Show Posts
1
General Tech / How to swap FC front subframe/suspension into first gen SA/FB
« on: May 09, 2015, 06:53:48 PM »
I know there is a write up on the club and another RX7 site but I feel they leave out a lot of good details and also cover different ways to do it. I feel that I have done the best way, both stong and functional without unnessarly work. I am open to any comments to make this write-up better or more helpful for anyone.
First off you will need to get some parts, so here is the list of needed stuff. All parts are from of course 86-91 FC RX7
Front subframe
Steering rack can be power or manual your choice, also need the mounting brackets and rubber insulators
Steering intermediate shaft
Steering column
Lower control arms, S4 have bolt on ball joints S5 are not, both will work
Steering knuckles or spindles
Hubs, 4 lug or 5 lug your choice, will need brakes to match
Calipers, rotors, pads (I choose 4 pot calipers of course)
Struts, shorter than stock springs needed, coilovers would be best, with upper mounts to match
Metal stock
Metal tube/pipe
Bolts/nuts
Metal working tools, welder, carbide cutting bits, drill bits, drill, grinder, cutoff wheel, chop saw... etc
Preparring the car for new parts:
First step is to remove the factory mounting studs, grind away or cut away the factory welds then knock them out with a hammer. I did both front and rear to end up using grade 8 standard bolts and nuts front and rear.
Measure and mark out spots to drill new holes for rear mounting bolts. This distance will varry by how you modify your subframe, more on that later. Drill holes large enough for the re-inforcing pipe. I used 3/8" pipe with 7/16" grade 8 bolts. You will have to drill down from the top and up from the bottom till you hit the re-inforcing bushings running horizontally for the old gear box and idler arm mounts. Once I hit these I then took my long carbide die gringer bit to them and removed enough material to make the hole line up all the way though. Install the new pipes, tight fit is preferred, and cut or grind down to fit the angle of the framerail.
Weld metal plate over top of pipe to weld bolts to.
Almost done with modifications to the body at this point just some minor seam bending left to do. I just used a cresent wrench and bent it slight amounts at a time in both places needed while test fitting the subframe.
Subframe modifications:
Front hole needs to move 1 inch forward, this will center the wheel in the wheel well. I did this by adding two pieces of metal to the front of the subframe like so
Drill holt the width of the front studs and then weld in extra reinforcing plate on the bottom of the subframe.
Paint it up all pretty
The rear mounting location use the same hole position just require a ton of spacing to level the subframe with the framerails. I started with the 1/2 inch that a bunch of other write-ups say, but found that a full 1 inch is required to sit properly. We welded on one 1/4" plate at a time, total of 4 to be a full 1 inch pad.
Then install subframe with self locking grade 8 nuts, making final adjustments to the crease below the framerails
Add some Ronin LS swap mounts...
First off you will need to get some parts, so here is the list of needed stuff. All parts are from of course 86-91 FC RX7
Front subframe
Steering rack can be power or manual your choice, also need the mounting brackets and rubber insulators
Steering intermediate shaft
Steering column
Lower control arms, S4 have bolt on ball joints S5 are not, both will work
Steering knuckles or spindles
Hubs, 4 lug or 5 lug your choice, will need brakes to match
Calipers, rotors, pads (I choose 4 pot calipers of course)
Struts, shorter than stock springs needed, coilovers would be best, with upper mounts to match
Metal stock
Metal tube/pipe
Bolts/nuts
Metal working tools, welder, carbide cutting bits, drill bits, drill, grinder, cutoff wheel, chop saw... etc
Preparring the car for new parts:
First step is to remove the factory mounting studs, grind away or cut away the factory welds then knock them out with a hammer. I did both front and rear to end up using grade 8 standard bolts and nuts front and rear.
Measure and mark out spots to drill new holes for rear mounting bolts. This distance will varry by how you modify your subframe, more on that later. Drill holes large enough for the re-inforcing pipe. I used 3/8" pipe with 7/16" grade 8 bolts. You will have to drill down from the top and up from the bottom till you hit the re-inforcing bushings running horizontally for the old gear box and idler arm mounts. Once I hit these I then took my long carbide die gringer bit to them and removed enough material to make the hole line up all the way though. Install the new pipes, tight fit is preferred, and cut or grind down to fit the angle of the framerail.
Weld metal plate over top of pipe to weld bolts to.
Almost done with modifications to the body at this point just some minor seam bending left to do. I just used a cresent wrench and bent it slight amounts at a time in both places needed while test fitting the subframe.
Subframe modifications:
Front hole needs to move 1 inch forward, this will center the wheel in the wheel well. I did this by adding two pieces of metal to the front of the subframe like so
Drill holt the width of the front studs and then weld in extra reinforcing plate on the bottom of the subframe.
Paint it up all pretty
The rear mounting location use the same hole position just require a ton of spacing to level the subframe with the framerails. I started with the 1/2 inch that a bunch of other write-ups say, but found that a full 1 inch is required to sit properly. We welded on one 1/4" plate at a time, total of 4 to be a full 1 inch pad.
Then install subframe with self locking grade 8 nuts, making final adjustments to the crease below the framerails
Add some Ronin LS swap mounts...
