Wheels and tires or sway bars for understeer

[Roadway 5.0]

If I'm fighting the steering in a corner it means I screwed up.

I was just driving the corners in these shots, no fighting the wheel or the car, no seat-puckering, just turning the wheel over and back out again like I might during a brisk-paced drive out in the country but still a good bit shy of "race pace". Street driving should be at g's half these or less, but even at the 2/3 level you should not have to be working very hard to make it happen and keep it smooth.

Norm

The “fighting” I’m referencing is the weight of the steering in a turn and the pace/reactions of hitting imperfections on a mountain road. Poor use of the term on my part, perhaps.

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[luc]

What do you expect?
You have a base suspension, coil-over that were done for look, narrow and not very good tires and in top of that a car that was designed to understeer because it’s safer for the average driver

Took my car out for some overly spirited driving and something doesn't feel right or "planted", when I enter corners I'm fighting with my car (i.e. you can feel load going to the opposing side of my steering input, maybe understeer?), currently I have a SR strut tower brace and St coilovers. I'm still on stock black accent package rims w/ 255/40/19 pirelli run flats [suck] and stock sway bars. Would it be better to go straight to wheels and tires or upgrade the sway bars, maybe even a K brace?[/QUOTE
What do you expect? You have a base suspension, coil-over that we’re done for look, narrow and not very good tires and a car that is designed to understeer from the factory because it’s much safer for the average driver

 

[MartinNoHo]

What do you expect?
You have a base suspension, coil-over that were done for look, narrow and not very good tires and in top of that a car that was designed to understeer because it’s safer for the average driver

I've had this car for 3 weeks roughly so I'm changing things I.E. I have lightweight rims and sticky tires coming. I got this car for such a cheap price I didn't care about PP1 package or anything. I could care less about the look, If i wanted looks without functionality I'd cut my springs, not buy a decent set of Coilovers. St coilovers are the same as KW v1s without INOX steel, which I don't need in CA as we don't have much road salts. Sure I could have went for JRZ or Ohlins, but ST was the best bang for the buck. I'm simply asking for a good order of upgrades.

 

[MartinNoHo]

If either TC or AdvanceTrac was still active - even if at reduced sensitivity - you were probably fighting one or the other of those. And it can be a bit frustrating, you trying to make the car do what you know it to be capable of, and it's not going there for you. Sound about right? While my '08 GT does not have AdvanceTrac (and its TC is pretty much worthless as far as what it's supposed to do is concerned), I do have a little stability control experience in other cars. ***

Until you have safely found out for sure that your car can do that much, one or the other of those nannies was probably saving you from yourself. Once this corona crap has died down and autocrossing has started back up, do yourself a favor and run a few autocrosses. Even if you've driven other cars pretty hard in the past, you still need high performance seat time in your Mustang in order to find out where the limits at least "kind of" lie and what it takes from you to get up there without blowing clear through them.

I don't think you should ever feel like you're fighting the car - if you do, you're probably overdriving it. You're either coming in to the corner too hot, or you're trying to use too much brake for the amount of cornering g's somewhere between entry and apex. Even cornering in the dry at 0.75g on those run-flats, you should be able to relax and just drive the corner.



*** the car being unwilling to do what's asked of it is pretty much what I've felt in the WRX and the LGT before it when I've forgotten to turn its stability control completely off. This has happened only when a combination of throttle, gear choice, and cornering g's happened that the system didn't care for, even though I knew it was within the car's performance envelope. You can't successfully bully it into doing what you want; all you can do is ride it out and wait for the kind of response you're looking for to return.


Norm

Well said, right when I got the car and installed the coilovers 3 days after I got the car, corona hit and I couldn't go to autoX or tracks leaving me with only canyon roads like ACH, big tujunga, etc. I want to learn the car with traction, then without. The out of the box setting of KW for my coilover was 1."2 front and .8" rear, this is also the highest setting. I thought, let me call KW, so I asked them If they have a recommended setting, and they said that's up to you, I saw some lowering springs with similar spring rates and 1.25" drops and thought that may be the way to go.

 

[luc]

I've had this car for 3 weeks roughly so I'm changing things I.E. I have lightweight rims and sticky tires coming. I got this car for such a cheap price I didn't care about PP1 package or anything. I could care less about the look, If i wanted looks without functionality I'd cut my springs, not buy a decent set of Coilovers. St coilovers are the same as KW v1s without INOX steel, which I don't need in CA as we don't have much road salts. Sure I could have went for JRZ or Ohlins, but ST was the best bang for the buck. I'm simply asking for a good order of upgrades.

