JMortensen

Just make sure they clip in. That's the important bit.

Yeah, bring your helmet too. My helmet was almost resting on the door halo, and I tried to squeeze it up as tight to the roof as I could. Ended up moving my seat to the right to compensate. I actually think it would have been better to block the window a bit and have it lower and further out than trying to get it all tucked in tight against the roof.

It is a rule in SCCA as well, and you should get the cage builder to fix that. It's tough to do a Z properly because there isn't a lot of room. Mikelly and bjhines both got their cars on the track (not with SCCA) with hoops similar to what you have, but I think it's a serious issue that should be fixed. If you get hit right in the dogleg area just behind the door, you're going to have your pelvis crushed before the cage gets involved. You can download the GCR here: https://www.scca.com/downloads Here is the pertinent bit: 9.4.1. BASIC DESIGN CONSIDERATIONS A. The basic purpose of the roll cage is to protect the driver if the car turns over, runs into an obstacle such as a guardrail or catch fence, or is struck by another car. It shall be designed to withstand compression forces from the weight of the car coming down on the rollover structure and to take fore/ aft and lateral loads resulting from the car skidding along on its rollover structure. B. Forward braces and portions of the main hoop subject to contact by the driver’s helmet (as seated normally and restrained by seatbelt/shoulder harness) shall be padded with non-resilient material such as Ethafoam® or Ensolite® with a minimum thickness of one-half (1/2) inch. Padding meeting SFI spec 45.1 or FIA 8857-2001 is strongly recommended. C. No portion of the safety roll cage shall have an aerodynamic effect by creating a vertical thrust. D. Roll cage or chassis design shall prevent engine intrusion into the driver compartment. E. Material: 1. Seamless, or DOM (Drawn Over Mandrel) mild steel tubing (SAE 1010, 1020, 1025) or equivalent, or alloy steel tubing (SAE, 4130) shall be used for all roll cage structures. Proof of use of alloy steel is the responsibility of the entrant. 2. Minimum tubing sizes (all Formula, Sports Racing, GT, and Production Category automobiles, and all automobiles registered prior to June 1, 1994) for all required roll cage elements (All dimensions in inches): Vehicle Weight Material Without Driver Mild Steel Alloy Steel Up to 1500 lbs. 1.375 x .095 1.375 x .080 1500-2500 lbs. 1.50 x .095 1.375 x .095 Over 2500 lbs. 1.50 x .120 1.50 x .095 1.625 x .120 1.75 x .095 3. Minimum tubing sizes for (all Showroom Stock, Touring and Improved Touring Category automobiles registered after June 1, 1994) for all required roll cage elements (All dimensions in inches): Up to 1500 lbs. 1.375 x .095 DOM / Seamless / Alloy 1501-2200 lbs. 1.500 x .095 DOM / Seamless / Alloy 2201-3000 lbs. 1.500 x .120 DOM / Seamless / Alloy 1.625 x .120 DOM / Seamless / Alloy 1.750 x .095 DOM / Seamless / Alloy (American Sedans may construct to these specs regardless of weight.) 3001-4000 lbs. 1.750 x .120 DOM / Seamless / Alloy Over 4000 lbs. 2.000 x .120 DOM / Seamless / Alloy Note: ERW tubing is not permitted in any car registered after 1/1/2003. Main hoop: 4 bends max., totaling 180º ± 10º Front hoop: 4 bends max. or Front downtubes: 2 bends max. Rear hoop supports: No bends.

Longer links have less angle change as the bar moves. The angle change affects the spring rate of the bar.

Walkerbk said what I was going to say. Focus the heat on the rail, draw it down to the floor. If they're stitched all the way down, I don't think you need to plug weld.

I do believe that is Mark Belrose's old car. I recognize the trans tunnel that his brother helped him fab up and it's got a VARA sticker on the dash, and I know he sold it to a guy in Oz. Car is BUILT. Stroker with 50mm Mikunis, etc. I'm sure it will be fixed and back out again. BTW Bathhurst is just awesome. Would like to visit and drive there someday. That's a bucket list item for sure.

Hey, just thought of another, simple solution! Non-plunging 930 CVs. Get 2, run one on each side. I'd bet that solves it. There might be a cheaper source, but RCV makes quality parts: https://www.rcvperformance.com/ultimate-non-plunging-fixed-930-cv-joint-chromoly-cage-and-28-spline.html

I doubt the CV is at too much of an angle. The 911 has the transaxle end of the CV something like 2" forward of the hub, then they run camber and they handle it fine. They do have deep pockets for the CVs to move into, you could completely extend the CV in the race and it wouldn't touch anything on the car. I think that's the difference. As far as the other options go, my LS should be in the vicinity of 400 ft/lbs with Z31T and Modern Motorsports chromoly stub axles and adapters, and aside from CV bolts loosening (fixed with safety wire) I've had no trouble.

I think WCR and Ermish's kits were designed for 510s, so they fit on R160 with similar track width. Add R180, fit still works. Add R200, now the shafts are too long. That's my guess anyway.

My memory is kinda fuzzy, but I seem to recall that the Z32 calipers weren't the best. The iron ones were heavy, the aluminum ones were flexy. I seem to recall people adapting them to S30s and other people saying: "Why didn't you just get some Wilwoods, they're less flexy and perform better?"

