GT350R Springs for GT (high rate, minimum lowering)

[NightmareMoon]

Not sure people realize just how soft the base springs are for a car this size/weight. PP1 rates are marginal but decent. Just a bit more (200/800) is really good for a street car that's enthusiastically driven.

Yeah I know a really good local autocrosser who's very very fast in these heavy high horsepower cars. Its been interesting to watch him try to get his base car to handle in FS. Definitely has struggled more than I did starting with a PP1 car (although he's an alien, and thus still beats me most of the time). His trouble is keeping the soft base springs off the bump stops, he has to run higher adjustable shock settings than I needed to get similar results.

Thing is, GT350R spring rates will be a bit much of a lot of people/roads. PP1 was a good spring rate IMHO from Ford, they just let us down with the cheap shocks and the car really needed a bit more swaybar (although yeah, bumpy roads and stiffer swaybards aren't a good match either).

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[shogun32]

higher rate springs don't make a car ride stiff as such - unless the spring rates are totally whacked. What makes the ride 'stiff' is the inability of the damper piston to move fast enough thru the fluid. If the car rides poorly it's almost always the damper that is at fault.

 

[Roadway 5.0]

Not sure people realize just how soft the base springs are for a car this size/weight. PP1 rates are marginal but decent. Just a bit more (200/800) is really good for a street car that's enthusiastically driven.

100% agreed. 200/800 is a sweet spot for the street. Match this with good dampers, a roll center correction/bump-steer kit if the springs lower the car, get a good alignment, and add sway bars.

These things alone will dramatically change the dynamic of the car for the better.

200/800 Options (that I know of):

Steeda Minimum Drop Fronts / BMR SP088 Rears
Eibach ProKit
Steeda Linear Sport Springs

 

[Jonyxz]

100% agreed. 200/800 is a sweet spot for the street.
200/800 Options (that I know of):

Steeda Minimum Drop Fronts / BMR SP088 Rears
Eibach ProKit
Steeda Linear Sport Springs

gt350 base fronts (0.38 drop) 194 lbs / sp088 rear with 1/8 spacer (0.25 drop) 800 lbs

This is the most atractive 200/800 combo for me as it keeps the drop at a minimum.

The pp1 rear idea was to keep stock height in the back and have oem springs in all 4 corners. But consensus seems to be that 728 lbs is apparently too low in the rear

 

[Jonyxz]

Not sure people realize just how soft the base springs are for a car this size/weight. PP1 rates are marginal but decent. Just a bit more (200/800) is really good for a street car that's enthusiastically driven.

What I dont understand is: I see people praising and recommending gt350r/sp088 combo (240/800) and even sp084/sp088 combo (300/800).
If these combos are balanced then logic tells me that a gt350 base/pp1 combo (194/728) should also work. Which is also a very similar rate to Steeda's minimum (200/750).
Are all these combos I mentioned somehow unbalanced?

 

[shogun32]

I see people praising and recommending gt350r/sp088 combo (240/800) and even sp084/sp088 combo (300/800).

you do? Citation? Then best to ignore said recommendations.

a gt350 base/pp1 combo (194/728) should also work

that combo does indeed work (ignoring drop) as far as chassis frequency is concerned.

 

[strengthrehab]

Do you, boo.

Run the springs you want. Dont care what others think.

 

[Jonyxz]

you do? Citation?

Here's a few...sorry, dont know how to link them so just quoting:

You can use the SP084 Front springs and the SP088 Rear Springs.

Dont let the SP088 "Drag" fool ya. They are 800lb/in and I have a ton of guys road coursing and DD with them on the PP shocks. Matter of fact, with those springs and the bumpstops trimmed....that "bounce" you hear about, is pretty much gone. :ford:

I just installed the SP084 front, SP088 rear, GT350 struts, with stock PP shocks. I went with the SP088 on Kelly's and he was right on that this is a great spring rate for the PP shocks. This is an excellent combination for both daily driver and track day. I think it's just as or more comfortable than stock. The steering is much more precise and responsive. Brake dive is almost non existent now. I've only been able to push the car in a parking lot so far but I don't notice much difference in balance from stock but it's so much better with control, grip, and stability. I may need a rear sway bar but I won't know for sure until the next autocross or track day.

