Toyota 8 in FB
04-12-12, 07:52 AM
#27
cool stuff bro..there was someone else on the other forum that had similar info on these rears. ..Did you get any help with this setup?
.http://*************.com/rotary_foru...ht=toyota+rear
.http://*************.com/rotary_foru...ht=toyota+rear
04-14-12, 04:34 PM
#30
Axle Suspension Brackets
Since I have a Tri-Link setup on my GSL-SE rear axle, I'm putting one on my Toyota 8, too. I'm modifying the rear underbody of the car so I can use a straight upper arm instead of the bent one that's necessary if you want to avoid cutting the floorpan (more on that later).
The geometry of the OEM setup isn't optimal, especially if you have more power than OEM. The forward attachment points of both the UCA and the LCAs should be higher in vehicle . . . or the rearward attachment points should be lower on the axle housing. Since I didn't want to make this too complicated, I took a hybrid approach -- raise the front attachment point of the UCA and lower the rear attachment point of the LCAs. To do this, I designed new axle brackets, which you can see in the attached images. There are multiple LCA attachment points for tuning. I have adjustable rear spring collars, so the adjustable shock brackets will allow me to set the attach point so the rear springs won't come loose when I jack the car. The orange LCA braces triangulate between the LCA brackets and the axle housing to add a little lateral stiffness; may not be necessary, but that's how I am . . .
As usual, I created these in PowerPoint, but the plan is to recreate them using a CAD progam so I can take the .stp file to a local laser shop and have them cut them.
I have access to CAD designers, but they're all very busy right now with their real work, so it will probably take a while. Anybody interested / able?
The geometry of the OEM setup isn't optimal, especially if you have more power than OEM. The forward attachment points of both the UCA and the LCAs should be higher in vehicle . . . or the rearward attachment points should be lower on the axle housing. Since I didn't want to make this too complicated, I took a hybrid approach -- raise the front attachment point of the UCA and lower the rear attachment point of the LCAs. To do this, I designed new axle brackets, which you can see in the attached images. There are multiple LCA attachment points for tuning. I have adjustable rear spring collars, so the adjustable shock brackets will allow me to set the attach point so the rear springs won't come loose when I jack the car. The orange LCA braces triangulate between the LCA brackets and the axle housing to add a little lateral stiffness; may not be necessary, but that's how I am . . .
As usual, I created these in PowerPoint, but the plan is to recreate them using a CAD progam so I can take the .stp file to a local laser shop and have them cut them.
I have access to CAD designers, but they're all very busy right now with their real work, so it will probably take a while. Anybody interested / able?
04-17-12, 01:00 AM
#31
FWIW, I'm pretty big in the Toyota off-road scene also, so I thought I would toss out the fact there are companies that make full floater kits for the rear axle (not that it's needed in this application), but ALSO disc brake brackets which use common and cheap Chevy calipers, both with or without parking brake cable attachments depending on your need. You just need to enlarge the center hub hole for the brake rotors to fit, or buy the pre-made ones. I figured I would let you know in case you guys are against giving up your disc rear axles for drum brakes. I did my disc conversion on my wheeler for about $300. Also, a complete drum to drum stock IFS rear axle (86+) goes for about $200 in the private party market as of right now in the 4Wheeling community.
Some Google searching for Toyota rear disc brake conversion will give you LOTS of info, you can find the year/make/model you need calipers/rotors from, which ones have the parking brake, which ones dont, etc. Or, you can buy it all in one place, this is just an example of one company that sells such bits and pieces:
http://www.sky-manufacturing.com/new...uct.php?id=128
~T.J.
Some Google searching for Toyota rear disc brake conversion will give you LOTS of info, you can find the year/make/model you need calipers/rotors from, which ones have the parking brake, which ones dont, etc. Or, you can buy it all in one place, this is just an example of one company that sells such bits and pieces:
http://www.sky-manufacturing.com/new...uct.php?id=128
~T.J.
