Handling Upgrade

[TeeLew]

This is super annoying. The one spring package that was a slam dunk they have to screw with.

When spec'ing springs, you are dealing with a few variables. There's the stiffness or spring rate, the available travel and the static ride height. There are other things, but these are the big 3.

I like the rates of these springs and the travel is more than adequate. The static ride is an issue. All of these canned spring kits lower the front more than the rear. Rake is the difference in ride height front to rear. Lowering the front more than the rear will make for a quicker turn-in, less entry stability and overall less understeer. Well, it's sprung towards oversteer from the factory, so sticking an extra chunk of rake in doesn't help. I think we're better off flattening the rides and getting the rear low enough so entry stability is increased.

All of these spring selection issues is why I went with the Maier kit and use race springs. Steeda's rear spring kit would work similarly. Ride heights actually matter and jacking them around by 10-20mm at a shot, particularly in the wrong direction, is disappointing.

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[MrMike]

This is super annoying. The one spring package that was a slam dunk they have to screw with.

When spec'ing springs, you are dealing with a few variables. There's the stiffness or spring rate, the available travel and the static ride height. There are other things, but these are the big 3.

Yep. I was hoping for an easy button pre-assembled package but it may not exist any longer.

From what I've read, the GT350 springs should have no issues with travel or ride height since the drop is only 3/8". My only concern is the spring rate of the rears. Hopefully it's not too harsh.

 

[PC_GUARD]

Yep. I was hoping for an easy button pre-assembled package but it may not exist any longer.

From what I've read, the GT350 springs should have no issues with travel or ride height since the drop is only 3/8". My only concern is the spring rate of the rears. Hopefully it's not too harsh.

Keep in mind the spring rate is progressive and not linear. It's probably not as firm as you'd think.

I prefer linear rate springs, but its on a whole different issue why I personally prefer linear.

 

[MrMike]

Keep in mind the spring rate is progressive and not linear. It's probably not as firm as you'd think.

I prefer linear rate springs, but its on a whole different issue why I personally prefer linear.

I didn't realize that, total oversight on my part. Found this thread involving the GT350/R spring rates: https://www.mustang6g.com/forums/threads/m-5300-w-fp-spring-rates.91226/

If the spring is progressive and the chart from Vorschlag in that thread is correct, that means that it's only gonna suck if I gun it over a speed bump or into a driveway. Minor bumps and road imperfections will be no issue.

Is my understanding correct?

 

[TeeLew]

Yep. I was hoping for an easy button pre-assembled package but it may not exist any longer.

From what I've read, the GT350 springs should have no issues with travel or ride height since the drop is only 3/8". My only concern is the spring rate of the rears. Hopefully it's not too harsh.

It's strictly my opinion, but they're stiffer than I would choose. The Roush springs are a similar rate. They lower the car more (30mm), but evenly front and rear. That might be of interest. They're Magneride springs, though, so they wouldn't go on a passive suspension car.

It's time to make a TeeLew specific spring kit. I probably only have to buy 10,000 to find out I'm the only one who likes a car with a softer rear spring.

(Then think about watching the Phoenix SCCA 'T' cars literally pulling front tires off the ground and I remember a race car book from the 1970's titled _Tune to Win_ where the author, Carroll Smith, writes, "A car is like a primate. It must squat to go.")

 

[MrMike]

It's strictly my opinion, but they're stiffer than I would choose. The Roush springs are a similar rate. They lower the car more (30mm), but evenly front and rear. That might be of interest. They're Magneride springs, though, so they wouldn't go on a passive suspension car.

It's time to make a TeeLew specific spring kit. I probably only have to buy 10,000 to find out I'm the only one who likes a car with a softer rear spring.

(Then think about watching the Phoenix SCCA 'T' cars literally pulling front tires off the ground and I remember a race car book from the 1970's titled _Tune to Win_ where the author, Carroll Smith, writes, "A car is like a primate. It must squat to go.")

Yep, the Roush springs wouldn't work for me since my car is a 16 GT.

Do you generally aim for 800 linear in the rear, or something closer to PP1?

My concern is that if I went with something with less rate but with a larger drop, it may effectively be less compliant for the majority of road conditions compared to the GT350 rear.

Looking at the rear GT350 spring graph, I think the rate will be fine up until it passes the 2" mark. I do not exactly make bottoming out a regular activity.

 

[PC_GUARD]

I didn't realize that, total oversight on my part. Found this thread involving the GT350/R spring rates: https://www.mustang6g.com/forums/threads/m-5300-w-fp-spring-rates.91226/

If the spring is progressive and the chart from Vorschlag in that thread is correct, that means that it's only gonna suck if I gun it over a speed bump or into a driveway. Minor bumps and road imperfections will be no issue.

Is my understanding correct?

Thats a reasonable assumption


I have a 1" key way into my garage, and coming out (again im on linear rate springs) and its "firm" but not terrible. Granted I ride the brake out to so i dont bounce and bang etc

 

[MrMike]

Thats a reasonable assumption


I have a 1" key way into my garage, and coming out (again im on linear rate springs) and its "firm" but not terrible. Granted I ride the brake out to so i dont bounce and bang etc

What's your suspension setup? Full FP Track or FP Track dampers with other springs and stuff?

