Hey guys, I wanted to start a new build thread on my car, a lot of plans changed over the last couple years, and I’ve had lots of time to think about the direction I want to take my build. Some people may remember my car from my old build thread which I think was called something like Hiroshima screamer- Cosmo first gen or something similar to that. If you want to go hunt for the thread to see the whole intro to the car, and the first iteration of the build then be my guest, I’m not going to post much of the backstory as to not bore everyone.



So I’m pretty sure I left that thread off explaining about the loss of the 13b re that I had in it, it had some issues, and I needed basically a new motor to be able to rebuild it. It needed new rotors, new housings and at least one new iron. At that time I didn’t have the money or time to put into that motor so I ended up buying a cheap fc that a tree fell on the windshield of, and stealing the 6 port out of it to toss in my first gen for the time being. I did end up completing the swap, with the 6 port running on my old haltech ECU. After I got it running and drove it around the block once, I immediately knew that engine wasn’t for me. It didn’t make the power I was hoping for, and I was starting to get busy with work and other stuff so I ended up just parking the car. A couple months into the storage of the car someone offered me a large chunk of money for the motor setup out of my car, I decided to take the money and I sold the motor, trans, and the header and pulleys that were on the motor. So now that’s pretty much when I decided that if I were to resurrect the car then I would be doing a ground up build with no cut corners. Here are a photo or two that show how the car looked when it had the 13b re in it. Some people may remember the chassis.








Around September 2019 I decided I was going to part the car out, I had a close friend who was doing a t2 swap in his fc, so I ended up selling my entire fuel system, turbo system and my entire electronics systems to him to help him out with his build. I also sold a bunch of my t3 suspension goodies and I sold my spare t2 trans.



Now the car sat as basically a gutted shell that wasn’t even a roller anymore. I tucked it away to the back of my garage because I had zero plans to touch the car in the next few years, and since I had stripped it down, I knew it would not be worth it to sell the car. I ended up buying an ap1 s2000, which was once of my all time dream cars, and 100% a forever car for me.



This all brings us to the present day (technically like April 2020 but close enough). If you’ve made it this far then now is where I start talking about my plans, and of course the progress, I’ve been working for a couple months on it to get a good stock of postable material so that I can hopefully keep up a decently regular posting schedule for the people who may be interested in the build.



So I own a 1983 rx7 s model. So pure base model, no sunroof, crank windows, no glovebox or hatch light, no hatch release in the car. Pretty much the lightest fb that was sold in 83. The body only has something like 160k on it (km because I’m in Canada) and is surprisingly rust free considering it was a drift car with the previous owner. There were a few things I knew I wanted, I wanted to keep the car light, it had to be fast, I wanted independent rear suspension, rack and pinion steering and most of all I wanted parts to be easy to buy for it. I’m not sure how it is in the states, but in Canada you can’t get anything for the first gen rx7s unless you buy something off a parts car in unknown condition.



Remember how I said before that I had bought that fc for the motor? Well I also parted the car out to recoup some money. I ended up keeping some parts for myself just in case. So I had a complete front subframe and almost complete rear subframe. I did sell the na lsd diff I had and I sold the left knuckle and hub assembly to a friend who bent his while pressing out the old bushings. This is ok because I will not be able to use the na diff anyways, there is no chance it will take the power I want to make, and I’ll just have to source a knuckle from somewhere (this is turning out to be waaaaay harder to find then I thought).



So this brings us to the time when I need to stuff fc irs in the back of my fb. There are a few problems here, I want the car to be extremely low, but I don’t want to destroy all suspension geometry just because my car is low. To counter act the crazy toe and camber you get from lowering an fc, I decided to raise the entire rear end into the car by a couple (a lot) of inches. This will lower the car without actually lowering any of the suspension. This leaves me with proper geometries and hopefully a car that still handles somewhat decent. Now this brings me to problem number two. By raising the rear end inside the car, and keeping the wheelbase of the fb the same, the front subframe mounts end up very close to where the back of the seat is going to be. This made me think again, about possibly putting a solid axle 8.8 in the back, but those just weigh so much and I won’t get the adjustability that I’m looking for.



