the RallyX7: Redux

[Whizbang]

So after some fiddling on a test shell i got how to FC subframe an FB down to near science. I hope to highlight the process a bit in this thread here. Im progess a touch faster than i expected, but rallycross season is soon. And if these ideas work great, ill probably translate them to the actual rally car.

Essentially the stock FB subframe mounting bolts are the key. The front bolts are retained, whereas the rear bolts need to be removed. Rather simple with a grinder and a cold chisel. The front bolts essentially locate your FC subframe.

The subframe itself has two stubs you have to grind off.

I then mount the subframe up via the front bolts, then mark and drill for the rear. This requires the use of a 6 inch bolt. I used grade 8 bolts. I also used some metal stock to support the top of the bolt. Its a rally car so i wanted overkill.

[Whizbang]

from this point i ditched the sway bar BUT! its easy as dirt to make it work. Just mark and drill for the sway bar mounts. drop two bolts for studs and viola! sway bar. I just want to see if i can maximize range of motion of the front suspension. i can always compensate with springs rates.

From here i stitch welded just about everything. This is somewhat time consuming prep wise as all the seam sealer had to be removed. Then i marked 1" spacings along the seams as to get a 1" weld, 1" space pattern for the stitching.

For the dampers, i aquired some FC struts. After disassemlbing the FC struts and the FB struts it seems the FB springs fits the FC spring perch. The FB tops will the attach to the piston. The threads are the same between the two. The only differnce is the half moon cut on the FC but i cant forsee any issues with it. Testing will tell.

[Whizbang]

After that point i had determined the mazda rear end is somewhat weak sauce. So i elected to strengthen it via some metal banding. And the Mr. Yuck thing i have no good explaination for. Aside from that its a Kia sportage 4.78 third member with the stock LSD and GSLSE axles.

[RX-7 Chris]

haven't seen you in a while. Cool Build

[Whizbang]

indeed it has. I actually made it through colorado about a montha and half ago.

[Whizbang]

Acquired a spring compressor so i can get the dampers assembled but my friend with the air tools works 3-12pm (nights) and i work mornings this week. So ill be getting this done tomorrow evening somewhat late. But the good news is i also sourced some 4 lug hubs locally (still want some spares) so i can get the front finished, finally.

Then i can focus on getting the FC steering column in.

[Whizbang]

well i got the suspension together. Essentially i took the Eibach springs for the FB and all the FB top suspension and put it onto the FC strut. Only qualm i have at this point is that there are not enough threads down on the retaining nut for my liking. Ill be seeing what i can do with that later.

I also am going to have to stay with the 5 lug fronts. Redrilling rotors is a pain and the wheels i planned on using do not clear the brake caliper. So screw it, 5 lug it is.

Also also i got the engine in the car!

[RX-7 Chris]

looks good. you need to get the engine all cleaned and painted, it really looks dirty with the fresh painted bay.

[Whizbang]

yea ill clean the engine up a touch. mostly because i want to see fresh leaks. Its all coming together rather well. Im aquiring some more needs parts this weekend. Silly stuff like a crossmember and some stock rotors. When i have more funding ill be getting a new brake master and booster along with the clutch master. Ideally, ill be getting this car driving before April, but that is a close call.

The rallycross season starts rather soon so well see if i make the first event in one of my own cars. I could run the Merkur worst case. Ill make a skid plate for it. The rx7 needs one as well...

anyways, back to the rx7, steering column might go in this weekend. Along with mudflaps and ill start cutting for the rear flares.

[Waffles]

I was thinking of getting my RX into rallX as well, but was having issues with the lack of suspension options. The FC seems to solve that and alot of other issues with the FB steering and suspension. i have a few random questions.


1. Have you test fit wheels yet, any idea what kind of offset you will have to run?

2. Have you test fit the drive shaft? Does the stock one fit with the placement or will you have to make a custom one/

3. how does the FC column fit in the FB? Will you shorten it or anything.

[Whizbang]

the stock FC column works for my build because of how flexibile everything is. overall its about the same length as the FB column and i used the stock mounting location on the dash and added an additional point for the bottom of the column (FB is more rigid). Only issue is wiring since the FC turn signals etc arent plug and play. You COULD reuse the FB column, and do a little cutting and welding to splice the FC splined end on as a friend has done for his swap, but that seems like more work to me.

Ill find out about the driveshaft this weekend but primlimary reports suggests its fine.

Im running stock FC wheels up front

[Waffles]

Thanks for the info. I might give this a try. Deferentially cheaper then all the rack and pinion conversion kits out there. I will finally use my welder and welding training for something practical, not just fixing rust, and making "art" for the woman.

[RX-7 Chris]

what are your plans for the head light switch, turn sig switch, ect?

[Whizbang]

i planned on just running the wires to a seperate switch for operation. Since the FC had rotary dials off the column, its really my only option. But again, for the purposes of the rally project, id rather have it done how i want to anyway.

[Whizbang]

so the brakes are on. But the crappy part is the transmission crossmember, i grabbed the FC transmission i knew was good but that obviously leaves issues with the mounting. I redrilled the hole for the FB crossmember to mount the FC transmission but sadly, its didnt exactly line up as i had hoped. So i think i may either A) grab anothe FB transmission or B) make the FC crossmember work.

only thought is when i replaced the FC transmission input seal i didnt put this thin metal circle back and im wondering exactly HOW important it was. So either way i have to put it back out...