milemarker60
Senior Member
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OK, I’ll weigh in here as I have had several of you PM me on the rear discs I am using on the TR6/M3. On a racing forum I ran across Mike Munson and Steve Pike who run and wrench a TR6 on the track circuit. They have successfully been using a rear disc set-up for many years that may not have been their initial design but have tweaked it with much success to an incredibly efficient and functional upgrade. This is not a cheap system as indicated by a previous poster that was available on eBay. The central adapter is a way over-engineered piece of .75” thick aluminum.
First of all, the adapter plate is machined/milled out of a solid chunk of aircraft grade aluminum. You most note that the bracket is .75” thick at the faying surface where it bolts to the swingarm behind the hub assembly. There is also the thickness of the rotor (.33”) to take into consideration but you are replacing the thickness of the drum so this is pretty much a wash depending if you are comparing cast iron or aluminum drums. Obviously this is going to net a change in track. The conversion utilizes a set of 10.6” 280ZX rear rotors that are already the correct bolt circle but will need the hub bore machined slightly larger to fit the TR6 hub snout. The brackets are designed to use Wilwood 120-6808 Billet Aluminum calipers readily available at Jegs, Summit, etc.. You will also need a couple of 3an-1/8npt adapters for the brake pipes, a brake proportioning valve and some helicoil/recoil/timeserts for the trailing arm brackets.
The system installed flawlessly. I chose to go with Larry’s Carbotech brake pads (panther plus) both front and rear. I also installed a lever action Wilwood proportioning valve that pops through the foot-well next to the pedal box, which allows for on the move adjustments. Without the sheetmetal on the car I have it set about 50% but this will obviously change as the weight of the car increases and whether I’m on the track or street.
Please note, you will not have a functional parking brake with this installation. There are no provisions for an extra parking brake caliper on the adapter as these were designed primarily for track operations where the added weight of such a system was not desirable. I initially added an electronic line lock to the front circuit without reading the full instructions of the system. I.E., can’t be engaged more than 60 seconds as it will burn up the solenoid. With that said, I have installed a Park Lock (dune-buggy part) into the rear circuit right where the splice in the pipes are under the drivers foot well. I cut a hole in the floorboard and have the little knob sticking up through a grommet right in front of the seat, well out of harms way. This system works just like the parking brakes in airplanes. You apply pedal pressure, push the knob and it holds the pressure to the calipers until released. Will work great for those occasional times I won’t trust the engine and trans to hold it on a severe incline which will be rare.
I have driven the car several times now and the brakes just keep getting better and better as they are bedding-in. My expectations of the system were shattered as I have performed several 80+mph to 0 stops in which the G-forces have to be close to the same as those of the M3 engine’s acceleration capabilities. Awesome!
This is definitely not a cheap conversion and in no way do I think it is mandatory for our little TR6’s but I felt that my project would potentially require as strong of brakes as I could acquire. I have talked with Mike and Steve about giving out their info and they obliged. I don’t believe they have any sets at this time available but will put an order in with their local machine shop as requests meet their minimum order criteria.
Don’t forget, this is going to change the track of your car and push each wheel out about ¾”. I am using a BMW BBS 17x8 wheel with a 20mm offset (.787”) so it washes out to about a 4” back space.
If you are interested drop an email to Steve Pike: marblepea@mindspring.com
Hope this answers the questions asked of me.
Pics below are before I installed the CV Axles.
Dave
First of all, the adapter plate is machined/milled out of a solid chunk of aircraft grade aluminum. You most note that the bracket is .75” thick at the faying surface where it bolts to the swingarm behind the hub assembly. There is also the thickness of the rotor (.33”) to take into consideration but you are replacing the thickness of the drum so this is pretty much a wash depending if you are comparing cast iron or aluminum drums. Obviously this is going to net a change in track. The conversion utilizes a set of 10.6” 280ZX rear rotors that are already the correct bolt circle but will need the hub bore machined slightly larger to fit the TR6 hub snout. The brackets are designed to use Wilwood 120-6808 Billet Aluminum calipers readily available at Jegs, Summit, etc.. You will also need a couple of 3an-1/8npt adapters for the brake pipes, a brake proportioning valve and some helicoil/recoil/timeserts for the trailing arm brackets.
The system installed flawlessly. I chose to go with Larry’s Carbotech brake pads (panther plus) both front and rear. I also installed a lever action Wilwood proportioning valve that pops through the foot-well next to the pedal box, which allows for on the move adjustments. Without the sheetmetal on the car I have it set about 50% but this will obviously change as the weight of the car increases and whether I’m on the track or street.
Please note, you will not have a functional parking brake with this installation. There are no provisions for an extra parking brake caliper on the adapter as these were designed primarily for track operations where the added weight of such a system was not desirable. I initially added an electronic line lock to the front circuit without reading the full instructions of the system. I.E., can’t be engaged more than 60 seconds as it will burn up the solenoid. With that said, I have installed a Park Lock (dune-buggy part) into the rear circuit right where the splice in the pipes are under the drivers foot well. I cut a hole in the floorboard and have the little knob sticking up through a grommet right in front of the seat, well out of harms way. This system works just like the parking brakes in airplanes. You apply pedal pressure, push the knob and it holds the pressure to the calipers until released. Will work great for those occasional times I won’t trust the engine and trans to hold it on a severe incline which will be rare.
I have driven the car several times now and the brakes just keep getting better and better as they are bedding-in. My expectations of the system were shattered as I have performed several 80+mph to 0 stops in which the G-forces have to be close to the same as those of the M3 engine’s acceleration capabilities. Awesome!
This is definitely not a cheap conversion and in no way do I think it is mandatory for our little TR6’s but I felt that my project would potentially require as strong of brakes as I could acquire. I have talked with Mike and Steve about giving out their info and they obliged. I don’t believe they have any sets at this time available but will put an order in with their local machine shop as requests meet their minimum order criteria.
Don’t forget, this is going to change the track of your car and push each wheel out about ¾”. I am using a BMW BBS 17x8 wheel with a 20mm offset (.787”) so it washes out to about a 4” back space.
If you are interested drop an email to Steve Pike: marblepea@mindspring.com
Hope this answers the questions asked of me.
Pics below are before I installed the CV Axles.
Dave