74_5.0L_Z

I am running the SubtleZ rear quarter panels, and the 23x9.5x15 tires fit well. The YZ rear quarter panels and the correct offset wheel will accommodate the larger 13.5 in wide rear FA slick (In hindsight, I sometimes wish that I had YZ rear Quarters). I bought the 15x10 wheels so that I would have the option of running the FA slick or running the 275/35/15 Hoosier A6 tires. I am willing to bet that my car would be faster on the latter of the two. The deciding factor for me right now is cost. A set of the A6 tires would run me $1100.00 and last for one racing season whether I use them or not (time kills them slowly). This year, I am not able to race as often as I did last year because I am back in school working on my masters degree in Mechanical Engineering, so a set of expensive, time-sensitive tires would be a waste. The used set of FA slicks cost me $108.00 shipped to my door. I figured if they work then great, and if they don't then I'm only out a few dollars. So far, I am quite happy with them.

These are the radial FA tires. I bought directly from Spinwerkes. They were great to deal with, but their web-site definitely needs work.

I have moved nearly everything that I can to the passenger side and as far back as possible (within the confines of the wheel base). The battery is behind the passenger seat, the radiator catch can is behind the right front wheel just ahead of the firewall and just off the ground, the fuel cell is 4" off center to the right. The coil, the computer, the mass air sensor and alternator are all on the right. I have lost some weight, but I fear that I can't lose much more without donating an organ. I am looking into a lighter steering column, lighter pedal assembly, and anything else that anyone could suggest. If I get really motivated, I will relocate the engine and transmission toward the passenger side by an inch. In the meantime, I look for passengers to ride along. They're usually pretty easy to find:burnout:.

Here are some pictures showing the new Spinwerkes 15x10 wheels (5.25" backspace), and the new to me Hoosier 23.0 x 9.5 x 15 FA radial slicks.

I'll try to get some pictures of the car with the new wheels and tires and post them tomorrow. Drax the answer to your question is yes. They are less responsive and more forgiving, and I believe the overall grip was better. We'll have to see how they wear. Cary, by the end of the day I was driving as you stated, I had to "increase my steering input velocity." I really like the way they drove after I figured that out. BRAAP, the tires you had on the back of that car were just obscene:mrgreen:.

For a while now Tube80Z (Cary) has been suggesting that I try out some FA slicks for autocross use. With my bodywork (SubtleZ kit), the only ones that would fit are the 23.0 x 9.5 x 15 slick which are designed for use on a 15x10 wheel. So, I finally got some wheels (15x10 Spinwerkes series 82 with 5.25" backspace) and some used FA slicks off the internet (R25B compound). The tires weigh 16 lbs each and are 22.9" tall. The Spinwerkes wheels weigh 15.8 lbs each. My old wheels and tires weighed 39.5 lbs and stood 24.7" tall. Putting the new wheels and tires on the car lowered the car 0.9", and increased the track by 2". The new tires really fill up the SubtleZ body work. I used the new tires at the autocross yesterday for the first time, and all I can say is that they rock. Absolute grip was slightly better than with the A6 tires, but the feel was completely different. With the A6, the maximum grip occurred at a lower slip angle. The A6 responded quickly to inputs but would loose traction if the driver pushed the tire past its ideal slip ratio. The FA slicks are different. They respond to inputs more slowly and require more slip to get maximum grip. If I needed to turn in deeper, I just had to turn the wheel. The front never seemed to wash out on me as it would have with the A6's under the same conditions. The set the air pressure at 25 psi at all four corners and left the camber where I had it last year (-2.1 rear and -2.5 front). These tires heat up very quickly in 95* F conditions. I made seven runs and had the best performance when the tires were cool on the starting line.

I've made some significant changes to the car, so it was time to rescale everything. First the engine changes: I Replaced stock 5.0L bottom end with a 5.4L stroker. The new bottom end has a 3.25" stroke and 5.4 inch rods as opposed to 3" stroke and 5.090" rods. Also the new bottom end has a main stud girdle and an aluminum flywheel. I replaced the Cobra intake with a Performer RPM intake. I replaced the stock rear sump pan with a custom Kevko racing front sump pan (this required modification to the crossmember to fit). Second, the wheel and tire changes: Last year I was using 16x8 centerline wheel and Hoosier 245/45/16 A6 autocross tires. This year I have replaced them with 15x10 spinwerkes series 82 wheels and FA slicks (23.0x9.5x15). Last year's tire/wheel combination weighed 39.5 lbs each, and the new tire/wheel combination weighs 32.0 lbs each. (I save 7.5 pounds of unsprung rotating weight at each corner . I put the car on the scales Friday night and here is what I got with me (185 lbs) and about 12 gallons of fuel in the car: LF = 648 Lb RF = 610 Lb LR = 692 Lb RR = 653 Lb. Total = 2603 Lb These were my percentages: (LF + RF)/ Total = (648 + 610)/2603 X 100%= 48.3 percent on the front 51.7 % on the rear. (LF + LR)/ Total = (648 + 692)/2603 X 100% = 51.5 % on left and 48.5% on right. my diagonals : (LF + RR) = (648 + 653)= 1301 (RF + LR) = (610 +692) = 1302. The car has lost 53 lbs since last it was scaled. 30 lbs of the lost weight came from the new wheels and tires. The rest came from changes to the engine (intake and flywheel mostly). The car has significantly less unsprung and rotating weight, and a measurably improved rear weight distribution.

