This past weekend it was time to setup the suspension. IMO proper setup is absolutely key to having a 911 drive in that legendary way. This means proper alignment and corner balance. I will walk through my process of setting up the car.
First, I put the car on scales. I have an old set of Intercomp wired scales. They still work great. I made my own scale ramps using some lengths of 2x12. I have one set that is cut for the wheelbase (minus scales) and a second set that extends in front of one end of the car. A 4x4 post prevents the car from rolling off the scales. This setup allows the ease of rolling the car on/off scales to make adjustments on the wood ramps.
I have previously measured the most level section of my driveway and always use this when setting up cars.
With the car sitting level and at a desired ride height (see previous post for pic) I will take initial measurements of the car. Yes, sway bars are disconnected for this step. I always run my scale wires through the passenger window so that I can weight the car with (me) driver weight. I can also use ballast if necessary to adjust up/down without a driver.
I will first preload the rear of the car up such that there is a weight shift to front wheels. Using the front adjusters I will set near equal front weights. Since the ride height was previously set this means you have to up on one side and down on the other to effectively shift weight without drastically changing ride height.
Afterwards the car is back on 4 wheels with a jounce or two to settle suspension. Then the rear weights are matched to the front.
Once the car is level and has a 98% CB number I will align the car. Often setting alignment can change the CB depending on how much ride height changes. I will follow up with final CB at the end.
I use Smart Strings for my alignments. They are easy to use and allow for adjustment of single wheels. The results are only as good as your string setup. Care must be taken to properly square them from the car. I use the wheel center cap lip as my known measurement point. The strings are set so that the FR/FL distance is the same and the RR/LR distance is the same. The F and R string offsets will be different due to individual car track widths.
The strings will have a height that bisects the center of the wheel. You will be measuring the difference from front and rear side wheel lips to the string. If the front distance is greater than the rear distance you have toe-in. I have my own preferred alignment settings and will not go into that here. The front and rear alignment settings are then set using thetie-rod end adjuster and toe adjuster cam bolts, respectively.
following toe adjustments I set the camber. I use a camber truss. This has 3 points and is adjustable for wheel diameter. I have previously spent time to setup the camber bubble gauge using a known level surface. This one is really easy to read. Place gauge truss on wheel. Read the center of the bubble. Then dial in your camber using the rear camber bolts and front strut tops.
Once you have set camber you have to go back and re adjust the toe. Moving the wheel in at the top changes toe settings. This is much more on the rear than at the front.
And then once you have your alignment completed you go back and finalize the corner balance. For a fast street car the 0.3% cross-corner weight percentage is good enough. But I didn't want good enough. Why not make it perfect. That'll do.
And once the car is corner balanced and aligned I pull off the strings and take a final weight of the car. HMM. Is that a calendar reading or the car weight? Yeah, pretty stoked to see such a low number.
I admit that the car is missing a passenger seat, seatbelts and some RS carpet. But even with all this I should still be under 2100 pounds. The build goal was sub-2200 pounds fully dressed with fuel, spares, tools and such. Lightweight is so much more fun.