Quick Coolant Reroute Question
 

'96 1.8L going into a '92 chassis. Going to be running MSPNP2.

On the front coolant neck, do i use a 90-93 block off plate or 94+? From what I have seen, most guys run the 94+ block off plate without the therm switch hole. I'm assuming you just don't use that sensor anymore from the stock 1.6 harness?

remove neck, add water plug and block off plate.

im still using coolant feeds for a turbo.

It really depends on how you have your MSPnP is configured.

If you set up an output of the MS to provide a closure to ground on pin 1R of the stock ECU connector, and configure it to close when CLT > [setpoint] (with a little hysteresis), then you can eliminate the front neck and run a solid block-off plate, or use it as a water source for the turbo. This ECU wire is functionally parallel to the thermoswitch:

https://www.miataturbo.net/attachmen...ine=1455556506

https://www.miataturbo.net/attachmen...ine=1455556506

I don't have the pnp2 yet, so the wiring diagram is new to me.

My brain was a little scrambled when I wrote that. I thought you were talking about a DIYPnP.

The MSPnP2 is already set up to control the fan. Go to the very bottom of the documentation (here) and look at the section for jumper J8. You'll need to install that jumper, which is not present by default, and the ECU will control the fan. You may then remove the thermoswitch.

https://www.miataturbo.net/attachmen...ine=1455557622

Appreciate it!

then just block it off and still use it. or source from the port just above the oil feed.

Thanks for the suggestions.

The cool-kids way:

https://www.miataturbo.net/attachmen...ine=1455561432
(Image stolen from BEGI)

An NPT barb or -AN fitting is screwed into the hole, and water for the turbo is sourced from this point. The line is connected to the top of the turbo, and the outlet water from the bottom of the turbo is plumbed into a low point in the system such as the mixing manifold.

This routing encourages convective circulation of coolant through the turbo after the engine is shut off.

https://www.miataturbo.net/attachmen...ine=1455562281

I'm just gonna go this route and not use the front thermo switch with the MSPNP2.