Road Course / AutoX Spring / Shock / Strut / Sways Package

[CitizenCrusader]

First off, I really did search to find this answer before posting. Please don't hate me if this question has been answered ad nauseum already, and thanks in advance for links to threads I failed to discover.

'17 GT PP 6MT, looking for an upgrade roadmap to get the slop, rock, and lean out of this chassis. I'm looking at the BMR "Handling" springs paired with FR "Track" dampers, so please let me know if I'm barking up the wrong trees. Starting from scratch on sways; recommendations welcome.

Goals:

* Viable road course setup without going all in on a full race prep that's unstreetable.
* The violent back-and-forth rocking on shifts has to go.
* Feedback from road without shaking my fillings loose.
* Stability on hard launches and braking.
* Predictable, linear weight balance on turns at speed.

In general, I'd say that I'm looking for a setup that's barely race ready / just over the line for street use. In fact the car will see mostly street use, but my threshold for tolerating reduced ride quality is quite high if the result is competitive.

Only mods so far are BMR CB005 and Steeda vertical links. I'm trying to lock this thing down properly before blower with high 600s RWHP goals comes along next Spring.

Thanks in advance for thoughtful responses with citations where appropriate, and for tolerance of my poor grammar, technical inadequacy, and ugly haircut.

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[Brian@BMVK]

Happy to assist you! This kind of thing is what I specialize in . Pm or email is fine.

www.bmacvehiclekinematics.com

 

[NightmareMoon]

What's your tire budget? Are you going to run a dedicated autox/track setup wheel and tire or try to do double duty with daily driver tires? No sense spending a bunch of money on suspension if you aren't going to run the tires you need to run to go fast.

If the PP is a 1, the GT350R is a 2, a Lambo or Ferrari is a 3, and a Race prep spring rate is a 4, where do you want to be?

I'd prioritize wheels and tires first, and adjustable shocks second. Obviously a stiffer spring will help in there for your goals of less dive and squat, but it sounds like you have a shifting technique problem Camber plates are basically a must if you're spending good money on half decent autox-track tires.

A base PP with cheap single adjustable Koni or Steeda shocks, with better rubber and a set of swaybars will completely rock an autox or trackday and daily drive as good or better than stock. Adjustable shocks will control most of the body motion without eliminating it or bump compliant suspension travel. Stock PP springs with adjustable shocks is the most pleasant dual duty setup I've ridden on yet.

For your goals, something like the BMR handling springs sound right, but you can go stiffer and still sort of daily drive it. The Steeda Dual Rate Ultimate springs are as stiff as you can go without a proper coilover setup, but there really aren't any aftermarket shocks which match well with them. The Konis survive and do what I need with these springs, but they're the weak link by this point.

For swaybars, I like the setup I have quite a bit (BMR front 35mm swaybar and a Strano Parts rear bar), but a BMR rear bar on soft would be a decent substitute.

You should be tempted by the Steeda geometry correcting control and and bumpsteer kit if you end up selecting a spring that lowers the car 3/4" or more. Its good kit.

 

[CitizenCrusader]

Abso. But not tonight. My eyes are heavier than a couple of bricks with diabetes.

 

[tj@steeda]

Abso. But not tonight. My eyes are heavier than a couple of bricks with diabetes.

Hello Scott,

If you would like, you can give Brian or Rod a call at 1800 950 0774 - they are very well versed in what you are looking to accomplish, let me know if I can help assist with an email introduction:

Here's our 2018 GTQ500 HPDE Car - https://www.steeda.com/steeda-2018-q500-hpde-car

 

[Bluemustang]

Positive recommendation for @Brian@BMVK
Great guy and knows how to setup a fantastic dual-purpose car.

I might suggest you take an analytical approach as far as target ride heights, spring rates and bar rates as well as geometry & alignment and putting together a system rather than purchasing a "one size fits all" suspension package. One that will suit your specific needs and goals for the car.

Good luck to you in finding the right setup for your goals.

 

[Roadway 5.0]

A base PP with cheap single adjustable Koni or Steeda shocks, with better rubber and a set of swaybars will completely rock an autox or trackday and daily drive as good or better than stock.
.....

You should be tempted by the Steeda geometry correcting control and and bumpsteer kit if you end up selecting a spring that lowers the car 3/4" or more. Its good kit.

+1.

Looking at street springs:

OEM PP - baseline
Eibach ProKit - Level 1
Steeda Ultralites - Level 2
GT350R/BMR Handling - Level 3
Steeda Dual Rate - Streetable threshold

- Mike

 

[Grintch]

Step one - what class do you intend to run in?

 

[CitizenCrusader]

Step one - what class do you intend to run in?

None. I outgrew autox after the 2007 season with a Mazdaspeed 6 in SM. I'm targeting an autox / road course handling setup for my car, but it'll never actually dodge cones.

I've seen you ask this question elsewhere, though, and agree with your methodology. I don't even know what stock class a V8 S550 runs in -- AS? SS? No idea. The autox community near me is super toxic anyway; no interest in going back to that.

