Electronic Speedo Calibration
Thread Starter
Intermediate
Joined: Dec 2004
Posts: 34
Likes: 0
From: Chicago, IL
Electronic Speedo Calibration
Hello Everyone!
I've got a '76 911S Targa whose Speedo seems to be reporting a large difference in speed...
Before I take it to the shop, I'm just wondering if anyone has any first hand experience in getting these things fixed, so I don't get overcharged, etc etc.
Is it a lengthy process? Is it a calibration or a replacement? (MPH is about 5-15 off depending on the actual speed)
Also, while I'm here: Does anyone have first hand experience with replacing carpeting on a '76 911S (or something like it? I assume they're pretty similar)? I'd be looking at doing the doors, and floor to start.
Parts would be purchased from Automotion (Performance Parts) and work would be performed at a local shop, again, interested in arming myself with the appropriate information before handing my money over to someone else!
Thanks for taking the time to read!
I've got a '76 911S Targa whose Speedo seems to be reporting a large difference in speed...
Before I take it to the shop, I'm just wondering if anyone has any first hand experience in getting these things fixed, so I don't get overcharged, etc etc.
Is it a lengthy process? Is it a calibration or a replacement? (MPH is about 5-15 off depending on the actual speed)
Also, while I'm here: Does anyone have first hand experience with replacing carpeting on a '76 911S (or something like it? I assume they're pretty similar)? I'd be looking at doing the doors, and floor to start.
Parts would be purchased from Automotion (Performance Parts) and work would be performed at a local shop, again, interested in arming myself with the appropriate information before handing my money over to someone else!
Thanks for taking the time to read!
RL Technical Advisor
Joined: May 2001
Posts: 11,870
Likes: 75
From: Portland Oregon
Hi:
Porsche speedometers have been optimistic as long as I can remember,.....1967. That goes for mechanical ones as well as the electronic versions.
If you take your car to a speedo shop that can put your car on rollers and calibrate it, then someplace like North Hollywood Speedometer & Repair can correct it.
For me, I simply carry that calibration sheet from the local shop in my car so I know the precise error that I am looking at.
Typically, these things always seem to read 4-5 MPH fast as long as your rear tire diameters are the same as stock.
Porsche speedometers have been optimistic as long as I can remember,.....1967. That goes for mechanical ones as well as the electronic versions.
If you take your car to a speedo shop that can put your car on rollers and calibrate it, then someplace like North Hollywood Speedometer & Repair can correct it.
For me, I simply carry that calibration sheet from the local shop in my car so I know the precise error that I am looking at.
Typically, these things always seem to read 4-5 MPH fast as long as your rear tire diameters are the same as stock.
Instructor
Joined: Nov 2005
Posts: 200
Likes: 0
From: Washington State
I agree with Steve.
Borrow or buy a cheap handheld gps http://www.garmin.com/products/etrex/. I already have one and my speedo is exactly 5mph on the plus side up to 100mph according to the gps.
Borrow or buy a cheap handheld gps http://www.garmin.com/products/etrex/. I already have one and my speedo is exactly 5mph on the plus side up to 100mph according to the gps.