Gt350R/SP088 (240/800)

Alrighty so I got this installed over the weekend. All I can say is, is that I am over the moon happy with how everything came out. It feels like a true sports car. I do not know how else to explain it. Less nose dive, smoother transitions, better turn in, it's all there and its all great. This is how these cars should feel. I was a little afraid it would be a little rough and harsh and it would be something I would have to live with. This is not the case. And let me tell you...our roads are absolutely terrible. My daily route is filled with bad roads, bumps, cracks, holes, bad patch work, etc. (especially on the interstate and in my neighborhood). I don't want to say it soaks up the bumps as it sounds like something a crownvics suspension does but that's essentially what it does. It stays so composed over the road and imperfections. To me, the compression and rebound is perfect with this setup. It all works together. Reminds me a lot of when I had the Greanleafprime GT500 setup on my first 07'. It just all simply works together.

that combo does indeed work (ignoring drop) as far as chassis frequency is concerned.

194/728 is a very similar f/r frecuency ratio to oem GT350R 240/890.
The fact steeda offers a 200/800 with a 1 inch drop but dials down to 200/750 with 1/2 inch makes me think the reason to increase to 800 is for the increased drop.

 

[Jonyxz]

After further reading and reading and reflecting I think I'll stick to the advise of changing dampers only and getting a feeling for that first.
If I feel I'm still longing performance I'll eventually go with the 200/800 setup.
Thank you all for the good advises.

 

[Bluemustang]

I say go straight to SP083s all around and FP dampers and don't look back. Embodies the spirit of what this thread is about - high rate, minimum drop. You can't get any better than this for a standard size, linear spring.
I call it GT350R+. The ride frequencies are well balanced and a definite handling improvement.

 

[Jonyxz]

I say go straight to SP083s all around and FP dampers and don't look back. Embodies the spirit of what this thread is about - high rate, minimum drop.

I know its a tested and appreciated setup. However, it feels like a risky choice (without testing) considering the roads around here. But I agree: its the spirit of this thread.

 

[Bluemustang]

I know its a tested and appreciated setup. However, it feels like a risky choice (without testing) considering the roads around here. But I agree: its the spirit of this thread.

Yeah. And that's a subjective thing to a certain degree. Also, if the roads are really bad, I find it difficult to go fast i.e. actually utilize the handling improvement.

 

[KellTrac]

So I picked up a 2020 GT PP1 car to play with. First round of mods (suspension) are on order.

-GT350R Front Springs
-GT350R Front SwayBar
-GT350 Monotube Front Struts
-BMR Camber Plates
-BMR Adjustable Bar End Links

-GT350R Rear Springs
-GT350R Rear SwayBar
-2020 PP Rear Shocks
-BMR Adjustable End Links
-BMR Rear Camber Lockout Kit
-BMR Toe Rods w/ FP Toe Bearings
-BMR RLCA Bearings

From a performance stand point, I really like the stock PP rear shocks. Always have.

I was actually planning on getting the M-18000-F FP Track Damper kit, but they are like "35 days out" apparently.

This combo I have chosen, I feel is perfect for a nice performing streetcar.

 

[shogun32]

2020 PP Rear Shocks

you lost me. Your PP1 already has 'pp rear shocks'. And you like them? Eek, they are the worst part of the whole package. And you're expecting them to cope with even higher spring rates? The Steeda pro-action adjustables will do as well and aren't backordered AFAIK.

I note the lack of any shifter, IRS or differential fixes. Any particular reason why?
You don't need to use the 'puck' differential kits - they make very noticeable (if intermittent) noise, but at least do the bolt upgrade with the bushing that fixes Ford's gaff.

For what it's worth I have a spare set of Steeda pro-Actions in a box with low miles on them.

 

[KellTrac]

I have extensively tested the PP rear shocks. On shock dynos and on track, and drag racing - etc.

I don't really see why people do not like them, personally. I see people ramble on about how various parts arent this, or arent that....and most often times I see people blame some parts for something that is totally caused by a part they don't even mention.

I think the OE PP rear shock could have a bit more extension controlling forces. If it did, it would be a homerun.

As for the IRS stuff, down the road I may tinker with some stuff. I have developed a lot of stuff for people already, but I never stop learning.

As for the Steeda (Konis with a little change to call them different) dampers, I am good.

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