blueovalz

This is correct. As Jon point out earlier, the 3/4" coarser pitch being used on the OUTER rod ends to adjust toe is really too coarse for fine tuning. The advantage of using the inner bearing adjustment with these 5/8" rod ends (slightly finer threads, and spread out at about double the length of the outer rod end spacing) does allow a finer adjustment. I over engineer everything, but I assume the 5/8" has sufficient shear and tension failure figures. The 5/8” bearing would have made my conversion a dream-job, but I couldn’t see using anything less the ¾”, but again, I’m sure you’ve looked this over well. These arms look nice, and appear to function well. With that said... I welcome a long term test of the arms: 1) oriented vertically, because that is where side forces are going to try to rotate the bearing brackets inboard. BTW, have you considered a split bushing instead, or a split metal bushing? 2) The effect of a stiff large sway bar pulling the inner bearing brackets up or pushing down as well (if the brackets are instead oriented horizontally as shown in the photos). I guess I would envision a splined bushing design that rigidly held the bushing in place rather than a poly (or what ever the material is) bushing. 3) The effects of heat in that area are also a consideration as well. What effect will heat have on the "clamping" ability of the bushings if one were to run their exhaust close to, or under the bushings? Aluminum has a different expansion coeficient than the steel tube inside or the poly bushing. What effect will heat cycling, under compression, have over time? 4) I can see where the pin (bolt) can be used to prevent twisting, but then that kinda disposes the "track tuning" advantage in that now you're locked into a specific setting unless you want a drastic change that allows another hole to be drilled in the tube further around the circumference. Lastly, again an issue I brought up about the exact spacing required for mounting sperical bearings in the orientation "we" all like to use in our custom arms. The formula car orientation in the earlier post is 90º rotated from our use (your's and mine), which helps a lot. It at least places the spacing error issue on the stronger part of the bearing race. In our designs, if that spacing is off even a few thousanths (which is a common difference from one strut to another), you're going to bind that bearing in an axis it is not designed for, which is why I had to use very thin shims to get mine exactly right (which was then built into the design on the next set). In tube-type arms, the tube may deflect a little which reduces the stress on the bearing itself, but the billet arm looks like it will not have this advantage. Please do not take this as any criticism, but instead as an opportunity to educate us on your design.

Interesting string of contributions here. I will not attempt to justify any design, but pass on my experience with the OEM arms. Yes, they flex, and relatively easily. Prior to the heim joint conversion on the outer end of the arms, I rigidly attached the inner pivot point, and then added a twisting force (representative of acceleration, and braking) to gain some insight on the arms strength. At about 75 lb/ft of torque, I could deflect the outer ends of the arms by about 1/8" (front outer bushing up, and the rear outer bushing down by 1/16" each). Now obviously, that amount of movement is going to be stopped by the strut rod/tube before that happens in a real application. Once I had completed my modification to the outer bearings, I tested the arm again, and found that the rigidity significantly improved (same deflection occurred at about 130 lb/ft of torque on the end of the arm). This was a fairly simple conversion. It would be interesting to see what seam-welding the entire OEM 280 arm (not the lighter 240 arm) to overlap the OEM spot welds would do to improve on that. It has been recognized already (and any racecar designer sees this ALL the time) that improving one part simply moves the problem on to the next weakest part (and on, and on). And an IDEAL lower arm (no arm or pivot deflection) is going to "pass" this problem onto the unibody. This string was a nice study in the Z suspension, but that's as far as I can go with it. IMHO, improving upon the OEM design is easy, but a perfect solution will eventually have the result of a completely different car. I'm a firm believer of the 80/20 rule, and when I start seeing only 20% more improvement, with 80% more work, time, and expense lying before me, that's when I step back and say "good enough, job done!" BTW: Just watched "Cloverfield"...It rocked!!!

I've alway wondered if there was ever an acceptable reason to totally screw up the front of my Z by hitting someone, and YOU'VE provided that single acceptable situation!

I use Black Beauty (which I think is another trade name for Black Diamond). Works well and leaves an etched finish which is smooth, even with aluminum.

My soon to be driveshaft safety loop is still "pink" but it will have hair growing soon. It will have about 1/4" clearance all the way around the driveshaft (entire drive train is solidly mounted). So if I put this midway between the joints, I should have no more than 1/2" of wobble at either end of the failed joint. It's a 3" axle housing clamp in case you're wondering. I'm going to modify it a bit more by using smaller bolts (perhaps some good grade 3/8") being four 1/2" bolts are a little excessive (and weighty) for what is needed here.

My heart skipped a beat on those arms, but for a different reason than being impressed with the appearance. Pray tell me, what keeps the inner pivot bar from rotating under high lateral loading. With the limited experience I've had with the apparent materials used in this setup, I would be extremely surprised that the tube will not spin if the arms were mounted either directly above or below the tube. My last concern is the outer heim joint spacing. I've built arms using this configuration, and it can be time consuming to set the bearing up for zero side loading when the spindle nuts are tightened down. I built mine by having the heims bolted securely to the strut before welding the threaded tube ends, and that worked fine for that strut, but found the next strut was not machined to the same exact width as the jig strut. Even a few thousands off (the machining tolerance on the OEM struts falls into this easily), and the ball inside the rod ends start binding in their housings, which stiffens the joint, and in time leads to early failure of the heim joint. It takes patience to swap from one strut to another with the use of some very thin shims to make the design work as intended. I see so many arms being designed in this manner (and mine myself) and wonder why this issue is never brought up.

