Welcome back to our lousy garage where the world’s least authentic Datsun 260Z is being restored. If you can call a process where a car is replaced with bits of other cars and clad entirely in foul-smelling fibreglass restoration.
Last time we left off with the suspension nearly finished and the chassis ready for the roll cage. Alas, we were wrong. Now, if the idea of combining a Ford steering rack and uprights with Driftworks Nissan S13 control arms sounds a bit insane, your intuition is just right. It is insane, but it almost worked. Until, of course, science kicked in the door and slapped us in the face with spreadsheets of ugly numbers and terrifying graph plots.
I’ll spare you the details, they’re tiresome. The bottom line is that our first take at the front suspension sucked big time. Mostly for two reasons:
– There was no camber gain in roll
– The front experienced horrid bump steer along the calculated suspension travel
If by now there is a sizeable speech bubble above your head with the letters WTF in it, you should never – and I mean never – start cutting and welding a car’s front suspension at random. We thought we’d had a rather good understanding of how things worked and yet we screwed up real bad. Lesson learnt: to build a proper race car, you need friends way smarter than you are. Thankfully this description fits my friend Tchangow quite perfectly.
So Tschangow came one evening, armed with a pen, a notepad, and a tape measure. Three hours later he had the whole suspension system sketched up. Another few hours later a wireframe simulation was created in CAD. By the next morning I knew we were in trouble. Our suspension looked OK at standstill, but once it started moving along the arcs defined by its arms, mean things started to happen. Things like front toe changing by 6 degrees during bump. If you’re wondering what that means, picture the car approaching a corner. You take the perfect line, aim for the apex, and as soon as cornering forces build up and the outside front suspension gets compressed (or you hit a bump), you find yourself hanging on for dear life as the car tries to spin and bite your hand off in the process. This is bump steer.
Bump steer is caused by the suspension arms and the steering linkage travelling along different arcs. Normally, they should be parallel and equal in length, so when the wheel moves up and down, steering is unaffected. However, if you mess up the geometry by installing a rack from a different vehicle and have tie rods pointing at silly angles with the control arms, your front wheels will have a will of their own. And they will win. And you will crash.
So it was back to the drawing board. But of course we don’t have drawing boards. We have a pile of greasy parts in the backyard and a strong tendency to improvise. If you’ll remember, all this trouble is because we’ve transplanted the whole S13 suspension under the Datsun, but the old Z must have her steering rack in front of the axle line, as there is no room behind it because of the big-ass VQ35DE engine that comes from the Nissan 350Z. This deprives us from the chance of using the great GeoMaster2 knuckles, which would’ve been our primary choice. If you take the steering rack from a rear steer car (such as the S13) and put it in front of the axle line, you end up with the road wheels turning in the opposite direction to your steering wheel. Now, that’s pretty hilarious when done by Buster Keaton in a Model T, but rather frightening in real life. So we needed a steering rack that had the same dimensions as that of the factory S13 item, but turned in the opposite direction.
However unlikely, it was actually me who came up with the ingenious – and in retrospect pretty obvious – idea to actually use a rack from a right hand drive vehicle, turned over, and placed in front of the axle. Remember, I’m from the continent, so I need the steering wheel on the left. An RHD rack would place the steering wheel at the wrong side. Simply turning it over would cause the wheels to move opposite to the steering. But moving it to the other side of the axle gives us just what we need. So if anybody fancies the same transplant in the UK, Australia, or even in Japan, just buy a decent, used LHD rack and flip it over.
OK, enough of all this oily nonsense, let’s look at the pictures you’ve all clicked at. That’s Aardvark’s painfully beautiful custom widebody with the Rota RBX’s all around. The reason it’s so pretty is that the car is due to appear at a classic car show on the 15th of April. This means that all this blessed backyard engineering was brought to a screeching halt two weeks ago and the empty shell transferred to OMG Visuals, where we tried to tidy up the semi-finished fibreglass panels and create some more from scratch. The idea is to finish and paint the shell before the show, have the car displayed, gain some inspiration from all the people falling over, drooling and crying from its surreal hotness, then take it back to Driftgarage where we’ll remove the fibreglass panels once more and actually build the car.
As far as I can tell we have all the parts assembled, so after the show there is only the small matter of finishing the roll cage, the stitch welding of the unibody, the installation of the suspension, and bolting in the 350Z’s engine, tranny and a few miscellaneous ancillaries. If everything goes according to plan, we’ll be putting out smoke this summer. Let us know if you like what you see!