Just another t25 build thread
 

First of all: A warning! I'm from Germany so my english might not be perfect sometimes but I hope you will understand me.:wavey:

I bought a Canadian 1.6 NA Miata because my old 88 RX7 Turbo II burned down and I was bored and now I just need to get it faster. I allready made a thread about that in the meet and greet section but I think that's not the right place to discuss and ask questions about my build... and I think I will have MAAAANY of them.:rofl:

Here's what I did to my Miata so far:

-changed the original suspension for some Vmaxx Hiltrac Xxtreme coilovers
-new black paint because it was painted horrible
-changed the original silencer for a magnaflow universal one because i had it laying around and the original one had a rust hole in it.
-low profile square headlights and turn signal intakes simply because they look cool:cool:
-RX7 Turbo II front brakes with 280mm 200SX brake disks
-changed the original ecu for aFlyin Miata Link one
-installed an Innovate LC2 wideband O2 sensor
-new gaskets and hydraulic valve lifters for the engine

It looks like this at the moment:
https://www.miataturbo.net/attachmen...ine=1397592996

So all the safety stuff is done now and the car runs great so far. Just not as fast as I want. Now I'm planning my turbo build.

I want to get round about 200hp out of my stock engine and I want to use a T25 turbocharger out of a 200SX. I'm going to weld a manifold and a 2.5" exhaust on my own.

On my list which parts I still need to get before i can start are:

-bigger limited slip differential
-better clutch
-better radiator

Please tell me if I'm missing anything important.

Which leads me to my first big question: I need a reliable cooling system and I've met a friend with a 450 hp Honda Civic yesterday. He had that nice small radiator in the engine bay which worked pretty well for him. I had the idea to buy such a radiator with a big core, put it on the left side of the front of my engine bay and add an oil cooler on the bottom of the right side and an intercooler on top of the right side. Could that work If I build a proper ducting? I thought maybe that could be a bit better than a normal front mount intercooler because all the stuff is not blocking the airflow to eachother anymore.:confused:

Next question: Is the coolant reroute important for my setup or is that more a thing for higher power engines?

And my last question for today: It has nothing to do with the turbo build but i was curious if all NA Miatas are that hard to drive in the rain because mine is breaking out damn easily and I even have new and good rims. Might the Miata be too light on the rear axle? Not enough downforce? I mean it's fun but I never had that on any of my cars before.:rofl:

The coolant reroute will work to even out the temperature between the cylinders for any turbo car. Without the reroute the rear cylinders are much warmer than the front ones and there is a greater chance of detonation.

Alignment and camber makes a difference with rear wheel traction.

The 1.6 rear differential is very weak and often fails at factory power.

The thick Honda radiator has been done before. It can work, but only if everything is sealed from the bumper mouth to the heat exchangers. You are in a cool climate so you will not have the type of trouble with cooling a 200whp car there that a person in the southern US would. An intercooler and a radiator both like to have a longer flow path to cool more before the exit.

I have a very similar build as you. My cooling system is totally stock, and I have had no issues so far. We'll see once summer comes, but I will probably end up with an aluminum Mishimoto anyways.

So do you think it would be better to do a front mount intercooler setup? My biggest problem aren't extreme outside temperatures but long trips at high speeds on the Autobahn with 130 mph and more.
Even with the stock car my temperature gauge starts moving when I'm driving as fast as the car can go for longer times. The temperature isn't rising to critical levels at the moment. It stays at round about 215 to 230°F but I think the stock cooling system is at it's limit.
This is the reason why I'm trying to find the best solution possible for my cooling system. I'm even thinking about doing a v-mount setup but that might lead to some expensive problems. I would have think about a new filler position and maybe even about a custom made radiator...

A coolant reroute goes onto my list...;)

For 200whp there's no need to reinvent the wheel. Get a solid radiator and a coolant reroute, duct it properly, and you will have no problems. Plenty of people run a FMIC in front of their rad at higher power levels than you run in much higher ambient temps.

Ducting is the key. All of the air coming into the bumper mouth must be trapped and forced to go through the radiator. The reroute will help with cooling with no other changes. Try it. Also add an oil cooler. The 1.8 cars all had a factory oil cooler that fit beneath the oil filter. I also use an external oil/air cooler on the track for high temperatures.

130mph in a 1.6 car is red line. For a long time that will be hard on the engine.