¯\_(ツ)_/¯ said:In reply to GladlyTheCrossEyedBear :
Yep, planning on a single piece- critical speed for a 3" steel driveshaft at this length will still be well past the top of 5th gear, so we should be ok. If I have issues I could return to a 2 piece design but it hopefully won't be necessary.
You're shortening it by 8" on an already short wheelbase car, a 1 piece shaft will definitely be everything you need. Plus less spinny bits to break
i love what you're doing, keep it up.
With a bit more trimming, the tunnel was ready for another fitup:
And then I just decided it wasn't going to get any closer to perfect so I zapped the transmission and support bearing mounts to the car:
Pulled the engine/transmission out again (really tight with the cross support welded under the car but it worked):
Did a bunch more welding until I was nearly out of argon, ending up here:
Then set about making templates for when I get a refill- a giant roll of this white paper was pretty cheap and it's way nicer than hoarding and chopping up cardboard:
And the driveshaft showed up already! Axle Exchange in NJ was easy to work with and very prompt, it was just "BRZ? What length? OK, you'll have it this week" and it uses normal 1310 u-joints so I can have a spare easily. Despite the larger diameter and steel construction, it's still 5lbs lighter than the stock 2-piece:
why not an aluminum shaft?
Hopefully you don't need the center support bearing. With the Kpower kit it was 5.5" shorter and had lots of vibration but that was aluminum. I think steel is more forgiving with harmonics?
In reply to fidelity101 :
Rocks. Might do one if I'm chasing tenths later and keep the steel one as a spare.
In reply to captainawesome :
Did you check drivetrain angles with the Kpower stuff? Wouldn't be the first kit that failed to account for something like that.
In reply to ¯\_(ツ)_/¯ :
Never did, but when I shortened the stock one I had to use a spacer to get proper driveline angles, so you may be on to something with that. It was roughly a 1/2" drop if I remember correctly.
In reply to captainawesome :
That's a LOT, at least based on the pretty mild shimming I've been doing to place this tunnel- hopefully that was it, and if not I'll find out the fun way.
In reply to ¯\_(ツ)_/¯ :
It sounds like you are going through more rigorous planning in this aspect than Kpower did, so I bet you are going to be fine. They did a great job with some of the kit and other parts were not well thought out. The shifter setup, driveshaft, and cooling system were the most egregious offenders.
Why not a carbon fiber driveshaft like Jesus 02wd intended?
In reply to paperpaper :
Carbon fiber has less than phenomenal impact strength...
paperpaper said:Why not a carbon fiber driveshaft like Jesus 02wd intended?
they unwrap in rally
Apropos of nothing.
It sounds GLORIOUS.
In reply to Pete. (l33t FS) :
berkeley yeah
And he just left the course mid run after coming through sounding like it was running less than stellar 
In reply to fidelity101 :
I know. we are poking fun at another car we compete against.
Welding, lots of it:
The underside has several pieces of the OEM floor structure folded over each other and then capped with what used to be the front of the lower tunnel- not the prettiest but it's really strong, don't want a rock coming through there:
Paint- this will get sealer at a later time and more paint but have to keep it from rusting:
Engine and transmission back in to check things again:
Plenty more sheet metal fun ahead for me:
And hey, the driveshaft fits! I'll need to clearance the shift rod a bit, the larger u-joint is too close for comfort:
Does the fuel tank go over or under the driveshaft?
In reply to Pete. (l33t FS) :
Over. Stock saddle tank has its' downsides but low and back seems like the right place for sloshy fuel to live.
Since the transmission tunnel is now in place, seat mounts could be made. I wanted these as low and back as possible, and while I could've waited for cage time to make them, it seemed like a reasonable thing to do sooner rather than later so that things like pedal placement could be figured out.
