28 Dec 2009

Fabricated a rear toe-control link – piece of cake. With that done, one side of the rear suspension is complete, so a wheel was bolted on to check fit-up. Guess someone did something right; it fits great, with the tire offset being right where it was designed.

Realized the rear uprights were inadvertently swapped side-to-side when the first suspension arms were made. Turns out it was due to how much better they package – with one exception. It moves the top pivot nicely rearward, getting it away from where the shock wants to go, providing a good straight shot at the inboard pivots. The one bad thing is that the brake calipers also swap sides, such that the emergency brake cables point toward the rear of the car. However, after staring at it awhile, that’s an allowable compromise compared to all the benefits. The caliper, specifically the e-brake bracket, sticks out behind the caliper by nearly 7″, fouling where the shock needs to go. But, since the e-brake cables have to be custom anyway, it ends up routing rather nicely, curving inward and forward, under the drivetrain, up and over the tank, and forward to the lever.

Started building up the second set of suspension arms. Since the spherical bearing for the front rocker-arms or suspension aren’t here, I’m working on the arms that use neither.

24 Dec 2009

Upper rear arm is complete other than a few gussets. Next is the toe-control link which is a piece of cake.

Still haven’t figured out why the O2 sensor reading is perpetually stuck at “14.70” all the time regardless if the engine’s running or not, whether the sensor’s plugged in, or whether I feed in a simulated signal. Nothing. That’ll be dealt with later.

Merry Christmas everyone! I hope everyone has a great holiday.

22 Dec 2009

Spent the day building up the rear arm, referring to my drawings, but ignoring them at the same time when they didn’t quite match what was needed… there’s going to be a lot of redrawing needed… sigh. Anyhow, the lower arm’s done other than lugs for the shock, then there’s making the top suspension mount.

In other news, Christmas came a bit early in the form of what I consider a “total coolant solution” from k-tuned.com. With this I’ll be able to easily plumb the engine – it’s a very versatile setup, exactly what I’ve been looking for.

In the last picture, Midi stopped in to see what was going on; for some reason I find this picture hysterical.

18 Dec 2009

Fabricated the spacer for the upper spherical bearing, drilled out the top tapered hole in the upright, pressed the bearing into the arm, and it looks pretty good, just have to find a couple high-accuracy bolts.

Also, the bottom arm has been corrected; stiffening plates are yet to be added at the outboard end. The lower arm is now basically non-adjustable, but it’s not an issue since the upper arm’s used to set both camber and castor.

Since the bearings for the rocker arm’s haven’t shown up, I’ll probably build one upper and lower rear arms to see if there’s any issues there. But before that, since the coated turbine housing is back, I’ll probably fire up the engine just to hear how well the turbo and muffler work to quiet it down, and to hear, for the first time, the sound of the turbo whistling! 🙂

17 Dec 2009

Alright, how’s this? Answer: as good as it’ll get. Note now-vertical rear pivot and clevis setup, requiring reworking a number of drawings – sigh. It finally sunk in to do the suspension the best I know how and let builders decide how they’ll implement it.

The spherical bearing sits lower than the tie-rod, so a spacer is needed to bring it up to the same height, and the tapered hole in the upright has to be drilled out to accommodate a bolt – oh well. Would the old upper arm have worked? Yes, at least until a really big pothole is hit while under hard braking…

16 Dec 2009

Making some changes in the front suspension. The rod-end at the top of the uprights are being replaced with spherical bearings and the arms are being changed to aim directly at the in-board pivots. The rear pivots are changing from horizontal to vertical bolts, allowing the rod-ends to aim directly at the upright. Pictures when the first unit is built.

15 Dec 2009

Spent the day working out the push-rod geometry. It means applying loads to tubes in the middle of their span, but since the spans are short and made from 1.5″ x 0.085″ square tubing, it’s not like they’re going to move much, but gussets are an option.

My car buddy, Alan, stopped by. He’s been a metal fabricator for decades, having helped to build, among many other things, the Nissan GTP cars. When he saw the mocked-up front A-arms, he said, “WTF is this?” That’s Alan, giving straight opinions – unlike internet forums where you’re not allowed to say something’s wrong with someone’s car. Anyhow, my defense was that I’d just built them the day before and that I wasn’t real happy about the zig-zag upper arm, either, and said I can do better – he said, “That shouldn’t be hard.” I gave him the Smokey Yunick autobiography for Christmas, because I think he and Smokey were separated at birth!

14 Dec 2009

Built one upper and lower front A-arm to test the design. Looks like it’ll work as-is with the shock mounted outboard. Installation ratio is about 0.65, which translates into a 300 lb/inch spring to get 130 cpm wheel rate. That’s not bad, and wheel rate rises slightly in compression.

With that out of the way, it brings up the issue of inboard suspension. What I prefer doesn’t mean much if everyone else like something different… so, I’v decided to go inboard. The reasoning is that since it’s more complicated, that’s what needs the attention. The simplier outboard solution uses the same A-arms and is a no-brainer to install.

12 Dec 2009

Started on the front suspension, tacked-together per the plans to see what’s going on, since a beta-builder reported trouble. If there’s a problem, it’s likely because the A-arms were modeled in CAD as point-to-point, while the real A-arms have threaded bungs at right angles to the chassis, so the tubes aren’t where they are in Software Land. The solution of which way to go, outboard or push-rod, will be answered in the next couple of days.