Steering Response

[Sixer Stang]

First time poster, and just have some questions someone can answer.

I currently have a 2010 mustang that I am wanting to turn into a track car, the handling of the car seems to be good however the steering does not seem to translate to the wheels very well nor does it seem to give much feed back. The steering feels over boosted and too light so I am wanting to increase the amount of effort it takes to turn the wheel while also making the steering feel more direct. Would upgrading the ball joints help any? Whiteline advertises a set of ball joints that are supposed to aid steering response are they worth it? Also I read somewhere that the wheel turns lock to lock with 17 inch wheels is 2.87 but with 18 inch wheels it's 2.6 turns lock to lock, it that true? Also will a smaller diameter steering wheel increase the effort to turn the wheel enough for it to be noticeable?
Any suggestions are welcome and sorry for the long post just trying to absorb as much information as possible before spending money on anything.

 

[Norm Peterson]

Can you provide a little more information?

• Tires (mfr, model, size, inflation pressures that you use)
• Wheels (diameter, width, offset if known)
• Shocks & struts (OE or not, mfr, age/miles)
• Alignment settings (actual cambers, casters, and toes).

2010 was kind of a transition year - so I don't offhand know whether you're dealing with hydraulic power assisted steering like what my original-style '08 has or electric power assisted steering (aka EPAS) like what the refreshed-style Coyote cars got. This matters (EPAS systems are noted for typically poorish subjective feel all the way up to the OE engineering level).

Also, what cars are you comparing this against.

My understanding concerning differences in steering angle/steering wheel turns associated with 18" vs 17" wheels on the S197 chassis is that the steering angle is more limited on cars originally fitted with the 18's. Probably because the wheels were either a little wider (GT, originally 8.5") or a quite a bit wider (GT500, 9.5"). The 17" wheels are only 8's. OE 18's for your year may have only been 8" wide, I'm not too sure about this either.


Norm

 

[Pentalab]

All 2010's are hydraulic power assisted steering. I don't find the steering over boosted at all..on my 2010.. How wide are your front tires, and what width is the front wheels ? Do you have any camber dialed in ?

 

[ddd4114]

You'll need more steering effort once you start putting on wider rims and stickier tires. I notice a huge difference in effort and feedback when I switch from a wide Hoosier to a (relatively) narrow street tire. You can also increase steering effort by increasing castor by a combination of lowering the car and using castor/camber plates, which is something you'll want to do anyway.

If you're more worried about steering precision than feel, replacing the OEM control arm bushings (especially if they're worn) will help a little. Stickier tires also give the feeling of better steering precision because they tend to have stiffer sidewalls and require less slip angle to generate peak grip. Higher tire pressure helps too, but of course you can overdo it and begin losing grip. I don't see ball joints making much of a difference unless yours are about to rip out. If they're extended ball joints, in theory they raise the roll center a little and could make the car feel more responsive, but I still don't see that making a huge difference.

What are your overall plans with the car? Honestly, you're not going to significantly change the steering feeling of a 2010 Mustang without significant modifications that would effectively make the car no longer a Mustang. I have a 2011 with EPAS, and I definitely notice the lack of responsiveness, but you learn to adapt to it and drive around it on the track. In my opinion, it's not worth spending too much time and money trying to solve it. Actually, if anything I'd prefer a bit less steering effort now because I start noticing fatigue after pushing the car for a few laps with wide Hoosiers.

 

[Sixer Stang]

Can you provide a little more information?

• Tires (mfr, model, size, inflation pressures that you use)
• Wheels (diameter, width, offset if known)
• Shocks & struts (OE or not, mfr, age/miles)
• Alignment settings (actual cambers, casters, and toes).

2010 was kind of a transition year - so I don't offhand know whether you're dealing with hydraulic power assisted steering like what my original-style '08 has or electric power assisted steering (aka EPAS) like what the refreshed-style Coyote cars got. This matters (EPAS systems are noted for typically poorish subjective feel all the way up to the OE engineering level).

