74_5.0L_Z

When corner balancing a car by adjusting the coil-over spring perches, you cannot change the left to right or front to rear weight distribution. You can only change the diagonals. During this round of corner balancing my car it took me three tries to get the car where I wanted it. Here is the procedure and results: 1. Disconnect sway bars. 2. Set tire pressures. 3. Verify steering is straight ahead. 4. Measure ride height at four corners (I measure at LCA attach points) 5. Settle car and roll onto scales. Take measurements of car with no driver. 6. Get in car and take measurements with driver in car. Here are the results from my first weigh before adjustments: No Driver: LF 616 RF 581 LR 595 RR 632 With Driver: LF 675 RF 581 LR 679 RR 682 The diagonals were a mess. No Driver (LF + RR)/Total = (616+632)/2424 = 51.4% (LR+ RF)/Total = 48.6% With Driver (LF + RR)/Total = (675 + 682) / 2617 = 51.9% (LR + RF)/Total = 48.1% I needed to take weight off the (LF + RR) diagonal and give it to the (LR + RF) diagonal. There are two way to do this. First, I can raise spring collars on the light diagonal, or second I can lower spring collars on the heavy diagonal. I opted for little of both. For the first adjustment, I lowered the RR spring collar 3/4 turn. I then resettled the car and rolled it back onto the scales to measure the changes. No Driver: LF 601 RF 595 LR 608 RR 618 Diagonal Percentages: (LF + RR)/Total = (601+618)/2424 = 50.3% (LR+ RF)/Total = 49.7% With Driver: LF 662 RF 593 LR 689 RR 672 Diagonal Percentages: (LF + RR)/Total = (662+672)/2617 = 51.0% (LR+ RF)/Total = 49.0% The diagonal got much better but still needed work. I needed to take more weight off the (LF + RR) diagonal and give it to the (LR + RF) diagonal. For the second adjustment, I raised the RF spring collar 1/2 turn. Again, I resettled the car and rolled it back onto the scales to measure the changes. No Driver: LF 593 RF 605 LR 617 RR 610 Diagonal Percentages: (LF + RR)/Total = (593+610)/2424 = 49.6% (LR+ RF)/Total = 50.4% With Driver: LF 653 RF 604 LR 700 RR 662 Diagonal Percentages: (LF + RR)/Total = (653+662)/2617 = 50.2% (LR+ RF)/Total = 49.8% I was happy with the diagonals at this point. One thing that should be noted is that the left to right and front to rear percentages did not change during this process. When I started, the percentages were as follows: Without Driver : Front percentage: (LF + RF)/Total = (616+581)/2424 = 49.4 percent Left Side percentage: (LF + LR)/ Total = (616 + 595)/2424 = 49.96 percent With Driver : Front percentage: (LF + RF)/Total = (675+581)/2617 = 48.1 percent Left Side percentage: (LF + LR)/ Total = (679 + 682)/2617 = 51.7 percent These percentages are the same as my final values as expected. The only ways to change the left to right and front to rear percentage is to move things around the car or to remove/add weight.

I am slowly putting my car on a diet. I would love to get down near 2300 lb. I still have the stock windshield, stock rear hatch, and stock dash. I also can lose some more weight on my doors. I have removed the glass and regulators, but otherwise the doors are intact with the factory inner door skins. I am also still carrying a passenger seat and harnesses even though I cannot carry passenger on track. How did you get your left to right balance so close. I have done almost everything I can think of to move weight to the right and I am still left side heavy. I am carrying a passenger seat and harnesses, my battery is behind the passenger seat, the Accusump is offset to the right behind the passenger seat, my radiator catch can and alternator are on the right, my fuel cell is shifted 4 inches to the right. I have also shifted the driver's seat about 3/4" to the right, and I am still have 51.7% left side weight. I am not terribly heavy (193 lbs with helmet on).

