Rear towers welded up- I normally weld thin stuff so this was different, have to work on my technique and settings a bit more but I'm certain they're plenty strong:
They're just sitting in the car here, I think the actual chopping and welding them in is going to wait a bit so I don't potentially strand this car on the lift while other things need to take priority:
So rad keep it up!
Next steps involve removing things first:
With any luck, this might be the last time the car sits on its' stock suspension mounts:
A step by step guide to installing these rear towers:
Start by cutting two large holes in the car- initial cuts are actually made from inside the wheel well, since the front edge of each tower aligns with a vertical piece of the unibody:
Allow yourself the inevitable moment of panic after you've cut some very large chunks out of a perfectly good car.
Check alignment, trim, repeat until things look like they belong together:
Lots of measuring side to side gets them equal, then tack the corners and install the modified subframe with that dropped trailing tab that allows for more travel:
Install 8" travel Bilsteins with a 1" spacer added to match the length of the Ohlins that eventually should go here, then check that this tower location looks right and allows full travel without anything crashing into anything else:
I measured 9.75" of travel at the hub, and that's with the little Bilstein bump ring thing installed so I'm going to call this almost exactly 10" of rear wheel travel. Neat.
Weld a lot more- the bases go to 2 layers of relatively thick steel but the wheel wells are basically paper so this was fun:
And even more weld goes from inside the wheel well to make sure all that metal at the base is tied in. The cage will brace these but it's good to make sure they're strong enough without it, too. Cubitron wheel on a grinder makes quick work of any boogers from the thin wheel well welds:
Paint:
And there we have it. I still need to get real misalignment spacers made for the Bilsteins, I used a little stack of washers and spacers to check travel, but it can become a roller again with what I have now for the rear. Front is next!
Love how it all just fits together. I know a lot of planning went in to making it look that easy.
In reply to AWSX1686 (Forum Supporter) :
I had the advantage this time of having already cut through the rear shock mounts on the L2wd car, so I knew there was good thick metal in the base area for these and I specifically made the boxes land on those two vertical gussets that brace the factory shock mount; those are thick by OEM unibody standards too. I'm looking forward to the (hopefully) much easier rear coilover installation/removal these should allow, the in the car/out of the car dance required by stock mounts or my L2wd towers is pretty annoying.
I knew of the V6 swap conversation, but somehow missed the newest rallycar build. I knew the rough direction it was heading, but WOW, the execution is stunning. Watching, learning, impressed.
¯\_(ツ)_/¯ said:Front is next!
Oops not quite yet. First I did something I was on the fence about:
I lopped both "buttcheek" sections of the body off, behind the rear wheels. This saves almost no weight, but I was going to block off those rear vents anyway since all they do is release cabin pressure and occasionally burp dust/mud/water backwards through them. I also think providing a more direct escape route for things thrown by the rear wheels to exit the wheel well may have benefits vs letting it all bounce around in there, the L2wd car can build up an alarming amount of mud in this area in short order.
Tape for template:
Trim/transfer:
Cut/bend:
A lot of welding, grinding, and some paint later:
Seam sealer for the inside too, it'd be annoying if these leaked at all:
OK now the front can be next:
I saw the dotted lines. Good idea.
Beefy! I dig it!
Front towers! Install fixture, tack bits:
Remove from car, weld a lot but move around enough not to warp much (hopefully):
Reinstall, with mild hammering to ensure the towers are fully seated on the fixtures:
Endless terrible thick-to-thin over OEM seam sealer welding:
Remove fixtures via screwdriver in the slots cut into the bottoms of the bolts:
Yes, I did drop one of the bolts into the totally inaccessible area between the factory tower and the new one:
Cut original tower tops out from underneath:
Flappy wheel all the boogery body welds, cubitron grind the inner towers and finish that with flappy wheel as well:
There's still a tiny little bit of welding I want to do in here, and I ran out of C25 so these will have to wait a bit for paint.
Since it's hopefully approaching roller status again, I reinstalled some stuff on the back. We're definitely going to need longer springs than these 14" 200lb/in ones I had laying around, but these will be ok for test fit purposes and probably even corner weighting for the real spring selection:
Reminder to self, still need real misalignment spacers and to do something clever with the bumpstop so these shocks can't destroy themselves.
Are those the same tower spacers you used to set up the towers on v1?
Nice.
Something that I wish I had learned a long time ago, and may be relevant for you. Mazda used some super special high strength steel in the SA/FB RX-7 shells that welds horribly. Apparently if you preheat it with a torch (I am not a metallurgist) it welds much more nicely.
I assume one lets it cool off first so you are not trying to weld hot tissue paper to cold plate 
Wow this thing just keeps getting cooler. Awesome work so far!
Little more welding and some paint and it's beginning to look like a rally shell:
Front struts- these are for development/spares and just like the rear, intended to be replaced by Ohlins, but for now it's another set of 40mm Bilsteins. The tabs are slightly different than the ones on the L2wd car, since I'm using a different (lower profile) top hat and also putting slightly more of the travel into droop rather than bump- I've discovered over time that I actually gave the L2wd car a little too much bump travel up front and it's actually better to bottom out with a couple inches of clearance remaining than to smack the skidplate on stuff.
Clamp:
Zap:
Paint:
And then I had to pull one of the springs off the rear again to do one of my favorite things, travel and clearance check:
The rear has 1.5" more travel than the front, and it's currently mostly in bump- luckily changing the overall shock length to tweak that is easy, and I'll likely make them just a bit longer to put some of that travel on the droop side instead.
It's a roller again, so I can get the lift back for L2wd car checks:
In an interesting turn of events, the flywheel (shipped from Spec) and the adapter (handed to us by Dylan before he set about securing the regional win at Overmountain) arrived at almost exactly the same time.
Bolt the flywheel up, seems right, gonna need to figure out a pilot bearing:
Adapter went on with two light taps of the orange mallet to get it onto the dowel pins:
Bellhousing and starter bolt on nicely too and everything looks to be concentric:
The slave cylinder is definitely a "zero is still not interference" sort of fit but I need to remake the line anyway so I think somewhere between a thin banjo fitting, a thin bolt, and a little filing/grinding here and there this will work just fine:
Reprep on the L2wd car takes priority, but I had to at least fit check this stuff. I'll be back at it soon.
I had to check one more thing- inexplicably, the 2GRFE crankshaft fits a stock BRZ pilot bearing. Hopefully the depth is about right, thank you to whoever probably standardized this 40 years ago.
Double. Check.
As you are probably aware by now, Subarus stuck the pilot bearing in the flywheel, not the crank. The input may not be reaching the pilot, depending on how the flywheel and the adaptor plate are machined.
Gut feeling says that even half engagement should be fine.
When mixing parts that don't really belong with each other, my Murphy's Law gland goes into overdrive when something looks like it just plugs in without any effort
I'm enjoying following along in this thread!
Any plans to re-route the exhaust based on recent damage to your other car at events?
In reply to rallyxPOS13 :
I'd love to not have the exhaust go under the fuel tank/diff/subframe but that's a future problem. Exhaust on a rally car is always a consumable but, definitely some more than others.
In reply to Pete. (l33t FS) :
Definitely going to check when I stick an actual transmission on it- plenty of access holes if I leave the clutch fork and oil pan off.
Does that flywheel let you use BRZ pressure plate and clutch? What's the plan there?
In reply to maschinenbau :
Yep, it's all BRZ dimensions outside the crank pattern. No weird spacers or anything and keeps the starter in the right place.
Hey, it was good seeing a GRM member out in the wild!
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