Also, what cars are you comparing this against.

My understanding concerning differences in steering angle/steering wheel turns associated with 18" vs 17" wheels on the S197 chassis is that the steering angle is more limited on cars originally fitted with the 18's. Probably because the wheels were either a little wider (GT, originally 8.5") or a quite a bit wider (GT500, 9.5"). The 17" wheels are only 8's. OE 18's for your year may have only been 8" wide, I'm not too sure about this either.


Norm

The tires are 205/55 they're some off the shelf brand that I can't remember right now, they're not performance tires but when my Mustang was a DD they were what was available to me so they're on there for the time being.

Wheels are stock wheels 17×8 all around.

Shocks and struts are Knoi str.t, unsure of what alignment it has as I have not done anything to the car in quite some time.

I'm dealing with hydraulic steering, and I'm comparing this against my 2011 golf gti. The gti has slightly more turns lock to lock in the steering wheel than the mustang, however the golf seems to be more responsive when turning i.e. I can just point and go where in the mustang I feel like I have to exaggerate my steering motions. Also the steering in the golf feels not nearly as light as in the mustang even though the golf is roughly a 500 pound lighter car.

 

[Sixer Stang]

You'll need more steering effort once you start putting on wider rims and stickier tires. I notice a huge difference in effort and feedback when I switch from a wide Hoosier to a (relatively) narrow street tire. You can also increase steering effort by increasing castor by a combination of lowering the car and using castor/camber plates, which is something you'll want to do anyway.

If you're more worried about steering precision than feel, replacing the OEM control arm bushings (especially if they're worn) will help a little. Stickier tires also give the feeling of better steering precision because they tend to have stiffer sidewalls and require less slip angle to generate peak grip. Higher tire pressure helps too, but of course you can overdo it and begin losing grip. I don't see ball joints making much of a difference unless yours are about to rip out. If they're extended ball joints, in theory they raise the roll center a little and could make the car feel more responsive, but I still don't see that making a huge difference.

What are your overall plans with the car? Honestly, you're not going to significantly change the steering feeling of a 2010 Mustang without significant modifications that would effectively make the car no longer a Mustang. I have a 2011 with EPAS, and I definitely notice the lack of responsiveness, but you learn to adapt to it and drive around it on the track. In my opinion, it's not worth spending too much time and money trying to solve it. Actually, if anything I'd prefer a bit less steering effort now because I start noticing fatigue after pushing the car for a few laps with wide Hoosiers.

The overall plans with the car are to have it be a dedicated track car, now I understand that I won't be able to completely change the steering feel of the car without going nuts, I am at least trying to find a way to increase the effort in steering a noticeable amount while making it also a bit more precise.

 

[Norm Peterson]

... I'm comparing this against my 2011 golf gti. The gti has slightly more turns lock to lock in the steering wheel than the mustang, however the golf seems to be more responsive when turning i.e. I can just point and go where in the mustang I feel like I have to exaggerate my steering motions.

Quite a lot goes into this, well beyond springs, dampers, sta-bars, and alignment settings. Bushings, for one thing, and certain other steering and suspension criteria. It's common enough for those other things to drive the design of the OE tires.

Also the steering in the golf feels not nearly as light as in the mustang even though the golf is roughly a 500 pound lighter car.

I suppose you could install a stiffer-than-OE power steering torsion bar - if anybody makes such a part. Though I really can't see any benefit in doing so, knowing what the PS in my own car feels like while running it hard on the track.

One instructor I had a while back did mention that it took a bit more steering input than he was apparently used to (I don't know what his point of reference might have been), but it certainly hasn't seemed to have been a handicap.


Norm

 

[ddd4114]

The overall plans with the car are to have it be a dedicated track car, now I understand that I won't be able to completely change the steering feel of the car without going nuts, I am at least trying to find a way to increase the effort in steering a noticeable amount while making it also a bit more precise.

In that case, the only things I'd do right now are replace the FLCA bushings and install some good caster/camber plates. It won't be a huge difference, but it's a lot simpler than making custom knuckles or installing a steering quickener.

