Tuner Pro/speed sensor setting
Thread Starter
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
Tuner Pro/speed sensor setting
I'm in the process of changing my Dana 36- 2.59 differential to a Dana 44- 3.45. My vette is a 91 and I believe it has the electronic speedo, VSS. I know they make the device that you wire in and then set to adjust for the change in the ratio to get the speedo to read correctly. However I notice in Tuner Pro under the Scalars the last two settings are "Vehicle Speed Sensor" and "Vehicle Speed Sensor Instrument Panel Pulse Divisor". The first is set at 4000 and the second is set at 0. Is it possible to change these settings to compensate for the change in ratio? If so does anyone know what they need to be set at for a 3.45?
Thanks
Chuck
Thanks
Chuck
Thread Starter
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
I'm going to check, but I believe mine has a reluctor on the output shaft and a pick up, no gears. Once I get it in the air I'll check. The cable operated speedometers have gears. My understanding is that some of the electronic speedo's had gears but I'm not sure mine does. I talked with PTAC today and they said I needed the adapter mentioned above. If I can change it in the program, I'd rather do that.
Team Owner
Joined: Jul 2004
Posts: 28,464
Likes: 3,288
From: Hartford WI
I'm going to check, but I believe mine has a reluctor on the output shaft and a pick up, no gears. Once I get it in the air I'll check. The cable operated speedometers have gears. My understanding is that some of the electronic speedo's had gears but I'm not sure mine does. I talked with PTAC today and they said I needed the adapter mentioned above. If I can change it in the program, I'd rather do that.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
To set vss for 3.45 you need the m6 speedometer gears and vss or you can try to rotate the A4 vss for larger speedometer gear. Lock fork will not line up with sensor dimples. There is also speedometer converter which canbe wired in. I looked in to it, but changed speedometer gears instead.
Team Owner
Joined: Sep 2003
Posts: 25,393
Likes: 2,741
To set vss for 3.45 you need the m6 speedometer gears and vss or you can try to rotate the A4 vss for larger speedometer gear. Lock fork will not line up with sensor dimples. There is also speedometer converter which canbe wired in. I looked in to it, but changed speedometer gears instead.
***The correct VSS for an A4 '91+ with 40+ gear offset is a very hard find. VERY .......
I've always preferred a mechanical correction for odo/speedo but with VSS and gears becoming so difficult to obtain if I needed to accomplish this (with an A4 and 3.0+ ratio rear) I'd likely use whatever you have now and invest in a DRA/ERA for correction. There's 2+ potential vendors out there.
Greg@Blowerworks might have gears you need. I believe I have only NOS 15 tooth drive. Driven depends on actual ratio and tire size you have.
'91 - '93 VSS can be seen in this thread (Thanks again James!)
https://www.corvetteforum.com/forums...-only-vss.html
Last edited by WVZR-1; Mar 23, 2019 at 09:12 AM.
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Thread Starter
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
Thanks WVZR-1, I got into it today and it has the gears driving an electrical pickup. I got the 15-40 using a calculator on TCI's site. I have 295/35/18 rear wheels and tires and when I use their calculator is comes up very close to 15-40. And you are correct, I can find the 15 but the I can't find the 40. I think I'll get the ERA and wire it in.
I was hoping I could change the setting in the program I mentioned in my first post to account for the change in ratio. Maybe someone with tuner pro knowledge will chime in.
I may go to the Tuner pro forum and see what I can find.
I was hoping I could change the setting in the program I mentioned in my first post to account for the change in ratio. Maybe someone with tuner pro knowledge will chime in.
I may go to the Tuner pro forum and see what I can find.
Melting Slicks
Joined: Aug 2011
Posts: 2,844
Likes: 176
Thread Starter
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
Those settings are actually in the "Vehicle Speed Sensor" setting in the scalars. As you said it starts at the 3614 and goes up. I'll try this and see what it does. It has a note "Set to 4K for SD" which I assume it is referring to Speed Density. It is currently at 4K. So my guess is if I divide my new ratio by the old ratio, 3.34/2.59=1.3320.
multiply the 4k by the 1.3320=5337.456, that this would be a good starting point, if this setting will correct it. I'll let you know what happens.
multiply the 4k by the 1.3320=5337.456, that this would be a good starting point, if this setting will correct it. I'll let you know what happens.
Thread Starter
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
Tried changing the "vehicle speed sensor" setting as described above and it didn't work. I'm going to get an electronic ratio adapter and wire it in. I know those work.
Thanks for everyones input!
chuck
Thanks for everyones input!
chuck
Thread Starter
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
Tried changing the "vehicle speed sensor" setting as described above and it didn't work. I'm going to get an electronic ratio adapter and wire it in. I know those work.
Thanks for everyones input!
chuck
Thanks for everyones input!
chuck