74_5.0L_Z

I just got the new ChassisShop catalog. The weld in ends (AKA tube adapters) are listed on pages 9 and 10. Here is a link to help you find the tube adapters on their web page: http://secure.chassisshop.com/categories/5625/ Finding them through their web menu was impossible. I had to search their site using the key words, "tube adapters."

The car is just a lot easier to drive with a passenger. The improvement manifests itself in the transitions. By that, I mean that the car is easier to drive into and out of the corners. I ran the car at Sebring in October, and I had an in-car camera on board for the first time. During the two day event, I made 14 runs (8 with a passenger on board and 6 by myself). Looking at the videos, it seems that the car is just a lot more prone to oversteer when I am alone in the car (both at corner entry and exit). I did weight transfer worksheets for both conditions, and the worksheet predicts more bias toward understeer when a passenger is on board. What this is telling me is that I need to do some combination of the following: 1. Bigger rear tires (the downside would be the inability to rotate tires between events). 2. Stiffer front springs (just slightly). 3. Softer rear springs (again just slightly) 4. Slightly stiffer front sway bar, or increased sway bar motion ratio. I plan to go with bigger tires next year. This year I had 245/45/16. Next year, I will probably run 275/35/15. I am on the prowl for some light weight 15x10 wheels.

Also, depending on which engine you use, nothing says that the crossmember has to be at the front of the frame. Because I wanted to angle my radiator, and because I have a Ford V8 in a very set-back location, I elected to move my crossmember back even with the sway bar mounts.

Looking good Jon. I especially like the routing of the tubes to the front strut towers.

Silly question: Do you have a forward rotation water pump on that motor? The factory water pumps that came in the 1982-1995 mustang had reverse rotation water pumps (the water pump and crank shaft rotated in opposite directions). If you try to turn the reverse rotation pump in the forward direction, then it will not pump water properly through the engine. With a reverse rotation pump, you need an idler pulley to control the belt tension and to provide belt contact around the water pump pulley. Here is my solution: The tensioner pulley came from Steeda, the mounting brackets for the tensioner are custom, and the belt is 49.5 inches. If you decide to go with Vee belts, try march performance. They have a very wide selection of pulleys and brackets (both vee belt and serpentine). Your alternator mounting should be fine. Mine is mounted with the centerline if the alternator pulley lower than the centeline of the crank pulley. I have about 1/4" between the alternator and the boot on the steering rack.

Is the accelerated wear occurring on all four corners, or is it happening more on the front or more on the back? How often do you swap the tires from front to back? What are your alignment settings? What do the temperatures look like in the middle of the tire? Regardless of tire temperatures, if the inside and middle aren't wearing but the outside, I would add more negative camber. I have't used the radial slicks, so I dont how much air pressure is typical. I run 32 psi in rear and 36 psi in the front with my Hoosier A6 tires. I swap the tires front to rear every other event (approximately every 10 runs). I put the Hoosier A6 tires on in May and now have about 50-60 runs on them. This set of tires is wearing very well compared to the two previous sets that I had on the car (Hoosier A3S04, and Kumho V700). The outside edge has gotten just slightly rounded, but not bad. I plan to flip them on their rims and swap sides before my next event in two weeks. I should be able to get better than 100 runs on this set of tires if the wear stays consistent. I think the main reason why this set of tires is wearing so much better than my previous tires is that I went with a much stiffer set-up. The car previously had 200 lb/in front and 250 lb/in rear springs with a 1" front sway bar, and now has 450 lb/in front and 425 lb/in rear springs with a 20mm front sway bar. Good luck and sorry for the ramble, but its 2 AM and I can't sleep....

I started with the subtle Z kit and made it my own. I added the bottom, bumper feature, and radiator inlet to the front air dam. I cut the hood apart, moved the hump back 25", and built the radiator outlet. I also added a more rounded leading edge to the hood. The hood is mounted using 6 dzus fasteners. The front four dzus fasteners attach to custom hinges, and the rear two attach to brackets on the firewall. If I loosen the two rear dzus fasteners the hood opens as normal. If I remove all 6, I can remove the hood. I have blended a set of stock fiberglass headlight buckets into the Subtle Z fenders.

