Rear Sway Bar: GT350 vs GT350R

[Darkhelmet22]

Still loving the GT350R sway bars.

Randy Probst discussing the Performance Pack 2's

• Front and rear anti-roll bars that resist twist by an additional 12 and 67 percent, respectively vs the PP1.

"The racer in me would put a little more front anti-roll bar in it, to tame a little too much oversteer in the entry phase, and later when I go to power."

I think the stiffer GT350R sway bars do the trick and make a great PP1 upgrade.

I love them too. I have nothing but good things to say about them, especially for the price.

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[SVT-DADDY]

I love them too. I have nothing but good things to say about them, especially for the price.

I really wouldn't want anything more for a bar in these cars for a street car.

 

[Performance nut]

Did they make the newer GT350 bars thicker or is this a typo: https://lmr.com/item/M5700N/shelby-gt350-sway-bar-spring-kit-ford-performance-15-18

 

[Niz55]

Newer bar? That is the onky frpp gt350 bar. They are 37mm front and 25.2mm out back. Is ok nothing special. I still prefer the steeda units.

 

[TheLion]

Still loving the GT350R sway bars.

Randy Probst discussing the Performance Pack 2's

• Front and rear anti-roll bars that resist twist by an additional 12 and 67 percent, respectively vs the PP1.

"The racer in me would put a little more front anti-roll bar in it, to tame a little too much oversteer in the entry phase, and later when I go to power."

I think the stiffer GT350R sway bars do the trick and make a great PP1 upgrade.

Probst's comments are exactly what BmacIL was talking about over in a another thread I've been frequenting. The GT350 and GT350R run the same front bar. But the rear bar on the GT350R (and the springs) is one of two variants that has more anti-roll than the regular GT350 (they may have changed it year to year).

The GT350R either has a 22.2 mm bar with 8 mm shorter mounting points (it's a lever, so effectively stiffens the bar) than the GT350 / GT PP rear bar or the GT350R rear bar is a 24 mm bar with likely the same mounting points. My guess is they might of had some issues using the same diameter bar but with shorter mounting points from a linearity standpoint. Could maybe put more stress on the ball joints in the end links? The shorter mounting points will result in greater motion ratio on the same bar vs. using a larger diameter bar at the same lengths. My guess is that at one point it did use a 22.2 mm with 8 mm shorter mounting points and then was changed either mid-year or next year models. It's not something they would advertise and may even forget to update their literature.

But take a look at the numbers:

GT350/R Front Springs = 240 lbs/in
GT350/R Rear Spring = 914 lbs/in
GT350R Front Sway bar = 34 mm
GT350 Rear Sway bar = 22.2 mm
GT350R Rear Sway bar = 24 mm (latest spec)

Now think about Probst's comments, he wants a little more front bar (or a little less rear bar). Adding more front bar might make it a bit more edgy as opposed to reducing rear bar. Both would reduce steering, but one would corner ever so slightly flatter but be ever so slightly less forgiving. Not sure if a little more edge or a little more give is good or bad in this case, I'm far from a Probst as far as driving skill goes. HOWEVER, look at what BmacIL is considering running (he's already running the springs and dampers):

@BmacIL Setup:
FP Track Dampers (they have GT350 valving / damping rates)
BMR SP073 Front Springs = 250 lbs/in
BMR SP073 Rear Spring = 980 lbs/in

BMR's rear springs are a bit stiffer than GT350/R rears, about 7%. So they will produce a little more anti-roll and a little less dive / squat than GT350/R rear springs, but a little more under steer as well (assuming the only difference was the springs on the same car). BMR's fronts are 4% stiffer than GT350/R fronts, but the ratio F/R is a little stiffer rear than front in the BMR biasing as opposed the GT350/R biasing.

Running a little more rear spring (SP083's) and a little less rear bar (PP GT / GT350 22.2mm) would give you very similar handling dynamics to what Probst was talking about. More anti-roll up front can be accomplished by less anti-roll in the rear without changing how flat the car is in the corner.

