Your thoughts on IRS

2morrow

DesignR/DriveR/RiceEatR
Joined
Nov 15, 2015
Threads
45
Messages
5,418
Reaction score
4,423
Location
NorCal Bay Area
First Name
Todd
Vehicle(s)
'16 Mustang GTPP
I can tell the difference every time I drive it. Especially when i push it to the limits.
GBME1535.jpg


Without the addition of IRS it wouldn't have enjoyed the success it has been experiencing especially in the global market.

 

Sivi70980

Well-Known Member
Joined
Feb 28, 2019
Threads
17
Messages
3,591
Reaction score
5,604
Location
Lacey, Washington
First Name
Mark
Vehicle(s)
2019 Ruby Red GT PP1 M6

hlh1

Well-Known Member
Joined
Jul 10, 2017
Threads
11
Messages
670
Reaction score
185
Location
Central VA
Vehicle(s)
2019 GT PP1 A10
Per my signature I've had several solid rear axles that were ok, but the first time I drove a S550 I was amazed. The IRS made the Mustang a GT car, instead of a drag car. I can get on the gas in a hard turn with the IRS and keep traction (I know, traction control helps here) and not go out of control sideways like would happen with my 95 Cobra with a Vortech. I always had to be very careful with the throttle on the solid rear cars. Sure, it's fun stepping out with the solid axle but I can hook up and go with my 19GT.
 


8GTOKLR

Well-Known Member
Joined
Feb 21, 2021
Threads
1
Messages
78
Reaction score
54
Location
California
Vehicle(s)
'19 DHG Bullitt
OP:

Stock Sloppy Solid vs IRS...The Solid is better

2000 Trans Am Owned
2003 Cobra Owned
2002 M5 Owned
 
Last edited:

Mikthehun1

Well-Known Member
Joined
Oct 2, 2018
Threads
38
Messages
9,446
Reaction score
15,957
Location
SJ
First Name
Mik
Vehicle(s)
19 GT a10, 19 Charger Scat Pack

Dr. Norts

Banned
Banned
Banned
Joined
Nov 3, 2016
Threads
27
Messages
1,241
Reaction score
988
Location
Ontario, Canada
Vehicle(s)
2015 Race Red Mustang GT

8GTOKLR

Well-Known Member
Joined
Feb 21, 2021
Threads
1
Messages
78
Reaction score
54
Location
California
Vehicle(s)
'19 DHG Bullitt
At what exactly?
The solid has less moving slush than the IRS. Mounting points, pivot points etc...

Count it out when you watch any video of the S550 by an aftermarket company showing the IRS deflection

Subframe mounting (4)
Upper and lower crtl arms both sides(8)
diff mounts (4)
Verical links (2)

Thats 18 areas of slop. oops dont forget toe links thats 20
 

Norm Peterson

corner barstool sitter
Joined
Jul 22, 2013
Threads
11
Messages
9,011
Reaction score
4,695
Location
On a corner barstool not too far from I-95
First Name
Norm
Vehicle(s)
'08 GT #85, '19 WRX
Per my signature I've had several solid rear axles that were ok, but the first time I drove a S550 I was amazed. The IRS made the Mustang a GT car, instead of a drag car. I can get on the gas in a hard turn with the IRS and keep traction (I know, traction control helps here) and not go out of control sideways like would happen with my 95 Cobra with a Vortech. I always had to be very careful with the throttle on the solid rear cars. Sure, it's fun stepping out with the solid axle but I can hook up and go with my 19GT.
The S197 Mustang's stick-axle suspension underwent major handling improvement over the triangulated 4-link suspensions used on the Fox/SN95/New Edge Mustangs that preceded it. Those earlier Mustangs were known for snap-oversteer.

The S197 probably represented as much improvement over the Fox (Fairmont)-based 4-link as people are saying the S550's IRS has over the S197. Maybe even more improvement.


Norm
 

Mikthehun1

Well-Known Member
Joined
Oct 2, 2018
Threads
38
Messages
9,446
Reaction score
15,957
Location
SJ
First Name
Mik
Vehicle(s)
19 GT a10, 19 Charger Scat Pack
The solid has less moving slush than the IRS. Mounting points, pivot points etc...

Count it out when you watch any video of the S550 by an aftermarket company showing the IRS deflection

Subframe mounting (4)
Upper and lower crtl arms both sides(8)
diff mounts (4)
Verical links (2)

Thats 18 areas of slop. oops dont forget toe links thats 20
:like:
 

edco

Well-Known Member
Joined
Jan 3, 2014
Threads
2
Messages
232
Reaction score
201
Location
St. Louis, MO
Vehicle(s)
2007GT & 2017V6_ great Steeda & AM mods
Interesting thread. I rural road surf and safari. Handling/suspension is more important than power to me. Bought the '17 V6 just to experience the IRS. No comparison in stock trim, the S550 is better. However, the '07 GT is handling modified over a four year quest. It is very good and IMO better than the ‘17 IRS pony in stock trim.

2007 GT
After-market mods: Caster camber plates, KYB GR2 shocks and struts, 1.2" lower springs, Steeda upper 3rd link, rear control arm relocation brackets, adjustable rear control arms, Detroit true track helical diff, Center Force dual friction clutch, Fays2 Watts link, Steeda G-Track front brace, Eibach sway bars, Ford racing strut tower brace, GT 500 front control arms, Baer Front brakes, Coast 4" dia. one piece aluminum drive shaft, Ford Racing 3.73 rear gears, Steeda X-Brace. HR 1" Track Spacers, P275/40R18 all four corners.

It took time to get the roll center, alignment, camber angle, pinion angle, and Watts link tuned. It was worth it. With Tremec 3650 trans on extreme climb/dive/turn E. MO hills the GT corners and runs with the best German cars and a Maserati.

2017 V6
On the S550, I spent no where near as much to tune the handling. The S550 is just a better chassis over S197. S550 Mods: Steeda: IRS Sub-Frame Braces, Extreme K-Member G-Trac Brace, Adjustable rear toe-links, Billet vertical Links, Caster camber plates, Billet rear shock mount. Then, H&R 24 mm wheel spacers. Eichbach sway bars. Bilstein shocks and struts. Under $3K mods total. I run the stock wheels and tire size. If you can afford the mods, buy them. Steeda engineering works! After mods the car feels like a different car. The tires sound different. Everything is more precise and tight, with great feedback and response. Best handling car I own.
 

Sivi70980

Well-Known Member
Joined
Feb 28, 2019
Threads
17
Messages
3,591
Reaction score
5,604
Location
Lacey, Washington
First Name
Mark
Vehicle(s)
2019 Ruby Red GT PP1 M6
OP:

Stock Sloppy Solid vs IRS...The Solid is better

2000 Trans Am Owned
2003 Cobra Owned
2002 M5 Owned
Pretty sure lap times at tracks around the world disagree with this.
 

obgod3

Well-Known Member
Joined
May 26, 2015
Threads
9
Messages
559
Reaction score
362
Location
N.C.
Vehicle(s)
2019 GT, PP1, 401A, A10
I dont know how someone cant tell the difference but I am sure it an happen also. My 19 vs my buddy’s 13 Boss 302….my 19 all day long. The boss is amazing and super fun to drive but Ill take the IRS all day long. I had a 83 GT and a 89 LX 5.0 and frankly I would never compare those to the new mustangs at all.
 

 
5 - Hypermotive - 1
Top