First time posting on thread.
Running a link ecu and I want to setup a gear detection so I can use my digital display with gear display. I've tried analog and played with the voltage but it doesn't work. Anyone got a clue on how to set it up?

 

You may have better luck asking in here: https://www.rx7club.com/link-vi-pec-297/

I'm not sure what the Link capabilities are, do you only want an indicated gear (RPMxSpeed calc), or are you hoping to set up a flat-shift/auto-blip type situation?

 

You have two basic problems to solve: (1) Getting your Link G4+ to correctly detect gear position, and (2) Getting the gear position data communicated from your Link G4+ to your digital display, presumably via CAN bus. I can help on problem #1 - I have my FD's factory vehicle speed sensor (on transmission) wired into DI#1 (digital input), which is also set as the driven wheel speed in the Link. Now that it knows driven wheel speed, there are a few ways to get the Link to determine gear position - I used the manual way via log analysis & plugging in the numbers after a short drive where you drive in each gear at a reasonably constant speed for a short time. There's also an auto calculate mode, but you really need some one to drive the car at a steady speed in each gear while you're driving the laptop. These screen shots from my Link config file may help.



This is the config for the FD VS sensor wired to DI#1; your calibration # may be a little different if your tire sizes or gear ratios differ from mine. I calibrated mine by driving a steady speed, and using a GPS/nav app to monitor my speed, set the cal # so the speed displayed in PCLink agreed.

This is the layout page & settings I have for my gear detection. Your #'s may be different if you have different gear ratios & tire sizes.

 

Using your above information and running an e-throttle, would you be able to combine the two for auto blip down shifts?

 

I believe you need an actual sensor in the trans that identifies the gear being selected for effective auto-blip.

 

Like Fenda sain, easiest way would be a switch on the trans that can detect gear positions 1 thru "n" fed to digital inputs; unfortunately the only OEM switches we have on an OEM FD tranny are setup to detect the 1-2/2-1 shift, reverse, and I think neutral. Another option would be using one of the 0-5VDC analog inputs by fitting a strain gauge sensor to your shift lever, and calibrating it while shifting - different strain gauge voltage outputs would tell the ECU which gear you're shifting to/from.

Neither of the above options work for me (since I'm out of available analog inputs), so I haven't deep-dived that feature any further. But I think it's possible. But to do it, and to enable similar features such as traction/launch control, you would need to provide a non-driven wheel speed input to your ECU. Did a little research on this using the OEM ABS sensors on the front wheels for that, but the issue there (at least with the Link G4+) is the frequency output of the factory ABS sensor & ring combo is too high - so you would need to add an external frequency divider/conditioner circuit to divide the ABS output pulse frequency by 4 or 8 to make it usable.

 

#2 isn't a great deal as it's all up to calibration
as for #1 the wheel speed sensor, I do have my abs or LR wheel as one of the DI. But it doesn't activate when wheels are spinning which I assume it just straight up doesn't work. As for now I just need to know how to get my speed sensor on the tranny to wire it into one of my DI's

 

after setting up Digital 1 to read the digital sensor on the tailshaft of my trans i tried both methods and eventually let the automatic method set my 3rd gear. i then just did the math for the other five gears (Tremec Magnum F) and filled in the blanks. i use the "DisplayLink" as my digital dash. my primary objective as to getting the gears synched was to do boost by gear. i have a G4X Extreme but i am pretty sure the system is similar.