74_5.0L_Z

I applaud Mongo's efforts on this rear suspension set-up. The entire thing is over-built, but that was intentional on his part because this was a prototype. If you notice, he has built adjustability into every part of it so that the optimal design could be attained through trial and error. I would love to build a similar set-up based on his design that has been optimized for weight. There are things that I would like to know: What does the camber curve look like (how much gain per inch of bump and inch of droop)? Where is the roll center? If you don't know these, then perhaps I can help you determine them based on dimensions.

I am sorry to hear about your car, but I am glad that your son was not hurt. I really like your rear suspension, but damn those are some huge heim joints at the top of the strut housing

The CV halfshaft angles are not important as long as they are kept in a reasonable range (<10 degrees). If it were me then I would lower the differential as far as possible with respect to ground clearance. I just lowered the mounting of my differential by one inch relative to the body for three reasons: First, I wanted to minimize my drive shaft angle. The driveshaft was running uphill from the transmission to the pinion, but now it is level in the horizontal plane. Second, I wanted the halfshafts to be at their minimum length at full droop. The reason for this is that I use 300ZX turbo halfshafts with the Modern Motorsports adapters. These axles were close bottoming during suspension motion when the axles were straight. By lowering the differential, the axles are always angled up toward the wheels even at full droop. I only have 2 inches of droop travel in my suspension. Third, the R200 is heavy (and the R230 is really heavy) and should be mounted as low as possible to keep the CG as low as possible.

I am interested in the Carbon Fiber BRE rear spoiler. How tall is it? Is the carbon fiber version a straight bolt on (No modification/sanding/painting of the spoiler required)? Can I order it with additional mounting points on the bottom (4 instead of two)? Can I order it with mount fasteners across the back face so that I can extend the height with a sheet of lexan? Can you post some larger pictures of this spoiler installed so that I can examine the quality a little more closely? I am trying to add a good looking basic spoiler that can be adjusted to increase/decrease rear downforce. Thanks, Dan McGrath

That what I am using. I also am using the Gorilla 7075 Aluminum Lug Nuts. http://www.summitracing.com/parts/GOR-44037BK/ To install the studs, I removed the front wheel hubs and rear axles so that I could work on the bench. I used a 280ZX rear brake rotor as a fixture to hold the hubs/axles while I installed the studs. To do this, I placed the rotor on the work bench with the wheel mounting flange face up. I then placed the axle /hub face down through the rotor. The rotor is a close tolerance fit to the hub center and the studs and was used to keep the studs square with the face of the rotor. I then fed each of the four studs through the back of the hub/axle, through the rotor, and installed a stack of washers and hardened M12x1.5 nuts (not the lug nuts!) on the opposite side of the rotor face. After all the nuts were installed, I drew the studs through the flange by tightening the nuts. The torque required to draw the studs through the flange can be considerable. Don't exceed 75 ft-pounds during the process or you can damage your new studs. If you reach max torque before the stud is completely installed, then flip the assembly over and tap the back of the studs with a hammer to make sure that they are fully seated. Finally, torque the nuts to 75 ft-lbs, and then remove the nuts, washers and rotor. Repeat for each hub/axle. Grease bearings and reinstall hubs/axles.

I drove a stock 260Z for seven years. It had the four speed transmission and 3.70 rear gear ratio. I think that I only got 14-15 miles per gallon. After I graduated in college in 1998, I built a 260Z with a 5.0L and T5 transmission and same 3.70 rear gear. I drove it as a street car for about five years and would get about 20-25 mpg on the highway (when I could keep my foot off of the floor). The key to making a drivable V8 datsun is installing an overdrive transmission. Without an overdrive the RPMs at highway speed are too high. For example, with a 245/45/16 rear tire 24.5" tall, a 3.545 rear and no overdrive, your RPMS will be 3400 at 70 mph. With the T5 transmission, 5th gear is 0.67 to 1 and your rpms with the same tire and same rear gear will be 2280 rpm at 70 mph. Which set-up do you think will get better gas milage, be more fun to drive on the highway, and have less wear on the engine. My current set-up has a 3.36 rear gear, but I have gone to a shorter tire (23.0 tall 275/35-15). I have also upgraded to a GForce T5 which has better gear ratios for 1st and second gear. The overdrive in the Gforce T5 is a ridiculous 0.59 to 1. Even with my short tire 70 mph is 2100 rpms in fifth gear.

