Will the new GT350 brakes fit an S197 car?

Tob

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I'm trying to answer that question.

For now, I'm holding off on the rear calipers/rotors as the IRS uses a different caliper design compared to that of the solid axle. Up front, things look quite a bit more promising. I'm going to compare the '15 GT350 setup to that of the '07-'12 GT500 Brembo rotor/caliper arrangement because it is far more popular than the '14-'15 GT500 brakes. That is not to say that you couldn't swap the latest Brembo/SHW hardware on the most recent GT500 as once you strip off the caliper and rotor you are left with pretty much the same spindle as used throughout S197 production.


So I started by taking a few key measurements off of a S197 wheel hub and sketched a model that would allow for fitment verification between the hub and each rotor. It isn't a complete model as it doesn't have to be - yet, anyway.

S197%20hub%20preview.jpg






I have some NIB '07-'12 Brembo GT500 rotors in storage that I pulled out to dimension. They measured 13.9" in diameter, 1.259" thick, and have a hub register diameter of 2.797" (the hole in the rotor that mates with the stub portion of the hub). I mated the rotor/hub in Solidworks for a baseline. I didn't sketch the vanes as they aren't needed.

S197%2020.jpg


S197%2019.jpg







I then mated a sketch I did of the GT350 rotor to the S197 hub. I didn't sketch the vanes on the ring or the surface extrude cuts on the hat but the sketch has the proper base dimensions needed for this comparison. Note, the GT350 hubs use a 14mm wheel stud whereas the S197 hub uses a smaller, 1/2" x 20 stud. Same bolt circle between the S197 and the S550, just a minor difference in stud diameter. The SHW hub register matches the diameter on the Brembo rotor (thanks Ford!) and the hat thickness is the same between rotors as well (.315"). Looks good so far...

S197%204.jpg


S197%206.jpg







The GT350 rotor hat has 15 radial mounted pins that slip into the outer ring, allowing it to expand/contract as necessary. I sketched them as a simple straight pin but in reality they are shaped like a "T" (the length and diameter I used are correct). Note that they are offset in the friction ring as opposed to being located in the center. Anyway, by making the GT350 rotor transparent, you can see that it clears the fillets/chamfers where it mates with the hub.

S197%2017.jpg






I then slipped a purple-ish/transparent GT500 Brembo rotor into place so that you could visualize the difference in fitment between the two. The GT350 rotor is a monster in comparison to the earlier rotor.

S197%2015.jpg


S197%2010.jpg


S197%2013.jpg







You can see that Ford moved the rotor inwards, which would make sense as a larger diameter rotor teamed with the equally massive six piston Brembo caliper, need to leave room for wheel clearance. How do the rotor face locations compare when using an S197 hub? The outer rotor face moves in .31" on the GT350 SHW.

S197%2014.jpg






The inner rotor face moves in by .45" (that's almost 1/2" for the Common Core generation).

S197%2018.jpg






That inner dimension means that the rotor face is now even closer the the steering arm on the spindle as well as the outer tie rod end. I need to verify the clearances there as things were already in fairly close proximity. If the rotor makes it past that potential hurdle the next one becomes how to attach the new GT350 radial mount caliper since the S197 spindle to caliper bolts are perpendicular to the rotor instead of parallel on the GT350's knuckle/caliper arrangement. That can be remedied with a bracket/studs, much like Brembo already uses (as does Stoptech, etc) on typical big brake kits. Here's a sketch of a Wilwood bracket that attaches to an S197 spindle to allow a radial mount caliper.

S197%20spindle%20and%20bracket.jpg






I'm unsure as to caliper clearance as I don't have any data on the six piston beauty from Brembo but I'm working on it. If it gets a pass that would mean a simple bolt-on up front. Bias may not be optimized depending on your current rears but that could be attended to easily enough. I'm waiting on Ford Parts to release some GT350 hardware for verification so it may be a bit before I can do an actual mockup. Could be a nice mod using factory Ford hardware.
 

Tob

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That means a lot coming from you two. One with a recent big factory Brembo swap and the other with Boss 302S "PWC ready" Brembo's. :beer:
 

DaFreak

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Ha Tob! You're the rock star here. I would love it if the crossed drilled rotors might fit with my setup. I know u will deliver the truth :)
 

Tob

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2015 GT350 SHW front rotor from Mike at Autonation showed up today. All I can say is that when I peeled back the packing - dayum. Easily the most attractive factory street rotor from Ford I have ever seen.


IMG_0521.jpg



IMG_0522.jpg



Fitment on a S197 hub when I can...
 

2010 Red&white

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Good investigative work ! I like it when the numbers decide the answer instead of one guys opinion . Thanks for all your efforts.
I look forward to the answer.
 

Tob

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My apologies as I've been tied up with other projects as well as a bit busy with family.

Just as the sun was setting tonight I opened up a few boxes and pulled out an OEM Ford S197 spindle, a low mileage S197 hub and nut (from my own GT500), and the SHW GT350 rotor.


k1108151707_HDR_resized.jpg





Boom.


k1108151709_HDR_resized.jpg




I sucked the rotor in tight to the hub with some lug nuts and took a closer look.


k1108151715_HDR_resized.jpg



k1108151713_HDR_resized.jpg





Hub register is a perfect fit as it should have been as is the bolt circle (5 x 4.5). Note the steering arm portion of the spindle in the next photo as that is where clearance has been reduced over typical S197 rotor. I actually envisioned it as being a hair worse than it is.


k1108151714b_HDR_resized.jpg





Clearance is about 7/16".


k1108151714_HDR_resized.jpg





The ears for the caliper are closer to the rotor face as well.


k1108151716a_HDR_resized.jpg



k1108151716_HDR_resized.jpg




I saw no less than 1/2" there.
 

Tob

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They are made by SHW in Germany. They only have about 300 or so employees, a relatively small number of employees when you compare them to Brembo, the previous rotor supplier for watever year top dog Mustang in recent years. They are far and above the best rotor to ever come on a street legal factory sale Mustang.

Here's a writeup I did a year or so ago on SHW.

http://www.svtperformance.com/forum...407-GT350-SHW-Composite-Brake-Discs&highlight
 

railroad

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Looks like the rotors are directional.
Are they marked L or R ?
Do the vanes go where they capture air or draw it?
 

Tob

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The rotors are indeed directional.

https://youtu.be/UPFPtNDBNHM?t=15m20s


The part numbers obviously call out a specific side but I have yet to look closely for a marking on the rotor or hat itself. According to the following article they draw air in. The verbage doesn't inspire much confidence in my view though.

http://www.torquenews.com/106/new-ford-shelby-gt350-mustang-features-world-class-brakes

...the GT350 front rotors use curved, directional fins to draw more air into the rotor than a traditional vented rotor with flat fins.
 

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