In June or July I decided I was going to build a tube chassis from scratch to set the body on so that I could mount the suspension without the binding factors of the factory sheet metal. I had ordered a tig welder a while back, and now was the time to learn how to use it!



First step for this crazy insane idea I had was to build a chassis jig to level out my floor in the garage as it is anything but flat. It’s a pretty simple metal structure with 4 castor wheels I snagged off Amazon for very cheap. They are only good for about 800lbs so we will see if they can hold the car up or not. I’m trying to keep the car extremely light so hopefully they will be enough until the car becomes a rolling chassis.





Just a quick interlude, if you don’t know what I’m trying to build, Google ets drift Ute, that’s a good example of where I’m heading, or there’s a 240z that was built in a similar fashion. I think you can find images of that one by looking up attacking the clock 240z.



I’m going to end this first post with “mounting” the subframes to the jig. I marked out the factory wheelbase of an fb, as I don’t want to change the wheelbase of the car. I enjoy the feel of short wheelbase cars, and by looking up similar wheelbase cars I have driven, I know that I don’t want to lengthen it. Then it was a couple days of measuring, levelling, then measuring again to get the subframes both centred and level on the jig, but also to get the subframes sitting at the right height that will give me adjustable ride height in the range I want it while keeping arm geometries right. I tack welded both subframes to the jig so that they can’t move if I accidentally bump them while building the car around them. The diff I’m using is just a placeholder, it’s an na open diff that a friend had laying around from his lsd swap last year, I will not be using this diff, but it works to get the spacing for the diff mount correct. Now that everything is sitting exactly where it needs to be I can start on building the actual car. The chassis jig is flux core welded for the people who notice that it’s not tig welded haha. I didn’t want to waste a ton of gas tig welding the jig that’s eventually just going to be cut up anyways once the car is rolling. The chassis of the car will be all tig welded. Here are a couple pictures of the chassis jig for the people who made it this far haha. If you have any questions about anything along the way just let me know, and I’ll do my best to answer them.

 

https://www.rx7club.com/build-thread...t-gen-1132273/

 

Awesome, was wondering what happened with this car. You are really turning it into something now!!

Great work. Some serious fab skills.

 

Thanks man, I’m just learning as I go haha. It’s definitely a slower project now then it was before, but that just means that I can go crazy with small details and make it exactly as I want it.

 

After I had the chassis jig all welded up, and I was happy where everything was sitting, and of course measuring hundreds of times to make sure that nothing will be sitting off once it’s finished and too late to change, I started on building the new floor. I have made a few changes with the actual interior size. The width remains almost the same, it is a touch wider as I have cut the sills off the car to make sure I have as much width as possible for both the cage and seats to sit in the car. The other big change I made was to actually shorten the seating area. I’m pretty short, 5’ 10”, so I don’t need crazy leg room. I know that this is a compromise, but I am comfortable in the car and can fully stretch out no problem, so taller people will just have to sit with bent legs a bit. I did this as my new motor is a bit on the long side, and I want as much room in front of the motor as possible, as well as mouthing the motor back as far as possible to try and correct some of the issues with weight distribution with a heavier motor. Granted, this is not a track car, so in reality the weight distribution isn’t a massive concern for me. The floor design I settled on was something similar to a lot of the space frames, a simple rectangle divided up into smaller rectangles. I have everything just tacked up right now in case I need to move a brace so that it’s easier to cut out and move. Eventually, during final welding most likely I will end up welding in smaller 1x1 box to triangulate each section of the floor. This will also make it easier to mount the actual floor boards too. I haven’t decided if I’m going to make the floor panels out of aluminum or if I’m going to use some carbon to make it even lighter. Here’s some pictures from the floor construction.







Once the floor was framed out I had to decide how high off the ground the floor will be once the car is sitting at it’s final ride height. The floor will be the lowest point in the car, there will be absolutely nothing under it. The measurement I settled on was 3 inches. That’s just high enough to slip my Jack under it, and my s2k front lip sits 3 inches off the ground and it only really scrapes on bad roads or big bumps. The actual height the floor is sitting at in the pictures is 5 inches, but this is because the wheel actually has a 2 inch spacer between the jig and the wheel, so actual ride height will be 3 inches. Now that everything is sitting where I think it needs to be, I just need to connect the subframes to the floor section. This will not be the full structure, I’m gaining my rigidity from the cage that is going to be being made soon. This is more so to locate everything and to connect the front subframe to the rear once via the floor.