I don't know if you've taken your car to a track yet, but I really don't notice the crappy steering response on a track nearly as much as I do on public roads. I just set my car up to have slight understeer, have just enough damping to keep the body under control, and it pretty much does whatever I want. If you're autocrossing, that's a different story, but you can still drive around the lazy steering response by trail-braking more. Playing with car setup and driving technique helps a lot simply because if it's balanced (and driven) well, you won't need that much steering input in the first place.

 

[Sixer Stang]

Thanks for all the input guys, but I'm also curious will a smaller diameter steering wheel (say 13 inch vs stock 15 inch) help at all or would it really not be that noticeable?

 

[Pentalab]

Thanks for all the input guys, but I'm also curious will a smaller diameter steering wheel (say 13 inch vs stock 15 inch) help at all or would it really not be that noticeable?

A 13" diam steering wheel would def be tougher vs a 15". I did that on a old civic eons ago... but it had no power steering. Flip side is smaller diam steering wheels have a more...'positive' / 'responsive' feel... due to their smaller circumference. IE: 90 degs on a 13" wheel = 10.2" . 90 degs on a 15" wheel = 11.78".

Who sells a 13" steering wheel, complete with air bags, radio control's etc ?

A 205mm won't even fit a 8" wide rim.

 

[Norm Peterson]

Thanks for all the input guys, but I'm also curious will a smaller diameter steering wheel (say 13 inch vs stock 15 inch) help at all or would it really not be that noticeable?

Given that you have power-assisted steering, it'll take only a little more effort, and it won't do much for feel. The smaller diameter will tend to exaggerate any twitchiness coming from you.

On 205/55's on 8" wide rims . . . it's not a combination that's endorsed by the tire industry and its standards, but it's not like you suddenly moved from pass to fail. That said, I don't know how much margin of safety you're giving up, or what it applies against. The taller the sidewall, the better off you'll be when you're running tires on wheels outside the wide end of the recommended rim width range.


Norm

 

[RED09GT]

It probably does feel overboosted with that small of a front tire.
I had wider tires on the front of my 1980 Mercury capri and never had smaller than a 225 on any 5.0 fox bodys that I owned.

The steering on these cars (especially the 2010) was highly acclaimed by the automotive journalists so I would at least start by putting a decent front tire on it before getting too critical about it.

 

[Sixer Stang]

A 13" diam steering wheel would def be tougher vs a 15". I did that on a old civic eons ago... but it had no power steering. Flip side is smaller diam steering wheels have a more...'positive' / 'responsive' feel... due to their smaller circumference. IE: 90 degs on a 13" wheel = 10.2" . 90 degs on a 15" wheel = 11.78".

Who sells a 13" steering wheel, complete with air bags, radio control's etc ?

A 205mm won't even fit a 8" wide rim.

This car is going to be built as a track car so it does not matter if it has air bags, radio, etc.
Sorry I forgot what tires I had on the car but they are 225 not 205, thank you for the info on smaller steering wheels.

Given that you have power-assisted steering, it'll take only a little more effort, and it won't do much for feel. The smaller diameter will tend to exaggerate any twitchiness coming from you.

On 205/55's on 8" wide rims . . . it's not a combination that's endorsed by the tire industry and its standards, but it's not like you suddenly moved from pass to fail. That said, I don't know how much margin of safety you're giving up, or what it applies against. The taller the sidewall, the better off you'll be when you're running tires on wheels outside the wide end of the recommended rim width range.


Norm

It probably does feel overboosted with that small of a front tire.
I had wider tires on the front of my 1980 Mercury capri and never had smaller than a 225 on any 5.0 fox bodys that I owned.

The steering on these cars (especially the 2010) was highly acclaimed by the automotive journalists so I would at least start by putting a decent front tire on it before ghetting too critical about it.

