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Super low IRS wagon build

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So I have been working on this wagon for some time now. I come from the traditional hot rod and custom world and I have been dying for a nice Japanese wagon to drive daily forever now. I bought it just over a year ago out of Duarte, California. It was a rag. Rust in body panels, wrecked front end, glass out of it, completely apart, etc. But it ran and was fairly complete, and the price was right. 


I spent a couple evenings putting what was there together and it started to look like a decent ride.






If i was gonna daily drive this thing, I wanted it to be at least relatively safe, so I did a retractable shoulder harness conversion. I used the seat belts from an old 75 Corolla I had. I put a reinforcing plate in the pillar and built receptacles for the mechanisms in the rocker.











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I found a rear clip for sale that I bought to do my IRS swap. Guy had nearly an entire car. I bought a door, core support, and a couple other things.


Fixed the front end so everything lined up. Replaced the core support and one of the fenders.










Just a tip to those with wagons. The window frame is different from sedans. This door was a sedan and the window frame fell short of the door opening. I had to cut the wagon window frame off and attach it to the sedan door, using the wagon glass as well.





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Now on to what I'm sure everyone is curious about, the IRS swap. I wanted to get the wagon down way low without invading the passenger compartment. I hacked everything stock out and started to fit everything. I built pockets for the crossmember to mount to in order to get the crossmember as high as possible in the wagon. It ended up about 2" higher than it is in the sedan.






Before the pockets went in, I fixed rust and reinforced the rockers with 16 gauge. The wheel well reinforcement is 16 gauge as well that I shaped the fit the wheel well. The pockets and all structural parts of the swap are built from 14ga. 




I built a jig to locate the mounting points of the irs. The jig was used through half of the swap to make it easier to access things while welding.











Here the floor is done and you can see my fabricated fishplates where the suspension mounts go.




Suspension finally hung


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I put a lot of thought into how to spring the car. I drive a lot of very low vehicles and nothing makes me crazier than a low car that rides like a jackhammer. It is possible to make a very low car ride reasonably comfortable. My big Buick Riviera, for instance, rides 2-3" off of the ground and you wouldn't know it while riding in it. I also had the space constraint issues of only having about 12" from the floor to scrubline. I originally wanted to make some sort of bellcrank setup with qa1 coils but the lack of space made every design too much of a compromise. I played around with the idea of a transverse leaf and looked into corvettes. I had already figured that I needed a spring rate of about 235 lbs/in or so and it so happens that one particular year of corvettes had a rear rate of 229 lbs/in. I found a spring on ebay for $100 and went to town. These springs weigh about 10 lbs and do not fatigue like a steel spring.




Spring had to be narrowed, I cut an inch and a half off of each end, redrilled and rebonded the end plates






This is the difference in width. The spring rate change is negligible.


The stock corvette style of attaching the spring to the spindle wouldn't work because there is some misalignment that the bushings wouldn't like, so I built a heim and shackle linkage.




Then I built the mounts on the spindles/arms




Clamped the spring in place for a mock up run, and it sits and articulates fine.


My 13" Advans barely fit. I had to dolly the lips over and portopower one fender out a bit (I think it was pushed in from the accident it was in) and now nothing rubs at all.




I don't have any up to date photos yet, It is almost done now. Shooting to be at cars & coffee in Irvine a week from this Saturday. Fitting the gas tank today, then I just need to finish shortening my 280zx struts and running my exhaust. Here are some photos from when I was finishing the IRS subframe and spring perch mount.













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I have been waiting to post this until it was very close to completion. Didn't want it to hang up here without being updated regularly. I work a lot and I am a mechanical engineering student in what is possibly my last year so time is slim most the time. I started this IRS swap in January and it has been stuck on my lift since. I only had about 3 hours a week average from January through June because of school, so I have been getting down these past couple weeks. Its gonna drive next week, thats the goal. UPS man showed up with all of my exhaust stuff today. Tank is nearly mounted. I can hear it running already! I wanna go to JCCS this year with it too. I want to daily drive it but I have been having second thoughts because so many cars get stolen at my college campus...

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