Originally Posted by Blown353
After a 5 (or so?) year hiatus with my car sitting in the shop gathering dust and cobwebs I've started working on it again.
One of the good things about taking a break is that several products I was interested in 5 years ago that were in their infancy or not available are now mature... and have several competitors to choose from.
One of these things I'll be needing is a new rear end. Right now my car still has a 12 bolt in it. With the turbos and an estimated 1100hp / 900 ft-lb on high boost I really should sell the 12 bolt and go 9 inch.
Yes you should. Even with a C-Clip Eliminator kit, this rear end will not be up to the job.
5 years ago there wasn't many options in the floater game for street use and the best choice at the time was probably big torino bearing ends. Now there are several street friendly floater options out there.
The car is going to primarily be a street car running on 275/315 tires (probably NT05, R888 or similar.) Possibly a few autocross sessions, maybe a track day here and there. Motor may make 1100hp on high boost but chances are most of the time I'm going to be cruising around at low boost and about 750-800hp to keep things somewhat sane.
I see several options now:
1. Stick with the big torino bearing ends. Simple, inexpensive. Possible premature axle bearing wear from heavy cornering
Yes. Ask SSLance.
, not as safe as a floater in case of an axle failure.
To me this is the biggest safety issue. When that entire wheel & axle flange comes off ... it's real ugly. Doesn't matter if you're going 40 on a Goodguys autocross course (with concrete barriers) or 100mph on a road course.
But since I won't be doing drag launches on drag slicks an axle failure is unlikely... but still possible. Convential axle & bearing setup might have a little axle flex and pad knockback which is now a concern since I'm also going to be switching to Wilwood FNSL4R radial mount calipers in the rear.
Yup. what most guys don't know is that pad knockpad is not caused by the brakes. It's caused by axle flange flex in the rear (and spindle flex in the front). True floaters eliminate the flex ... so no pad knock back.
Might have to change axle bearings every few years from cornering wear & tear depending on how hard I beat on the car.
2. One of the Mod-Lite floaters from Speedway that Ron likes. My only concern with this style of floater is the distance from the hub wheel mounting face to the back of the calipers seems gigantic.
It is ... on purpose. The caliper & rotor are farther inboard with the goal being to get them out of the wheel ... so the air can cool them. When the rear brakes are tucked deep int to the wheel, they don't get any cooling airflow ... unless you duct them. So the brakes run much hotter ... and transfer that heat to the wheels & tires. This makes the rear tires hotter than normal, reducing traction on corner exit. Moving the rear brake out from inside the wheel gets it in the airflow ... cooling it ... and keeps the rear tires cooling in track conditions.
That will require a wide axle to keep the entire hub and brake assembly inside of the wheelwells
This would be defeating the purpose.
to prevent the rear of the calipers from hitting the frame on suspension compression. It will also require wheels with lots of backspace because of that wide axle, but since I'll be ordering new wheels anyway I'm not too concerned about it.
If your frame is right next to the tires ... with say 3/4" tire-to-frame clearance ... you typically want the axle width wide enough to mate with 4.5" of wheel backspace or greater.
3. A Strange Pro-Touring floater. Appearing as more of a "street" design than the taken from racing Mod Lite, based on the rotor hat appearance the overall width between the back of the caliper and the wheel mounting surface of the hub seems much narrower than the Mod-Lite which should ease any clearance concerns.
Yes it does. This is a better fitment choice if your goal is to tuck the brakes inside the rear wheels. You are correct this is more of a street set-up & less for racing or track duty.
4. One of Chassisworks new Pro Touring floater setups. Looks similar to a C6 rear cartridge based setup, only much larger.
Great things from the mind of Chris Alston. This thing is bad ass. Those bearings are bad ass. This is a very well engineered piece. Price might its only hurdle.
Components are fairly expensive though and I'm worried about long term parts supply as the bearing cartridges and axles look like they might be proprietary. One of my buddies who is a Chassisworks dealer is going to speak with Chris regarding the long term availability of the hubs, maybe they're shared with another OEM application...
This is a proprietary bearing. I know Chassisworks will be in business long after Chris is gone, because his son is involved. So I wouldn't worry about availability for 20+ years.
5. One of the Speed Tech Chicane C6 hub based setups, although I'm not sure they'll do one for a Chevelle.
I talked to Blake @ Speedtech on this rear end a few months back. While they're not building many currently, they will & I think they'll build it however you want.
I like the idea of using OEM bearing and parking brake components for availability and ease of replacement in the future. Also makes it easy for brakes and rotors, just order for a C6 rear. I have read a little about some issues with the C6/C7 hubs under heavy use, but I haven't rear enough to make a educated decision yet.
As long as you're running the HD verison (C6 ZR1 or C7) these are rated pretty good. Bearings rated 1515# & 1080#. Not as beefy as regular floaters where the bearings are rated 1800# & 1800#. But way better than any a single Big Ford/Torino ball bearing ... not meant for thrust loads.
I've ruled out the Baer floater... while it seems like a very nicely designed package it also appears to be designed around their brakes and I'm just not that happy with the selection of piston areas of their calipers for a stout manual braking setup.
Center section will probably be a Strange HD aluminum case, 3.50 gears, S-trac posi, but that's independent of housing and axles anyways.
I suggest their light weight Nodular case, as it handles heat better. Aluminum is fine for drag racing and "ok" for longer run track duty, but the lightweight Nodular case works better & is within 2#
Anways, I'd love to hear thoughts and recommendations. I'm just getting started checking out what's the latest and greatest on the market and refining my new shopping list (currently at a T56 Magnum, hydraulic clutch setup, new rear end, ditching the C6 PBR brakes and Hydroboost for a Wilwood Aero 6 / FNSL4R manual setup, CNC dual master cylinder & balance bar setup, and on, and on...)
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