FC subframe in FB
 

I read the thread by Omid on installing an FC front subframe in an FB.
I would like to hear from those that have done this swap, pros/cons.
Was it worth it? Please provide details.
thanks

Pro:
-FC front suspension
-R&P steering
-possibly easier to mount a S4/S5 2nd gen motor (by using FC mounts)

Con:
-Fabrication involved
-not a direct bolt on


(fwiw, I haven't done it yet, but I'm stripping my FC for parts this weekend :D)

what would be real trick is 240sx s13 rear in a FB.

I read through Omids swap too but one thing he fails to go into is how to mount a 12a to a FC subframe. Thats the tricky part. Putting it in looks simple. Your best bet is eventually save your pennies for a 13B 6 port or turbo out of a FC.

^ And the point of swapping a Nissan rearend would be what?

I guess that makes it a mad tite driftorito. ........................................yo

for the independant rear? also the myriad of diffs that go into a s13? to eliminate rear bottoming out. I don't know about you guys but my 83 with RB springs and tokico blues bottoms out the rear on almost anything.

Independant rear = good. Changes the roll center in the car brings it in line with the center of the car.

Yes a panhard is a good way to change the roll center but it has a tendancy to bind. The watts link is the better setup but where is the roll center on the rear? Inline with the Passengers ass.

Independant rear...good stuff like two eggs and bacon.

Actually, the panhard setup works better and binds less than the watts link. When installing lowering springs, the bump stops need to be shortened about 3/4".

actually, the springs are still to soft. I did whack down the bump stops. the watts links will bind if the bushings are bad. The watts link is alot better at locating the rear because of the geometry that it imposes on the control arms.

Now the panhard bar will not locate the rear like a watts link. As the rear goes through its motions the panhard will pull the rear away or closer to the roll center of the car.

T

Sounds like you have it down. The 1st gen was used by Mazda as a test mule for the 2nd gen irs. It will take major fab skills to install any irs, have fun.

how so? Nothing was carried over from the FB to the FC suspension wise. I would say the FC is closer to the FD brethern but thats a reach seeing as the FD has dual a arm front and rear.

Acutally Trichod, I don't think it would be that hard. I was measuring up the rear subframe of a s13 and it looks fairly close to the frame rails of the FB. The only major thing that would slow down such an endeavor is the the strut mounting by way of notching the frame and boxing it with some 3/16th's plate. There is tons of room back there because of the live axle swinging around.

Btw is that your car in your avatar? I like it. Superclean, do you have anymore pics?

The mules were factory test cars that they installed the irs in, never went into production. The front suspensions are nearly identical, except for the r&p and relocating the main link between the tire rods and the motor mounts.

One problem I see with the irs is, will it clear the fuel tank? If it is being built as a drift car, then it's time to chop out the spare tire well and install a fuel cell.

Is that my car in my avatar, it sure is. https://www.rx7club.com/build-threads-293/unvieling-12a-bp-widebody-462184/

Why did you go matte black? stealth? or is it radar absorbing? Lol.

Inital Measurements it looks like it will clear the tank. No I am not into drift. I have 2 first gens. One is a 79 ITA car that I unfortunately have to build to SCCA's Rules. But my 83 is more of a project or cure to solve all the problems where mazda failed. Lack of IRS being one. IRS would make a much better street car as it could absorb the ungrateful california roads. Yeah I know it seems alot of work for a smooth ride. But Since I cut up my last project car. I need something new.

Little bit of stealth, little bit of old school ratrod, and I couldn't decide on a final paint color. That turned out to be a good thing because the 2nd and 3rd time I pulled into my driveway, I caught the front lip, scraped it, cracked the air dam, and the fender in 2 places. The paint is a single stage urethane, tough as nails, will never see a wax job, and I don't have to worry about. Touch ups are easy.

8-Ball, sorry for the jack.

trochoid, I admire the work you've done on your car and intend the following as constructive information for general readers only.

Roll cages in street cars can often cause more injury than no roll cage. Most collisions on the street aren't rollovers, and cages are designed for people in helmets and 5 point harnesses. On the street they can cause serious (possibly fatal) head and rib cage trauma as your t-shirt clad, helmetless self smacks into the metal tubing.

I actually think the s13 rear sub frame is a little wide for the fb but it could work. I actually have a spare s13 subframe sitting directly behind my SA and it looks like it would be close. If you need some pics pm me and I will take some for you. Also there is a very long thread floating around some where with a guy who has a v8 conversion in his FB and is planning on making it a Convertible or Targa with IRS. He is pretty far into the IRS conversion but I dant think it has been finished. I will try and find the thread.

Sorry for the thread jack :uh:

Thanks for the concern, and I am well aware of the dangers. I don't have a full cage, only the roll bar with removeable doors. Every inch of the tubing is padded with the proper padding, and the rear hoop is set so if I am involved in a rearend collision, the seat back and headrest will catch the seat at the same time. I rear ended a kid in high school in my dad's pickup, and watched as his seatback failed and went flat to the back seat. You know, everything is in slow motion when these things happen and I remember the details vividly, even nearly 40 years later.

Perhaps my biggest potential danger is getting my left foot pinned by the bottom mount for the door bar in a driver's side impact.