression and rebound but that doesn't apply. You could try more rake though. Adjust the front suspension down a turn to see if that improves transitions.

I would add rear toe in and make sure the thrust angle is zero to rule out a mismatch in rear toe from one side to the other. I think that's what confused my car's EPAS and caused a hang in the steering a long time ago.

You might like bigger sway bars. Say, a GTPP rear and either GT350R front or an adjustable one from one of the many suppliers of those.

 

[TeeLew]

By 'twitchy' do you mean the rear is unstable and the car tends towards ovesteer? I honestly think this is a more common situation than accepted. If so, here's what I'd try.

Several psi (up to 5) higher on front pressure
Rear toe-in up to 3mm per side (measured on rim)
Lower rear ride height (1 turn per side)
Higher front ride height (1 turn per side)

A stiffer front spring and/or front compression damping would also be something to consider, but that's something for later.

My rule of thumb is that you should never have to drive with your fingertips on entry. You should have closed fists when you're driving and be confident on turning the car in aggressively.

 

[Bluemustang]

OP I think it's fine to test it out a little bit on the canyons. Just be careful and realize that track driving is a whole nother level. But by no means would I say you can't have fun with it on the street lol. The car is made for enjoying.

And I don't agree with those who say testing & tuning is irrelevant on the street. I do think it is incomplete though, because it won't reflect the rigors of a track and enough of how the car behaves at different speeds, pushed to its limits. Any body can find the limit on a low speed corner on the street. Higher speeds, now that's a different story. Means you're pushing it entirely too hard and you need to be on a track for your safety and others.

Still I think you can feel the tendencies of the car's balance on the street well enough to be helpful.

As to your original question, I'm having trouble understanding what's happening or what your issue is. As mentioned, you might like a stiffer sway bar.

 

[MartinNoHo]

OP I think it's fine to test it out a little bit on the canyons. Just be careful and realize that track driving is a whole nother level. But by no means would I say you can't have fun with it on the street lol. The car is made for enjoying.

And I don't agree with those who say testing & tuning is irrelevant on the street. I do think it is incomplete though, because it won't reflect the rigors of a track and enough of how the car behaves at different speeds, pushed to its limits. Any body can find the limit on a low speed corner on the street. Higher speeds, now that's a different story. Means you're pushing it entirely too hard and you need to be on a track for your safety and others.

Still I think you can feel the tendencies of the car's balance on the street well enough to be helpful.

As to your original question, I'm having trouble understanding what's happening or what your issue is. As mentioned, you might like a stiffer sway bar.

Steering seems to hang for a second as mentioned by the previous post and doesn't like quick weight transfers.
When you say stiffer sway bar, you mean just the front bar right (i have the non pp rear sway bar)? Although, I always thought tighter sway bars in the front tunes the car to favor understeer, which is the last thing I want, I've been reading a lot of forum talk and it seems like the general consensus is that the car has enough power to be pushed into oversteer, and less mechanical grip in the front might be helpful for turning. So based on what your forum posts and BMACL (forgot his exact name but it was Brian for sure) I ordered front sway bars, and the cradle lockout. If it makes a huge difference I'll go LCA bearings and diff bushings as well!

 

[MartinNoHo]

By 'twitchy' do you mean the rear is unstable and the car tends towards ovesteer? I honestly think this is a more common situation than accepted. If so, here's what I'd try.

Several psi (up to 5) higher on front pressure
Rear toe-in up to 3mm per side (measured on rim)
Lower rear ride height (1 turn per side)
Higher front ride height (1 turn per side)

A stiffer front spring and/or front compression damping would also be something to consider, but that's something for later.

My rule of thumb is that you should never have to drive with your fingertips on entry. You should have closed fists when you're driving and be confident on turning the car in aggressively.

Understeer and slow weight transfer into corners. I will be trying more Psi in front than rear, but my coilovers that are KW v1 or roush equivalents (ST suspension which is the best bang for your buck coilovers under 1200!) recommend 1.5 inch drop front and 1 inch rear which is the same out of the box setting roush tells you to put. However, I really enjoy having my car 1.5 inch dropped all around, it looks great and never scrapes. More so, I wish KW could give me a compression and load graph for the coilovers, which they won't because it is their intellectual property. After annoying them all I could get out was that the front spring rate is 288 lbs/inch avg. I was trying to eventually mimic Kakonn's build, when these Coilovers go bad instead of revalving (same cost as getting new coilovers) i'm going straight to MCS.

 

[Bluemustang]

Steering seems to hang for a second as mentioned by the previous post and doesn't like quick weight transfers.
When you say stiffer sway bar, you mean just the front bar right (i have the non pp rear sway bar)? Although, I always thought tighter sway bars in the front tunes the car to favor understeer, which is the last thing I want, I've been reading a lot of forum talk and it seems like the general consensus is that the car has enough power to be pushed into oversteer, and less mechanical grip in the front might be helpful for turning. So based on what your forum posts and BMACL (forgot his exact name but it was Brian for sure) I ordered front sway bars, and the cradle lockout. If it makes a huge difference I'll go LCA bearings and diff bushings as well!

The first thing you said is making me think front control arm bushings binding. Turning up the rebound on your dampers and/or running a stiffer front sway bar will make it respond quicker. On my car when I added front control arm bearings, made a huge difference in the steering feel and response. It's cat quick.

For high speed sweepers and transitions, sounds like you need more spring rate and more damping possibly. If it's soft it'll make it less responsive. What are the spring rates on your coilovers? Also, the 1.5" drop up front is likely not helping matters. It drops the roll center below the COG and thus increases the roll couple. Many of the best handling setups are going to be less than 1" drop.