First, tacked the landing plates (1/8" thick) in and cut some .75"x1.5" rectangle tube to length, then plopped the seat in. Nice and far back, with plenty of adjustment forward if needed (yes I trimmed down the excessive side bracket later for final fitment):
Moving way back should hopefully do a few things- get the weight of the squishy human ballast onto the rear wheels, give us some usable room in the cabin, make the shifter actually reachable, and most importantly, get that nice thick factory B pillar involved as the first line of defense if we smack something sideways. I could also use more headroom than I have in the current car, hence the super flat profile tubing.
Also something I don't frequently see discussed is how far inboard the seats can sit. This is hard to push much further inboard than stock BRZ seating, but it's a nice spot to give plenty of clearance to the door bars- both in case of impact, and that gap is a nice place to put the codriver bag and triangles and whatnot:
Although Sara hasn't necessarily selected her seat yet, I'm using this Momo Daytona since I like how they fit and the ones in the current car are holding up well. The seat mounts are mirrored and with the OMP brackets having plenty of adjustability, should fit whatever she chooses as long as the width isn't crazy different.
Onward with the thick-to-thin deeply annoying welding of the plates:
You can see the slot I cut in the floor for the angle iron runner to sink into- rather than notch the (very much structural) angle iron I decided to notch the thin floor instead and stitch it back together after. That area is actually a box section and is closed underneath. The inboard front landing plate is extra long, because the transmission mount lives there and I figured why not brace it while I'm doing this:
The windows cut into the tops of the tubes are how I welded the lower edge since it's basically resting on the floor- then I zapped those sections back in:
Next, angle iron runners- these aren't strictly necessary, I could've just made the crossbars exactly the right distance apart and put weld nuts on those, but I'd like some adjustability here and having the entire base of the side brackets resting on something instead of hovering in the middle makes me feel better:
I also welded a 1" tube crossbar to these as an antisubmarine strap mount before dropping them in- there's some debate as to whether this is better than an eyelet on the floor, but my personal preference is not mounting any safety system directly to the lowest part of a rally car:
Welded everything to everything:
I also stitched the crossbars and angle to the floor everywhere that they were close to touching:
These things are really stiff and hopefully we never have to really test them:
Paint:
If the gaps between the welds on the tunnel are jumping out at you, me too- seam sealer and final floor paint waits until I'm sure I'm not welding more.
Only had one afternoon this weekend but put it to good use on some tube fitting- despite having tried every combination of fwd/rwd cooling system bits, I couldn't really find an easy parts-bin way to get the coolant pipes to all come out of the front of the engine, so I opted to make a wraparound pipe from the water neck at the back of the heads instead:
To fixture the tubes (since I don't have equipment to weld or tack aluminum) I jammed PVC pipe caps in the junctions- for the 1.5" aluminum tubing I was using, 3/4" PVC caps were about right to slot things together:
Also made some little standoffs (just thin wall steel tube and weld nuts) to mount the tube:
Ended up here, it'll need a silicone 90 degree coupler and an inline filler cap:
Originally I had planned to have another 90 on the end and a radiator cap on the tube, but discussion with smart friends led to concerns about hanging that much aluminum off a vibrately engine so, this is the layout. The lower tube is also going to be adapted with a much simpler, shortened 90 degree pipe:
This setup will allow for a stock BRZ radiator using stock upper BRZ radiator hoses on both ends, which are a nice S-bend shape and should allow for plenty of misalignment if the radiator ever moves due to rally car things happening.
I'm actually a bit amazed you don't have a spool gun or other aluminum joining method at this point.
In any case, good progress!
In reply to irish44j (Forum Supporter) :
I really should just get a tig and learn to use it, it's definitely a major gap in my skillset.
It's too bad you can't send that pipe to the passenger side. Is it possible to build or modify the stock water neck to exit the other direction similar to the K swap layout?
captainawesome said:It's too bad you can't send that pipe to the passenger side. Is it possible to build or modify the stock water neck to exit the other direction similar to the K swap layout?
Certainly could, or even weld something up to make it go through the valley under the intake- ultimately I decided that the solution that doesn't have any welds on cast parts or more complex fabricated bits was probably the simplest.
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