GT350R Springs for GT (high rate, minimum lowering)

[keeph8n]

No problem man! I like to help

I would do Ford Performance Track Handling dampers all around. Koni yellows would be my second choice. They are sharper handling than the FP Track dampers by a little bit, but also noticeably more harsh/crashy. That's not to say that the Konis are a particularly harsh damper with these springs, but that the FP dampers ride excellent with these spring rates. For a weekend & track car: Koni. For a daily that sees occasional track: FP dampers.

Went ahead and ordered the GT350R springs and Track Pack struts this morning. That with the GT350R bars and a host of BMR goodies and Steeda rear mounts should be a good entry level setup to get my groove back with road course work. Then I can go to a set of Coilovers and really see what’s up.

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[BmacIL]

Went ahead and ordered the GT350R springs and Track Pack struts this morning. That with the GT350R bars and a host of BMR goodies and Steeda rear mounts should be a good entry level setup to get my groove back with road course work. Then I can go to a set of Coilovers and really see what’s up.

I think you'll be surprised at how competent it is.

You got these?
https://parts.autonationfordwhitebe...6-mustang-track-strut-and-shock-kit-m-18000-f

 

[keeph8n]

I think you'll be surprised at how competent it is.

You got these?
https://parts.autonationfordwhitebe...6-mustang-track-strut-and-shock-kit-m-18000-f

Yes that is what I ordered to go along with the GT350R springs and bars.

 

[2015Etrac]

Yes that is what I ordered to go along with the GT350R springs and bars.

I run GT350R springs and front and rear bars on my daily driver. It's a great setup. I was told the front bar comes with bushings, it doesn't, so make sure you order them.

 

[MajHazrd]

How is the daily ride quality of the GT350R springs?

My plan was to use Eibach Pro Kit, Eibach sway bars and Koni Yellows.
I liked the idea of the BMR SP083 kit lower the front 7/8" and back a 1/2 inch. A little more rack would look good.
I use mine as a daily driver, track days and occasional autocross.

After reading this thread, I'm thinking I need to reconsider which springs to get.

 

[BmacIL]

How is the daily ride quality of the GT350R springs?

My plan was to use Eibach Pro Kit, Eibach sway bars and Koni Yellows.
I liked the idea of the BMR SP083 kit lower the front 7/8" and back a 1/2 inch. A little more rack would look good.
I use mine as a daily driver, track days and occasional autocross.

After reading this thread, I'm thinking I need to reconsider which springs to get.

I've used mine as a DD for 3.5 years, and nearly 2 years with this suspension. I love it and wouldn't change it for anything softer. The ride is firm but not harsh. The handling rewards you every time you get back in the car. Not a single regret.

 

[2015Etrac]

How is the daily ride quality of the GT350R springs?

My plan was to use Eibach Pro Kit, Eibach sway bars and Koni Yellows.
I liked the idea of the BMR SP083 kit lower the front 7/8" and back a 1/2 inch. A little more rack would look good.
I use mine as a daily driver, track days and occasional autocross.

After reading this thread, I'm thinking I need to reconsider which springs to get.

I daily my car with GT350R springs, GT350R sway bars, and Koni shocks and it rides great. Like Bmac said, the ride is firm but not bad at all. I'm 100% happy with the setup. I wanted something that I could daily drive but would still be fun on the backroads, and handle any future track or autocross events.

 

[Norm Peterson]

How is the daily ride quality of the GT350R springs?

My plan was to use Eibach Pro Kit, Eibach sway bars and Koni Yellows.
I liked the idea of the BMR SP083 kit lower the front 7/8" and back a 1/2 inch. A little more rack would look good.
I use mine as a daily driver, track days and occasional autocross.

After reading this thread, I'm thinking I need to reconsider which springs to get.

Wheel rates for the GT350R springs are something like 235f/215r which seems to be entirely live-able, at least with decent damper valving.

As far as bumps are concerned, GT350R springs are actually a few lb/in softer than the springs I now have on my '08, which is still decent in what passes for daily driving these days. Even with that stick-axle ride quality handicap.

I think you've got a consensus.


Norm

 

[BmacIL]

Wheel rates for the GT350R springs are something like 235f/215r which seems to be entirely live-able, at least with decent damper valving.

As far as bumps are concerned, GT350R springs are actually a few lb/in softer than the springs I now have on my '08, which is still decent in what passes for daily driving these days. Even with that stick-axle ride quality handicap.

I think you've got a consensus.


Norm

Bingo.

When I was searching for what I was going to put on this car, I knew that I wanted a setup around 1.5-1.7 Hz ride frequency. That is a nice middle ground between a comfy DD (stock, around 1.3 Hz) and a track car (2.0+ Hz). I succeeded.

 

[Bluemustang]

Bingo.

When I was searching for what I was going to put on this car, I knew that I wanted a setup around 1.5-1.7 Hz ride frequency. That is a nice middle ground between a comfy DD (stock, around 1.3 Hz) and a track car (2.0+ Hz). I succeed.

