NSX-R gauges install on 1997 NA2

[francisluu]

My car's still being worked on at the moment and, in the meantime, I wanted to do a quick gut-check with folks who have installed genuine Honda NSX-R gauges in their cars. We've followed the guidance on Mita's website and installed the individual gauges (with their own dial-specific circuit boards) onto my original USDM 1997 NA2 circuit board. This is supposedly to continue incrementing the car's odometer reading in miles (which is what I want).

Is this the way to do it? Will the speedometer (which I'm fine with reading in KM/H of course) sweep correctly or will its calibration be off?

I've been reading on some discrepancies between the NA1, NA2 pre-facelift, and NA2 post-facelift cars with regards to these gauges and the former (NA2 post-facelift a la NA2 NSX-R) being plug and play while that may not be the case for the other cars.

Thanks!

 

[drew]

>This is supposedly to continue incrementing the car's odometer reading in miles (which is what I want).

The pulse rate of the Metric and Imperial boards are the same. The mechanical gear ratios are different from kilometers vs miles.

I recommend using the NSX-R boards and transfer the Imperial odo and trip meter.

> Will the speedometer (which I'm fine with reading in KM/H of course) sweep correctly or will its calibration be off?

No and Yes.

No: The speedo sweep is greater and will likely require the change of an onboard resistor (i have notes somewhere). So it will not read correctly.

Yes: You will need to calibrate the tach and speedo if you change the boards. Again, recommend using the R boards.

In fact, not that much more expensive to just build a whole other cluster with all the unused parts to defray your costs.

 

[francisluu]

>This is supposedly to continue incrementing the car's odometer reading in miles (which is what I want).

The pulse rate of the Metric and Imperial boards are the same. The mechanical gear ratios are different from kilometers vs miles.

I recommend using the NSX-R boards and transfer the Imperial odo and trip meter.

> Will the speedometer (which I'm fine with reading in KM/H of course) sweep correctly or will its calibration be off?

No and Yes.

No: The speedo sweep is greater and will likely require the change of an onboard resistor (i have notes somewhere). So it will not read correctly.

Yes: You will need to calibrate the tach and speedo if you change the boards. Again, recommend using the R boards.

In fact, not that much more expensive to just build a whole other cluster with all the unused parts to defray your costs.

I really appreciate it. It sounds like a wholesale swap of all new components would work minus speedo calibration, leaving the old boards to be placed into another housing to sell (as an option)?

 

[drew]

At some point you have a Ship of Theseus situation. There is only maybe $300 in parts that you can build a whole new NSX-R cluster, pennies at this point. Especially if there is an issue with the stepper motor connection screws.

Taking out the long machine threaded screws in the back of the stepper motors should scare the heck out of anybody working on the unit. Do it as few times and as carefully as possible. Do not underestimate how easily one can mess this up with hair thickness connections that are easily severed.

 

[francisluu]

Do you have the notes on how to change the resistor (or what to change it to) to correct the sweep of the speedo?

 

[drew]

>Do you have the notes on how to change the resistor (or what to change it to) to correct the sweep of the speedo?

In general, replace R7 with 11kΩ
EUDM <1995 = 13kΩ
USDM >=1996 = 12kΩ

This is rough notes. It would also change on the sweep on the gauge being installed...there are more than I'd like to think about.

The "we've" still doesn't fix the calibration that you will need to go through too.

Here is what "we've" is on track to do:
-disassemble entire cluster down to component parts, which is risky
-modify USDM circuit board. Replace resistor on PCB
-install NSX-R gauges on USDM PCB, reassemble, risky
-calibrate

Then do the opposite with re-making a 1997 cluster unit with your NSX-R boards. Replace resistor and go from there. Lots of risk with a ton of extra points of failure for not real reason.

You can DIY calibrate here

FYI, I have an early NSX-R cluster. I have examined the PCBs and they are customized over the standard board. I don't know why, but there are a few less components and there is technical handwritten notes on the board. I do not know what is the reason for the factory modification. I suspect the later NSX-R would be similar.

Highly recommend using the NSX-R boards and swap out ODO and trip meter only.

There is no reason not to do so as you have a 1995+ vehicle. Most NSX's on the road are <=1994, hence Mita's advice to use the previous board, the pin out is different as well. You don't have that problem.