NA tubular K-member in an NB
 

So as I am sourcing parts for my NB ls1 swap, I have come across what i think is a good deal on a V8R subframe kit, with kmember, trans mount, motor mounts, etc. My question is, this was originally purchased for an NA car, and I am planning my swap on an NB. I know the only real difference is in how the steering is mounted, can anyone be a little more specific on this? I can weld pretty good so is this going to be any more than me cutting/relocating the steering rack mounting brackets?

The shape and location of the mounts is different, and the NB has larger mounting bolts. I would think the easiest solution would be to use an NA rack, but you can probably figure out the mods by looking at pictures or actual examples of the two different subframes. You might get away with cutting the mounts off the stock NB subframe and welding them to the tubular one, just be aware that they are not in exactly the same locations.

Mike

I would contact V8R directly and ask what the differences are.

I kind of think the frame itself is the same because there is a couple of extra holes in them that are not used in the NA but Steve is right just call Flyin Miata or V8R and they will know for sure.

if it doesn't work out perhaps you would share the lead with us?

So I just called V8R and talked to them for a little while. He said the same thing that CVX_20 did in that it will be much easier just to pick up a NA rack and use it instead. He said the differences between the racks are minimal, can anyone support that? I know the bolts are a different size, but is there any real advantage/disadvantage between the two?

My car will be an occasional weekend racer, but mostly just an agressive daily driver, so I think this is the way I am going to go.

The only thing that hasn't been discussed is the little tubes that come across the rack from the valve to the cylinder inside the rack. They are different from NA to NB, which only matters for pan clearance. The pan needs to be modified anyway, so just keep the location of the tubes in mind.

So, no problem. just use the NA steering :)

Mike

What Ill probably do is just pick up an NA rack since I am sure I can find one for cheap, and then compare the two once I come to that point. If the fab doesn't look bad, Ill move the mounts. If it looks to be more trouble than its worth, then I'll stick with the NA rack. This deal will also have a Flyin Miata oil pan included.

NA rack will work in this sub-frame and is a bolt on. The only other part you need to change is the u-joint at the bottom of the steering shaft. The NA uses 2 small diameter splined sections and I believe the joint can be mounted in either direction. The NB uses one small spline and a larger one at the rack so it installs in one direction only. Other than that joint and the rack, all of the NA/NB parts interchange.
When dealing with the rear sub-frame, all NA/NB sub's fit all models. The difference in track width is done in the upright spindle itself. Comparing the two side by side it is visible in the casting. For the Exocet I am using an NA sub-frame, NB uprights, NB LCA's and tubular UCA's to maximize the rear track so that the wheels/tires will fit past the frame tubes.
If you do use the NB uprights on an NA car you need to change the wheel offset by 5mm or trim the fender lip by 5mm across 10"+/- at the top of the arc. Nadine took the cut well with a small body saw and the skilled hands of my body guy. Took him 3 minutes!