The Mustang Forum for Track & Racing Enthusiasts

Taking your Mustang to an open track/HPDE event for the first time? Do you race competitively? This forum is for you! Log in to remove most ads.

  • Welcome to the Ford Mustang forum built for owners of the Mustang GT350, BOSS 302, GT500, and all other S550, S197, SN95, Fox Body and older Mustangs set up for open track days, road racing, and/or autocross. Join our forum, interact with others, share your build, and help us strengthen this community!

S550 GT350R Race Car Build Build Thread Profile - S550 Mustangs

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Great Shakedown today. Wet in the morning, so I took it steady, bedded the brakes, and got a feel for the car. It's LOUD, way louder than my Boss 302 with Long tubes and open side pipes -- gonna need ear plugs :)

Need to move the dead pedal as it's too close to the clutch, and the driving position will take some getting used to, as I had to drop the seat 1.5" and move it inboard to avoid my helmet hitting the side roof bar -- the S550 package with a cage is way tighter than the S197 with a cage. With the lower seat position I lost a few of my normal reference points.

Used Contis for the first few sessions, and the car was loose, especially the rear. Experienced the same in the 350R on the same tires to a lesser extent, so I softened the rear sway bar, and increased rear wing -- time improved to slightly better than the 350R on the same tires, on a very green (drying) track.

Switched to Hoos R7's and times got a lot better -- 1+ seconds faster than the R on a Dry, but green track with more much more throttle lifting than in the 350R to avoid max rpm late in 3 segments of the track and one high speed corner, where I probably need more wing.

Perhaps, not surprisingly, it's a very different car to drive (compared to the 350R) anywhere close to the limit: Throttle response is way more aggressive, the increased torque, lower weight and reduced rotating/unsprung mass are very apparent. Brake performance is slightly better, which is a real shout out to the OEM Brakes, although the AP brakes are WAY lighter, enable the use of 18" wheels, and likely need proper cooling ducts to get even better performance, especially for trail braking.

I need to download the AIM data and look at back to back performance to the 350R for more detailed insight.

A VERY encouraging first outing -- Fun!!

OD23shXFQEuRx08fKs8Gvw.jpg

fprbd7EYRLCiN5DZrcr8Qg.jpg
 
Last edited:
Specifically which suspension torques are you checking/are the most important?


Sent from my iPhone using Tapatalk

I paint marked everything during the build. Checked all the Suspension Paint Marks and (sample) torque checked Front Struts, Rear Camber and Toe Links as I figured they are the most likely to move (I swapped out the splined blots in the front strut, which wouldn't move, to plain bolts to get more camber).
JygEuNP1SBi08patzHyIPw.jpg
ex4hyiGtSTOlMPHhBRlIwA.jpg
 

ArizonaBOSS

Because racecar.
Moderator
8,730
2,734
Arizona, USA
giphy.gif
 
277
161
Thank you for sharing this build. What a beautiful, badass R you have built! Has to be a great feeling to get it on the track and enjoy it.
 
At VIR today with good friends. Shakedown #2.

First session, windshield (1/4" Optic Armor) started to buckle in at 150mph. (watch the circular sticker under the mirror):

www.youtube.com/watch?v=QoDKp08QNQI

Managed to get a support fabricated for session #2.

IMG_6533.jpg

Ditched the (slower) Contis after 2 sessions.

Then had wheel balance issues -- the lighter body with Cortex solid bushings is WAY more sensitive to Tire slippage than the street car. Rear wheel vibration caused the Magneride controller connection to vibrate enough to loose CAN bus connectivity and put the car into limp mode.

Got the wheels re-balanced and looking forward to tomorrow!
 
Last edited:

TMO Supporting Vendors

Top