Dan Baldwin

I'm planning on getting the Kumhos with full tread depth and using them on the street and as rain tires at the track. I may run them at the track in the dry for a few laps only to gauge whether or not the Hoosiers are starting to go off, but never for a full session until they're worn down to maybe 3-4/32.

My plan is to install '82-'83 rear disks and calipers on my '71. I'd like to do my best to get the same brake proportioning as stock. I have some technical questions regarding brake proportioning. I would like to achieve (for now) stock ZX brake proportioning. To this end, I will try to remove all hydraulic devices affecting line pressure between the master cylinder and the rear wheel cylinders from the Z system, and replace them (along with the master) with any hydraulic devices affecting line pressure from the ZX system. What I would like to know is: What are these devices on both systems and where are they located? Also, does anyone know the piston areas and caliper working radius (approximately the radial distance from the wheel centerline to the caliper piston centerline) for the Z and ZX offhand? Thanks,

Will just be doing the rears, keeping the stock front rotors and calipers. For now, anyway. Wish I could mount the aluminum 4-piston calipers from my RX-7 convertible. They're lighter than the stock calipers. I ordered the brackets from Lynchburg (VA) Nissan. Parts guy there is Riley Curtis, tell him I sent you. He may or may not be able to get brackets for you, but ynktya. Sorry, but I don't have the number handy. Dan

Actually, I decided to do the swap last year, as for some reason with street/track compound brake shoes I was having to adjust the drums constantly. Then I ordered up the Maxima brackets from Lynchburg Nissan (parts guy there orchestrated my 3.1 build all those years ago), and he was able to get them for me. Then at Lime Rock I went back to stock Nissan shoes and the brakes stayed more consistent, so I figured to just keep the drums, and hoard the brackets Hopefully I'll get around to installing rear disks and new bearings before Watkins Glen (July 18-20), but you know me....

Woohoo, all the usual suspects are showing up to help me out, thanks! Starting to look like Kuhmos. The 32s are a bit pricey at $145, and are getting a lot of not-so-good press. I forget what the RA1s were last time I priced them, but I think it was ~$125. Full-tread Kuhmos are $115, I've known folks to drive them on the street, and I've never heard anything bad about them. I don't plan to use them in the dry at the track except perhaps to judge when the Hoosiers are starting to fall off. Posted to the other Z lists, but I think I've made up my mind.

Thanks, Ross. Several fairly quick guys in my club use the A032Rs, and no one uses the RA1s, so maybe that's my best choice. Tire rack does have some BFG R1 rains for cheap ($75), but as they're not the G-Forces, I suspect they're beyond their shelf life.

I need new "street" tires for my 240, which I will also be using as rain tires at the track. I don't put enough miles on the Z to worry about a treadwear rating of 60 or less. I'm thinking Yokohama A032Rs or Toyo Proxes RA1s. Maybe even Kumhos. Experiences? Size is 225/50-15. Thanks!

After preaching the virtues of the stock 240Z brakes for quite a while now, I think I'm gonna actually ditch the rear drums. At Summit Point last week I was having to brake before turn 4 not to make that turn, but to be going slowly enough out of it to still be able to brake enough for turn 5. A buddy in an M3 lightweight had no such worries and was able to carry as much speed through 4 as he dared. Anyway, I've got the Maxima brackets and will be sourcing '82-'83 calipers, rotors, and proportioning valve, so if anyone's got this stuff lying around.... Will keep the forum apprised of developments. Next track event: Watkins Glen, July 18-20.

Found an ignition faq that sez to remove the inductive loop from the pre-75 tach, and run the tach input to the msd tach output. How you do dis? Last resort is to buy the $45 8920 MSD adaptor, which is supposedly a sure-fire fix.

I've got a pertronix ignitor in place of the points. Hooked up the MSD, no problem, but of course the tach didn't work. Experimented by connecting the former coil + wire to coil+ with the MSD. Tach then worked, but the motor wouldn't run (shorted out the MSD, I guess?) Uplugged that wire and the car ran fine again. Then I tried the Chrysler ballast resistor, to no avail. No tach still. Ideers?