Start with the basics and give us some more information: What are your suspension settings? (Caster, Camber, Toe in front, and camber and toe in the rear) Which sway bars are you running front and rear? If this was your first autocross some of the front end push was probably driver induced. You may have been going into the corner too hot and trying to steer while still on the brakes. Its better to get your braking done in a straight line then turn the wheel as you remove your foot from the brake pedal. Oops: Johnc beat me to the punch.

It does not look as if the top of the strut tower or the suspension attach points on the frame have moved. I also do not see that damage compromising the structural integrity of the front end (at least not much). I would not have any problem using that car especially since you plan to install a cage. I would make sure that you either tie the cage into the front strut towers, or install some form of strut tower brace. Strut tower bracing is good practice for any Z that will be used for high performance driving regardless of previous front end damage.

First, the toe link does not need to be perpendicular to the strut housing. So you can gain a little length by moving the inboard end of the toe link toward the front of the car. Second, you might try 5/8" rod end for the toe links. The 5/8" rod ends are a bit shorter than the 3/4" rod ends. Besides, the toe link will not be nearly as stressed as the fixed rod end. As far as turnbuckles go, make your own using these weld-in end from ChassisShop: http://secure.chassisshop.com/partlist/502/ Be sure to buy matching left hand and right hand adapters, cut your tube, weld them up, and Voila. You've got a turnbuckle.

Though that car does not fit my aesthetic taste, I have to admit that the builder has some serious skill. I can appreciate the effort that goes into creating something like that from my limited experience with fiberglass.

Making the control arm too long can put you in a situation where you won't be able to dial out enough negative camber. With my set-up and ride height, I get 2.2 degrees negative camber at static ride height with the camber plates adjusted as far outward as possible. If I lower the car the minimum negative camber increases at the rate of about .74 degrees per inch. I would not make your control arms any longer than 15" or you not be able to adjust your suspension to give you less than 4 degrees of negative camber at ride height. If the control arm is a little short when it is adjusted to minimum length, then you can increase that length with the rod ends. But if it is too long at its minimum length. I'd err on the side of being too short at minimum adjustment. That is why mine are stock length at minimum adjustment. But hey, that is just me.

Jon, My control arms are 14.5" long when adjusted to their minimum length. I also have the adjustable aluminum/delrin inner pivot bearings adjusted to give me the widest spacing of the inner pivots. The rear camber plates are adjusted as wide as possible to minimize my static camber. With my rear suspension set up this way, I can go through the entire range of motion without binding the CV axles (specifically the passenger side). If I were to use inner pivots that were centered on the inner mount, then I would add 0.375" to the minimum length of the control arm. So, I would make the minimum length of the control arm 14.875". One way to alleviate the CV binding without lengthening the control arm is to lower the differential to the point where the minimum length of the CV axle occurs at full droop. Lowering the differential is on my to-do list. I may actually finish it some day....

Wouldn't it be a whole lot easier to lower the outer pivot (ala BlueOvalZ) than to raise the inner. Oops, Cary already mentioned that.

What kind of primary lengths do they end up with on those 180 degree headers? They seem long compared to most tuned headers. I imagine that the equally spaced exhaust pulse outweighs wave tuning. I've always loved the bundle of snakes.

Yes, the frame rails extend rearward to the crossmember in front of the differential. My frame rails follow the path of the original floor support/frame rails. If I were to do it again, the SFC would be made of 2x3 tubing that sits tight against the rocker panels, and the rear main hoop would sit on top of it. As it is my frame rails are 2.5" square tubing that penetrates the floor such that 1" is inside the car and 1.5" is below the floor. By routing the SFC tight against the rocker panels, you can keep them even with the floor pan and not loose ground clearance. You can see in the last picture the frame rails hanging low below the car.

If I understand you correctly, you are planning to do something similar to what I did. The tubes that converge above the T/C pivot point tie into the cage. The lower tube ties into the lower door bar and rocker panel. The middle cluster ties into the upper door bar.