04-17-12, 05:03 PM
#32
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Since I have a Tri-Link setup on my GSL-SE rear axle, I'm putting one on my Toyota 8, too. I'm modifying the rear underbody of the car so I can use a straight upper arm instead of the bent one that's necessary if you want to avoid cutting the floorpan (more on that later).
The geometry of the OEM setup isn't optimal, especially if you have more power than OEM. The forward attachment points of both the UCA and the LCAs should be higher in vehicle . . . or the rearward attachment points should be lower on the axle housing. Since I didn't want to make this too complicated, I took a hybrid approach -- raise the front attachment point of the UCA and lower the rear attachment point of the LCAs. To do this, I designed new axle brackets, which you can see in the attached images. There are multiple LCA attachment points for tuning. I have adjustable rear spring collars, so the adjustable shock brackets will allow me to set the attach point so the rear springs won't come loose when I jack the car. The orange LCA braces triangulate between the LCA brackets and the axle housing to add a little lateral stiffness; may not be necessary, but that's how I am . . .
As usual, I created these in PowerPoint, but the plan is to recreate them using a CAD progam so I can take the .stp file to a local laser shop and have them cut them.
I have access to CAD designers, but they're all very busy right now with their real work, so it will probably take a while. Anybody interested / able?
The geometry of the OEM setup isn't optimal, especially if you have more power than OEM. The forward attachment points of both the UCA and the LCAs should be higher in vehicle . . . or the rearward attachment points should be lower on the axle housing. Since I didn't want to make this too complicated, I took a hybrid approach -- raise the front attachment point of the UCA and lower the rear attachment point of the LCAs. To do this, I designed new axle brackets, which you can see in the attached images. There are multiple LCA attachment points for tuning. I have adjustable rear spring collars, so the adjustable shock brackets will allow me to set the attach point so the rear springs won't come loose when I jack the car. The orange LCA braces triangulate between the LCA brackets and the axle housing to add a little lateral stiffness; may not be necessary, but that's how I am . . .
As usual, I created these in PowerPoint, but the plan is to recreate them using a CAD progam so I can take the .stp file to a local laser shop and have them cut them.
I have access to CAD designers, but they're all very busy right now with their real work, so it will probably take a while. Anybody interested / able?
04-18-12, 08:15 PM
#33
FWIW, I'm pretty big in the Toyota off-road scene also, so I thought I would toss out the fact there are companies that make full floater kits for the rear axle (not that it's needed in this application), but ALSO disc brake brackets which use common and cheap Chevy calipers, both with or without parking brake cable attachments depending on your need. You just need to enlarge the center hub hole for the brake rotors to fit, or buy the pre-made ones. I figured I would let you know in case you guys are against giving up your disc rear axles for drum brakes. I did my disc conversion on my wheeler for about $300. Also, a complete drum to drum stock IFS rear axle (86+) goes for about $200 in the private party market as of right now in the 4Wheeling community.
Some Google searching for Toyota rear disc brake conversion will give you LOTS of info, you can find the year/make/model you need calipers/rotors from, which ones have the parking brake, which ones dont, etc. Or, you can buy it all in one place, this is just an example of one company that sells such bits and pieces:
http://www.sky-manufacturing.com/new...uct.php?id=128
~T.J.
Some Google searching for Toyota rear disc brake conversion will give you LOTS of info, you can find the year/make/model you need calipers/rotors from, which ones have the parking brake, which ones dont, etc. Or, you can buy it all in one place, this is just an example of one company that sells such bits and pieces:
http://www.sky-manufacturing.com/new...uct.php?id=128
~T.J.
Regarding the brakes -- I have a homemade big brake setup on the front that is brake torque matched to my OEM brakes. Since I'm unlikely to find another OEM rear brake setup with the same torque values, it would drive me to a whole new rear brake setup: new rear brakes + new rear pads + aftermarket prop valve + park brake adaptation + . . . +. You get the picture. With a pair of adapter brackets that I have already designed (more on those soon), I can use my existing rear brakes and avoid a domino of changes that will ultimately cost me a lot more.