For me the droop limiter was more for keeping the springs seated when the car is jacked up or when I lift a front wheel in a turn. My limiters are set so that the springs are "almost" loose at full droop. Without the limiters, the struts will allow the front wheel to droop more than an inch below the point where the springs are in their seats. I've been wanting to come back and do some more with this topic, but I have been busy lately. I am working on my Masters Degree in Mechanical engineering and that eats up all of my time. I have only run the car at two events this year, so it is mostly collecting dust in the garage. I plan to take the summer off from school, so I plan to do some serious playing with the car. I have a brand new set of Hoosier 275-35-15 tires that need to be used and abused. It would be interesting to play with the droop thing some more, and I am also contemplating replacing the droop limiters with helper springs to allow the tire to stay on the pavement without changing my ride frequency. I'll update this later in the summer. Dan

My Ford powered 260Z has been driving for better than 10 years now. For most of that time, the engine was a stockish 5.0L with Edelbrock heads. The car evolved from a street car, to an occasional drag racer (12.2 @ 113 mph), to a full time autocrosser. During the first 10 years, the car was equipped with a World Class T5 transmission (that came from a junkyard), a king cobra clutch, and a Tilton hydraulic release bearing. The transmission lasted 10 years. Two years ago, I upgraded my engine to a 331 stroker making 365hp/375tq at the wheels on a SuperFlo dyno. The old transmission finally died with a bang when I took all of the teeth off second gear powering out of a corner. Post-mortem on the transmission also revealed that the input shaft was twisted about five degrees. I had found the limit of the stock T5. I have since upgraded to a G-Force T5, and I am extremely happy with the results. The new transmission weighs nearly the same as the stock T5 (~75 pounds), has better gear ratios, and can handle 500+ horsepower. I was also able to reuse my Tilton HTOB, and my King Cobra pressure plate. I did however have to purchase a new disc because the G-Force T5 uses a bigger input shaft with 26 splines rather than 10. Because I primarily autocross my car, weight is everything. The Tremek TKO weighs about 140 pounds, and the T5 weighs ~75. So, for me the decision was a no-brainer. If it were me, I would go with the G-Force T5 unless I were to combine drag racing, slicks, and more than 500 hp. Dan

For me the solution was to add additional U-joint to the steering shaft. This also requires an additional constraint to control the motion of the shaft. Here are some old pictures of my car that show the extra universal joint and the rod end used to control the motion. Here is a picture from below (Again a very old picture). In this picture I have gone to a front plate mid-plate motor mount system so the stock motor mounts are out of the way and there is a lot of room under the engine. If look back at some of my old posts (circa 2001-2003), I have discussed the important considerations for adding an additional u-joint to the steering shaft. Remember, phasing is important. Also, looking at your engine position, it looks like you could move it farther back. The back of my driver's side cylinder head is 1" from the firewall, and my harmonic balancer is directly above the rack (1" above). Can you move the engine toward the passenger side at all. My engine is centered left to right, but if I were to do it again I would mount the engine offset 1 to 1.5 inches to the right. Good luck, Dan

I looked at the Goodyear radials, and they look like a good option with one minor problem: They cost nearly twice as much as the Bias-Ply. I can't afford $400.00 per tire.

I'm past the point where I'm trying to make them work. I plan to buy some NEW tires. I have 15 x 10 wheels and want the best tires I can get in terms of traction and longevity. The ones that I have found that will fit are the following: Hoosier 275/35-15 A6 Goodyear 23.0x10.5-15 Bias Ply slick (250 compound) I have never run the Goodyears and was hoping to get impressions from someone that had. Cameron, have you found a favorite tire? I think you tried the Avon slicks. Did they work and last better than the Hoosiers?

Ok, I've gone through several sets of the used Hoosier 23x9.5-15 FA slicks. I typically get 3 to 4 events before they die. I get them cheap, but not that cheap. I am tired of buying used tires, so I plan to order some new tires this week. Here are the tires I am considering: Hoosier 275/35-15 A6 Goodyear 23.0x10.5-15 Bias Ply slick (250 compound) The initial cost for each is the same. Does anyone have any experience with the Goodyear? How is the longevity? I would really like a set of tires that wil last for a whole season. If anyone else has a good suggestion for a tire that fits the 15x10 wheels, I'm all ears.