Winning.

 

[MajHazrd]

Thanks for the responses. I going to switch to either the OEM GT350R springs or the BMR SP083. More likely the OEM's. I like the linear springs and it sounds like the Koni's soften up enough to give a good ride quality. I like taking it on roadtrips with my wife and don't want to get to harsh that she won't go. With the PP1 package, the ride is great and bit stiffer would be OK. On tight tracks I want to remove some of the body roll and understeer are my goals. I shredded the OEM P-zeros at a short tight track this fall. My son's 2000 GT's front tires looked like he went to Walmart to get groceries running about the same lap times! We have done a lot of work on the 2000's suspension.

One point of confusion from messages between BmacIL and GTP, what is the drop of the OEM GT350R springs, .7" or .3"?
BmacIL:
That'd be an awesome combination and I may have gone with it if the 1/8" spring spacers were available at the time. R front springs are a 0.7" front drop.
GTP:
So to confirm...
GT350 front spring @194#, -0.3" front drop
SP088 rear spring @184#, -0.5" rear drop + Steeda 1/4" or 1/8" spacer to fine-tune the stance

The spring rates for Eibach Pro-Line progressive springs:
Front:
OE rate: 28 N/mm (160 lbs/in)
PRO-KIT progressive rate: 35 - 55 N/mm (200 - 314 lbs/in)
Rear:
OE rate: 117 N/mm (668 lbs/in)
PRO-KIT progressive rate: 140 - 160 N/mm (800 - 914 lbs/in)

 

[Norm Peterson]

On tight tracks I want to remove some of the body roll

Just a side note, when the body's inertial motions - roll in particular - are well-damped you don't seem to notice the amount of roll as much. Steady-state, the movement can still be there, but the whole business is more composed and you're not "overshooting" the steady-state position by nearly as much. Kind of takes its set in one shot and stays there.


Norm

 

[BmacIL]

Thanks for the responses. I going to switch to either the OEM GT350R springs or the BMR SP083. More likely the OEM's. I like the linear springs and it sounds like the Koni's soften up enough to give a good ride quality. I like taking it on roadtrips with my wife and don't want to get to harsh that she won't go. With the PP1 package, the ride is great and bit stiffer would be OK. On tight tracks I want to remove some of the body roll and understeer are my goals. I shredded the OEM P-zeros at a short tight track this fall. My son's 2000 GT's front tires looked like he went to Walmart to get groceries running about the same lap times! We have done a lot of work on the 2000's suspension.

One point of confusion from messages between BmacIL and GTP, what is the drop of the OEM GT350R springs, .7" or .3"?
BmacIL:
That'd be an awesome combination and I may have gone with it if the 1/8" spring spacers were available at the time. R front springs are a 0.7" front drop.
GTP:
So to confirm...
GT350 front spring @194#, -0.3" front drop
SP088 rear spring @184#, -0.5" rear drop + Steeda 1/4" or 1/8" spacer to fine-tune the stance

The spring rates for Eibach Pro-Line progressive springs:
Front:
OE rate: 28 N/mm (160 lbs/in)
PRO-KIT progressive rate: 35 - 55 N/mm (200 - 314 lbs/in)
Rear:
OE rate: 117 N/mm (668 lbs/in)
PRO-KIT progressive rate: 140 - 160 N/mm (800 - 914 lbs/in)

The R springs drop the front 0.7" and rear 0.25". I helped @mindys install this on his car and it is what we measured. I believe @2015Etrac posted similar/the same. The SP083 drops are 0.88" front and 0.75" rear (or 0.5" rear if you have the older version).

The ride of this setup isn't harsh, but it can be a bit clumsy/noticeably stiff in parking lots with big bumps/grade changes or over certain curbs occasionally. That type of thing happens so infrequently for me that it's not a bother, and the ride on normal roads is more than acceptable. Firm and controlled. The faster you go the better it is.

 

[MajHazrd]

I like it! I'm going to go with the Eibach sway bars and Koni's to control the initial roll (like Norm said) and the BMR SP083 kit to balance the system out, control braking dive, acceleration and steady state. The PP1 is really very good, I'm going to go for that extra control.
Thanks everyone.

 

[BmacIL]

I like it! I'm going to go with the Eibach sway bars and Koni's to control the initial roll (like Norm said) and the BMR SP083 kit to balance the system out, control braking dive, acceleration and steady state. The PP1 is really very good, I'm going to go for that extra control.
Thanks everyone.

You will enjoy that. I would personally try it w/ the stock sway bars first and then try the Eibachs after in order to tune the car. Too much bar can make the car overly sensitive to road undulations and in the rear, can go as far as limiting the ability to put power down.

Start the Konis at 1 turn from soft in the front and 3/4 turn from soft in the rear. For autocross/track, you may want to increase that on both ends. The balance between front and rear will be up to you, but you'll probably want a little more damping up front.

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