These are both great options, but not for me.
04-18-12, 08:26 PM
#34
Thanks for offering. One of my designers came through, surprisingly. I guess car projects are interesting enough to pull priority
Once I have these made, welded in, and tested, I might make more if there's any interest. Let's see how it goes . . .
Once I have these made, welded in, and tested, I might make more if there's any interest. Let's see how it goes . . .
04-22-12, 06:49 PM
#35
Upper Control Arm / Tri-Link
As I mentioned earlier, I like the tri-link concept for a variety of reasons, but I didn't like the bent upper link. When Jim Susko designed the setup, he did the best he could with the big restriction that the OEM floorpan not be modified. He came up with an ingenious setup that gave good geometry while respecting that limitation.
Montana Kid did an updated tri-link that took the upper link through the floorpan and used a boot to seal it off. I thought that was also very crafty, but I decided to go a different route, which has proved to be a little tricky, but I think it will work well.
The objectives were:
1. Straight UCA, no bends
2. Raised body attachment point for better planting of the rear end under accel
3. Robust, double-shear design
4. Allows suspension to travel to full jounce without interference of any sort with a Toyota 8
The first image is a general depiction of what I wanted to do, from the perspective of a section taken through the middle of the car. There you can see the floorpan and the key body reinforcements that need to be considered. The scale isn't perfect, but the concept should be clear.
The next images show the body-mounted bracket that I designed and fabbed . . . and my friend welded (I'm not so good at that). The central part of the bracket was made from a discarded trailer ramp. It was 1/8" steel and about 8" wide. The min width to be able to get the 5/8" X 2" bolt in to hold the heim joint was 6", so I cut it down the middle and welded it. The heim joint clevis and reinforcemetns are also 1/8" steel. The side "shrouds" are much thinner steel from the hardware store that unfortunately warped when welded to the thicker stuff. It's thin enough that we should be able to push it back into the proper position when we weld it to the floorpan.
After it's welded in place around the full perimeter, I'll cut out the floorpan from beneath to give a direct shot from the rear axle to the heim joint clevis. I'm leaving this part for last because I think the floorpan would spring out of shape if I cut it first.
This bracket spans from the upper section to the lower one, so I think it will add a little strength to the body. I'm confident that it won't make it weaker, at least. If I have to cut the upper channel to allow full suspension jounce, I'll weld a 2" square cross-car reinforcement above the floorpan to compensate, which is shown in the first image.
Montana Kid did an updated tri-link that took the upper link through the floorpan and used a boot to seal it off. I thought that was also very crafty, but I decided to go a different route, which has proved to be a little tricky, but I think it will work well.
The objectives were:
1. Straight UCA, no bends
2. Raised body attachment point for better planting of the rear end under accel
3. Robust, double-shear design
4. Allows suspension to travel to full jounce without interference of any sort with a Toyota 8
The first image is a general depiction of what I wanted to do, from the perspective of a section taken through the middle of the car. There you can see the floorpan and the key body reinforcements that need to be considered. The scale isn't perfect, but the concept should be clear.
The next images show the body-mounted bracket that I designed and fabbed . . . and my friend welded (I'm not so good at that). The central part of the bracket was made from a discarded trailer ramp. It was 1/8" steel and about 8" wide. The min width to be able to get the 5/8" X 2" bolt in to hold the heim joint was 6", so I cut it down the middle and welded it. The heim joint clevis and reinforcemetns are also 1/8" steel. The side "shrouds" are much thinner steel from the hardware store that unfortunately warped when welded to the thicker stuff. It's thin enough that we should be able to push it back into the proper position when we weld it to the floorpan.