Steel

Those are some serious brakes Ironhead. Nice! I remember Dave at AZC used to drill the stock rear hubs for 5 lugs and as part of the deal he put them on a lathe to true them, just in case someone had backed into a curb in 1973 while parallel parking. I would assume you could do the same for the TTT front hubs if desired. FWIW I have an engineer friend who was telling me not to use AL front hubs, as the AL expands at different rates than the steel bearing races and he has seen quite a few spun wheel bearings in Mustangs with AL hubs. Suppose that's only a problem for the serious road racer types. I have AL hubs, so if I have problems, plan is to switch out to something else entirely...

CobraMatt was 8 seconds faster than Greg at VIR with his LS7 big wing car IIRC, so without rules, can go quite a bit faster than that...

You can sort a Z and make it handle. Just takes more work than it does on a newer car with a better suspension design. Took 2nd overall at an autocross this summer, along with 5th on another occasion. But if you're expecting to put poly bushings and KYBs in one and be at the front of the pack, eh, not so much...

Prepping for track days next year. Should have something for you in about 6 months...

I think the easiest way to reduce front lift is to duct the radiator to the front of the car, so that all the air that goes in the nose has to go through the rad and can't go under or over the rad support. Even better would be to take the air out of the rad and send it back outside of the car, either to the sides or out the hood. I also think that a wing shape under the crossmember could potentially work, but the front end of the Z packs so much air into the engine compartment that you'd have a hard time accelerating the air with your foil, as it would exhaust into the high pressure area under the hood. In other words, it probably won't work much or at all without first dealing with the huge amount of air that's packing into the front of the car. None of the cars tested in the windtunnel had a radiator duct, unfortunately. They did close up the hole in the nose to varying degrees, which is better than nothing, but I think they left a lot on the table in that respect.

I believe I have an extra set if you need them. Dunno what they're going for, but I'll offer them for $50 and cover shipping. PM if you're interested.

Stock bushings need to be pressed in. If they're loose, that's not going to work. Probably the wrong bushing. Poly should be tight in the control arm. The idea of poly is that when you tighten the bolt down, the sleeve that goes through the middle of the bushing gets pinched in the crossmember and stays stationary, and the poly slides on the sleeve. IME the Z bushings are way too wide, so that when you bolt it all together there might be 1/8" or 3/16" of bushing sticking out past the sleeve. If you tighten the bolt down enough to pinch the sleeve in the crossmember, the way it should be, the bushings are so compressed that it makes it damn near impossible to move the control arm. What would really help here is taking the bushings to a belt sander and removing some of the extra bushing material.

Increasing track width increases grip on that end of the car, so widening the front end should help with understeer. I suspect your problem with the hump is bumpsteer. I had a similar issue with a hump right on the exit of a corner. My Z would do an emergency lane change kind of maneuver as a result of the bumpsteer (running really low with 3/4" bumpsteer spacer, but no other bumpsteer mods at that time). I fixed the bumpsteer by slotting the front crossmember and moving the lower control arm pivots up about 7/16". One issue that might arise with an offset spacer is ball joint wear. You're increasing the leverage on the ball joint. Not sure if it's a big problem or a minor one, but theoretically should be different than stock.

Not usually necessary, but a dirt cheap and easy way to do it is to take a piece of 3/8" hard fuel line, pinch the ends in a vise, drill holes and attach to existing holes in the chassis and fender. I had to do a brace on zredbaron's car because he barely had clearance between tire and fender and then bent the fender just a hair. When he turned the wheel the fender hit the tire. Took about 10 minutes, worked great.

I have a suggestion: DON'T make a super strong support that comes off of the strut towers. If you are reinforcing the chasis for stiffness, end all of that at the front swaybar mount. Everything forward of that doesn't need to be super strong, and if you make it strong and get into a minor accident, it will take out the strut towers and make repair more difficult. If you haven't reinforced the chassis then you need the stiffness up front as that helps to keep the upper and lower frame rails in alignment. Just don't overdo it and run back to the strut towers. Not necessary to attach to the strut towers to support the weight of the rad, intercooler, ac condensor, whatever else you decide to put up there.

The popular one is the Subaru rack. If you search "subaru power steering" I'm sure you'll find some threads. The electric is the go to now, but I'm not convinced it's the best answer. I've heard racers complain about dead feeling steering, and that is certainly the case in my Kia which has it. If you just want to steer in parking lots, it's an easy out. I have a custom Woodward rack. Was expensive and required lots of fabrication to the front xmember, but I love the way it feels and I love the 75% faster than stock ratio I ordered with it. I can go through entire autocross courses without having to move my hands on the wheel. Here is my thread on it:

I would add "cheap" to your light, simple, and beautiful characteristics. Cost was the main reason I bought a Z - bought it for $1500 - and the 6 cyl was the reason I didn't buy a 510. I am an autocrosser and started the sport just after the Miata hit the market, so the Miata has been ever-present and always appealed to me. When I finally bought a 99 midway through building my Z, I had a moment where I considered selling the Z and building the Miata instead. From a stock vs stock comparison, they are both slow in a straight line but the Miata is WAAAAAAAAAAY more capable and fun to drive, and you can do the same sorts of things like engine swaps, etc. I sold mine when I was short on cash, but I would like to have another. The prices are starting to creep up on Miatas already though, so I may miss the window of opportunity. That 350Z is nearing the zone as well...

Have you seen this one? Posting GT2 race times in home built 350. https://www.turnology.com/features/car-features/video-homebuilt-350z-sets-118-at-mosport-rivaling-alms-gt2-times/

There are a lot buried in threads here (and many many many dead links), but easier to look through my photos on FB: https://www.facebook.com/Jon.E.Mortensen