The rear subframe was what I decided to tackle first as it seemed to be the most complicated. I used some 2x3 tubing for this, it’s nice and strong but does not weigh much. I had to get a little bit creative with the mounting as I didn’t want to invade into the seating area too much because it’s already shorter than it should be. Pictures here will speak better then words so here they are.







Once I had the diff and subframe all attached to the floor, again just tacked in case something needed to be changed, I had to decide how I was going to mount the fifth point, or the rear camber arm thing fc rx7s have. Mine will not be a camber adjuster anymore as I’m going to be running solid aluminum bushings in the subframe which will not allow the subframe to tilt anymore. I went back and forth about using it but I ended up deciding to throw it in as another mount to help keep the subframe where it belongs under hard acceleration and such. I just played with the angle a bit until it was sitting where I wanted it to, not really any rhyme or reason to this as I don’t think the angle matters at all. I welded up a simple bracket for it and welded it to a cross member connecting the two diff mounts.





This last photo has the front subframe mounts already in, I just done have a picture of only the rear end.

This is all I have for this week, next post should be the front subframe mounts, and then starting to clearance the body to be test fit onto the chassis for the first time.

 

This is insane!
That is going to be a nice thread to follow.

 

Looks like the trans tunnel will double as an armrest, haha.

That's quite an undertaking, keep up the good work! Love seeing these wild builds come to life.

 

Thanks man! The transmission and tunnel will definitely be very high inside the car. It’s going to be interesting once it comes time to be designing the interior.

 

It’s been a while since I’ve posted on here. I’ve been working out a lot of issues with the front end and the fitting of suspension. Where I left off I was still laying out the basic shape of the chassis. I had just finished the rear end.



For today’s update I will connect the front subframe to the chassis and I’m going to start prepping the body for its first trial fit.



The front subframe was not too difficult. I took the same shape I used on the rear and made 2 legs sticking out from the floor for the subframe to connect to. The rear of an fc front subframe dips down, so there was a space between the flat chassis leg I built and the subframe mounting hole. Luckily this was a pretty easy fix. Every mounting hole on the chassis has a tube welded inside the rectangle tubing to help the tube keep its shape when the bolts get tightened down. For the rear of the subframe I made these tubes longer so that they stuck down to be a flat mounting surface for the subframe, and so that I didn’t have to place a spacer between the frame and the subframe every time I take the subframe out. Here are some pictures of what I did.





Now comes the more exciting part. Since the floor is laid out now we can do our first test fit of the body. Step one of doing this is to remove everything that is bolted to the car, and remove all the glass as there is a good chance the chassis will be flexible once the floor is cut out and I don’t want to break any of the windows. The windows were relatively easy to remove with 2 people and some mig wire. I got all the windows out without breaking a single one so this I took as a win.





Now that the car was as prepped as it was going to get I dragged it outside so as not to fill the entire garage with smoke and went to cutting the entire floor out, the firewall and the front end off the car. My neighbours must have thought I was crazy cutting this much out of the car. Now that I had some clearance we tested the weight of the body. Luckily it doesn’t seem to weigh too much, and me and my dad were able to easily pick it up and move it around. The chassis is also very stable and not anywhere near as flexible as I figured it would be. I have a picture of it sitting on the garage floor, and man is it small when it’s sitting on the ground haha. The roof barely comes up to my waist, and I’m not tall by any means.






Now it was time to toss it on the chassis and see how it fits. As expected there was lots more clearance to be made.




This photo here shows the wheel at essentially full droop. These stock fc wheels have tires that are much too big for the car on them so I can’t actually put the suspension at ride height to show as the tire runs into the quarter. This is another area that’s going to need some massaging and clearance.

This is all I have for this update, in the next one the body comes back off the chassis and I start making the necessary clearance, and make some mounts to hold it to the chassis, as the body is going to be removable.