There's two ways to change anti-roll: 1. more or less bar 2. more or less spring

Running a little more spring and a little less bar however keeps your rear more independent and allows for better traction on bumpy roads. Some tracks are very smooth and a little more bar and less spring may be better if you want to maintain dive / squat characteristics. But a little more spring and a little less bar reduces dive / squat, increases anti-roll and I think the biasing of a 34 mm bar up front and a 22.2 mm bar out back with SP083 springs and FP track dampers would be simply fantastic!

This is not a drastic change from an known good OE setup. It's more or less a small tweak to it. The OE setup is good, but it can always be improved. That's why the 2019 GT350 is not running identical Aero and suspension setup as the 2015-2018 GT350. That's why the 3rd Gen 5.0 uses Direct Injection and Wire Arc Plasma Transfer cylinder liners instead of Port Injection and the 2mm cast iron cylinder liners in the 2nd Gen 5.0 like mine.

Those are all improvements, some are artificially planned to keep selling cars, newer looking, better handling and faster models. Some are due to time constraints (I read an article that said the 5.0 developers wanted to go DI with the 2nd Gen 5.0 but didn't think they could get it to pass emissions on their time table so they went the safe route with Port, otherwise the 2nd Gen 5.0 with DI would probably have made similar power stock as it's does with Port Injection and a Power Pack 2 by giving up low octane fuels).

In my experience OE suspension setups are always a good starting point and they are designed to work as a system. All suspension setups are. Just look at my recent bout with an Audi RS5 on a back road, that car out handled my mostly stock PP GT like it was nothing, even though we were neck and neck in a straight line, once the corners started it was good night. Yah yah, it's a $70,000 AWD car with an electronic center diff, torque vectoring diffs etc. vs. a $28,000 car with a mechanical Torsen, but it shows how well tuned it's suspension / drive train was (and tires) and how much confidence that driver had that I didn't to use that power in corners when I dared not.

But even that car can improve handling wise if changes are made in a careful and thought out manner. It's not perfect. And because you alter the OE dynamics doesn't mean your necessarily going to screw it up if you understand what your doing.

 

[Mikepol2]

OK I have tried really hard to read and understand all 14 pages of this thread but came up a little unsure so...

I have a 2018 GT with PP1. I did not like how it wanted to roll and understeer on our twisty, hilly, 40-60 mph western PA roads, but don't plan to take it to the track.

So I installed a set of GT350 wheels and tires. The turn in and cornering are much better, I love the setup.

I also want to install better sway bars that will give another cornering improvement.

I do not want to change my springs or dampers. I prefer the look of the car as-is, not lowered; and I don't want stiffer springs that are going to give a harsher ride or make it harder to hook up on acceleration from a stop.

So all that being said, it looks like from this thread, if I install the GT350R front and rear sway bars, and use my existing PP1 sway bar mounting brackets and bushings, I should be good to go.

Can anyone give a thumbs-up to this plan? Thanks guys.

 

[BmacIL]

OK I have tried really hard to read and understand all 14 pages of this thread but came up a little unsure so...

I have a 2018 GT with PP1. I did not like how it wanted to roll and understeer on our twisty, hilly, 40-60 mph western PA roads, but don't plan to take it to the track.

So I installed a set of GT350 wheels and tires. The turn in and cornering are much better, I love the setup.

I also want to install better sway bars that will give another cornering improvement.

I do not want to change my springs or dampers. I prefer the look of the car as-is, not lowered; and I don't want stiffer springs that are going to give a harsher ride or make it harder to hook up on acceleration from a stop.

So all that being said, it looks like from this thread, if I install the GT350R front and rear sway bars, and use my existing PP1 sway bar mounting brackets and bushings, I should be good to go.

Can anyone give a thumbs-up to this plan? Thanks guys.

