'79 Brat EJ22 Retrofit Build Thread

[mka]

Okay, made some pretty significant strides that warrant photography and a novella of an update - (over a month ago since the last one... Jeez, life comes at you sometimes). I've also figured out how to insert photos from and Imgur hosted upload, so while kludgy I get to keep adding photos without deleting the old ones.

The donor Impreza is almost out of my shop - I'll have it hauled off early next week and until then the neighbors are gonna have to deal with it being in the driveway. I've begun cutting away any mounting pieces or sheet metal with bolt holes and mounting bracketry I think I may need. This includes some of the firewall, the access panels for the fuel tank, and most significantly rear shock towers and transmission tunnel. So far I've only completed the removal of the towers, but considering the geometry involved I figured it was probably a good idea to take some time to go about it halfway properly. 

Before cutting anything off the body I had to remove the fuel tank and rear subframe. The subframe was quite an interesting proposition, and I managed to do it without disconnecting the rear struts from the knuckles, but that was a shortcut that turned out to probably take more time than what I'd maybe hoped as it required some creative jack and jack stand work. For those following in my footsteps in the future I might recommend taking the time to remove the struts from the knuckles, then replacing the wheels before undoing the (surprisingly few) subframe bolts while supporting the diff and carrier on a low-clearance transmission jack. I had to strain on the bushings while also rolling this on its drums to get everything out from underneath, but without the struts it would have been a much easier proposition to roll it out from under the car. This also being said, this would also be a moot point if I had a lift, which would have made a lot of this much, much easier. Oh well, wishes and fishes and whatnot.

I got the fuel tank out pretty shortly afterward, but with this particular car in this particular locale, all of the rubber and hoses were very, very, very tight and dry on their fittings, so more cutting of tubing than I would have liked had to take place. that being said I'm not sure which tank I'll be using yet, the brat or the impreza, so I'll likely need to reroute fuel lines anyway.

Once I'd given everything  with fuel a chance to drain and/or evaporate overnight, I began the dirty, dirty work of actually cutting away the pieces I'd need, beginning with the rear strut towers. (Fire extinguishers nearby, don't you fret)

I'm not sure how much of these towers I'll really be needing, so I decided to just take the whole interior wheel well. To somewhat preserve their geometry I braced them with a few pieces of angle iron tacked into place. I've been considering the difference in width of these cars, and the plan is to use the angle iron to keep everything aligned by cutting out the extra width (to be measured still) somewhere in the middle, then rejoining them with another "bridge" piece of angle and either clamps or tack welds to keep everything nominally aligned while I splice everything else into place. Wish I could say this was my original idea but there's a build thread I found (I think over on NASIOC), where someone doing a similar swap (WRX Sedan of similar year) into a Gen 2 Brat did a similar setup to get the rear suspension Frankensteined in. 

 

Other things to consider:

Part of the reason I got such a good deal on this donor was the rust damage at the rear driver's side (left) strut tower. Going to have to make sure I remove or mitigate all the cancer there somehow so as not to doom my Brat build from the getgo.

Also after looking at the rear subframe some, if I am going to splice it shorter, I'll need to get creative with the linkage and where it mounts. I'm not sure yet if i'll need to shorten the linkage AND the subframe, or if there's a way I can maintain the linkage geometry without running into clearance issues with the differential, all while keeping it under the Brat. Food for thought I suppose, but I'll tackle that problem when I get there. For now I forge on to cut out the transmission tunnel and a few pieces of firewall, as well as take a final pass over to pick off any other scraps I may find useful. Once the Impreza shell is well and truly gone, the Brat goes back up on jackstands so I can start removing the old rear end on that to begin making room for the new rear driveline.

 

Onto the next steps!

 

Edited May 15 by mka

[mka]

Got the transmission tunnel and parts of the firewall out as well as the remaining brake and fuel lines. The husk is now well and truly a husk.
Some might ask "why the firewall?" when i have a perfectly good Brat firewall  and my response is to preserve the mounting hole patterns for the Impreza parts like the brake master cylinder and passthroughs. I may not need them all but this way I at least have good templates or even pieces to splice in where I need them later.

Getting the Impreza body scrapped this week and putting the brat back up on stands to get the rear end removed. 