Time for another update as I have made a few changes to the car. I have replaced the front crossmember with a custom built unit and replaced the 260Z rack with a 240Z rack, I have completely rewired the car, I have removed the window regulators and door glass, I have replaced the rear drop legs with TTT units, I have installed a 3 quart Accusump, side view mirrors, and air ducts for the front brakes. I am also now only running track day events. I think I am done with autocross. Total Weight: 2617 with 6 gallons of fuel and me in the driver's seat (Front Weight: 1257 , Rear weight 1361), (Left Weight: 1353, Right Weight 1266) LF = 649 Lb RF = 607 Lb LR = 703 Lb RR = 659 Lb. (LF + RR) = (662 + 661)= 1307 (RF + LR) = (708 +623) = 1310 These were my percentages with me in the car: (LF + RF)/ Total = (649 + 607)/2617 X 100%= 48.0 percent on the front 52.0 % on the rear. (LF + LR)/ Total = (649 + 703)/2617 X 100% = 51.7 % on left and 48.3% on right. Here are the final numbers with fuel but no driver: LF = 593 Lb RF = 605 Lb LR = 617 Lb RR = 609 Lb. Total = 2424 Lb These were my percentages for the car without driver: (LF + RF)/ Total = (593 + 605)/2424 X 100%= 49.4 percent on the front 50.6 % on the rear. (LF + LR)/ Total = (593 + 617)/2424 X 100% = 49.9 % on left and 50.1% on right. The car has gotten a little lighter and has gained a little more rear percentage. Here are the rest of the current stats on the set-up. Roll Centers: Front 1.9 inch, Rear 4 inch Spring Rates: Front 500 lb/in, Rear 400 lb/in. Sway Bars: Front 20mm with shortened arms, Rear none Struts: Front, Koni 8610-RACE Rear, KONI 8610-1149 Alignment: CAMBER: FRONT -2.2, REAR -1.5 TOE: FRONT 1/8" toe out, REAR 1/8" TOE IN CASTER: FRONT 6.5 Degrees TIRES: Avon 240/600-15 radial slicks mounted on 15 x 10 wheels at all four corners Power: 396 rwtq at 4000 rpm, 386 hp at 5950 rpm (greater than 350 ft-lbs of torque from 3000 rpms to 6000 rpm all measured in 4th gear. Gear: 3.36 CLSD, G-Force T5 (2.95, 1.94, 1.33, 1.00, 0.8) I have been very happy with this as a track setup (though I have only done four track days so far). I will be running at Daytona on the infield course April 9th, and I'll be back at Daytona to run the Rolex course may 5th.

For mine, I made sure that the air that entered the front of the car had nowhere to go except through the radiator. The fan is only necessary when you are not moving. If you give the air an escape route after it goes through the radiator, then the cooling will be more efficient regardless of the fan. http://forums.hybridz.org/topic/70097-show-your-custom-front/

I have a 1995 Mustang electric fan mounted ahead of my radiator in my front air dam. The fan was originally meant to be mounted behind the radiator as a puller, but I have it mounted as a pusher. The important thing is that I kept the flow direction the same. The inlet side of the fan is facing forward.

I hope those fans are intended to be mounted in front of the radiator (intended to push the air). Most fans are mounted behind the radiator and pull the air through the radiator.

The Futofab is a much better design. On the Fotufab tension rod, the bolted connection between the dog leg and the clevis end can accommodate the changing angle between the control arm and the tension rod as caster is adjusted. On the T3 rod, there is a rigid connection between the dog leg and tension rod. The holes in the dog leg would have to be oversized to accommodate any caster adjustment and will limit the range of caster adjustment available.

I assume there is a question in there somewhere... So, what is the spring rate and free length of your springs? How much travel do you have available from your nominal ride height to when you either bottom the strut or stack the coils of your springs. If you run soft springs, then you have to have lots of available travel. Otherwise you will either bottom out the strut or stack the spring. In either case, the lower spring support will take some serious abuse and is likely to fail. I have had the same Ground Control coil-overs on my car for about 15 years. I have thousands of street miles on the car, hundreds of autocross events, and several track days with no issues. The key to a correctly functioning coil-over system is making sure that your suspension doesn't bind or bottom out during use (ever).

That carburetor is way too big for that engine. A 600 cfm would work much better. How is the engine mounted in the car? Is it mounted solidly using a mid plate sandwiched between the bell-housing and block? If the engine is not mounted solid, then that alternator mounting could cause problems when the engine moves around during acceleration. The exposed flex plate for the transmission shouldn't be a problem, but I would make some kind of cover. You do need a transmission cooler of some sort, or you will burn up that transmission on the street. This was obviously someone's drag race car, so they didn't worry about transmission heat. I have a T5 in my SBF (331 stroker) powered car. I use a Tilton hydraulic throw out bearing and 7/8 clutch master cylinder. If you look back at some of my older posts, I provide details of the installation.

I have Borla Pro XS mufflers on mine. I love the way they sound. They are mellow at part throttle but scream at full throttle. I've had people say that they don't mind getting passed by me because they love the way my car sounds.