After it's welded in place around the full perimeter, I'll cut out the floorpan from beneath to give a direct shot from the rear axle to the heim joint clevis. I'm leaving this part for last because I think the floorpan would spring out of shape if I cut it first.
This bracket spans from the upper section to the lower one, so I think it will add a little strength to the body. I'm confident that it won't make it weaker, at least. If I have to cut the upper channel to allow full suspension jounce, I'll weld a 2" square cross-car reinforcement above the floorpan to compensate, which is shown in the first image.
04-23-12, 10:46 PM
#37
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04-26-12, 09:09 PM
#38
Upper Control Arm / Tri-Link Bracket Installed
Got it welded in last night. It was relatively simple. I didn't cut the floorpan until after the install, so it wouldn't spring out of place. We tacked it in numerous spots around the perimeter to hold it in place, then I watched underneath while my friend welded from above. Interesting to watch the metal take on a bright glow then see the paint catch fire as the weld bead progressed. After he finished, I cut out the enclosed floorpan section with a die grinder / cutoff wheel to expose the underside of the bracket. After some work with a drum sander, it looked fairly clean. I left a healthy portion of the front body channel in place to retain strength. There's still plenty of access to fit the retaining bolt and to allow the UCA to articulate.
Next steps:
1. Begin checking rear axle location / clearance
2. Clean the underside with thinner to remove grease and oil
3. Apply seam sealer to fill any pinholes and crevices
4. Paint
This install left some fairly large ratholes at the forward end between the bracket and the body channel. I'm considering filling the whole area with something after sealing the seams. Great Stuff comes to mind, but I don't know how well it would stand up on a car or take paint. Ideas?
Next steps:
1. Begin checking rear axle location / clearance
2. Clean the underside with thinner to remove grease and oil
3. Apply seam sealer to fill any pinholes and crevices
4. Paint
This install left some fairly large ratholes at the forward end between the bracket and the body channel. I'm considering filling the whole area with something after sealing the seams. Great Stuff comes to mind, but I don't know how well it would stand up on a car or take paint. Ideas?
05-02-12, 09:08 PM
#39
Modified Axles Back from Machine Shop
I just picked up my modified axles. Since I had "when I get around to it" pricing, it took a while, but the results were good. In addition to making the ends of the Toyota axles look like OEM GSL-SE axles, the shop pressed in my studs, bearings, collars, and snap rings. I fit my rotors and wheels -- all looks good. I need to install the bolt in the center that retains the register or pilot, then they'll be complete. I kept the original Toyota bearings and seals. I'm on a budget, they seem OK, and they're easy enough to replace if necessary.
Last edited by elwood; 05-02-12 at 09:11 PM. Reason: Images didn't load
05-21-12, 08:45 PM
#41
Axle Suspension Brackets - Installed
My welder buddy wasn't available for a while, so I didn't make much progress during the last couple of weeks, but he's back on the job, and we're moving ahead.
The brackets I explained in post #30 were created in CAD by a designer at work. Then I took the .stp file to a local laser shop (I live in the greater Detroit area, so there's one about every mile), and they cut them for me. After doing this, I might never make a bracket by hand again! The results were excellent, the effort was next to none, and the cost was reasonable. It would have been especially difficult to make these by hand, since there were so many holes that had to align.
We welded them to the axle housing, using short sections of bead and alternating between the various sites to avoid warpage. I had fasteners with spacers installed in multiple locations to keep the brackets aligned.
After the brackets were welded in place, I test fit the whole thing in the car -- fits like it was made to go there. The 1/2" narrower WMS - WMS width is perfect for my setup.
Next up are spring seats and a Watts linkage.
The brackets I explained in post #30 were created in CAD by a designer at work. Then I took the .stp file to a local laser shop (I live in the greater Detroit area, so there's one about every mile), and they cut them for me. After doing this, I might never make a bracket by hand again! The results were excellent, the effort was next to none, and the cost was reasonable. It would have been especially difficult to make these by hand, since there were so many holes that had to align.
