This topic is very interesting as this is potentially my next project, the only difference is I'll be using a 280Z. They are cheaper, usually in better shape, and more readily available in this area.
Here's what I have so far.
The main questions to be answered
1) How to control the ATTES ET-S?
2) which diffs to use front and rear?
3) Does the trans with transfer case fit in the Z tunnel?
4) Front or rear rack and pinion and which unit?
5) Which front suspension/brakes?
6) Which rear suspension/brakes?
7) What is a rough cost estimate?
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1) How to control the ATTES ET-S?
Some of the clips come with the factory controller but it's not adjustable.
How about the "Full Race" adjustable controller for $600?
http://www.full-race.com/store/r14-awd-skyline/ets-pro-center-diff-torque-split-controller-for-r32-r33-r34-skyline-gt-r-1.html
You also need the factory actuator pump/solenoid assembly. Hopefully this can be found used and separate from a clip.
Here's a clean custom install showing the actuator assembly
http://www.speedhunters.com/2010/03/car_feature_gt_gt_garage_ito_with_prostock_gt_r/
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2) which diffs to use front and rear?
It would be nice to use the factory diff in the front, because it's included with the swap engines and it's aluminum. Assuming this is an open diff? It needs to be moved forward on the engine/pan so the engine can be moved back against the Z firewall.
This s30 builder in Auckland was looking at an AWD potentially but he's just doing RWD for now. He was thinking the front diff needs to come forward on the engine about 9.5"
(scroll down about 1/10 of the page)
http://japanesenostalgiccar.com/forum/viewtopic.php?p=60319#p60319
The guys at Full Race did a R14 RB26 AWD build. That's the reason they developed the ATTES controller. They moved the diff forward 7". It shows where they cut the pan but it doesn't show it after it's welded. Assuming they welded it up because they don't say otherwise.
http://nissanroadracing.com/showthread.php?t=2680
This Pro Stock GTR has the diff moved forward 8", and they cut the pan to do it.
http://www.speedhunters.com/2010/03/car_feature_gt_gt_garage_ito_with_prostock_gt_r/
I also think that Nat0's idea of a separate diff in the front is viable. Just build an oil pan separate from the diff. Full Race says you need a limited slip rear diff and I'm assuming that the front diff is open. What is available with matching ratios in an aluminum housing, locker rear and open front? What ratio is best here? I'm thinking 3.6 but the R32 is 4.1?
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3) Does the trans with transfer case fit in the Z tunnel?
The Aukland builder attempted to answer this one. He thinks it can be done just bumping out or adding a panel on the existing tunnel, that it won't interfere with the seats.
(2/5 down the page)
http://japanesenostalgiccar.com/forum/viewtopic.php?p=60319#p60319
The Full Race Guys did a clip job using the tunnel/firewall from a R32 clip, they said they wanted it to look OEM. I think this is a little excessive, but I think they also did this to move the firewall back, which is not necessary with the s30.
(1/2 way down the page)
http://nissanroadracing.com/showthread.php?t=2680
I really think transfer clearance can be accomplished by bumping out or adding small panels in the floor by the tunnel.
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4) Front or rear rack and pinion and which unit?
This question is tied into the front suspension choice but it deserves some separate discussion.
The Aukland builder is going with the s30 unit, mainly because he's retaining the s30 front suspension (for now). Full Race is going with the R32 because they are using the R32 front suspension.
It would be nice to retain the s30 unit, it's lighter than anything with power assist and has a nice quick ratio. Hopefully the car is still not too heavy in front to need power. But the front uprights have to be swapped for AWD and that's going to dictate whether the rack is front or rear. So this question gets answered when the front suspension choice is made.
Here's an interesting rack solution that may be overkill. They went to extremes, probably to avoid bump steer.
http://www.speedhunters.com/2010/03/car_feature_gt_gt_garage_ito_with_prostock_gt_r/
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5) Which front suspension/brakes?
The Aukland builder did not discuss the front suspension for AWD, he was using s30 stuff because he's initially running RWD.
The Full Race guys are using a mix of parts, some z32 some r32, come custom. They don't really say what they ended up with. They are also using the r32 sub frame.
I'm thinking of two options, the z32 upright with some custom arms, or a generic FWD strut with a custom lower arm. Something that has 5 lug hub and can put upgraded 4 piston calipers. The z32 and r32 are rear steer so that dictates the rack and pinion being the same. What is a good manual rear steer rack with a fast ratio? Something equivalent to the s30 rack, it just seems like a nice piece.
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6) Which rear suspension/brakes?
Both the Aukland builder and Full Race are using the r32 rear sub frame and suspension. The Aukland guy added urethane bushings. The Full Race guys don't really get specific on this aspect.
I'm seeing two options, either an upgraded s30 setup, with a custom tube lower arm and a 5 lug hub and upgraded brakes. Or the r32 setup but upgraded to reduce weight. Maybe copying the geometry and replacing the sub frame and arms with tubing. Something like the Pro Stock GT-R but not that excessive.
I think just for the street and maybe an occasional track day you could get by with a basic strut suspension. Stiffer springs, bigger roll bars and urethane links combined with heim joints would help that choice also. The Full Race guys and the Pro Stock car are competitive race cars, my project doesn't have that goal.
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7) What is a rough cost estimate?
I've already been told this is going to be $25K to $30K. I'm going to try for less than $20K. The last project went way overboard such that I can't afford to keep it. This one is going to be more compromise and more sweat equity.
$1500 Builder 280Z
$4500 RB32 engine trans ecu harness
$1600 Wheels and tires
$1500 Flares, air dam, spoiler
$ 400 Racing seats
$1500 Build materials, steel tubing, alum sheet, SS header tube, etc
$1400 Coilovers
$1500 Suspension parts, urethane bush, uprights, hubs, etc.
$1500 Custom CV axles
$1800 Brakes
$ 300 Aluminum radiator
$ 300 Intercooler
$ 500 ECU chip
$ 600 ATTES controller
$3000 Miscellaneous
$21,900 Total (oops, already over)