Martin:
good handling is the result of a good package where all the different suspension parts are designed to work together, a chassis stiff enough ( that's why the PP1/2 have extra bracing) to let the suspension work as designed, the right alignment, the right tires combination and the correct way of driving the car because traction is a direct consequence of weight transfer
Obviously the first thing would be to go to a square set of wider tires such as 275/40 or 285/35 and that will help understeer but that by itself will not make it a great handling car
Here is what I would do if i was you:
1/ Add all the PP1/2 chassis stiffening parts
2/ I have no idea what sway bars would work good with your coil over no why you decided to go to coil over. Get, for dirt cheap a full used PP1 suspension kit ( I would give you mine free if you were willing to drive to fresno)
3/ A set of PP1 replica wheel in 19X10
4/ 285/35/19 good tires
5/ A good alignment by a shop that know what they do ( not only being in the green)
6/ And for you the driver, some high performance instruction at a race track

 

[MartinNoHo]

Martin:
good handling is the result of a good package where all the different suspension parts are designed to work together, a chassis stiff enough ( that's why the PP1/2 have extra bracing) to let the suspension work as designed, the right alignment, the right tires combination and the correct way of driving the car because traction is a direct consequence of weight transfer
Obviously the first thing would be to go to a square set of wider tires such as 275/40 or 285/35 and that will help understeer but that by itself will not make it a great handling car
Here is what I would do if i was you:
1/ Add all the PP1/2 chassis stiffening parts
2/ I have no idea what sway bars would work good with your coil over no why you decided to go to coil over. Get, for dirt cheap a full used PP1 suspension kit ( I would give you mine free if you were willing to drive to fresno)
3/ A set of PP1 replica wheel in 19X10
4/ 285/35/19 good tires
5/ A good alignment by a shop that know what they do ( not only being in the green)
6/ And for you the driver, some high performance instruction at a race track

Thanks for clarifying Luc, could you tell me what parts are added onto the PP1/2 for chassis stiffening from what I understand it's a K brace, strut tower brace, and thicker rear sway bars. I went coilovers because I only heard good things about KW coming from the bmw community as I wanted my mustang to handle like a e46 m3 or e90 m3 (I drove my friends gt350 and loved it but its out of my budget). I have 19X10 square setup coming (SVE R357s roughly 23 lbs a piece rotary forged) with 285/35/19s firestone firehawk indy 500s. I'm going to a reputable shop for an alignment soon, I did one at my friends shop but as you said we only looked for the green. As for the sway bars, I'm not entirely sure whether to get rear or front, or both, but from what I understand it will allow me to adjust my car for understeer or oversteer.

 

[Norm Peterson]

I have 19X10 square setup coming (SVE R357s roughly 23 lbs a piece rotary forged) with 285/35/19s firestone firehawk indy 500s.

You've got a decent wheel & tire package coming. Not exactly top-shelf, but decent with enough room to see substantial growth on your part.

Basically, your overall improvement is going to be the result of "seat time, tires & wheels, everything else", in that order of importance.

And the more you know (and the more you discover during that seat time), the more sense/gut-level understanding you'll be making out of peoples' suggestions/recommendations and the better your choices are likely to end up being. Trying to guess what to do and details of your modification path before you get to that point ends up being something of a crap-shoot.


Norm

 

[K4fxd]

I'm highly disappointed in the base suspension. It feels terrible in long sweepers. I believe it is the rear moving causing the unstable feel. (comparing to a C7 Vette)

I am going to start by bracing the rear. Then I suppose the front will be the next step, after that I will add hard bushings. At that point I believe I will be at the limit of the stock tires (which are pretty good for what they are)

YMMV

 

[Bluemustang]

I'm highly disappointed in the base suspension. It feels terrible in long sweepers. I believe it is the rear moving causing the unstable feel. (comparing to a C7 Vette)

I am going to start by bracing the rear. Then I suppose the front will be the next step, after that I will add hard bushings. At that point I believe I will be at the limit of the stock tires (which are pretty good for what they are)

YMMV

The base car is very softly sprung and the dampers are lacking. You need more of both to handle the roll of pushing the car. That said, the subframe lockout IMO is one of the best mods for the car. Makes the front and rear much more connected.

 

[BmacIL]

I'm highly disappointed in the base suspension. It feels terrible in long sweepers. I believe it is the rear moving causing the unstable feel. (comparing to a C7 Vette)

I am going to start by bracing the rear. Then I suppose the front will be the next step, after that I will add hard bushings. At that point I believe I will be at the limit of the stock tires (which are pretty good for what they are)

YMMV

Yes, the base is very disappointing when driven at more than 6 tenths. The PP is better for sure but not that much. Check out my build thread for a 4.5 year evolution from base, no-options GT to highly track competent car that you can still DD. This platform has so much potential.

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