There are several threads already regarding the building of roll cages. I will tell you that no one makes a roll cage that you can purchase that fits properly. If you want it done right, you are going to have to find a good race car chassis fabricator or do it yourself. I can pretty much guarantee that the cage at the link you provided will be junk.

It would be more meaningful to compare the racks based on the rack movement per revolution of the pinion. For instance the 240Z rack moves 1.81 inches per revolution,and the later 260Z and 280Z racks moved 1.59 inches per revolution. I like the idea of power steering, but I also want a rack that is shorter than the S30 rack (center to center of inner tie rod pivot points).

The threaded bracket is for the factory exhaust hanger.

That is much better Where did you get those clevises?

They are just pressed on. Just twist them while you pull and they will slide off. If you still have trouble removing them, then use the rack housing to push them off. To do so, you could place a clamp collar around the shaft between the rack stop and the end of the housing and then turn the pinion to push the rack stop off. Another option would be to remove the pinion so that the rack shaft is free to float in the housing and use the housing like a slide hammer to drive the rack stop off.

The cross member is the same but the rack bushings are different. The 280Z bushings are wider and the one nearest the pinion is contoured a bit differently.

It think that the rack in your car has been replaced with a unit from a later S30 (260Z or 280Z). The factory racks from a 240Z would have an aluminum pinion housing.

No problems at all, but I am running 23 inch tall tires (275/35/15 Hoosiers, 240/600/15 or 23.0 x 10.5 -15 Avons). You are more likely to have problems in the front with larger diameter tires. The issue that you will encounter with high backspace and large diameter on the front is rubbing of the tire on the T/C rod or frame at high turn angles. I used to run 245/45/16 tires (24.7 diameter) with the 5 inch backspace and had rubbing issues. I coped by limiting rack travel with the larger diameter tires.

With coil-overs, you can run 5.0 inches of backspacing all around without spacers using 15 inch wheels. You will have more space between the tire/wheel and the strut on the rear than on the front. On the front you will have about 1/8 inch clearance and on the rear you will have about 5/8 inch clearance. I wanted to tuck my rear tire in a bit more in the rear, so I opted to go with 5.25" back space and use a spacer on the front wheels. I have the SubtleZ fenders and quarter panels on my car and the 15x10 barely fit under the fender and quarter lips. The advertised clearance for the SubtleZ kit is 1.5 inches more than stock (I believe). The 280YZ kit advertised clearance is 3.5 inches more that stock (If memory serves). Therefore, the 15 x 12 should fit all around with 5 inches of backspace. I would err on the side of caution and purchase the wheels with a little extra backspace (say 5.25 or 5.375 inches) and plan on adding spacers as required. If you have too much backspace then you can add spacers to fix it. If you don't have sufficient backspace then you have problems that cannot be fixed cheaply. If you go to a 17 inch wheel, you can run a little more back space than with a 15 inch wheel. How much more I cannot say because I have not run 17 inch wheels.

I have a couple of comments: First, Have you considered lowering the differential by flipping the poly bushing in the mustache bar or by adding a spacer between the mustache bar and the frame. I have the differential in my car lowered by about 1/2" using washers above the mustache bar. Second, how do you like the TTT Drop Mounts? Are they aluminum? I am contemplating getting either the TTT or the ArizonaZCar drop mounts.

Is this only a problem on the 240Z? I've had two 260Z and have never noticed the firewall flexing.

I would like to see pictures of the tubular ARB set-ups installed on the Z and ZX cars. I would also like to see the details (tube OD, ID, length, arm length, bend angle, mounting).

I've been looking into this a bit as well. http://1speedway.com/index.php?route=product/product&path=76&product_id=90

I think we are on the same page. I just misunderstood your intention initially. I am watching your build with interest, and wishing I had the time and energy to do another ground up build.

My pet peeve is the frame rails hanging below the stock floor. At ride height I have less than 2.5" of clearance (ground to frame rails). So my frame limits how low I can set the car. For reference, I have about 3.5 inches of clearance between the ground and the bottom of the front cross member which is approximately in line with the floor pan. I autocross and run track days, so the lower the better as long as the suspension geometry is correct and nothing scrapes the track. If the frame rails didn't hang down, I would feel comfortable lowering the car an additional inch. If the floor, cross member, and engine were raised, then I would lower the car even further. If I were starting with a clean slate like you, I would build everything around the desired ride height. As with everything I've done to my car, I would do it differently if I did it again.