Dan Baldwin

How do you use the car? If you're not roadracing (and maybe even if you are) you don't need any more in the brakes department if you ask me. I've had great success with the stock brakes on my ~195 hp Z at numerous race tracks. You just have to be sure the pads and shoes are appropriate high c.f., high temp materials, and that you use fresh brake fluid. I did have to adjust the drums pretty frequently, though, which was my main reason for going to rear discs. I mounted '82-'83 calipers and rotors using Maxima brackets (difficult to get, but I got mine through Lynchburg Nissan last year), and used an '81 ZX master cylinder. Got rid of the Z prop valve and installed a 280ZX one. That whole deal wound up costing me ~$350-$400. It could be done for cheaper using junkyard parts, though. Think about why you really want bigger brakes before you start shelling out $$, though. A lot of performance can be had with the stock setup, as hard as that is to believe.

For larger displacement V-8s, I believe OHV cam-in-block architecture is ideal. A look at a Ford DOHC v-8 vs. a GM LS-1 illustrates that you can get MUCH more displacement out of a MUCH smaller engine by sticking to cam-in-block. The DOHC does breathe better at higher rpm, but not enough to make up for the displacement disadvantage. Plus, the DOHC engine has a MUCH higher c.g., and is VERY bulky and costly. Check the hoodline of a Corvette vs. a Cobra Mustang. As far as "new" vs. "old" technology, Deusenbergs had DOHC and 4-valves/cylinder way back when in the 30s. Internal combustion technology is OLD, OHV or DOHC. Would you rather have a modern aluminum 4.7 liter DOHC that revs to 8000, or a modern aluminum OHV 5.9 liter that revs to 6500? Same power potential, but the OHV engine is cheaper and has a lower c.g. No doubt DOHC wins the hp/cu. in. honors, but what about hp/engine weight (more important if you ask me)? Food for thought.... My thoughts, anyway.

Interestingly, the current hot setup in ITS (no V8, but a still-heavy I-6 up front) is stiffer springs in front and NO rear roll bar. Why this works is beyond me, since I run stiffer springs out back (albeit much less stiff than ITS levels at 160F, 200R) with a 1" front bar (adjusted to the stiffer of two settings) and a 3/4" rear bar (adjusted to the softest of three settings). I LOVE the way the car handles now. It would seem to me that the ITS setup should cause the car to push quite a bit. For every day use, it's probably not a bad idea to remove the rear bar in a V8 Z, given that it should have a lower polar moment of inertia, and could use the additional rear traction relative to an L6 car. If you use a larger-than-stock front bar, you should reinforce the mount to the frame rails. I just ran long bolts up through the rails and used a 1/4" steel backing plate on top of the rails. If you don't reinforce some way or another, a stiffer bar will tear out the mounts. Ugly.

Kick. Ass. Really like the straight-tube bracing. MUCH stiffer than bent-tube braces, which have to be WAY bigger/heavier to do anything at all. What did you do to that bald guy who sat on your car? Hope you didn't hurt him too bad.

A ZX drive shaft won't fit a 240Z diff. When I installed my ZX 5-speed, I moved the diff to the '72+ location (~1" aft), and used a '73 drive shaft and it fit fine. I think if you're not moving the diff, you can use the same drive shaft you've got now. As far as I know, the trannys ARE the same length. The ZX 1st and 2nd gears are much taller than the Z's, so you may want shorter (numerically higher) diff gearing sometime soon. I ran mine with the 3.36 for a while, and with the 3.1's torque it wasn't a problem. O' course when I installed a 3.70 LSD, I got a big boost in off-the-line performance, though.

I've got what I consider to be a really good street/track compromise. 2.5 degrees neg. camber front, 2 degrees rear. ~4.2 degrees caster (T/C kit increased it from stock). 1/16" toe out. Springs are 160 lb/in front, 200 rear. Adjustable 1" bar in front, 3/4 rear. Car turns in GREAT. In fact, speaking of RX3s, my instructor of a couple years back who races an RX3 in GT3 complimented me on how well the car handled. It exhibits kind of a servo-steer effect. i.e., turn into a corner correctly and it's spooky how little effort is required at the wheel to carve through the turn. Wheeee!