We welded them to the axle housing, using short sections of bead and alternating between the various sites to avoid warpage. I had fasteners with spacers installed in multiple locations to keep the brackets aligned.
After the brackets were welded in place, I test fit the whole thing in the car -- fits like it was made to go there. The 1/2" narrower WMS - WMS width is perfect for my setup.
Next up are spring seats and a Watts linkage.
05-23-12, 09:58 PM
#44
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Idk the one I picked up is pretty rusty more than I hoped but it was free so I can't complain too much. I am wanting to do a fc front subframe swap at the same time but my car is my dd so the search for another shell begins. My plan is similar to gen1onr. Only time will tell. O and elwood your google site has been a amzing help in my build plan. Great job sir.
05-28-12, 06:47 PM
#45
Upper Control Arm / Tri-Link Bracket Completed
. . .
Next steps:
1. Begin checking rear axle location / clearance
2. Clean the underside with thinner to remove grease and oil
3. Apply seam sealer to fill any pinholes and crevices
4. Paint
This install left some fairly large ratholes at the forward end between the bracket and the body channel. I'm considering filling the whole area with something after sealing the seams. Great Stuff comes to mind, but I don't know how well it would stand up on a car or take paint. Ideas?
Next steps:
1. Begin checking rear axle location / clearance
2. Clean the underside with thinner to remove grease and oil
3. Apply seam sealer to fill any pinholes and crevices
4. Paint
This install left some fairly large ratholes at the forward end between the bracket and the body channel. I'm considering filling the whole area with something after sealing the seams. Great Stuff comes to mind, but I don't know how well it would stand up on a car or take paint. Ideas?
I did use Great Stuff to fill the ratholes front and rear, and I think it was a good choice. It filled the whole cavity, and I was able to go back over the areas later with seam sealer, and it adhered to the Great Stuff without any bad reaction.
Then I painted the underside and re-carpeted the top side. Luckily I had some of the original carpet left from the job I did 5 years ago. After brushing contact cement on both sides, it stays put nicely.
06-10-12, 09:47 PM
#46
Brake Caliper Mounting
To mount the OEM GSL-SE calipers on this axle is a little tricky. If you want to attach a bracket to the axle housing using the 4 axle retainer bolts there are two options -- inboard of the flange and outboard. Outboard requires a step in the bracket and some tricky machining or welding. Inboard allows you to use a flat plate, but requires spacers to position the caliper, an offset in the park brake bracket, and alternate brake hose routing.
I chose the inboard route, since it's a lot easier and cheaper for me to make flat parts. I designed my bracket out of 3/8" stock (same thickness as OEM) and made a "C" shape that captures all 4 bolts for added stiffness. The mouth of the "C" is just large enough to fit over the thin part in the axle. I mounted it with M10-1.25X40 screws. These same screws worked to mount the caliper to the bracket, coupled with 3/4" thick spacers and a washer to get the caliper centered over the rotor.
Where the park brake cable bracket mounts to the calipers, I used flat head screws to provide extra clearance, and I make new brackets out of 1/4" stock.
Next is brake line plumbing.
I chose the inboard route, since it's a lot easier and cheaper for me to make flat parts. I designed my bracket out of 3/8" stock (same thickness as OEM) and made a "C" shape that captures all 4 bolts for added stiffness. The mouth of the "C" is just large enough to fit over the thin part in the axle. I mounted it with M10-1.25X40 screws. These same screws worked to mount the caliper to the bracket, coupled with 3/4" thick spacers and a washer to get the caliper centered over the rotor.
Where the park brake cable bracket mounts to the calipers, I used flat head screws to provide extra clearance, and I make new brackets out of 1/4" stock.
Next is brake line plumbing.