 

[Bluemustang]

Good call btw on the cradle lockout and stiffer front sway bar. The cradle lockout will make the car feel connected and stop the rear from moving around.

 

[MartinNoHo]

The first thing you said is making me think front control arm bushings binding. Turning up the rebound on your dampers and/or running a stiffer front sway bar will make it respond quicker. On my car when I added front control arm bearings, made a huge difference in the steering feel and response. It's cat quick.

For high speed sweepers and transitions, sounds like you need more spring rate and more damping possibly. If it's soft it'll make it less responsive. What are the spring rates on your coilovers? Also, the 1.5" drop up front is likely not helping matters. It drops the roll center below the COG and thus increases the roll couple. Many of the best handling setups are going to be less than 1" drop.

290 lb/ inch in the front avg as it is progressive
788 lb/ inch in the rear
St out of the box is set to 1.2 front and .8 rear, roush who buys their coilovers from KW and St recommend 1.5 and 1.0 rear.
Also does which front control arm bearings do you have?

 

[Bluemustang]

290 lb/ inch in the front avg as it is progressive
788 lb/ inch in the rear
St out of the box is set to 1.2 front and .8 rear, roush who buys their coilovers from KW and St recommend 1.5 and 1.0 rear.
Also does which front control arm bearings do you have?

I have Steeda's bearings, but I wouldn't recommend them. If you're to upgrade those I would recommend J&M. They work just fine, but having an issue with mine on the passenger side where it isn't oriented straight up with the mounting bracket. It's partially cocked. Probably a looser manufacturing tolerance on that bearing - it happened to a buddy of mine. I'd be more confident going with the J&M.

Given the progressive spring rate, makes it harder to determine what's happening. My first thought is your rear spring is pretty soft comparably. This is not terribly uncommon with coilovers. I've seen a few with pretty soft rears like yours. From what I've been able to see from handling guys/track guys is that they typically run higher rate rear springs. Even look at Ford's spring rates - they tend run ~4x higher (lb/in) in the rear. So what that tells me is you have a much higher front bias. But again it's hard to tell what's happening because your rates change depending on load. But if your rear is comparably soft you might be able to get away with running a stiffer rear bar too.

I'm going to guess what Roush recommends is what they think will look good stance-wise (think "hard parker"). The front suspension is very susceptible to geometry change with lowering. This is why the better handling setups don't drop the car very much.

https://whitelineperformance.com/bl...oll-centre-and-how-does-ride-height-affect-it

Increasing the distance between the RC and the COG leads to greater roll couple, which means more roll. Your higher spring rate is imparting roll resistance but your lowered suspension geometry is fighting against it, essentially.
Now I don't think this is causing what you're describing. Just trying to educate.

 

[MartinNoHo]

I have Steeda's bearings, but I wouldn't recommend them. If you're to upgrade those I would recommend J&M. They work just fine, but having an issue with mine on the passenger side where it isn't oriented straight up with the mounting bracket. It's partially cocked. Probably a looser manufacturing tolerance on that bearing - it happened to a buddy of mine. I'd be more confident going with the J&M.

Given the progressive spring rate, makes it harder to determine what's happening. My first thought is your rear spring is pretty soft comparably. This is not terribly uncommon with coilovers. I've seen a few with pretty soft rears like yours. From what I've been able to see from handling guys/track guys is that they typically run higher rate rear springs. Even look at Ford's spring rates - they tend run ~4x higher (lb/in) in the rear. So what that tells me is you have a much higher front bias. But again it's hard to tell what's happening because your rates change depending on load. But if your rear is comparably soft you might be able to get away with running a stiffer rear bar too.

I'm going to guess what Roush recommends is what they think will look stance-wise (think "hard parker"). The front suspension is very susceptible to geometry change with lowering. This is why the better handling setups don't drop the car very much.

https://whitelineperformance.com/bl...oll-centre-and-how-does-ride-height-affect-it

Increasing the distance between the RC and the COG leads to greater roll couple, which means more roll. Your higher spring rate is imparting roll resistance but your lowered suspension geometry is fighting against it, essentially.
Now I don't think this is causing what you're describing. Just trying to educate.

That's very informative thanks, I always thought the lower the COG the better, but I always thought it can't be that simple. I guess Ill get my car back up to highest settings recommended by KW, i'll install the rear cradle lockout, but now I am wondering if the front sway bar is unnecessary and I should've bought the rear sway bar. More so, ST now sells sway bars for my car but it's identical in diameter to BMR, steeda, etc. Due to this untraditional suspension path I've accidentally put myself on, I'll have to start experimenting until I get the car dialed in the way I like.

 

[Bluemustang]

That's very informative thanks, I always thought the lower the COG the better, but I always thought it can't be that simple. I guess Ill get my car back up to highest settings recommended by KW, i'll install the rear cradle lockout, but now I am wondering if the front sway bar is unnecessary and I should've bought the rear sway bar. More so, ST now sells sway bars for my car but it's identical in diameter to BMR, steeda, etc.

Re: the sway bars, I think you're still good getting the front one. If you can front and rear adjustable you can fine tune the balance afterward. Generally I am not a fan of the big rear bar at all, but given your comparable soft rear spring, it might be warranted.

Generally the COG lower is good, but not at the expense of the roll center. Most suspension manufacturers won't tell you - that once you lower the car your suspension geometry changes. Many times that it isn't good. And of course most of them won't. They're trying to sell parts. Most folks that are just lowering the car for looks won't notice because they're not pushing their car hard enough. Some will notice they're getting bumpsteer issues when before there wasn't any. The bumpsteer also changes when you lower the ride height. Both problems can be fixed by the aftermarket if you so choose.

Yeah, I think raising it back up is a win-win. You get more suspension travel for bumps and improves your geometry some.

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