My Suspension Plan What you Think

[bnightstar]

Hi All,

I want to improve my car performance over the winter.

I regularly track my car on a short 2km track here is my last best lap:



Current Mods:

Square: 275/35 Zestino 07RS (Soft 140TW) on stock PP1 wheels.
Steeda Camber Plates
FP Strut Tower Brace
Steeda Front Swaybar
Good Allignment

As you can see my car sit very good with no sign of under/oversteer so happy with balance. My goals for the winter as to add coilovers but try to keep the balance if possible.

Planned Mods:

Apex SM-10 19x11 ET26/ET52 with 295/30 Zestino 07R (Medium 240TW)
Steeda StainlessSteel Brake Lines
Steeda IRS Full Pack
Ohlins R&T 515 lbs / 800 lbs
Steeda Roll Center and Bumpsteer Kit
Steeda Adjustable Endlinks
Steeda Extreeme G-Trac Brace
KennyBrown Jacking Rails
Gloc R12/R10 brake pads

Do you think there is something I'm missing and will this setup help me improve my lap times ?

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[Norm Peterson]

If you're happy with the car's understeer-oversteer handling balance, don't throw all of those planned mods at it at the same time.

Start with the wheels and tires alone and see what the car seems to want then. That may be different from now, where you haven't yet identified something about the car that it's not doing as well as it should, or is doing something that it shouldn't.

I doubt that the jacking rails will help lap times by enough to matter, so get those only as you find a need for them when jacking the car up for tire changes and such.

Pretty sure I heard a momentary tire chirp under deceleration at about 0:36, which tells me that the revs weren't matched on a downshift. And I think there was more than a bit too much coasting, if you're actually going to chase personal-best lap times (it doesn't matter so much if you're mainly out there just to enjoy being able to drive hard without running the risk of getting arrested and your car impounded).


Norm

 

[Stang55]

Impressive driving! Best of luck with the build!

 

[bnightstar]

If you're happy with the car's understeer-oversteer handling balance, don't throw all of those planned mods at it at the same time.

Start with the wheels and tires alone and see what the car seems to want then. That may be different from now, where you haven't yet identified something about the car that it's not doing as well as it should, or is doing something that it shouldn't.

I doubt that the jacking rails will help lap times by enough to matter, so get those only as you find a need for them when jacking the car up for tire changes and such.

Pretty sure I heard a momentary tire chirp under deceleration at about 0:36, which tells me that the revs weren't matched on a downshift. And I think there was more than a bit too much coasting, if you're actually going to chase personal-best lap times (it doesn't matter so much if you're mainly out there just to enjoy being able to drive hard without running the risk of getting arrested and your car impounded).


Norm

Yeah there is a need to improve my driving as well Norm.

I'm not heel toe on downshifts and I for sure coast to much.

My car is good in the under/oversteer department but I don't like the amount of BodyRoll the car has and I want to have Coilovers to you know be able to have two setups 1 for street and 1 for the track.

I want to start doing more competitive Time Attack next season but the cars in my class are like 5 sec faster than that video.

I give the car to a Pro driver and his best was 1:08.1 so I have a lot of room for improvement.

I think that basic next step if I focus on wheels and tires should be something like:

Wheels + Tires
Brake Pads (As I'm still on my OEM ones and run through them fast).
Brake Lines (As I run Motul 660)
IRS Full Pack (Just because is nice to have)

But overall I want to buy all of the list through winter because shipping parts to BG is time consuming.

 

[bnightstar]

(it doesn't matter so much if you're mainly out there just to enjoy being able to drive hard without running the risk of getting arrested and your car impounded).

Norm

We don't get arrested for speeding here we just get fines (they are not that expensive). However speeding on our roads is dangerous because our roads are super crappy one time there was a window from a house in the speed lane.

 

[NightmareMoon]

I’m concerned your lap times will increase despite lots of money and time spent because you’re switching to harder tires.

 

[shogun32]

Ohlins R&T 515 lbs / 800 lbs

One of the Ohlins resellers here State-side recommends against those spring rates, esp the front one. Lots of people run 250 or 300 front, 1000 rear. So first off 800 rear seems off and 515 front is way off. something like 350 or maybe even as high as 400 front would seem to be better. Plus you want the frequence fore/aft properly balanced. which 515/800 very much isn't.

Steeda Roll Center and Bumpsteer Kit

are you dropping the car at least an inch?

Gloc R12/R10 brake pads

If this is your normal track I very much doubt you'd get enough heat into them to work right. Maybe go up a compound from Ferodo but seems to me your PP1 Ferodo pads are more than adequate.

What's costing you time an acceleration is your gear choice. Some of those corners should use 2nd. And if you can get your hands on 3.73 diff that's probably worth doing. But try 2nd gear first.

Also you're squealing tires in straight up braking. So wider fronts will likely help. But to repeat myself I doubt you're getting the tires hot enough to work right. Med compound might do better but unless you know you've got the tires up to proper temps you're chasing the wrong solution.

 

[bnightstar]

I’m concerned your lap times will increase despite lots of money and time spent because you’re switching to harder tires.

They are very close time wise actually between Soft and Medium we have two guys running same car with the 2 different compounds in 0.1 sec time difference so it should be fine.

 

[bnightstar]

One of the Ohlins resellers here State-side recommends against those spring rates, esp the front one. Lots of people run 250 or 300 front, 1000 rear. So first off 800 rear seems off and 515 front is way off. something like 350 or maybe even as high as 400 front would seem to be better. Plus you want the frequence fore/aft properly balanced. which 515/800 very much isn't.

