Proposed 1999 Miata Install - Please Check My Plan

[Bryan@UnderbiteRacing]

Hi -

I received my RaceCapture Pro Mk2 this weekend in the mail and had some time on a flight this morning to map out my proposed re-wiring of the accessories to include the RaceCapture and clean things up a bit. Since I'm a rank newb, I would greatly appreciate another set of eyes (or 10) to see what I'm planning to do before I actually do it.

If I've misunderstood any of the concepts in my reading and drawn something that's goofy, please let me know. I'm also curious about the questions in the red boxes which are a bit Miata-specific.

Thanks in advance for any help! I'm looking forward to having data available for my next track events to help me go faster!

Cheers,
Bryan

[brentp]

Hi,

Sorry for the late reply! Love your wiring diagram.
For your question about the way of grouping together pullup resistors for RaceCapture, you should look at the SensorX breakout board. It can be bundled in-line with your wiring harness for a clean install.

Not sure on your brake switch - if it's bare, then you will need a pull up resistor. The Miata should have a pretty clean square wave signal for tach.

Let us know how it goes!

[cj9694]

How did this install go? I am very interested in the Tach setup because I am about to do it on my 1990 Miata. Did you need any kind of resistor for the tach signal? What did you need to do in order to calibrate it to work with the RCP?

[Bryan@UnderbiteRacing]

Hi -

Sorry I missed this earlier.

Phase 1a of my installation went really well - other than having to work in the driver's side footwell of my '99. At least your ECU should be on the passenger side and more accessible!

I tapped into the tach signal wire at ECU and brought it straight into my RaceCapture Pro Mk2. It didn't require any resisters or fancy programming. I don't have the car here with me, but any adjustments to the settings was very straight-forward (pulses per rpm, etc.).

I didn't wire in the existing gauges; now that the unit has proven itself reliable, I'm contemplating pulling out and selling my fancy oil pressure and water temp gauges and installing just the sensors to run back to the RCP.

Best of luck!

Cheers,
Bryan

[cj9694]

Thanks for the update.

so you plan is to use the stock miata sensors on the car already? Do you have a plan as far needing a pull up resistor in line or who the calibration might go? The miata oil pressure sensor as least has known resistance values but the temp sensor is one of those mystery (doesn't work for shit with the stock gauge) sensors that I would really like to pull data from.

I am glad the tach is so easy to wire in though.

[Bryan@UnderbiteRacing]

Sorry - I wasn't very clear. I have after-market sensors and gauges in the car now, but (I believe) they're based on a 0-12V signal. Rather than cutting into their wiring harnesses and doing all the voltage dividing, I was thinking I'd remove those to sell and just install 0-5V sensors wired direct to the RCP2.

But yeah, the tach, throttle position and brake switch were really straight forward.

Cheers,
Bryan

[cj9694]

Awesome, thanks Bryan. Any plans to wire up a wideband O2 like the Bosch lsu 4.9? I am trying to figure out if this sensor can be run directly to the RCP3 or if you still need a controller.

[Bryan@UnderbiteRacing]

Hi -

I've don't have plans for any additional sensors. I'm still learning to use the system and interpret the data I already have!

Good luck with your install!

Cheers,
Bryan