R-springs on GT350

[modernbeat]

Actual spring rates the car sees have to take into account the spring rate from the rubber bushings, any rubber mounts and the tires. Damping has to account for the "shocks", any rubber bushings, rubber mounts, and tires.

 

[8250RPM]

Thanks Jason. So both F&R? What about the R shorter rsb end links? Thoughts on adding that to possibly balance the front and rear? I'm have cup 2's in 305 square for the track.

The sway bar end links are the same for all mustangs including all versions of the GT350 track pack, tech pack & R. The Rear R sway bar is different then the non R.

 

[JAJ]

@JAJ thanks for calculating the effective rates. Now I'm really confused. Sound like you have a chart of this, if so can you please post a screen shot of it?

 

[bpracer]

The sway bar end links are the same for all mustangs including all versions of the GT350 track pack, tech pack & R. The Rear R sway bar is different then the non R.

Do you know how it is different? The diameter is the same from what I've read.

When I look up the part using both an R and my VIN on fordparts.com, I come up with the same part 5A772.

 

[8250RPM]

Do you know how it is different? The diameter is the same from what I've read.

Correct the diameter is the same, the end link holes are .312 inward. I have both bars and both have different part numbers.

 

[bpracer]

What's the part number?

 

[VoodooBoss]

So making the bar shorter effectively makes it stiffer. Are the front bars the same?

 

[bpracer]

So making the bar shorter effectively makes it stiffer. Are the front bars the same?

It certainly makes a lot more sense, if that is the case we know the "arms" are the length on the actual bar itself. This was always confusing about the exact meaning.

GT350
Rear stabilizer bar
22.2mm DIA x 3.9mm wall (0.87 x 0.15 in)
GT350R
22.2mm DIA x 3.9mm wall (0.87 x 0.15 in )
with 8mm (0.31 in) shorter arms than GT350

Of course, this is what they said about the spring rates...

GT350
Front spring rate
34 N/mm (194 lb/in)
GT350R
42 N/mm (240 lb/in)
GT350


GT350
Rear spring rate
160 N/mm (914 lb/in)
GT350R
160 N/mm (914 lb/in)

 

[8250RPM]

I found out pestering my parts guy and he kept telling me the end links were the same part number for all mustangs front and rear. When I asked him to check all the sway bars is when we found it. Yes the front is the same part number on all GT350/R. I still think the R springs lower the car 1/2" or so compared to non R springs. Now that I have my vorshlag camber plates on the way I'll find out for sure. I also have 4 forgeline ga1R open lug 11x19 and 4 psc2 305/30ZR19. These alone are 1/2" shorter. But looking at this pic to me is more then 1/2" lower. I honestly believe the R is 1 " lower then non R's. I don't think ford would install transportation spacers for just 1/2".


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[bpracer]

Ah, fordparts.com does not give the "real" part number, but the prices are different for the two bars.

 

[8250RPM]

Do you know how it is different? The diameter is the same from what I've read.

When I look up the part using both an R and my VIN on fordparts.com, I come up with the same part 5A772.

Gt350 R. Fr3z 54772 G
Gt350. Fr3z 54772 E

 

[bpracer]

Having two sets of springs with the same ride height and two different rear sway bars allows for quite a few tuning combinations to try for different tire widths, etc.

 

[bpracer]

Having two sets of springs with the same ride height and two different rear sway bars allows for quite a few tuning combinations to try for different tire widths, etc.

This is the after height, it looks the same to me. All the after heights were within an eighth of an inch, some even higher. Maybe the springs will take a set, one would hope not or they aren't good material.

 

[bpracer]

Gt350 R. Fr3z 54772 G
Gt350. Fr3z 54772 E

I have an "Fr3z 54772 G" on order. I'm really glad these parts are so cheap, list is <$80, the good guy price is dirt cheap.

 

[8250RPM]

This is the after height, it looks the same to me. All the after heights were within an eighth of an inch, some even higher. Maybe the springs will take a set, one would hope not or they aren't good material.

This pic is with GT350R springs installed? Do you know your before and after height measurements?
Are the tires in the pic stock gt350 tires sizes? Can't make it out on my phone.
Did you do a suspension relearn?

 

[bpracer]

This pic is with GT350R springs installed? Do you know your before and after height measurements?
Are the tires in the pic stock gt350 tires sizes? Can't make it out on my phone.
Did you do a suspension relearn?

Stock MPSS tires

I don't know about a suspension re-learn?

Before
LF 27 7/8" RF 28"
LR 28 1/8" RR 28 3/16"

After
LF 28" RF 28 1/16"
LR 28 1/8" RR 28 1/4"



A quick measurement and they are probably 1/16' -1/8' lower now, definitely not 1/2" lower over the original springs.

 

[bpracer]

Stock MPSS tires

I don't know about a suspension re-learn?

Before
LF 27 7/8" RF 28"
LR 28 1/8" RR 28 3/16"

After
LF 28" RF 28 1/16"
LR 28 1/8" RR 28 1/4"



A quick measurement and they are probably 1/16" -1/8" lower now, definitely not 1/2" lower over the original springs.

 

[8250RPM]

Something doesn't seem right about your ride heights. The R sits 1" lower then the non R and the tires alone are 1/2" of that. So the springs should drop it 1/2". A relearn is needed anytime the suspension is serviced. It must have all 4 wheels off the ground and the cars weight supported on a lift or jack stands. A scan tool is needed to do the relearn.


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[bpracer]

Something doesn't seem right about your ride heights. The R sits 1" lower then the non R and the tires alone are 1/2" of that. So the springs should drop it 1/2". A relearn is needed anytime the suspension is serviced. It must have all 4 wheels off the ground and the cars weight supported on a lift or jack stands. A scan tool is needed to do the relearn.


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The Magna-ride was not touched. I don't see how it can have the capability to adjust static ride height, so how can a "re-learn" affect the ride height?

 

[8250RPM]

Correct it does not effect ride height or static ride height. But if the springs lowered the vehicle at all or if the struts/shocks were replaced or removed they should be relearned. Have you driven the car since replacing the springs with the R springs? Any notice in ride or handling?


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