06-26-12, 08:51 PM
#47
Watts Link Pivot
I decided to use a Watts Link, like the original suspension setup did, but with the following differences:
1. Mounted to the bottom of the axle for clearance to fuel tank, body-mounted brackets, and such
2. Attached to the center of the axle for equal performance on right and left turns
3. Pivot mounted in double shear for added durability and protection from jacking
4. A true ball bearing pivot setup for bind-free operation
Advantages of a Watts Link over a Panhard are more accurate centering of the axle during suspension travel and maintenance of a similar roll center, whether turning left or right. I think the advantages are small, but I saw this setup and wanted to try it.
The pivot is from a Mustang rear suspension upgrade kit from Total Control Products. I got the pivot, bearing, snap ring, axle-side standoff, and lower side standoff. In their kit, they use this thing in single shear. It has a 3/4" center mounting bolt, so it's probably OK, but I wanted to be sure and also provide a jacking point (that's how I'm used to lifting the rear of the car). So I made a double-shear bracket out of 2" X 2" X 1/8" square section tubing and 2" X 1" X 1/8" channel. The 4 mounting bolts are 3/8". It only adds a little weight and allows the pivot to rotate about 90 deg -- which should be more than enough.
The trickiest part was to clear the OEM drain plug. The brackets leave just enough space to get the necessary 24mm socket in there.
This arrangement drops the rear roll center, putting it below the axle pumpkin, so I will probably need a rear swaybar to keep handling balance (haven't used one in years). We'll see . . .
1. Mounted to the bottom of the axle for clearance to fuel tank, body-mounted brackets, and such
2. Attached to the center of the axle for equal performance on right and left turns
3. Pivot mounted in double shear for added durability and protection from jacking
4. A true ball bearing pivot setup for bind-free operation
Advantages of a Watts Link over a Panhard are more accurate centering of the axle during suspension travel and maintenance of a similar roll center, whether turning left or right. I think the advantages are small, but I saw this setup and wanted to try it.
The pivot is from a Mustang rear suspension upgrade kit from Total Control Products. I got the pivot, bearing, snap ring, axle-side standoff, and lower side standoff. In their kit, they use this thing in single shear. It has a 3/4" center mounting bolt, so it's probably OK, but I wanted to be sure and also provide a jacking point (that's how I'm used to lifting the rear of the car). So I made a double-shear bracket out of 2" X 2" X 1/8" square section tubing and 2" X 1" X 1/8" channel. The 4 mounting bolts are 3/8". It only adds a little weight and allows the pivot to rotate about 90 deg -- which should be more than enough.
The trickiest part was to clear the OEM drain plug. The brackets leave just enough space to get the necessary 24mm socket in there.
This arrangement drops the rear roll center, putting it below the axle pumpkin, so I will probably need a rear swaybar to keep handling balance (haven't used one in years). We'll see . . .
07-15-12, 08:58 PM
#50
Driveshaft
Since I upgraded my rear axle to a Toyota 8" design, the pinion snout is longer than the one on my FB rear axle and the pinion flange bolt pattern is different. I had an existing aftermarket driveshaft that was a 2.5" diameter steel unit that went from my Turbo II transmission to my GSL-SE rear axle. I could either modify that one or sell it and start from scratch.
Since I was able to sell the existing steel D/S for a good price, I decided to go with a totally new aluminum driveshaft. The FB has a relatively long driveshaft that can see very high RPMs, so it's very sensitive to balance. I decided to go with a Quarter Master aluminum driveshaft because they have a reputation for being very precise, the price is fairly reasonable, and my HP levels aren't extreme.
If you go this route, realize that Quarter Master only makes the driveshaft itself, and only makes it with 1310 series U-joints. These are the most common ones in the aftermarket industry and have external snap rings, which are somewhat easier to service than the internal ones.