Here's what I did: Maxima brackets '82-'83 calipers and rotors (new or COMPLETE rebuilt calipers, some rebuilts are only the hydraulic portion, no new sliders) '81 master cylinder (I tried to make an '82-'83 work and messed up a master and a booster) '73+ booster (replacing my smaller '71) 280ZX proportioning valve (which I located directly above the warning light assembly, next to the m.c.. Did away with the old prop valve). I *think* this should keep me at close to reasonable front/rear bias. I've got different c.f. pads for the rear to fine-tune. Seemed to work fine on the road and at the Glen, but I lost it in turn 6 (no fault of the brakes) and haven't gotten the car back from the body shop. It'll be ready for Lime Rock on Nov. 19 and 20, though.

Pete, Regarding street/track rain tires, this past weekend changed my mind. I was thinkin' I'd get Kumhos, but in my SLOW '91 240SX I was pretty much the fastest guy on the track during the raining/wet track session at NHIS, after being passed by nearly EVERYbody in the dry sessions. Tires are Bridgestone RE730s. Apparently WAY better than the Kumhos in the wet. I'm guessing that DOT competition tires just can't get up to temperature in the wet. So I'll be getting Yokahama AVS intermediates for the Z (no 225/50-15 size RE730) for use as street tires and rain tires at the track, based on test results at tirerack.com.

Car looks kick-ass, Pete. At least the wheels are rwd offset, and don't look so wagon-wheel. It sucks that tire manufacturers are beginning to ignore 15" and smaller diameters. Trend seems to be towards taller, lower-profile, not any wider tires. Since I'll probably never have flares or coil-overs, 225 is about as wide as I'll ever go on my Z. The selection of 15" 225 tires dwindles every year, but there are still some good ones available. If I had to get new street wheels right now, I might get 16s due to street tire availability. Then again, I believe the streetable competition tires will be available in 225/50-15 for some time now, which is what I plan to run for street/track rain tires. Looks are of course subjective, and even I'll admit that the 225/50-14 Hoosiers I use look pretty roller-skatey. Lower overall gearing, lower c.g., lighter weight, and lower cost are all benefits, though.

How do you use the car? If you're not roadracing or driver's schooling, you don't have anything to worry about. If you are, your hp level has more to do with what you need for brakes than anything else. With 340hp, you should consider something more than the stock drums. Just be sure you keep the F/R balance in mind when you modify. Too much rear and you'll be spinning. You want the fronts to lock just before the rears. I put '82-'83 ZX rear discs on my Z, but I only have ~180 or so rear wheel hp. Ross, Mike, and others have PLENTY of ideas for ya.

How are you using the car? Street, drag, autoX, roadrace? How much hp? If you're roadracing AND have BIG hp, you *might* need wheels bigger than 15" to accomodate big brakes, but I doubt it. TALL wheels are needed for the current crop of HUGE cars to keep them from looking ridiculous. Taller wheels on a sports car that is appropriately small (240Z) look pretty goofy to ME. No more wagon-wheeled Zs please!

Can't believe nobody pointed out the better overall gearing with a shorter tire. The 245/45-16 will give ~4% greater thrust at the contact patch. Plus they'll look better IMO. And of course they're cheaper. And lighter (all else being equal). No more wagon-wheeled Zs please!

I used my stock 240 halfshafts, but some have reported that the R200-specific 280Z halfshafts are required (they're shorter). Mine work fine, though. You'll have to swap the input and output flanges with ones from an R200 280z. You have to use a plain cover in place of the finned one, or modify the moustache bar and rear crossmember that runs aft of the diff. My LSD measured 23 lb-ft breakaway, and I think the factory spec is 18-30. You can shim if you want more.

Oh yeah, and if I DO need to, what's the procedure? Single flare the end, w/ maybe 1.5mm protruding from the tool, then use the double flare tool on the very end of the flare? Brakeless in New Bedford,

Now I'm worried, I just did two short lines from the switch assembly to the ZX prop valve I just installed. Took some practice, but I did get a couple of good-looking single flares. Waiting on a master cylinder and booster, so I haven't checked for leaks yet. Getting them tomorrow AM, leaving for Watkins Glen (7+hr drive) tomorrow afternoon (ambitious, ain't I). Guess I might try to do some shorty double flared lines in case the ones I installed Sunday leak. Dang, I thought it was going to be a short night working on the car. So, blueovalZ, do you have any leakage issues w/ your single flare connections? Did you do them yourself? Do I absolutely NEED to double flare them? Thanks

Pardon me if I'm an idiot here, but shouldn't the brake lines be SINGLE flared? I don't see how a double flare would work.