 

Looking at it I assumed the removal would be an easier task than it was - there's way more structural stuff in there than it appears at first glance, especially were I've cut it. Took me much longer than anticipated to finish the removal, especially since I was using a 4.5" angle grinder to do it. Were I to do this again or make suggestions to other folks - use a good reciprocating saw at the support ribs - it will make for much cleaner cuts.

Edited May 19 by mka

[moosens]

Is this where some guy chimes in to break your stones about not having a reciprocating saw? Oh wait that’s FB

Cool deal. I’m with you for having as opposed to finding out later you have not. You can trash it when the job is done I always say. 
 

Keep up the good work. This is very likely on my horizon. 

[mka]

On 5/19/2025 at 5:09 PM, moosens said:

Is this where some guy chimes in to break your stones about not having a reciprocating saw? Oh wait that’s FB

Cool deal. I’m with you for having as opposed to finding out later you have not. You can trash it when the job is done I always say. 
 

Keep up the good work. This is very likely on my horizon. 

LIkely so 😅.

I do own a reciprocating saw, but it is a battery powered model, and the sole remaining battery i have for it is tired. I got through one support rib with it before it decided it had had enough. Probably time to start consolidating to a singular brand of battery tool anyway, so that'll probably get replaced sooner rather than later now.

 

In other news... I'M BACK TO ONE PROJECT CAR. I bought this brat from an enterprising young man who runs his own scrapping and junk removal service. We kept in touch a little after I brought the Brat home and he offered to pick up a load of scrap from me including the impreza hull last week. Later in the afternoon the day of loading he sent me the following:

 

Bittersweet, but now I've reclaimed a great portion of my workshop floorspace. Granted I've still got a huge pile of parts in the place where the roller once sat but at least now I can walk around it, and that pile will slowly and steadily decline as I shift pieces over to the Brat. I suspect this is going to be the last major step achieved for a while - it's fixing to get really hot here for the forseeable future and I'm working on this in the driveway, so I'm going to have to start getting up early and invest in a shade tent to get much done on this for a while. As long as I'm making baby steps in a forward direction though, it'll get done.

 

Edited Monday at 05:30 PM by mka

[mka]

I've managed to keep the momentum I've built this last few days by removing the hull of the Impreza  from my shop. In the interest of clearing the walkway even more I've decided to start preparing to transplant the rear end, which means removing the old one.

 

This turned out to be easier than expected - probably  in part because of the practice I had pulling the subframe from the Impreza, and partly because this one had fewer and more accessible bolts holding the thing on. 

I've learned a few things from today's endeavors. 

1) the Impreza fuel tank is too long/wide to fit in place of its original counterpart in the Brat. This "too wide" feature seems to be a trend and for good reason - the wheelbase left to right when measured before removal were a good nine inches different, give or take. As such I'll likely either end up needing to reuse the original tank and run an aftermarket pump (most appealing, easiest on my wallet), or building/locating/modifying a new fuel cell to fit. Whether or not I will be able to use the original tank largely relies on item 2.

 

2) While the wheelbases are different, it looks like the differentials and housings themselves are very similar in size and shape - so much so that I'm tempted to think they used a modified version of the molds for the diff cases - or at least a very close one. The only visual differences I've been able to scope out at a glance are a few missing bolt holes on the Impreza cases vs. the Brat. There will probably be something more significantly different that I find as I dig into it more.

The big "what if" that stands currently is how much fabrication I will need to do in order to get the Impreza differential and subframe parts onto the Brat without causing interference problems with the original fuel tank. If I'm extremely lucky I might even be able to reuse a couple of the mounting bolt holes and front crossmember from the original brat - albeit with a bushing refresh. My plan here is to remove the struts from the Impreza rear end next - which should then allow me to roll the existing crossmember under the Brat bed to check and see what lines up and what doesnt.

 

3) Lastly and certainly not least - if the preceding items line up, I believe that again with some creative angle grinder surgery I can, similarly to the front end, move the pivot points for the rear suspension inboard far enough to maintain the stock Impreza components without completely custom control arms. Adjustable arms may still be smart and will probably end up being necessary to keep things tracking straight but at least this way I can still drop in off-the-shelf components for an Impreza instead of destroying my bank account.

 

Onto the next one...