I switched to all ARP M12 x 1.5 wheel studs and use the Gorilla open end lug nuts. The lug nuts are 7075 aluminum and are incredibly light. The black anodized finish is very nice too.

If it was my engine, then I would really have to find out what the bottom end consisted of. At the very least, I would pull one cylinder head and the oil pan. With the head off, I could get numbers off the piston. The numbers on the piston would give the manufacturers information on dome/dish volume. The same information is published for the cylinder head combustion chamber. Then with the head off, I'd measure the "in the hole" depth of the piston to the deck, and also get an exact value for the stroke. These days there are a lot of stroker 302s running around. What are the specs on the old cam? I am wanting something a bit bigger for mine. Currently, I have a Crower 15511 hydraulic roller.

VERY NICE!!!! I've considered doing something similar for a long time (I even have a set of those shock/springs under my workbench). Do you have target camber curves and roll center heights in mind?

I feel your pain. I too am working on my masters degree. Twelve years after getting my BSME at the University of Florida, I find myself working on my MSME at UCF. I am taking one class per semester while working full time. At this rate, I should finish sometime in 2011. I really miss having a life, and my car has been aweful lonely in the garage for the last year or so.

If you have aluminum/delrin bushings on the stock lower control arms, then you should be very careful about how much you add caster via the Tension/Compression rod. The aluminum delrin bushing are made to rotate about a fixed axis (the bolt at the crossmember). When you move the outboard end of the LCA forward to get more caster, you need a joint at the inboard side that can pivot in three dimension (a spherical bearing). The aluminum/delrin bearing will bind if the control arm is too far from perpendicular to the centerline of the car. So, if you want to get caster from the T/C rod, you need spherical bearings at the inner pivot of the LCA. Dan

Years ago, I ran a set of those wheels on my old 260Z. The center hole has to be opened up quite a bit, and the lug nuts are not compatable with the datsun wheel studs. I changed all of my lugs to the Toyota studs (the toyota studs have a 1.5 pitch while the Datsun studs have 1.25 pitch). All in all, it was a royal pain to fit those wheels on my old car. I only went through the hassle because the wheels were free, and because I was a poor college student.

Jon, get some 8" springs. With the spring rates that you are using, you should be using the shortest springs that you can get away with. I say this not just for clearance reasons, but for spring buckling reasons. Read this link and you will understand why: http://www.efunda.com/designstandards/springs/spring_buckling.cfm Assume that you are trying to stay below the green line. And regarding my oil pan: The pan on my car was made specially to be 1" shallower than stock. The stock pan is 7.5" deep and has 5 quart capacity, and my pan is 6.5" deep and has 7 quart capacity (side kick-outs).

Do you think that you will ever be adjusted that low? I doubt it unless you are using really tall springs. In the spring rates you are going with an 8" spring is the tallest spring that you would want. You can see where my 500# 8" front springs are adjusted to for my ride height in this picture: At that ride height, my oil pan is less than 3" off the ground.

My front suspension is droop limited using cables, but only to the point that the front springs are at their free length when the cables are taut. To make mine, I attached a 1/4" clevis yoke to the top of the strut tower inboard and forward of the upper spring seat, and connected this clevis to a sway bar end link using a 1/8" cable and thimbles. I've attached some low quality pictures that show the set-up with the car at ride height (slop in the cable). These cables are not as close as they look to the brake lines. In two years of autocrossing with these cables installed, I have seen no evidence of contact. My rear suspension is droop limited by the strut assemblies (I sectioned them a little more than I should have). I have about two inches of droop travel in the rear from nominal ride height.

I think you have too many degrees of freedom in your lower control arm / TC rod. The rod end at the junction between the control arm and TC rod needs to be a solid end and not a spherical bearing. Otherwise, the effective length of your TC rod will change as the control arm rotates about its long axis. Oops, BJhines beat me to it...

Here is an older picture (old engine and no paint) of the car in which you can just see the mid-plate: The mid-plate sandwiches between the block and bellhousing. The mid-plate is 0.090" steel and mounts to two brackets welded to the frame ~1" forward of the firewall.

I use a front plate and mid-plate to mount the engine in my car. It works great, frees up a ton of room under the engine, and makes the engine a structural part of the car. The set-up does transmit some mechanical noise, but it is not a bad as I would have thought.