Miata Radiator Replacement

[paultg]

What are folks replacing their miata radiators with, and who are you buying from?
Any fitment issues?

My 1.8 swap ran a bit hot last year (needed to keep the heat on). The current radiator came with the car (it's all metal so it's not original, but it's pretty old I think, at least 5 years old).

I can get a stock replacement for <$70 on eBay. I know it will fit. Thinking of doing more of an upgrade but worried it is not needed and that fitment will be difficult with my 1.8 running stock 1.6l intake tubing and an FM throttle body adaptor.

Paul G.

[jeffw]

Fitment can be an issue. I think the stock radiator is around 1". The stock radiators are terrible. When I punctured my aluminum racing radiator and had to put the stock one back, I was seeing 20+deg higher water temps (over 240degF).

I have a 37mm Koyo and it fits fine with the stock fan and shroud. Before the oil cooler i was seeing 220degF on the hottest days, and the oil cooler helped bring that down another 5-10degF.

Most of the aftermarket aluminum radiators on ebay are 54mm so you'll run into challenges. Some of them come with slim-line fans.

The CXRacing radiators on ebay have a reasonable rep on the mazdaracers site. I also know some folks that have bought this:

http://www.ebay.com/itm/MIATA-MX5-90-97 ... 0639562432

It comes with fans and shrouds.

[jeffw]

Paul:

I know someone that just bought www.ebay.com/itm/180777567295 and it seemed decent. no idea how it will go long-term. Under $140 shipped.

[6PAK72]

And that someone ran it for two years prior until a stone punctured it.

Also, it DOES have an interference issue with the throttle box, so don;t waste your money on the fan shroud - put the fans onto the springs right through the radiator.

You'll see what I mean.

Take a look at #42 of you need.

[paultg]

Thanks guys. I'm hoping to stop by the test day and will take a peak at your setups.

Paul G.

[CP]

Springfield Dyno here. It's considerably thicker than my old Ron Davis units. May have to block it off with cardboard on Friday though.

[paultg]

Thanks Cy, but I'm pretty sure that won't fit. It looks enormous!

My thottle body intake tube (from the air box to the intake) already hits single stock fan I have (on the driver side), and I couldn't keep the A/C fan because it didn't fit anymore. - Paul G.

[CP]

You could always modify the plastic "cage" that the fan sits within/remove some material to allow for more clearance. Or change your intake setup. The SD radiator is the thickest one that I could track down. I was pushing coolant temps into the high 230s during a few races last year in August, and that was with ducking out of the draft down the front straight every lap, stock belly pan in place and foam tape all around the radiator to force the air to pass through it. The motor was breaking up over about 6500rpm at those water temps and I don't even want to know how much timing the ECU was pulling out. So I'm hoping that this radiator solves the issue. Looks like I won't find out on Friday 8^(

I've got a good stock 99 radiator that you can have for free, but I don't think it fits a 1.6. Check to confirm and let me know/I'll bring it up for you on Friday if it'll fit.

[dinoracer]

Paul

Just got an email from Good-win-racing, they're running a sale on the Koyos. Still expensive, but at least a little less so if you go that route.

[paultg]

I've got a good stock 99 radiator that you can have for free, but I don't think it fits a 1.6. Check to confirm and let me know/I'll bring it up for you on Friday if it'll fit.

Doesn't look like the 99+ units are compatible with the early cars. But I'll try to see ya on Friday to say hello if I can sneak out of work a bit early.

Paul G.

[paultg]

Paul

Just got an email from Good-win-racing, they're running a sale on the Koyos. Still expensive, but at least a little less so if you go that route.

Thanks Tom. The 37mm Jeff mentioned is on there for $279. A bit more than I want to spend but it seems like this has the best chance of fitting based on internet research. I'll have to take a better look though in person before I purchase. - Paul G.

[CP]

Doesn't look like the 99+ units are compatible with the early cars. But I'll try to see ya on Friday to say hello if I can sneak out of work a bit early.

Paul G.

Green w/ yellow #7, covered with "racing scuffs"...shouldn't be hard to find (in a dry garage I hope)