Haggard-hawk

**SSlowBoat** · 01-11-2021, 06:29 PM

Originally Posted by rentedmule

I like my LS brakes with EBC Yellostuff pads. Enough power for auto-X (on 315s) and they held up well on a lapping day. What are you doing for swaybars? Can you swap them in STU? Are rod-ended suspension parts legal in STU? The Watts may bump you if anyone is paying close attention. I also have a C7 hub kit that I got through a group buy on FRRAX ready to install now. The adapters weren't too bad but decent hubs aren't cheap!

i have seen ls calipers spread when tracked hard.

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**rentedmule** · 01-12-2021, 07:08 AM

I hadn't thought about the Watts rod ends being in a different location, that would put it in a grey area for sure. The top ESP car in our region ('10 Mustang) runs one and he's a stickler for rules so I'll assume it's legal! I have rod ends on the axle side of my rear LCAs so I could be kicked out of ESP for that. Our club is reasonable - people recognize that a relatively heavy, 25 year old, solid axle RWD car needs more than a few bushing changes to compete for FTD.

I have about $900 USD into my C7 hub setup with SKF hubs and ARP studs. Jim Dulaney (can't recall the name of his company) offered them as a GP in early 2019. I can grab some pics the next time I'm in the shop if it would be useful to you. The adapters felt damn solid and were machined to allow the hub to slide into them. It was a super tight fit. When my R888's give up I'll run A7's and I didn't think stock hubs would hold.

**Catmaigne** · 01-12-2021, 02:40 PM

Originally Posted by rentedmule

I have about $900 USD into my C7 hub setup with SKF hubs and ARP studs. Jim Dulaney (can't recall the name of his company) offered them as a GP in early 2019. I can grab some pics the next time I'm in the shop if it would be useful to you. The adapters felt damn solid and were machined to allow the hub to slide into them. It was a super tight fit. When my R888's give up I'll run A7's and I didn't think stock hubs would hold.

If he's the guy I'm thinking of, I believe his site is rrsusp.com. I couldn't find pics of his C7 hub adapter online, but I assumed they would resemble the earlier x-tracker adapters with revised dimensions. If you could share pics, that'd be great.

I'll have to find my notes that I took when I dimensioned the C7 hub, factory hub, and stock LS spindle. I tried preserving the stock track width when designing my own, but found that it would only leave a few mm of thickness behind the C7 hub's dust seal. I pried the seal off to see if there was any room to spare, but there isn't. I decided to widen the track width a tiny bit to increase the factor of safety there being that it's responsible for supporting the weight of the car. I ran a few FEA's and liked what I saw. I also spaced out the bolts that hold the adapter to the spindle a tiny bit because the threads were very close to the large OD of the C7 hub making cracks likely. The mounting holes in the spindle might need to be reamed out a tiny bit because of this.

I made a fancy version CNC version to submit to Xometry, but producing it without volume made it costly. I made a simpler version for manual machining that I'm gonna prototype soon, it looks like this:

hub3.png

**Catmaigne** · 01-12-2021, 02:43 PM

Also, these showed up:

0112211354a.jpg

The basic plan is to run the stock CTSV1 Ferodo pads up front and 14" Camaro SS rotors with the hubs bored out. I might need a small wheel spacer, 8-9mm max probably. The rear is getting new rotors and some Power Stop Track Day pads. Hopefully the brake balance will be reasonable.

**rentedmule** · 01-15-2021, 07:11 AM

The calipers look great, I'm jealous!

SSlowBoat - what do I look for to tell if an LS caliper is spreading? Will it start to leak?

Here are some pics of the hub setup. I had them partially assembled and lock-tited together and it was only 12F in the barn last night so I didn't feel like disassembling them:

20210114_200146 by Rented Mule, on Flickr

20210114_200111 by Rented Mule, on Flickr

20210114_195952 by Rented Mule, on Flickr

20210114_200003 by Rented Mule, on Flickr

20210114_200016 by Rented Mule, on Flickr

The small tabs are for mounting cooling ducts

**Catmaigne** · 01-15-2021, 04:03 PM

You'd be able to tell if they've spread if the pad wear has a taper to one side rather than wearing them evenly. I'd imagine there'd be a lot of material left on the inside edge of the rotor near the hat and heavy wear on the outermost diameter. Basically the heat and pressure of track driving causes the caliper fingers and piston tops to no longer be parallel, so the caliper goes from being U shaped to V shaped.

**Catmaigne** · 01-17-2021, 03:59 AM

Here's cross sections of my C7 hub adapter (left) vs. what the other guy's should look like. I beefed up the locating hub ring that fits into the spindle by widening the track width slightly. Was trying to decrease chances of shear from driving on bumpy roads. If the ring cracks, then the car is being held up by 4x M10 class 10.9 bolts.

The locating hub ring on his version would have 2.5mm thick walls assuming 0.5mm clearance on each side. The stock f-body hub ring I measured was ~4.25mm thick and is made of some kind of forged steel. It also extends much farther into the spindle than what I'm seeing on his adapters, which would worry me because the stock spindle already has a big chamfer on it. Maybe the OE unit is overengineered? Can't say, I have no data on what forces it would see hitting a pothole on I95.

c7hub.jpg

**shownomercy** · 01-18-2021, 06:40 AM

That xsection to the right is a big oof for stress concentrations. Just going 4340? Or something more exotic?

**Catmaigne** · 01-18-2021, 10:51 AM

Originally Posted by shownomercy

That xsection to the right is a big oof for stress concentrations. Just going 4340? Or something more exotic?

Jim D's original design is made of 4130. The Strano and Detroit Speed clones are said to be made of "alloy steel," so I'm guessing it's the same 4130 or 4140 steel. If someone were making them out of 4340, I'd imagine they'd advertise it as that stock is way more expensive. They're all said to be hardened, but whether or not that's during post processing is a mystery.

I ordered a disc of 4140 prehard to prototype one on. I'm gonna try testing the hardness using the old ball bearing trick at different points along the radius, so hopefully it'll be harder at the hub ring than whatever mysterious forged steel the OEM hub is made out of. If not, I could try quenching it at home.