bjsinfield

Is there a surplus input in a 90-93 Miata MSpnp to implement a vehicle speed sensor input?

Thanks

cjernigan

iTrader: (13)

You can calculate this by entering your gear ratios and tire sizes in MLV. It will of course only be accurate for one gear so choose wisely and hit the space bar to mark things in your datalogs.
There is no proprietary speed sensor you can use though. The only persons I know actually using a speed sensor for datalogging on a miata is Keith at FM with his rally computer and Reverant with his Innovate LM series datalogger.

compy

It would be intresting to get these ABS speed sensors hooked up to the megasquirt for the purpose of traction control.

Matt Cramer

There isn't one built into it, but the processor has an extra ADC converter that could be used for the output of a frequency to voltage converter. You'd need to design a circuit for the VSS input and build it on a proto board.

compy

That doesn't exactly sound like the easiest thing in the world .

Joe Perez

iTrader: (8)

Doing it with a freq/voltage converter would suck...

I'm wondering... In the MegaTune setup, under Advanced, there's an "Anti-Rev System (traction control)" screen. Opening this reveals two modes of operation: RPM-based and VSS-based. It suggests that there is some provision somewhere for directly reading a VSS signal, however the "Help" function for this screen is empty, and I can't seem to find any solid info at the msefi forums.

Matt Cramer

There was a schematic of this on the old Sourceforge site, but it seems to have been lost when it was moved over to the MSExtra.com site. It did use a frequency to voltage converter chip but I have not been able to find the schematic for this and I'm not how well it ever worked.