I am leaning a bit toward the rear weight bias as the major player, but that is just my gut feeling. Unfortunately, there is not much left that I can move toward the rear or remove from the front. In the mean time, I'll just plan on having a passenger along. Its not a bad thing. I like the company. I was thinking about charging admission. The price being the use of a video camera. My plans for the next year or so include wider wheels and tires and getting the new engine in the car. When the new engine goes in, I plan to offset it and the transmission ~3/4" to the right (currently they are centered). This should help even out the left to right balance. Jon- I could raise the front a bit, but I really like the way the car is sitting. I will probably explore some other options first. Some of them are to go a little stiffer on the sway bar, install stiffer front springs, or install softer rear springs. The easiest of these would be a stiffer front sway bar. Changing springs forces me to re-corner balance the car. Changing ride height forces me to re-corner balance and realign the car. A sway bar change stands alone. I've had my eye on one of those Speedway engineering tubular sway bars.... Cary- I also want to start playing with some aero downforce. There is currently no spoiler or wing on the rear, and I may be making a bit of downforce with my front end. A rear wing may help balance the car a bit during the faster sections. I would really be interested in what you are doing with a splitter. Do you plan to write it up in the aero section?

I installed the 20mm sway bar and ran autocrosses on Saturday and Sunday. Both events were at BCC: Saturday was practice, and Sunday was competition. I made the first two runs Saturday by myself. The first impressions of the new sway bar was that the car felt a little more stable, but was still a little loose in the rear. I felt that I had made some improvement, but I was thinking that I needed to do something more. For the next run on Saturday, I took a passenger. I strapped my friend Gary, who is approximately my same weight (185 lbs), into the passenger seat and away we went. The car felt incredible. All looseness in the rear end had disappeared, and I ran the course almost two seconds faster than my previous runs. For the fourth run on Saturday, I ran by myself again. The car felt extremely loose compared to the previous run when I had a passenger. I was so floored by the difference that I decided to run the entire event on Sunday with a passenger. So, how did I do on Sunday? I beat the other two guys in my class (EM)by almost four seconds on a 35 second course. I had the fourth fastest overall time out of 80 plus entrants. The only people who beat me were in two cars that will be at nationals and one in a F125 shifter cart. One of the cars that was faster than I was a Super Stock Corvette, and the other was a A Prepared S2000. The Corvette beat me by ~0.5 second, the S2000 beat me by 0.004 seconds, and the F125 beat me by 1.2 seconds. Here is the riddle: Why did adding 185 lbs to my car help so much? Before we can answer that, we must look at the effects of adding a 185 pound passenger to the car: First, The additional weight balances the car left to right and improves the rear weight distribution. With just me in the car the rear weight percentage is 51.6% and the left side percentage is also 51.6%. Adding the passenger increases the rear percentage to 52.6% and balances the car left to right. Second, The additional weight lowers the suspension natural frequencies all the way around especially in the rear (125 pounds of the passenger goes on the rear and 60 pounds in the front). Aside from lower the natural frquency, the additional weight also helps match the frequencies left to right. Third, the Magic Number (from the WTW) for the car with just me in it is 5.24. Adding the passenger increases the Magic Number number to 6.22. A higher number indicates a greater tendency toward understeer and less toward oversteer. My guess is that the improvement is a result of all of the above. It would be nice to determine which has the strongest influence, so that I can optimize the handling without the additional weight. So, what is giving me the most benefit? Is it the balanced weight left to right? Is it the increased rear weight percentage? Is it the higher Magic Number? Is it something that I have completely overlooked? Man, I really love this stuff.

I have those spacers (and grade 5 fasteners) on my car. I think I'll replace those fasteners now just to be on the safe side. Thanks for the info.

Mine is no longer street driven, so generally I'm not worried about hitting curbs. I do however have trouble getting the car on the alignment rack at the local Tire Kingdom. The sump on my oil pan and my sub-frame connectors are only 3" off the pavement.

I too really liked the wankel site and was inspired to track down a copy of "Aerodynamics of Propulsion". Unfortunately, I wasn't able to find a copy for purchase, so I borrowed one from the NASA library.

The main reason that the vette and Z31 angle their radiators is so that they can fit a larger radiator under the same hood line. If placing the radiator at at angle gives you the benefit of using a larger radiator, better fans, or more room, then go for it. You don't have to cut a hole in the hood just because you angled the radiator. The air will find its way out, but if the air exiting the radiator has an easy path to a low pressure area then you have an easier time keeping the engine cool. If you don't plan on some sort of hole in the hood, then perhaps angling the radiator rearward would be best. If you take that path, make sure that you seal the radiator core to the opening so that air will not spill around the edges. Air spilling around the radiator rather than going through the cooling fins absolutely ruins the cooling efficiency. Also make sure you have a good air dam with an under tray so that you create a good low pressure area behind the radiator. For an example of this, look at a new Corvette.