Thanks for the reply, David. Only one! I replaced the Jacob's coil (I didn't have their whole system, just a regular coil) with a Blaster2 and still had the problem. Will install the MSD 6AL tonight (been meaning to get one for a while anyway, so it's not really specifically for this prob). Tried to reproduce the problem yesterday (let the coolant temp go up by leaving the fan off), but couldn't. Outside temp was much hotter when I had the problem. 3psi was/is the regulated line pressure. Will try increasing it. Car never ran hot in traffic with the stock fan. When the fan clutch siezed, I installed a too-low-cfm electric. Whoops. BTW, I'm talking about Boston traffic, which is worst have had to deal with. Stop-and-go, all day, every day. I have a 3-row 260Z radiator, no shroud, Tripac 11" 880 cfm fan. Flushed the system last year. Usually run 25/75 antifreeze/water with Water Wetter, but I think it's more like 50/50 now. Will likely change it before going to the track next Mon/Tue. I'm going to get a header blanket to keep the carbs cooler, and reroute the fuel lines to keep them cooler, and replace the lousy Puralator fuel press. regulator with a Holley before I go to the track. In the future, I'll get a more serious fan and/or a more serious radiator. Dan

Hi all. My 3.1 liter '71 (as always a work in progress) currently has an overheating problem due to too small an aftermarket electric fan. That is not the main subject of this post, however. A few weeks back, I took the Z to the dyno, and suffered some higher rpm power loss, a succession of downward spikes in the torque curve above 5000 generally, which got worse with each successive run. Don't know if this is ignition or fuel delivery related, but I suspect the former. Anyway, I had to drive the Z to Boston yesterday evening, and of course got stuck in traffic a few times (had to pull off once to cool 'er down). I noticed that as the temperature rose, I developed a serious misfire (at least that's what it felt like), and as the temp cooled back down, the misfire went away. So, I believe this is the same problem I was running into at the dyno. That is, something's breaking down directly related to engine temp. What does that sound like to you guys? Here's what I got: Fuel system: Carter fuel pump (could feed three 3.1 liters) mounted near the fuel tank Purolator fuel pressure regulator set to 3 psi Stock fuel lines, including return line 2" Jag carburetors Ignition system: Stock distributor w/ Pertronix Ignitor replacing points Jacob's Energy coil Jacob's helically wound wires NGK BP6ET plugs Just got my MSD-6AL today, along with a new Blaster 2 coil. Will install Sun. or Mon. Might solve the problem? Might get new plugs and wires, too. All informed ideas welcomed and appreciated. Thanks, Dan Baldwin '71 240Z 3.1 COMSCC #7 SPB

As far as sway bar load goes, one way to measure it would be to jack up one side of the car and measure the spring's compressed length on the lifted side. Then lift the front of the car and measure the spring's free length. The difference multiplied by the spring rate gives you the compression introduced by the sway bar when one side of the car is lifted by a jack. Double this to get the compression caused by a car cornering fast enough to lift the inside wheels (this should be conservative for steady cornering, maybe about right accounting for bumps, undulations, etc.?). Then you'd have to work the geometry to get the sway bar load, which will be greater since it has less leverage on the control arm than the spring does.

I'd like to see the design. Load from the sway bar is not insignificant, and it sounds like you may be relying solely on a threaded rod for bending strength near the point that probably sees a pretty big bending moment during hard cornering. I'm assuming the 6061 is T6 heat treated. No welds on the part, I assume? If so, the Al is T0 around the weld (much weaker). Probably already considered by you, but worth mentioning: 6061-T6 has a tensile strength of 42 ksi, vs. ~55 ksi for mild steel Al doesn't have a definite fatigue limit like steel does, and fatigue cracks can develop over time even though applied stress is low. Design should minimize stress concentrations and not give cracks any excuses for forming. Dan Baldwin M.S., B.S. Aerospace Engineering

Here I go again.... For a street car, the stock setup with fresh fluid, good street/track pads, and Nissan shoes is more than adequate. Good performance, light weight, cheap, and easy. That's what I run on my '71 3.1 liter for track days (15 - 25 min. stints). Braking performance is excellent, pedal stays firm, and I have no problem keeping up with M3s. My usage, while a bit less severe than REAL racing (I do track days and time trials), is orders of magnitude more severe than what a street or strip car sees. As far as the 510 cast iron drums go, they're ugly and heavy, and I can't imagine they would improve performance. I think that one must be a myth made up by 510 owners so they can get our aluminum drums. My only brake mod other than pads is stainless steel flex lines. Didn't like relying on the 30 year old rubber lines. Dan Baldwin '71 240Z 3.1 COMSCC #7 SPB

I have a welded up front mount and aluminum moustache bar bushings. Lotta gear whine, but I think it sounds cool. Dan Baldwin '71 240Z 3.1 COMSCC #7 SPB

Almost all turbos, including the 280ZX turbo, are blow-through. Draw-through, literally, sucks. Old Crown kits were draw-through. Blow-through: turbo before FI or carb Draw-through: turbo after FI or carb Dan

Sorry, "'81+ ...." should read "'79+ ..."

