spacecad3t wrote: What do you make of these settings that Google Gemini provided?
1987 Porsche 944 Front Alignment Specifications
- Camber: -0.6° to -0.1° (Street/stock); -1.5° to -2.5° (Performance).
Caster: 2.3° to 3.0° (Positive).
Toe: 0.04° to 0.13° (Positive/In).
Performance Setting (Street/Track): -1.8° camber, +0.3mm toe, higher positive caster.
Key Notes for Alignment:
- Caster: 944s use ~86 degrees to 90 degrees of inclination for steering stability, often measured with a digital angle finder on the struts.
Toe: Measured by turning the threaded tie-rod bars. Often, 1/16" toe-in is used to achieve near-zero toe under load.
Adjustment: Camber is adjusted via the eccentric bolt at the top of the hub assembly. It requires removing the brake duct to access.
Recommendations:
- Street/Occasional Track: -1.8º Camber, +0.3mm Toe, Front sway bar: Soft.
Performance/Auto-X: -2.0° to -3.0° front camber is recommended to overcome understeer, often requiring camber plates at higher levels.
A few parts of that Gemini output look plausible at a glance, but there are also some clear red flags and a couple statements that are just wrong for a stock 944 front end.
The front toe range it lists, 0.04 to 0.13 degrees toe-in, is in the ballpark of what you’d expect for a street 944. That part doesn’t bother me.
The caster range it gives, 2.3 to 3.0 degrees, is the big one that doesn’t line up with what most 944s actually measure at stock ride height. A healthy, unbent 944 typically ends up closer to about 4 degrees of positive caster (often a bit more), and you generally don’t “set” caster precisely on these cars the way you do on some other suspensions. If a shop hands you a printout showing 2.5 degrees caster on both sides, I’d be thinking bent parts, shifted crossmember, or the rack’s procedure/settings are wrong.
The “86 to 90 degrees of inclination” comment is basically nonsense in this context. It’s mixing up terms and units. Caster is a few degrees, not 86 to 90. There is a thing called steering axis inclination (SAI/KPI), but that’s also not 86 to 90 degrees and it’s not something you set with an angle finder on the strut for an alignment.
The camber adjustment description is also off. On a stock 944, front camber adjustment is not an “eccentric bolt at the top of the hub assembly.” The practical adjustment you have without camber plates is limited, and it’s not accessed by removing a brake duct to get to an eccentric at the top of the hub. If an alignment tech goes hunting for that, they’re going to waste time.
The “performance” recommendations (-2 to -3 degrees camber, etc.) are generic track advice. It can be a valid goal for autocross/track, but on your car with stock top mounts you likely won’t reach those numbers without adding camber plates or other changes, and it’s not factory spec.
If you want to keep it simple for your stock setup, I’d tell the shop to prioritize equal left/right camber, get caster even side-to-side, and set front total toe to a small toe-in in that 0.1-ish degree total range. Even if you don’t plan to adjust the rear, have them measure it and give you the printout, because rear toe being off will dominate how the car feels.
If you paste the alignment sheet you get (before and after), I can tell you if the numbers look like a normal 944 or if something is off.