 

[CitizenCrusader]

Positive recommendation for @Brian@BMVK
Great guy and knows how to setup a fantastic dual-purpose car.

I might suggest you take an analytical approach as far as target ride heights, spring rates and bar rates as well as geometry & alignment and putting together a system rather than purchasing a "one size fits all" suspension package. One that will suit your specific needs and goals for the car.

Good luck to you in finding the right setup for your goals.

Cheers.

 

[CitizenCrusader]

+1.

Looking at street springs:

OEM PP - baseline
Eibach ProKit - Level 1
Steeda Ultralites - Level 2
GT350R/BMR Handling - Level 3
Steeda Dual Rate - Streetable threshold

- Mike

"Streetable threshold" sounds like where I want to be. I had a set of those blue springs from Florida like 20 years ago on an SN95, and they sagged rather badly after about a year on the car. Is it time for me to stop holding a grudge?

 

[kz]

None. I outgrew autox after the 2007 season with a Mazdaspeed 6 in SM. I'm targeting an autox / road course handling setup for my car, but it'll never actually dodge cones.

I've seen you ask this question elsewhere, though, and agree with your methodology. I don't even know what stock class a V8 S550 runs in -- AS? SS? No idea. The autox community near me is super toxic anyway; no interest in going back to that.

F Street. With all the mods you can run CAM C as long as you're on 200TW tire.

 

[CitizenCrusader]

What's your tire budget? Are you going to run a dedicated autox/track setup wheel and tire or try to do double duty with daily driver tires? No sense spending a bunch of money on suspension if you aren't going to run the tires you need to run to go fast.

One ring of rubber to rule them all, bud. The car just got brand new 4Ss like 8 weeks ago; no plans to discard them early.

If the PP is a 1, the GT350R is a 2, a Lambo or Ferrari is a 3, and a Race prep spring rate is a 4, where do you want to be?

Remember Tiffany Amber Thiessen in her Saved By The Bell days? THAT'S where I want to be. Of the options you gave, call it a 3.

I'd prioritize wheels and tires first, and adjustable shocks second. Obviously a stiffer spring will help in there for your goals of less dive and squat, but it sounds like you have a shifting technique problem

I'm open to that being the case. This isn't nearly my first rodeo with a clickety-clack car, though, and of the several I've owned and raced, this is the first I've owned that rocks forward and back so much on the shifts. You're right to call this out as a possible factor, though. Criticism accepted.

Stock PP springs with adjustable shocks is the most pleasant dual duty setup I've ridden on yet.

The hell you say?! I'm raising an eyebrow so hard right now, Spock would be proud.

For your goals, something like the BMR handling springs sound right, but you can go stiffer and still sort of daily drive it. The Steeda Dual Rate Ultimate springs are as stiff as you can go without a proper coilover setup, but there really aren't any aftermarket shocks which match well with them. The Konis survive and do what I need with these springs, but they're the weak link by this point.

For swaybars, I like the setup I have quite a bit (BMR front 35mm swaybar and a Strano Parts rear bar), but a BMR rear bar on soft would be a decent substitute.

You should be tempted by the Steeda geometry correcting control and and bumpsteer kit if you end up selecting a spring that lowers the car 3/4" or more. Its good kit.

OK you got me back by the end there. All good info.

Hey so, you guys are kinda good at this.

 

[Dana Pants]

Michelin 4s isn’t a track tire.

Most shifting happens while turning. Any movement back and forth is user error and dangerous. Almost any abrupt movements and uncontrollable vehicle behavior are user error.

This is last weekends autocross on stock PP1 springs, Konis, and a stiff rear bar. The run includes a smooth shift in and out of 3rd gear.

There is nothing wrong with the car driving experience, but bigger wheels, tires, more camber, and stiffer springs would make it faster.

 

[Grintch]

None. I outgrew autox after the 2007 season with a Mazdaspeed 6 in SM. I'm targeting an autox / road course handling setup for my car, but it'll never actually dodge cones.

I've seen you ask this question elsewhere, though, and agree with your methodology. I don't even know what stock class a V8 S550 runs in -- AS? SS? No idea. The autox community near me is super toxic anyway; no interest in going back to that.

Yet you asked for a Road Course / AutoX package. AutoX has rules, as does some forms of road course work. Nothing will ruin your day like finding out your latest mod bumps you into a class where your car is way underprepared and uncompetitive. And if you are smart you will look ahead and ask if I ever wanted to run TT or Solo, I would want to run this class, so need to follow those rules. I used to do some PDX and TT instructing, and every event I would hear I wish I had bought this or not modified that.

But if you will be running outlaw/uncontrolled. Application is the next question, which you seem to have covered.
Next is tire selection, as the suspension has to suit the tire. MP4S is only half the question, size also matters. As some things help or hurt wheel clearance. And staggered vs square matters too.

But your answers so far suggest a pretty street oriented car. And most of the suggestions suit that use.
The only hole I see (or missed) is that additional/adjustable camber is mandatory up front for performance use.

P.S. If you are changing tires or rotating them at the track, jacking rails or as a minimum some form of jack pad/jack point protection is a very good idea.

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