74_5.0L_Z

Just thought I would add my impressions of the FA slicks at the end of their useful life. When I first installed these I was impressed with their overall grip, but thought the slip angle would take some getting used to. Well, as the tires aged, the slip angles kept growing and the traction kept diminishing. This can be expected with any race tire as it ages. However, these tires go away quickly. All totalled, I got about 20 good runs, 20 mediocre runs, and about 10 runs that were scary as hell because I had no traction. For the price that I paid, I guess they worked well enough (I only paid $100.00 for a set of four). Next season, I will fork out the money for a new set of Hoosier A6 275/35/15 tires. The FA slicks are not in the same league as the Hoosier A6 tires for autocross.

As Dan Juday stated, "there are sevaral factor to consider" when designing the front track width for use with the SubtleZ front fenders. On mine, the front track is 66". I am using the FA slicks which are very short (22.9") mounted on 15x10 wheels. I posted pictures elsewhere to show how they fit and looked on the car. I'll post a few more here: At 66", it looks like I have a little bit of clearance at the front tires, but you need a little wiggle room to allow for suspension motion while the wheels are turned.

My car is just approaching the minimum weight that I am likely to see based on the compromises that I am willing to make and the choices that I made. If I were willing to gut the doors and remove the dash, I could lose about 130 more pounds. If I had constructed the cage of 1.5 x 0.095 tubing rather than 1.625 x 0.120 tubing, I could have saved about 35 lbs. My custom front air dam and hood are heavier than simple fiberglass skins (My air dam with fan installed weighs 20 pounds). Replacing/ removing the glass is worth ~60 pounds. There are many other little gains that are beyond what I am willing to do. If minimum weight is important to you then start with an early 240Z shell. The later 260Z and 280Z shells are heavier. (Jon beat me to it)

My car is pretty stripped. There is no carpet, undercoating, or sound deadening material. The center console, heater/AC, windshield wipers, and radio have all been removed. The stock seats have been replaced with Momo Start2007 fiberglass racing seats which are about 15 lbs lighter than stock. The battery has been replaced with an odessey PC680 which weighs a mere 15 lbs. I do have a pretty extensive cage in the car and an ATL 12 gallon fuel cell with steel can. The car also still has the full dash, all the interior plastic, and all of the glass installed. The car itself without me and fuel weighs 2350 lbs. To me that is pretty light. To get it very much lighter will require me to sacrifice the convenience of roll up windows (I could save 100 pounds by gutting the doors).

My cables are set-up so that they are not adjustable. I used 1/8" multi-stranded cable, thimbles, and crimp connectors. The top is secured to the strut tower next to the spring using a clevis yoke, and the bottom is attached to the sway bar end link. I made the length of my droop limiter such that the spring is slightly loaded at full droop. My wife is out of town and has the camera, so I can't go out and take a picture.

JustOlson asked, "Are you worried about scrapping the frame rail under hard turns? Looks like it was getting close before your switched to the shorter tires." I was a little concerned, but I had no problem while on course. My car doesn't roll nearly as much as it used to. Since then I have added a slightly stiffer front sway bar and droop limited the front suspension. I did have trouble coming on and off the track because there was a slight dip and my frame rails would scrape. Before the next event I plan to raise the front up a little bit by replacing the 450 lb/in springs with 500 lb/in springs. I may then move the 450 lb/in springs to the rear in place of my 425 lb/in springs that are currently installed.

The front leading edge of my rocker panel is 4.25" off the ground, and the rear is 5". The center of my front crossmember is 2.75" off the ground, oil pan is 3", and the lowest point of my exhaust is 2.5". The lowest point however (the leading edge of my frame rail/ subframe connector) is 1.75" from the ground. Loading this thing on and off the trailer this past weekend was fun. I may have to lift it up a little.

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.