Hey wut up Picasso, thought I wou;ld register to share some of my insight from my experience thus far.
Here is a link to my current progress so I dont have to repost all the pics again
http://www.sr20-forum.com/showthread.php?t=1016
Pics on the 1st and second page
Now, someone mantioned the front being the hard part and the rear being easier, that is quite the contrary. The front will be very easy, just reference the pics.
A simple cut of the gtir firewall to move the mounting locations for the rack and rear tranny mount to the b13 firewall and that is done for steering and it makes the clearance for the gearbox and beginning of the drive shaft. None of this is structural, so it is not a big deal and if you dont have a spare firewall or front clip to use as a donor, then just use sheet metal, probably some 16ga steel. Plus you guys are RHD right. So get the gtir front clip and just straight up swap the firewalls, that is really easy and eliminates alot of fab work, especially since you will have the shortened gtir steering column.
Next remove the b13 front subframe and vertical mounting points from the frame rails, remove hte "L" shaped frame spars from the gtir, and weld in place on the b13.
The Left side motor mounts are also easy. The forward one bolts right in. The rear one will bolt on once the frame spars are replaced on the b13 with the gtir spars. There are no threaded bolt holes for the rear left side tranny mount, so just TID it on or put in some thread inserts.
Onto the right side mount, you can leave that and use the b13 sr20 mount, or remove it by drilling the spot welds and removing the seam sealer and put the larger, beefier gtir mount on with a tig welder.
Now that that is done, drop in the motor and drive around on FWD unti you come up with more money to finish the driveshaft tunnel and move onto the rear.
So there are alot of steps to the front but none of it is structural except the frame spars, but those are easy, they will only go on one way. The rear is going to be all structural, so that makes it more difficult as it is extremely important for it to be pefect.
Remove the fuel tank and toss it, you will need a fuel cell or gtir fuel tank. Might as well use a fuel cell.
Now the the fuel cell is out of the way you can see alot more room to work with. The FWD unibodied cars bolt the rear suspension arms straight to the unibody, and the gtir uses a rea subframe to mount the suspension, dif and all. So now you need to cut out the whole rear section of the car.
Right behind the rear seat, take a measurement to see where the forward most mounting point will be on the subframe, mark it and make the cut a few inches in front of that. Now cut all the way to the rear past the spare wheel well. Your trunk should be completely cut out now all the way to the outside of the ram rails. The reason is a new rear stubframe will need to be fabbed from chromoly to be welded to the frame rails that will curve up into the trunlk area a al s13/rnn14 (if you can source a junk rnn14 body down there with a good rear, just cut out the area of the gitr and the b13 and swap...done) style.
When building the rear stub frame you will incorporate a fuel cell into the rear end where the spare wheel well usd to be, so whel you weld this thing in it will be of sheet metal to create the new floorpan in the rear and the rea stubframe and fuel cell all in one. Now you bolt the subframe to the stub and the rear is almost done.
The last thing I did not mention is makeing the driveshaft tunnel. That part is really easy. Jus tuse some sheet metal, steel or aluminum. For wither materila just bend and put in place, then use seem sealer/chemical welder. For steel hit it with a few spot weld and then seam seal it. Now have the custom drave shaft made and done.
The hardest part of the rear is to make sure to take proper measurements for the makinf of the stub frame so the gtir subframe will sit low or high enough. In this you can also customize suspension geometery if you like by raising or lowerg the subframe placement just like using subframe spacers on a s13. But the good thing is the suspension geometry for the rear will be correct because it will remain mounted to the subframe aslo helping make the rear rigid to handle the applied torque to the rear that the FWD chassis was previously unable to hold.
Thats it in a nut shell, of course you will run into things along the way, but if you have the right tools or access to them and can TIG weld well or know someone who can it is fairly easy, just very time consuming for those of us who's profession is not fabrication and costly because of the rear stub frame that must be built.
Jeremy