I'm actually following Kenny Brown and did his Academy he suggest higher rates for Front at least 450/500 which is why I'm going with the coil-overs at first place. For the rear yeah maybe will need other springs BMR083.

Ohlins drop is 1" so yeah I will need the rollcenter correction.

I'm happy with the DS2500 but they are down in like 2 days on that track and in order to improve my times I need a lot more driving so not changing pads every 2 days will help I hope.

 

[shogun32]

515/800 is negative 34% frequency. You want positive 3-10%.
400/1500 for example. A car is supposed to have weight shift fore/aft as well as left/right. I don't see the point of trying to negate chassis tilt with super-high rate springs.

 

[bnightstar]

515/800 is negative 34% frequency. You want positive 3-10%.
400/1500 for example. A car is supposed to have weight shift fore/aft as well as left/right. I don't see the point of trying to negate chassis tilt with super-high rate springs.

I plan to switch to Slicks and that chassis tilt is dangerous with really sticky tires as the chassis tilt could overload the tires and make the car spin. Vorshlag did a test with Ohlins with the stock spring rates and the car was amazing on 315 Hoosiers.

 

[Norm Peterson]

My car is good in the under/oversteer department but I don't like the amount of BodyRoll the car has

How much of this "amount of BodyRoll" might be more about perception? What I'm getting at here is that since your track driving should be significantly harder than your street driving, you're simply going to get more roll and you'll be evaluating your observations based on your street experience to date.

Once the overall roll resistance gets down in the lower 2°/g range, reducing it further becomes an exercise in diminishing returns. Keep in mind that about 0.5°/g of the roll you see from either inside the car or from a distance outside it is coming from tire vertical stiffness effects not being "infinite". No amount of suspension stiffening can reduce this component of observed roll.

and I want to have Coilovers to you know be able to have two setups 1 for street and 1 for the track.

Adjustable shocks and struts can give you your two separate setups.

I want to start doing more competitive Time Attack next season but the cars in my class are like 5 sec faster than that video.

I give the car to a Pro driver and his best was 1:08.1 so I have a lot of room for improvement.

I think that basic next step if I focus on wheels and tires should be something like:

Wheels + Tires
Brake Pads (As I'm still on my OEM ones and run through them fast).
Brake Lines (As I run Motul 660)
IRS Full Pack (Just because is nice to have)

But overall I want to buy all of the list through winter because shipping parts to BG is time consuming.

What you really need to do is solve known problems and address possible deficiencies as they become noticeable. Even if you were to end up with some of the parts on your list, that doesn't mean you'll need all of them. "Nice to have" may or may not be the right thing to have, and if it isn't you'll be in for a wait at a later date anyway. Haste makes waste, or something like that.

You do need real track pads.


Norm

 

[bnightstar]

How much of this "amount of BodyRoll" might be more about perception? What I'm getting at here is that since your track driving should be significantly harder than your street driving, you're simply going to get more roll and you'll be evaluating your observations based on your street experience to date.

Adjustable shocks and struts can give you your two separate setups.
"Nice to have" may or may not be the right thing to have, and if it isn't you'll be in for a wait at a later date anyway. Haste makes waste, or something like that.

You do need real track pads.

Norm

My other close track is actually a track with very fast corners.



As you can see here the Roll is much more and it's actually making me to not push as hard as I'm not confident in the car not sliding out on me.
Also my car is bouncing on the straight which annoying as well.

I want coilovers because Kenny Brown suggest using more spring on the front of the Mustang to make it turn faster / instant so you can brake later (maximising the strength of the Mustang) and turn late. And you want the rear as soft as possible to prevent oversteer.
I can't get that from Shock and Struts because they are valved to like 350 lbs front springs max.

You say that I may not need some stuff on that list what you don't like in my list ?

 

[shogun32]

drive your car more like this

 

[Norm Peterson]

My other close track is actually a track with very fast corners.



As you can see here the Roll is much more and it's actually making me to not push as hard as I'm not confident in the car not sliding out on me.

I'm not seeing much of any roll there. I know I'd hardly notice it at all from the driver seat.

Also my car is bouncing on the straight which annoying as well.

Hard to tell how much is the car bouncing and how much is camera shake.

I want coilovers because Kenny Brown suggest using more spring on the front of the Mustang to make it turn faster / instant so you can brake later (maximising the strength of the Mustang) and turn late. And you want the rear as soft as possible to prevent oversteer.
I can't get that from Shock and Struts because they are valved to like 350 lbs front springs max.

The strength of the Mustang is more about accelerating off the corner than about the braking coming into it or minimum speed through the middle. Early to the throttle coming off is why you late-apex, which requires the sharpest portion of your corner to be both slower than and earlier than what a momentum car would use, and your turn-in is then later. That's what permits (requires?) later braking, it's not about the braking defining what follows.

As long as this car has to fill any street driving function, KB's advice may be too hardcore. Real race cars on real race slicks are likely to get faster as you stiffen the suspensions up from typical street-intended aftermarket, but you're not there yet. At best, on tracks that are as technical as what I think I'm seeing (lots of slow corners, lots of time below 80 kph at Dracon) you could look at what the top autocrossers in CAM-C are doing. They just "feel" more like autocrossing than "big track", which was my immediate thought for certain segments on my home track courses.

What comments did you get from the pro driver who ran 1:08's (against your 1:10.x)?

You say that I may not need some stuff on that list what you don't like in my list ?

Aside from the jacking rails, Shogun has covered most of what I'd have posted. What I really think you need to do is make your wheel and tire upgrade first, and by itself. Plan on making adjustments to your alignment, see where just that much puts you, and go from there instead of trying to guess from here.


Norm

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