For a carbureted engine, the answer is pretty much all of it. The wiring in the engine compartment is mostly for the headlights and turn signals with just a few wires going to the engine. The wires that went to the starter on the straight 6 will now go to the starter on the V8. The wire that went to the coil on the 6 will now go to the coil on the V8. Some combination of the alternator wires will be reused depending on the alternator and voltage regulator that you end up using (I bought a Power Master 1 wire alternator with internal voltage regulator and made it simple). If you run mechanical water temeperature and oil pressure gages then you can delete those two wires. Another thing that you can stand to loose is all of the inter-lock relay crap.

Go to this link and scroll down: http://www.kevko.net/ford.htm They make about any pan you like. I had them make a custom 6.5" deep front sump road race pan for my car.

The weight transfer worksheet is an implementation of the Total Lateral Load Transfer Distribution (TLLTD) material presented in Race Car Vehicle Dynamics (RCVD) by Milliken. In the text (chapters 16 and 18) Milliken states the basic relationships between spring rates, motion ratios, static weight distribution, track width, and other vehicle variables to the TLLTD in a steady state corner. Within the text, are some suggested starting points for setting up a car that will be driven on a road course type circuit. On page 605, the following recommendations were given: (begin quote) Ride Frequencies: Non-Aero Sedan________________1.6 to 2.0 Hz (with front higher) Aero Cars _____________________3.0 to 5.0 Hz (with front higher) Roll Gains: Sedans________________________1.0 - 1.8 deg / g Aero Cars______________________0.25-0.5 deg / g TLLTD's To insure initial understeer, calculate the TLLTD to be 5% more than the weight distribution at the front. (end quote) What this is telling you is that if you have 50% of your weight on the front tires, then the front suspension should supply ~55% of the total roll stiffness. Remember, these are only suggested starting points for road racing cars. Cars intended for other purposes (like autocross) will use slightly different values (My car is set up with 2.5Hz frequencies, and Cary and others are exceeding 3 Hz frequencies). There are a couple of weight transfer worksheets available. The one that we keep referring to is marketed by Smithees out of Australia. As far as I can tell, this worksheet directly implements the gospel according the Milliken. The WTW provides a very user friendly worksheet to input the vehicle parameters. The worksheet then provides a "magic number", which is the difference between the static front weight percentage and the percentage of the roll resistance provided by the front suspension. If the number is greater than 5%, the prediction is that the car will tend more toward understeer, and if the number is less than 5% then the car will tend more toward oversteer. Although this tool isn't exact (because of inaccuracies in user measurements), it is a great tool for visualizing the effect of suspension changes like spring rates and roll centers.

Black plastic. It comes in 24" wide rolls. I got mine from Coleman Racing.

Thanks, The car cools very well. It never gets hotter than 190 F. When I dynoed the car a few months back, the car was on the dyno for two hours and never got hot. Here is a link to the bodywork construction thread: http://forums.hybridz.org/showthread.php?t=121617&highlight=emulates&page=3

As promised, here are some photos showing the fender installation: The first picture shows the car as it is today (with the hood removed). In the picture, you can see the 1 x 0.058" tube that connect the two fenders. The brackets on the end of the tube are constructed of 1/8" plate welded to 1.125 x 0.058" tubing that slide over the transverse tube. The next four picture show the hinges and front structure during the construction phase two years ago. In this picture, you can see the hinges of course. The hinges were made by slipping two pieces of the 1.125 x 0.058' tubing over the transverse tube and welding two lengths of 1 x 0.035" tubing. Each piece of the 1 x 0.035" tubing has two dzus bracket welded to retain the hood. The small diameter black tube with the rod ends has since been deleted (it was only there for alignment during welding). In these pictures, yo can also see where I had to massage the inner mounting flange of the fenders to clear the strut tower structure. I only removed enough material to clear. When I was making the front fender supports, I was trying to come up with a structure that could be used to pull the car off the track if required, but that would also give in that event of an accident without affecting the suspension attach points. I apologize for the size of the pictures, but it is easier to see the detail in the bigger pictures.