Since the motor is set with the #1 cylinder at TDC on the ignition stroke (that is what I surmise with your previous post), then the number one plug wire must be placed on the cap where the new rotor is currently pointed (or the closest one). Then just turn the whole distributor a small amount to get the final tuning.

That is my thought as well. If the axle were straight in the normal ride height, I would think the efficiency of CVs over U-joints would be minimal to non-existant. But there will always be changes in this geometry, especially if you include aerodynamic downforce devices.

McMaster-Carr also sells them.

Jon may have cleared this up when he stated that the OEM pedal may only be a 4:1 ratio, which makes the overall front ratio about 28:1. To answer your question, yes, I'm using the 15/16" MC, and 1 3/4" front for piston calipers (and 1 1/4" rear four piston calipers with NO proportioning valve). The pedal movement is not much, about 1/3 of total pedal distance to the floor is used, and it is very firm.

I would like to add a note about front to rear ratios as well. The harder the braking force applied (which is allowed with really sticky tires and aggressive driving, the wider that spread between front and rear. What this means is that a race car, with identical set-up as a street car, will require a different ratio or bias if race tires are used verses street tires. This is due to the increased weight transfer forward under the faster deceleration. This is my set-up (40:1), using a brake booster, and it works extremely well. In fact the "feel" (yeah, I know that's a subjective term) and pedal travel is very nice and short.

It amazes me to see the level of fabrication from the HybridZ membership. And you Jon, heck, somebody has to take the fabrication limelight away from you once in a while :biggrin: :biggrin:

No kit. Summit racing madrel bent tubes, Stan's flanges and 2-to-1 collectors, ebay O2 bungs, and lots of time.

. :biggrin::biggrin: It's all about constant improvement (and a forgiving spouse), and I'm kinda anal about both. The tubes are 1 3/4", so they are about 1/8" larger than the tri-y headers. The flanges are from Stan's headers (I believe) with the wider 3" bolt pattern, which fits the AFR 205 heads (and the RHS 225 heads as well). The exhaust bolt pattern was a big issue for me when I chose these heads. Fortunately, I found a good flowing set of head WITH a decent bolt pattern that would allow a lot of flexibility in primary tube configuration.

Sorry to contradict the "cold" statement, but resin is VERY sensitive to temperature. This is a chemical process, and as such, is accelerated with temperature. A piece layed up in the summer with 90º temps will harden in just a few minutes, with 1/2 the amount of catalyst in it compared to a piece layed up during the winter which may take an hour to set. This is stuff that you'll get a feel for when you do more parts. Temperature is very important. During winter lay-ups, I try to heat the garage if possible, but if not, at the very minimum, I warm the resin and catalyst before mixing and lay-up. This will help a lot!

I finally got my headers back from Jet-hot, and they look NICE. The differential pinion angle is reset for the new motor (slightly different angle due to different engine dimensions), and the World Class T-5 G-Force gear-set upgrade arrived today as well (big dang gears!). I'm JAZZED!

My 930 CV conversion cost me a lot more than $400. $50 each for the 930 CVs, $300+ for machinging the adapter plates, $200+ for the axles, and another couple of $100 for boots, flanges, and misc stuff to complete the set-up (total more than $900, and that doesn't count the research, trial and error, and spare parts needed to fab up the initial design). In reality, this is not too bad a deal (depending on reserve).

I'm assuming there is a bronze bushing (actually, it's more a sleeve) in the tailhousing that the output shaft fits inside. The driveshaft yoke then slips over the tailshaft, and into this bushing to keep everything aligned at the end of the output shaft. They wear just like everything else.

This is almost verbatim in what I had to do as well in order to get these "tight" inserts inserted. The only difference was that I tacked them without the angle. The higher up you cut, the easier it will be to avoid a misfit due to warping when welding.

Backspacing on the front is 5", and on the back is 4.5".

I don't think some of you specific questions have ever been addressed, but they have been tossed around on this forum in the past. Nobody (none that I know of) has ever done a quantitative study on the bearing load increases for high wheel offset. As a general observation, I've never seen a post that said, "My bearing failure was caused by...wheel...offset by..." I am hopefull that the amount of extra offset I have with my wheels is somewhat compensated for with the increased camber, thus shifting the contact patch inboard a small amount.

Are you intending on replacing the bronze bushing as well? If so, any tips would be appreicated. I'm planning on doing this to a generic T-5 before too long, and this would be of interest to me.

I am! I had no idea what the quote applied to. It does my heart good to know that there are folks concerned for my happiness. :biggrin:

I'm placing mine in the middle of the driveshaft, but the reasoning is because the Z driveshaft is relatively short. A loop in the middle, if tight enough will guard for failure at either end, but I have an advantage: My entire drivetrain is solidly mounted, thus I can use a perfectly round loop that has only .200" clearance between it and the driveshaft tube. On those cars using rubber (or flexible) mounts, the clearance must obviously be larger, which will cause a little more ruckous should either joint fail.

This is my version of a fuel door. When I put my car back on the street, I wanted to have a means of fueling the cell without opening the hatch every time. Even though it is on the hatch, there have been others that have done this on the quarter panel where the OEM door is. There are some strings on this, but I can't imagine what the key search word would be. I believe most of this type of modification has been done when wider flares were installed.