The basic parts of a driveshaft assembly are as follows:
Slip Yoke: Fits in the tail of the transmission and has lobes for the front U-joint
Front U-joint: Connects the Slip Yoke to the Driveshaft
Driveshaft: The central tube, with U-joint lobes at either end
Rear U-joint: Connects the Driveshaft to the Pinion Yoke
Pinion Yoke: Connects the rear U-joint to the Pinion Flange on the rear axle
To adapt the Driveshaft central tube to my application, I ordered a Slip Yoke, Front U-joint, Rear U-joint, and Pinion Yoke that fit my application, mounted the yokes on the car, measured from U-joint center line to U-joint centerline, then sent those pieces and the measurement (36 1/4" in my case) to Quarter Master so they could build my shaft and balance the entire assembly.
The slip yoke for the RX-7 Turbo II transmission has a 23/25 spline pattern, which means the transmission has 25 splines on the output shaft, while the slip yoke has 23 (it has two missing splines). The only available aftermarket yokes adapt to a 7260 style U-joint, which has internal snap rings. To adapt to the driveshaft, the front U-joint needs to be a 7260 to 1310 conversion style, which is available through Spicer and others.
The Pinion yoke that adapts to my Toyota 8" rear end has a 3.340" square bolt pattern w/1.808" pilot and M10 fasteners. It adapts to a 1310 style U-joint, so the rear U-joint is a typical 1310 to 1310 part.
The Quarter Master shaft is 3" dia vs. my previous 2.5" part, so I did careful checking for interference throughout the full range of suspension travel before I sent for the new shaft to be built.
I installed it today, and the fit is good!
This reply, and most everything I've done to my car are available here -->
https://sites.google.com/site/elwoodsturbofb/
It's a work in progress, so please reply with corrections or updates.
Since I was able to sell the existing steel D/S for a good price, I decided to go with a totally new aluminum driveshaft. The FB has a relatively long driveshaft that can see very high RPMs, so it's very sensitive to balance. I decided to go with a Quarter Master aluminum driveshaft because they have a reputation for being very precise, the price is fairly reasonable, and my HP levels aren't extreme.
If you go this route, realize that Quarter Master only makes the driveshaft itself, and only makes it with 1310 series U-joints. These are the most common ones in the aftermarket industry and have external snap rings, which are somewhat easier to service than the internal ones.
The basic parts of a driveshaft assembly are as follows:
Slip Yoke: Fits in the tail of the transmission and has lobes for the front U-joint
Front U-joint: Connects the Slip Yoke to the Driveshaft
Driveshaft: The central tube, with U-joint lobes at either end
Rear U-joint: Connects the Driveshaft to the Pinion Yoke
Pinion Yoke: Connects the rear U-joint to the Pinion Flange on the rear axle
To adapt the Driveshaft central tube to my application, I ordered a Slip Yoke, Front U-joint, Rear U-joint, and Pinion Yoke that fit my application, mounted the yokes on the car, measured from U-joint center line to U-joint centerline, then sent those pieces and the measurement (36 1/4" in my case) to Quarter Master so they could build my shaft and balance the entire assembly.
The slip yoke for the RX-7 Turbo II transmission has a 23/25 spline pattern, which means the transmission has 25 splines on the output shaft, while the slip yoke has 23 (it has two missing splines). The only available aftermarket yokes adapt to a 7260 style U-joint, which has internal snap rings. To adapt to the driveshaft, the front U-joint needs to be a 7260 to 1310 conversion style, which is available through Spicer and others.
The Pinion yoke that adapts to my Toyota 8" rear end has a 3.340" square bolt pattern w/1.808" pilot and M10 fasteners. It adapts to a 1310 style U-joint, so the rear U-joint is a typical 1310 to 1310 part.
The Quarter Master shaft is 3" dia vs. my previous 2.5" part, so I did careful checking for interference throughout the full range of suspension travel before I sent for the new shaft to be built.
I installed it today, and the fit is good!
This reply, and most everything I've done to my car are available here -->
https://sites.google.com/site/elwoodsturbofb/
It's a work in progress, so please reply with corrections or updates.