I had the tires installed over a year ago and totally forgot they are 225 and not 205, but I do plan on investing in a nicer set of wheels and tires as I progress with getting the car more track ready. I recently installed BMR rear lower control arms and relocation brackets along with stiffer adjustable sway bars front and rear, and the stiffness of the car was quite noticeable and really seemed to give the steering a more direct feel. (i'm assuming the decrease in body roll around corners is what's giving me that more direct feel) With all that being said I am planning on dropping the car 2 inches and need some advice on what suspension parts I should invest in next. I know I should need an adjustable pan hard bar along with an adjustable upper control arm plus camber plates, but I have read mixed things on bumpsteer kits. Does anyone have any advice on that or any suggestions on what I should buy next? I want all suspension components to be installed in the car and ready for the lower ride height before just installing the lowering springs. I am fairly mechanically inclined, but I'm young and this is my first time building a car for something so I need all the advice I can get.

 

[ddd4114]

If you're going to keep the STR.T dampers or switch to another strut that uses OEM-type springs, these are the only springs I've found that are worth buying: https://www.maximummotorsports.com/MM-Road-Track-springs-2005-14-Set-P1445.aspx

Most lowering springs are far too soft for track use, and you can easily make the car handle worse because you'll likely run out of suspension travel once you start pushing the car. I tried a set of Eibach lowering springs when I first started playing around with my suspension, and I didn't notice any improvement over OEM springs. Once I put the MM springs on, I dropped seconds off my lap times. However, I had Koni Yellows, not STR.Ts, so I don't know if you'll have enough damping for the MM springs. You'll likely still be faster with MM springs even with an underdamped setup, but it won't be great for the response issues you're noticing.

For lowering springs of any type, you'll need an adjustable panhard bar and shorter bump stops, but you won't need any bumpsteer correction as long as you retain the OEM mounting points. I didn't need an adjustable upper control arm, but of course your results may vary. Camber plates are a good investment for a track car and will probably save you money in tire wear, and you'll definitely need an alignment at least to correct the toe.

Down the road, I'd suggest investing in some decent coilovers, but they're very expensive. If this is your first time building a car and (I assume) you have little or no track experience, I'd save your money for now. I'd focus on getting a new set of wheels with some decent summer tires, getting at least -2 deg camber, and otherwise saving your money for seat time. It's actually not such a bad thing to try using the OEM springs when you're first learning to drive. Yes, the car responds more slowly and you'll be giving up some performance, but the effects of weight transfer will be more apparent and it will force you to drive smoothly to be fast. A stiffer car is harder to control when you inevitably push it over the limit. Plus, once you start driving your car on a track more, you might find other things that need attention more - namely brakes.

 

[Norm Peterson]

You can always take a "wait and see" attitude toward adjustable PHBs, as the PHB can be swapped without involving any other components or adjustments. I'm also going to push for making a better decision on the amount of lowering.

Here's a datalog of one of my better laps at a track that I do have some familiarity with. The peak lateral g figures tabulated in the box are NOT the highest g's the car has achieved on that track. Car had Strano stabilizer bars, Koni yellows, somebody else's rear LCAs, wider Pilot Super Sport tires on 18x11 wheels . . . and it was still on the OE springs. That was in a combined advanced/instructors run group, and you should probably be aware that I was well into my sixties before I ever set foot (tire?) out on a big track.

Lateral g's is the red trace, speed is in blue, and the bottom of the little data box at the upper left sits at about 1.15g for a right turn.



I'm in the process of putting together a build thread elsewhere. Haven't decided whether I'm going to copy/paste it anywhere else yet (this site constantly freezes for me, a few moments at a time when it's unresponsive to keyboard input) but I'll PM you with the link if you're interested.

I think this is the accompanying video ↓↓↓ . Keep in mind that my car still has its air bags, A/C, radio, and full interior, and only takes tire pressure and shock adjustments to swap between street duty and track time.

Though I do have a separate set of wheels and tires for longer periods of time/miles between track days.