Diff, yes brakes, yes (with appropriate bracket, and some modifications, so I guess that means "no" to your question) suspension, no (you wouldn't really want to anyway, '70-'78 Chapman struts far superior to '81+ semi-trailing arms) Dan Baldwin '71 240Z 3.1 COMSCC #7 SPB

OK, here goes, pics of my car at Mosport and Watkins Glen: Dan Baldwin '71 240Z 3.1 COMSCC #7 SPB

I was also very impressed with the TTs. The stock NA seemed low for 222hp, though. The fact that the L28 turbo, with Wolf Racing computer controlled ignition and injection, was only a few hp ahead of me was very encouraging. I developed a stumble above 5500 which I hadn't noticed at the track. Don't know if it was fuel starvation or ignition yet. I'm figuring 177 at the rear wheels must be on the order of 208 at the flywheel, huh? For pictures, go here: http://www.zccne.addr.com/ click on "members", then "240-280Z", there are a couple of pics, one at Mosport, the other at Watkins Glen. Also, I've got some pics from the dyno day with my recently installed headlight covers and front and rear BRE spoilers. How do I include them in a post? Or I guess I could submit them to the webmaster for inclusion in the member rides section?

Can't be restated enough, do NOT do this. Street car, track car, or show car, NO, NO, NO! Dan Baldwin '71 240Z 3.1 COMSCC #7 SPB

I ran my car on Avalon Racing's dyno in Manchester, NH on Saturday. I was pretty pleased, but I'm sure most of you V8 and turbo'd Zs will only chuckle at the numbers. Best run of 176.6 hp at the rear wheels. I was only hoping for 165, so WOOHOO! Engine is a 3.1 liter, 10.1:1 CR, 290/.503" cam, 2" Jag carbs on modified (to match carb diameter) N36 intake manifolds. I did have a miss above 5500 that I haven't noticed at the track. Stumbled pretty badly, gotta find out why. Others that ran: 240 w/ 280ZX turbo (11psi) 182 rwhp Z31 ITS car 147 rwhp 280Z ITS car 153 rwhp Z32 NA (stock) 179 rwhp Z32 NA (intake/exhaust) 189 rwhp Z32 TT (intake/exhaust) 314 rwhp Z32 TT (intake/exhaust/ECU) 339 rwhp 1.6 liter Miata 89? 98? (I forget) Dan Baldwin '71 240Z 3.1 COMSCC #7 SPB

Diesel or L28 crank? Go to http://www.zcluboftexas.org/ , click on "about the Z", then "L28 Bore & Stroke Combinations" for a lot of good info, incl. stroke, head cc, pin heights, deck heights, etc. Unfortunately piston data is for Z22, Z24, and KA24 pistons, not L-series. BTW, deck height is the dimension from crank centerline to the block's deck (what the head gasket and head sit on). Pin height is the distance from the wrist pin to the top of the piston. Anyway, this page should get you started on what you want for piston spec. Let me/us know what you come up with before you order to double-check that it'll work, clearance- and compression ratio-wise. I'd reconsider using L24 rods, too. If you're going to this much trouble, you may as well do it right. Another benefit to longer rods Tim didn't mention is reduced peak piston acceleration, which varies linearly with stroke, with the square of rpm, and linearly with 1 plus the ratio of stroke to rod length. I assume you're getting forged pistons so you can up the boost and or redline? Dan Baldwin '71 240Z 3.1 COMSCC #7 SPB

Depends a bit on your setup, but I'd say you want between 30 and 45 lb-ft breakaway. My LSD had 23 lb-ft 5 years ago, and this has been sufficient for track work with street tires, but I get inside wheelspin with Hoosier track tires. Dan Baldwin 71 240Z 3.1 COMSCC #7 SPB