DIY Reroute

[Otaroko]

Im looking at doing the simple reroute on a 96 NA8 by way of switching the front and rear covers without a spacer. Blew one of the devil hoses today because I was too lazy to change it when I changed everything else a while ago so Im looking to improve efficiency while Im in here.

I have a couple of questions though:

1) For the temp sensor, would extending the harness and installing it in the cover at the front of the engine be okay? I was looking at the rear of the engine and there is a bolt head plug just above the outlet line to the "oil cooler" that I have seen one person use for their sensor but it seems that most people have no idea what this plug is for.

2) Would routing the heater core as I have illustrated, with the heater core inlet routed to the front where the t-stat is originally located be detrimental in any way?

Feel free to chime in with any criticism or experience!:banana:

Simple diagram of planned reroute
Planned reroute.jpg

Picture of bolt plug. It is situated above the outlet being pointed to.
m2_head_rear_plug1.jpg

[amaff]

I can't answer your heater questions because I deleted all of that before ever doing the reroute, but since you're going the DIY route I will tell you there's a Cadillac Escalade upper-radiator hose that, with a little trim on each end, will run from the back of the head, under the intake manifold and to the Miata's upper-radiator inlet. It removes a LOT of the failure points that most reroutes (kits or DIY) introduce with a different hose on each end and a pipe between the 2 to connect them.

I don't remember where I have the part number written down, but if you ask for an upper radiator hose for a 2002 Cadilla Escalade it should get you what you need.

Keep a couple of cutoffs from your old radiator hose to use as guards for the hose anywhere it gets near hard objects to prevent chaffing. Zip tie them on and they'll protect the new hose, now running where Mazda never intended a hose to run.

[iscariot]

Coolant Temp Sensor affects fueling and fans. Installing it in the head means it'll react slower due to the thermal mass, so you might have hot start issues and your fans may run longer than need be. That's why they're installed in relatively smaller bits.

There's a restrictor for the heater core in the pipe that runs underneath the exhaust manifold. I ran a sorta similar setup when I did my hodgepodge reroute - sourced from the back of the head via m-tuned reroute to the lower radiator hose - but I had very little heat. I had to install a valve from a toyota to restrict the flow some to get any heat.

And I would discourage using any long hose - it's a lot easier to snag some pipe and cobble up a bead to it.

[amaff]

And I would discourage using any long hose - it's a lot easier to snag some pipe and cobble up a bead to it.

Not sure I understand that...how is trimming the ends of a single rubber hose more difficult than running 2 hoses with a pipe connecting them, that you then need to roll a bead onto to keep the hoses seated, and in so doing more than doubling the possible points of failure (ie: connections and parts) in the system?

[iscariot]

On my old setup I mounted the pipe to the intake manifold with some cushion clamps. With that setup I didn't have to worry about any hoses getting rubbed and was able to run regular preformed hoses that I could route around my IC piping without anything touching.

[amaff]

To each their own. Mine doesn't really chafe on anything, but I did put shielding on to make sure that doesn't happen under load & heat. Any possible rubbing is easily mitigated like I pointed out. Most of the racers I know who run reroutes run the single hose because you only have to worry about 2 connections and 1 hose. Not 4 connections on 3 different hoses.