I've since swapped in a set of aftermarket springs that are considerably stiffer than OE (BMR GT handling springs, in 260/220 rates) but which only lowered the car by about 5/8" (the rear initially dropped about an inch, so I shimmed that back up by 3/8" or so - and I'm currently thinking of taking it up another quarter inch). As of the time stamp for this post, that build thread doesn't know about the BMR springs. Maybe I'll get to it today, maybe I won't.


Norm

 

[Sixer Stang]

If you're going to keep the STR.T dampers or switch to another strut that uses OEM-type springs, these are the only springs I've found that are worth buying: https://www.maximummotorsports.com/MM-Road-Track-springs-2005-14-Set-P1445.aspx

Most lowering springs are far too soft for track use, and you can easily make the car handle worse because you'll likely run out of suspension travel once you start pushing the car. I tried a set of Eibach lowering springs when I first started playing around with my suspension, and I didn't notice any improvement over OEM springs. Once I put the MM springs on, I dropped seconds off my lap times. However, I had Koni Yellows, not STR.Ts, so I don't know if you'll have enough damping for the MM springs. You'll likely still be faster with MM springs even with an underdamped setup, but it won't be great for the response issues you're noticing.

For lowering springs of any type, you'll need an adjustable panhard bar and shorter bump stops, but you won't need any bumpsteer correction as long as you retain the OEM mounting points. I didn't need an adjustable upper control arm, but of course your results may vary. Camber plates are a good investment for a track car and will probably save you money in tire wear, and you'll definitely need an alignment at least to correct the toe.

Down the road, I'd suggest investing in some decent coilovers, but they're very expensive. If this is your first time building a car and (I assume) you have little or no track experience, I'd save your money for now. I'd focus on getting a new set of wheels with some decent summer tires, getting at least -2 deg camber, and otherwise saving your money for seat time. It's actually not such a bad thing to try using the OEM springs when you're first learning to drive. Yes, the car responds more slowly and you'll be giving up some performance, but the effects of weight transfer will be more apparent and it will force you to drive smoothly to be fast. A stiffer car is harder to control when you inevitably push it over the limit. Plus, once you start driving your car on a track more, you might find other things that need attention more - namely brakes.

You can always take a "wait and see" attitude toward adjustable PHBs, as the PHB can be swapped without involving any other components or adjustments. I'm also going to push for making a better decision on the amount of lowering.

Here's a datalog of one of my better laps at a track that I do have some familiarity with. The peak lateral g figures tabulated in the box are NOT the highest g's the car has achieved on that track. Car had Strano stabilizer bars, Koni yellows, somebody else's rear LCAs, wider Pilot Super Sport tires on 18x11 wheels . . . and it was still on the OE springs. That was in a combined advanced/instructors run group, and you should probably be aware that I was well into my sixties before I ever set foot (tire?) out on a big track.

Lateral g's is the red trace, speed is in blue, and the bottom of the little data box at the upper left sits at about 1.15g for a right turn.

View attachment 70039

I'm in the process of putting together a build thread elsewhere. Haven't decided whether I'm going to copy/paste it anywhere else yet (this site constantly freezes for me, a few moments at a time when it's unresponsive to keyboard input) but I'll PM you with the link if you're interested.

I think this is the accompanying video ↓↓↓ . Keep in mind that my car still has its air bags, A/C, radio, and full interior, and only takes tire pressure and shock adjustments to swap between street duty and track time.

Though I do have a separate set of wheels and tires for longer periods of time/miles between track days.

I've since swapped in a set of aftermarket springs that are considerably stiffer than OE (BMR GT handling springs, in 260/220 rates) but which only lowered the car by about 5/8" (the rear initially dropped about an inch, so I shimmed that back up by 3/8" or so - and I'm currently thinking of taking it up another quarter inch). As of the time stamp for this post, that build thread doesn't know about the BMR springs. Maybe I'll get to it today, maybe I won't.


