74_5.0L_Z

Great job guys!!!!! Did you try out the headlight covers? Do you need any help crunching the data? I am good at that. I am a mechanical engineer, and one of my prime responsibilities is making test data comprehensible. I would love to help.

I used a hand held grinder with a 4.5" cut-off wheel and tin snips. The metal that I removed from the firewall forward (not including fenders, hood, crossmember, front apron) weighed 95 lbs. The tubing that replaced it weighed less than 50 lbs. Oh, do yourself a favor: Remove all of the undercoating and sound deadening material before you start. It's easier to do that before you have the car bolted to your fixture. Don't ask me how I know that....

"I'm not quite seeing where you are attaching the tube chassis to the structure points of the z!" You'll discover when you cut off the front end that all the metal of the Z is very soft and flimsy. At that point you will not feel very comfortable attaching anything to the firewall as a stuctural element. My solution was this: First, hard mount the car on a surface that gives you a good reference to work from. For me, I built a 2 x 12 wooden structure topped with 1" MDF that just barely fit between the stock frame rails (25.1" wide). This structure extended from the rear (Point C of the factory frame drawing) to past the front. I then aligned the car on this structure and bolted it down. Then I made sure the whole thing was level. From that point on the car did not move relative to the structure. Next, I built frame rails (similar to pparaska's). These were welded to the rear cross member, to the floor pan, and to the firewall. After I had the frame in place, I built the roll bar. It is tied into the rear shock towers and the rear of the rocker panels. From this, I extended door bars forward through the firewall. The door bars then connect to the hoop in front of the firewall. The point where the lower door bar meets the firewall hoop is also welded to the front of the rocker panel, and also meets a bar that angles to the frame above the T/C mount. The point where the upper door bar penetrates the firewall is just below and outboard of the clutch master cylinder. This point is triangulated to the frame and to the strut tower. The bar across the top of the firewall hoop was mainly there to connect the top legs that go to the strut towers. My front end is attched to the car through the framerails, rocker panels, and door bars. However you decide to do yours, spread the load through as much surface area as possible.

You mean something like this:

anyone?

Has anyone here done business with http://demonspeedshop.com/. They have some pistons that I want, and they are considerably cheaper than everyone else (~$75 less than summit for a set of eight). This seems like a really good deal. Almost too good to be true. I would really like to get some feedback about these guys before I send them $500.00. Thanks

I am using the griffin 24 x 19. It works very well. The only time that I even have to turn on the fan is in stop and go traffic.

I would not go back to bare metal to fix the low spots. Just rough up the area with 80 grit, and apply a thin layer of filler centered on but larger than the low spot. After it cures, blend and reprime. You will probably have to repeat several times before all of the low spots are gone.

Try Parrish-Heacock insurance. They insure racecars/show cars for stated/apprasied value. Their rates are very reasonable, but they limit use to a ceratin number of miles per year. You must also own a primary use vehicle other than the Z.

Terry, I'm glad to hear that you will be flattered rather than insulted. I am currently working on making a hood very similar to yours. I plan to post pics next week. As always, you are one of the best sources of inspiration on this site. Thanks, Dan

Theses guys have what you are looking for: http://www.vintagewheelsus.com/

I don't think that the aero mods that benefit the racer and that benefit the average street driver are mutually exclusive. I think that we are going to find that some of the simplest mods will net the best overall gain. For example, closing up the front radiator opening and controlling where the air goes will reduce overall drag and reduce front end lift. The same goes for enclosing the inner wheel wells (not covering them). I hope that we will establish a baseline for a stock bodied car and then progressively make changes to see the results. Add headlight covers Add different air dams Add rear spoiler(s) Change ride height/angle I have faith that that we will all be happy with the results. By the way, I have been doing some work to my car in hopes of reducing its drag and improving its front end lift. Here are pictures that shows my progress (and my daughter). My next order of business is to close off the area above the bumper and modify my hood to vent the radiator air (very similar to Terry Oxendales hood).

I'm in.

So far, I love the Odyssey battery. I moved it to the shelf behind the passenger seat. By changing to this battery, I was able to remove 30+ pounds from the car. Also in doing so, I have reduced the polar moment and lowered the CG (just a tiny bit).

The number that I used in my Quarter2.xls program should not be taken as gospel. It is a number that I arrived at by analyzing the coast down graph published in the 1970 review of the 240Z by Car and Driver. What I did was pick two point on the coast down graph (80 mph and 20 mph) and estimated the slope of the curve at those two points. The slope of the coast down curve at any point corresponds to dV/dt. Using the instantaneous accelerations at those two points, I solved the following : m*dV/dt=CdA/2*Rho*V^2 + Cr*V + C In this equation dV/dt was estimated from the graph at two points. V is the velocity at the two points chosen. Rho is the density of air C is a constant value that I used to account for the force needed to start the car moving from rest on a flat surface. The variables CdA and Cr are the drag coefficient times frontal area and the static rolling resistance. The units of CdA are ft^2 and the units of Cr are lbf/mph. One factor that I neglected in my original analysis was the inertia of the wheels and tires. To account for this the inertia of an original equipment tire, wheel and brake assembly would have to be measured and the equations would need need an additional term. m*dV/dt + I* dw/dt = CdA/2*Rho*V^2 + Cr*V + C where the term I x dw/dt is the mass moment of inertia of the rotating parts times the change in rotational velocity. Although I was trying to be as accurate as possible, it should be remembered that I made the Quarter2.xls program for fun. Even neglecting the inertia of the rotating assemblies, I believe the number to be accurate within +/- 15%. As stated on the downloads page, I welcome input to increase the program's usefulness and accuracy. Dan

My roll bar is angled back at a 10 degree angle, and is hard against the wheel well. This angle puts the roll bar parallel to the trailing edge of the front part of the quarter window.

I am in the process of replacing the stock seats with aluminum racing seats with the side bolsters. This in combination with padding should go a long way towards protecting my ribs. Oh yeah, I do have 5-point harnesses in the car.

I had similar design requirements. I have more several images in my album. http://album.hybridz.org/showgallery.php?cat=500&ppuser=7833

Fits fine if the engine is installed in the same position as mine.

Be careful with that last statement. Don't be too cheap. Stay away from the KYB gas struts. They are cheap, but are way too stiff in bump and too loose in rebound. I am using the Koni 8610-1149 with 250 lb/in rear/ 200 lb/in front. I don't find the ride very harsh, although I don't drive it on the street very much. If your going cheap then get the cheap konis or illuminas.

Be careful with that last statement. Don't be too cheap. Stay away from the KYB gas struts. They are cheap, but are way too stiff in bump and too loose in rebound. I am using the Koni 8610-1149 with 250 lb/in rear/ 200 lb/in front. I don't find the ride very harsh, although I don't drive it on the street very much. If your going cheap then get the cheap konis or illuminas.

I can't quite put my finger on it.....