 

[JustSomeGuy]

I have a base GT and installed the lower k-member, three piece strut tower brace, FP track handling pack and most of the Steeda catalog, as well as 19x10 wheels. The difference from stock is dramatic. My wife thinks my car rides too hard now, I absolutely love it. It’s all straight forward installs… lowering the rear cradle isn’t as hard as it might seem-

 

[TeeLew]

Yep, the Roush springs wouldn't work for me since my car is a 16 GT.

Do you generally aim for 800 linear in the rear, or something closer to PP1?

My concern is that if I went with something with less rate but with a larger drop, it may effectively be less compliant for the majority of road conditions compared to the GT350 rear.

Looking at the rear GT350 spring graph, I think the rate will be fine up until it passes the 2" mark. I do not exactly make bottoming out a regular activity.

I haven't really settled on what I feel is the best, but I think about an 800 linear in the rear is tough to argue against. When had the rear of my car stiffer, it wanted to do kind of a hop thing as I'd go to throttle which would hurt traction. As I've softened the rear, that feeling has gone away and traction is much better. None of this seemed to have much influence on actual balance; it just drives off the corner straighter. 800#/in is the range where it's gone for me. Couple that with as stiff of a front as you dare. I don't think even 300 #/in is that big of a deal as long as you are allowing compliance in the rear of the car.

As far as 2" of travel on that spring is concerned, that's where you'll be at static ride height. The 'soft' portion of the spring is taken up in collapsing the soft portion of the spring, which determines the static ride height of the car. On the road, you only see the stiff portion of the spring.

After looking at the present available options, I think this is going to be my go-to recommendation. BMR 'Handling' front spring (246 #/in rate, 0.875" drop) and then use the Steeda strut ride height kit to bring the front back up 3/8" or just the spring with a spring rubber installed (which would raise both rate and ride height). In the rear, use the BMR 'Performance' rear spring (740 #/in, 0.5" drop) or the Steeda Ultralite Rear (800 #/in & 1" drop). If you decide you want the car to have a more sharp turn-in, then remove a front ride height spacer. If you want a more secure rear end on entry, add one. If you want either the front or rear spring stiffer, add a spring rubber.

YMMV.

 

[MrMike]

I haven't really settled on what I feel is the best, but I think about an 800 linear in the rear is tough to argue against. When had the rear of my car stiffer, it wanted to do kind of a hop thing as I'd go to throttle which would hurt traction. As I've softened the rear, that feeling has gone away and traction is much better. None of this seemed to have much influence on actual balance; it just drives off the corner straighter. 800#/in is the range where it's gone for me. Couple that with as stiff of a front as you dare. I don't think even 300 #/in is that big of a deal as long as you are allowing compliance in the rear of the car.

After looking at the present available options, I think this is going to be my go-to recommendation. BMR 'Handling' front spring (246 #/in rate, 0.875" drop) and then use the Steeda strut ride height kit to bring the front back up 3/8" or just the spring with a spring rubber installed (which would raise both rate and ride height). In the rear, use the BMR 'Performance' rear spring (740 #/in, 0.5" drop). If you decide you want the car to have a more sharp turn-in, then remove a front ride height spacer. If you want a more secure rear end on entry, add one. If you want either the front or rear spring stiffer, add a spring rubber.

YMMV.

Looking at the spring rates on BMR's site and having read threads that discuss their springs over time, I understand why you're suggesting this setup.

Going from an out of the box setup to having to use a ride height kit or a spring rubber doesn't sit well with me. Annoying. There's also the ye olde GT350/R front with SP082 rear option, I guess.


Any thoughts on Steeda Min Drops? They're 200/800 with a 0.5" drop.

Steeda techs seem to feel that their Pro-Active plus Min Drops are a very safe option, but I've seen a lot of... mixed feedback about non-computer controlled adaptive dampers.

 

[TeeLew]

I just don't like the feel of the softer front. It's the same with the BMR minimal version. I consider 250#/in as kind of a threshold, so if I'm going to the effort of changing springs, then I'm at least getting there.

 

[PC_GUARD]

What's your suspension setup? Full FP Track or FP Track dampers with other springs and stuff?

My full setup is

FRP track dampers
Steeda ultralites
Complete roll center kit
rear toe and lca spherical bearings

Thats it, im not done but my car rides and handles like an amg or M car.

 

[MrMike]

I just don't like the feel of the softer front. It's the same with the BMR minimal version. I consider 250#/in as kind of a threshold, so if I'm going to the effort of changing springs, then I'm at least getting there.

Got it. So the bare minimum you would do personally is the old GT350R front / SP082 rear set based on your preference for a firm front.

 

[MrMike]

My full setup is

FRP track dampers
Steeda ultralites
Complete roll center kit
rear toe and lca spherical bearings

Thats it, im not done but my car rides and handles like an amg or M car.

Ultralites look like they have the same rates as the min drops but a much larger drop. This makes me think min drops could still be a solid option.

Do you think your lack of SO-friendly suspension is mainly from the springs, or NVH from the roll center / bearings?

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