For drag racing, I dunno. I've got some pretty good footage of my 3.1 smoking both rears way back when I had an open 3.36 diff. For road racing it's a MUST, though. After the 3.1 build and 5-speed install, I'd planned all kinds of mods before the LSD install, but one trip to the track convinced me that LSD would give me my best lap time improvement and fun factor per $$ spent. If it's not a street car, you could have the 3.54 welded up (by someone who races Zs and has done it before, of course)

Velly intellesting. I have a '90 convertible RX-7 and I just had to get rebuilt front calipers for it. They are LIGHT! Thinkin' about selling it maybe, too. Hmmmm....So maybe I could do the vented Toyota 4-piston swap, but put the Toyota calipers on the Mazda and the Mazda calipers on the Z. Hmmmmmmmmmmmmmmmmm............ Gotta get through the rear disc swap first, though. Through a comedy of errors it's turned into a time- and money-consuming pain in the ass.

John, go here: http://www.ideal-z.com/howto/rearbrake.htm for the part number. I'm knee-deep in the swap now. Gots my brackets, '82-'83 rotors, should have calipers tomorrow, got my Carbotech Panther pads, got a ZX prop. valve on the way (I know, I should replumb and install an adjustable one, but this was essentially free), got my '82-'83 new master cylinder (this'll work, right? Guess I'll see), got my new bearings, seal, and nut for the stub axles, hmmm, what else..... Wish me luck.

Twisted off the little "nose" at the end of the actuator rod coming out of the booster, which pushes the piston in the master cylinder. I believe these come in two lengths. I destroyed a "shorty" (unthreaded portion ~8mm long), but probably need the long one for use with the new 280ZX master. (that's why I was messing with it in the first place). If anyone out there has either, or can get it, I want it and will pay for your efforts. Thanks,

Congrats on your understeer excorcism, John! I wonder if the 280Z is more prone to suspension bottoming-out than the 240, as I don't *think* I've run into this problem in my 240 (lowered ~1", 160 lb/in front 200 lb/in rear springs). Scary about the wheel cylinder. Yikes! I've got most of my rear disk conversion hardware now, might get started on that this weekend. Woohoo! Speaking of suspension setups, the hot ticket for racing these days (on a 240, anyway) seems to be stiffer springs in front than in back, and NO rear anti-roll bar! Seems odd to me, though, as my car's pretty neutral with the 160/200 lb/in springs and 1" front/3/4" rear adjustable bars. I guess things change when the car is lowered to the SCCA-legal limit and mucho stiffer springs are employed.

I've bought '82-'83 rotors, but for some reason my brain keeps making me think I should've gotten early ZX rotors. So, put me at ease and tell me that with the Maxima brackets, I want the '82-'83 calipers AND rotors. Thanks,

Despite 6061-T6 being referred to as "strong", its Ftu is 42ksi, compared to 55ksi for mild steel (7075-T6 is up around 75 ksi.) Filling in radii with weld returns the material to the T0 state, so post-welding T6 heat treat would be required, or you've substantially reduced the material's strength right where the stresses are highest. The load from the caliper is primarily transferred through shear in the bracket lugs, with tension in the top of the lugs and compression in the bottom, as viewed when mounted. My fear is that repeated tensile loading at the top of the lower lug, where it is very thin, will lead a crack initiating there, followed very quickly by failure of the part. This is NOT the place to try to save less than a pound per side. Machining out of 125ksi steel with as generous radii as are allowed would be the minimum I'd go with if stock parts can't be found (I've got mine right here, tee hee). Loads for 1-g braking assuming a 70/30 distribution under braking, 2800 lb car, brake force at one rear tire = 420 lb. Assuming a 12" tire radius, the load into the bracket (at a radius of 4.25") is 1185#. The fabbed brackets out of 1.25" 4140 Mike mentioned are the only ones I feel remotely OK about so far, for the offset bracket. I would do an FEA of the aluminum one before I let it get near the back end of my car. Dan Baldwin M.S., B.S., Aerospace Engineering

Yikes! Loads that go into that bracket are quite huge. Aluminum is weaker and more prone to fatigue than steel. Not a good idea.

I'd get a flat-top piston (ZX) bottom end. Kind of a big job, but the NISMO catalog recommends against shaving the head to get increased compression. Going from the dished pistons to flat-tops with an N42 head takes you from 8.3:1 to 9.8:1 compression. 93 octane required. You will feel the difference. If you do go the head-shaving route, you wouldn't have to shave the N42 nearly as much as a p90 to get a decent compression ratio.