Norm

So is there a certain amount of spring rate I should look for as a minimum? And yes I understand I should invest in more track days as I have only attended one event, however I do plan on attending more in the upcoming months. (Either in my Golf GTI or Mustang if it's ready) Anyways my reasoning for wanting to drop the car is for a much lower center of gravity, but I'm open to any ideas on amount of drop and what springs to use etc that are good options for the track (I don't care too much about sacrificing comfort on anything seeing as this car will not be my daily driver). Also does anyone have any suggestions on wheel and tire combo? I have pilot sports on my Golf and loved how much grip they had at the track so should I stick with what I know or is there other tires out there that someone would recommend?

 

[ddd4114]

I wouldn't want to drop the car any more than 2", and even that is pushing it without running into issues with suspension travel. The spring rates for the springs in my link start at 320/260 (they're progressive, so that's at ride height), and that's probably the softest I'd want on a track car. A lot of the Spec Iron race cars run something around 500/300, but they're using MCS coilovers. I ran 550/275 for a while and liked those rates with a ~1.5" drop. Also, another concern with lowering an S197 a lot is getting a jack under the car. With my ~1.5" drop, I can easily get my jack under the car with 275/35R18 street tires, but it's a tight fit with 315/30R18 Hoosiers especially if the pressures are a little low. I have to drive my car on ramps at the track just to change wheels unless I'm lucky enough to park on level asphalt.

In theory, you're correct that lowering the car reduces the CG, which reduces weight transfer, which reduces load transfer, which should improve handling. There are also aerodynamic benefits. However, as you lower a car with struts, the front roll center drops very fast, and without stiffer springs, this would actually increase roll. Even if you add enough spring to limit roll, you still have to be concerned about running out of suspension travel and hitting the bump stops. At some point, you will need such high spring rates that the loss in mechanical grip is far worse than the gain from reduced weight transfer.

For wheels, I'd go right for an 18x10" or 18x11" setup. S197s are heavy and can use as much tire as possible. I bought a set of 18x10.5" Enkei PF01's from Sam Strano that I've been using for a few years, and they're nice because you can rotate the wheels to any corner. Vorshlag has several wheel offerings including an 18x11" Forgestar package, but I think the offsets are different front/rear (they would have to confirm).

For tires, any summer tire around 200 treadwear should be fine for starting out. You can find plenty of 200-treadwear tire comparisons with some Google searching, but if you're just starting out, I'd prioritize cost over ultimate grip. You're going to burn through at least one set before you're really comfortable with the car. Unless something has changed recently, the RE-71R seems to be the "best" summer tire on the market, but it wears really fast compared to its competition and it will probably get greasy by the end of a 20-min track session. The Michelins are nice tires, but they're rather expensive.

 

[Sixer Stang]

Wouldn't a linear spring be better than a progressive one? Also is there a reason for front springs having a significantly higher spring rate than the rear? Wouldn't a similar spring rate at all 4 corners provide a more balanced feel?

 

[ddd4114]

The majority of coilover springs are linear, and it's easier to dial in the car using them. However, there is nothing wrong with progressive springs, and they're better suited for street cars or dual-purpose cars. It really depends on the rate vs. displacement, and that's why it's a lot easier to work with linear springs than to figure that out.

There are two reasons for having stiffer springs in the front. First, the springs on the rear axle act in parallel, so stiff springs will make the ride harsh. This matters more for street driving, but there are tracks that have noticeable bumps (Mid-Ohio comes to mind) or are simply in rough shape (anybody drive Nelson Ledges before they repaved it?), and you don't want to make the car twitchy. Second, the front roll center is much lower than the rear roll center, so when you go through the math, you need a lot less spring rate in the rear to maintain balance.

 

[Norm Peterson]

Personally, I think that even reduced lateral load transfer tends to be given more credit than it deserves. Yes, you get a net gain. But that's a net gain, where the gain you make at the outboard tires is partially offset by the inboard tires running at a slightly lower coefficient of friction because less load got transferred off of them. On 200 treadwear or higher tires in an untimed HPDE environment, I don't think chasing this is worth the hassle. Maybe in timed events it is, but at that point you should have enough seat time under your belt to be running consistent lap times in any given session.


Norm