I've been driving my 924S a few months now and am enjoying it quite a lot. I started out by doing a lot of major work before I even hit the road with it, but now I'm down to some minor issues. Two I'd like to ask about now are...What's the typical error seen on the early cable driven speedometers? I'm running box-stock tires and wheels and see I'm off 10mph at highway speeds. I drove past a radar speed warning sign and it said I was going 57mph when my speedometer just touching 70mph. That's quite an error! It is accurate at low speeds, however. We have these same speed warning signs at the facility I work at and they agree with what I see on the dash 25mph=25mph. Is there any way to fix it so it's more accurate across a greater range? Another issue is a build up of smudge on the rear window glass at the grid lines that make up the rear window defroster. I was able to remove some of it with window cleaner, but there's still plenty there. Is something like CLR to harsh a chemical to expose the defroster grid to? I'm sure it'll make short work of the crud on the window, but I also really want the defroster to work afterwards!

Thank you for your suggestions!

 

I would check via GPS rather than the cop-in-a-box. I've seen those with pretty decent errors, >10%.

 

CLR is pretty harsh stuff, but I'd be more worried about drips onto anything below if you use it. Depending on what you're looking to fix with the defroster, what about something like DeOxit? If you can get the 100% stuff (DeOxit 100, I believe), maybe that's what you're looking for? Otherwise, what about light polishing with some ScotchBrite?

Cheers