You will need new front brackets and both front and rear bushings in addition to the bars.

 

[Norm Peterson]

I do not want to change my springs or dampers. I prefer the look of the car as-is, not lowered; and I don't want stiffer springs that are going to give a harsher ride or make it harder to hook up on acceleration from a stop.

You can change the dampers and still keep your OE springs, as the firmness of damping does not affect ride height. I suppose it's possible for the lower spring seat height to vary slightly from one shock/strut mfr to another, but the difference there should be down around the difference between having a full gas tank and a near-empty one, or having somebody sitting in the car vs nobody inside.

You can tweak adjustable dampers to suit your own ride & handling/other performance preferences.


Norm

 

[Mikepol2]

Thanks guys, I really appreciate it.

 

[Mikepol2]

Update...

Installed the GT350/GT350R front 34mm and GT350R rear 24mm sway bars and bushings, with the new front brackets. Because I also have stock GT350 wheels and tires, I had a custom alignment done. There is an overlap in the alignment ranges between the GT350 specs and the GT PP1 specs, so now the car's alignment meets both sets of specs. The alignment was important, it was very hard to drive before getting it done. No other suspension mods. Between the sway bars, wheels and tires and alignment, I absolutely love it. Talk about handling like it's on rails compared to the stock PP1 setup. Ride is a little bumpier and the 295 front tires tramline more than the stock 255's obviously, but since it's not a daily driver I could care less. Total net cost for the wheels, tires, sway bars and alignment, less what I made selling the stock wheels and tires, was $705.

 

[Niz55]

I am actually going from 295 up front to 275. Way too much tramlining and just overkill for the street.

Enjoy the sway bars.

 

[Flyhalf]

I'd like to share my experience/doubt
I track regularly my 18 pp1.
Bmr springs with also the lockout cradle
Recently updated to FB shocks and struts .
Car feels better already .
Still lots of body roll .
My car oversteer. Same stuff of what Randy Pobst described.
I have a bigger splitter than pp2 with huge hood louvers .. with my bigger tires (285 or 305 depending the time trial classes) I think I've generated some additional down force./grip (Pp2 generates 24lbs at 80 so maybe more?)
My point is
I want to make the front swaybar stiffer .
Car rolls a lot especially on fast turns and fast change in direction .
I'll go with front BMR .
350 rear .
Althiugh some said 350 and pp1 swaybar are the same?
Please let me know
Fly

 

[BmacIL]

I'd like to share my experience/doubt
I track regularly my 18 pp1.
Bmr springs with also the lockout cradle
Recently updated to FB shocks and struts .
Car feels better already .
Still lots of body roll .
My car oversteer. Same stuff of what Randy Pobst described.
I have a bigger splitter than pp2 with huge hood louvers .. with my bigger tires (285 or 305 depending the time trial classes) I think I've generated some additional down force./grip (Pp2 generates 24lbs at 80 so maybe more?)
My point is
I want to make the front swaybar stiffer .
Car rolls a lot especially on fast turns and fast change in direction .
I'll go with front BMR .
350 rear .
Althiugh some said 350 and pp1 swaybar are the same?
Please let me know
Fly

Good plan. Non R GT350 and PP are same outer diameter. I believe that the wall thickness is different, so it's a slightly stiffer bar. Not much though. Good idea to get an adjustable front.

 

[Norm Peterson]

Might want to list which BMR springs . . . and your big splitter has probably made the car a bit aero-loose (oversteer being worse at higher speeds would be a good indication), meaning the rear aero needs some attention to get things back in balance aerodynamically.


Norm

 

[BmacIL]

Might want to list which BMR springs . . . and your big splitter has probably made the car a bit aero-loose (oversteer being worse at higher speeds would be a good indication), meaning the rear aero needs some attention to get things back in balance aerodynamically.


Norm

He has the handling springs (250/980 lb/in).

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