Hi, I have a 356 replica with a VW pan (1972) with Porsche VDO gages problem is if I'm going 50 on GPS my speedo say I'm going about 59 I'd say about a 20% error, is there a adjustment or correction for this?
Original Post
Replies sorted oldest to newest
Hi, I have a 356 replica with a VW pan (1972) with Porsche VDO gages problem is if I'm going 50 on GPS my speedo say I'm going about 59 I'd say about a 20% error, is there a adjustment or correction for this?
Is the odometer working correctly (10 miles driven = 10 miles on the gauge) or is it faster too? If both the speedometer and odometer are incorrect, you can get a ratio adapter to attach inline with the speedometer cable to fix it. A shop that sells them will help you pick the right one. Assuming that you don't want to change tire sizes to fix it.
However, if the odometer is correct, but the speedometer is wrong, the problem is in the gauge and would need disassembly for recalibration of the spring or magnet. I know some have tweaked the spring themselves, but I don't know the procedure. Recommend taking it to a speedometer specialty shop for the work.
It could also be, if the gauge has been disassembled before, that the needle was removed and simply not been put back on the shaft at the original angle.
However, if the odometer is correct, but the speedometer is wrong, the problem is in the gauge and would need disassembly for recalibration of the spring or magnet. I know some have tweaked the spring themselves, but I don't know the procedure. Recommend taking it to a speedometer specialty shop for the work.
It could also be, if the gauge has been disassembled before, that the needle was removed and simply not been put back on the shaft at the original angle.
"with Porsche VDO gages" - does that mean 914, OEM 356, replica 356 or 911/912 gauges? What's tire size?