The weather here in New Mexico was brutal hot for the past few weeks. I drove Sharka and tried to use the weak a/c a few times. It… sorta helps. You know, on the hottest days, it’s better than nothing. It’s still not spectacular and only runs about 10 minutes before cutting out.
Since the rebuild, Sharka has run a 37mm Koyo radiator. It’s been a good radiator, but in the hot heat, it’s pretty marginal. Ducting and a coolant reroute allow it to be “enough” but… it’s not fun. Add a hot condenser and it really isn’t enough to cool down a turbo Miata in 110*F New Mexico traffic.
The last straw came after a particularly hot drive home. I parked, got out, and was greeted at the door by my little girl. She smiled at me real big, looked down at Sharka’s nose, and said “Sharka peed.”
The old Koyo radiator had finally cooled it’s last.
I replaced the Koyo with Flyin Miata’s crossflow radiator. It’s a lovely unit. According to FM’s testing, it’s the most efficient radiator you can buy. That’s gotta be worth something, right?
Honestly, I’ve wanted this one for years. I installed the Koyo about 3 months before FM put their crossflow on the market. Many dirty words were spoken.
But now I have one.
I bought a new fan shroud to go with the radiator. I already had the Stage 2 Airflow Kit and have been very happy with it. No need to get new fans. But a custom made shroud to go with the radiator? Yes please.
The fan shroud is slightly shorter in addition to having different holes for the more corner-oriented rad inlet and outlet. It’s not much shorter, under 10mm in total size difference, but it’s nice having something pre-made that I didn’t have to hack up.
Ignore the hacking on the old fan shroud. That’s a different story.
The edge of the fan shroud closest to the rad inlet was the one trouble spot. It was too close to the inlet to allow a hose to fit on. This wasn’t much of a problem though. Tin snips took care of that edge and a bit of filing took care of sharp edges.
The fan mounting boss nearest to the radiator inlet tube is really in a perfect spot. It’s just far enough away to allow a hose and clamp to slide onto the tube with ease. No forcing was required. I was impressed by the tight tolerance and good fit.
Really, everything fit well. The radiator dropped in easily. Nothing required banging. There were no surprises.
Well… almost. The FM crossflow rad is universal for NA and NB. If you have an NA, you have to add on the side radiator mount pieces (barely visible above). I truly didn’t know these were separate pieces and was scratching my head while swapping them. Even after working on these little cars for so long, there’s always something new to be learned.
With the hood closed, the radiator neck juuuuust touches the inner bulge on my Garage Vary hood. The hood closed completely, but it was a pretty firm touch between the two parts. I didn’t want to be applying pressure to the rad neck for its whole life when I could easily cut a relief hole.
So I cut a hole in my rare, freshly painted, Garage Vary hood.
It was only in the lower skin. This bulge in the hood really is quite thick. I had to trim my intake heat shield months ago when I decided to start using the hood. Worth the effort though.
As for cutting it – super simple. I drew a circle around the trouble area and did a few quick cuts with my Dremel. A little sanding cleaned up the edges and a little paint took care of bare fiberglass. It was barely 10 minutes of work.
I don’t have to use it too often, but my spill free funnel always comes in handy. Even though it has “spill free” in the name, I always have a towel handy to soak up any stray coolant.
I mixed up some 70/30 coolant and filled up the radiator. I fired up Sharka and a dozen fan cycles later, 99% of the bubbles were out of the system. Nothing to it.
I installed this radiator about two weeks ago and have been driving quite a bit. It’s amazingly efficient. Cruising temps are around 86*C, which is about a 4* reduction from the Koyo’s cruising temp of 90-92*C. It warms up pretty quickly at stop lights, but cools off again once we start moving again. No bad behavior has been detected.
I’m really impressed. FM has made a great radiator. I should have bought it years ago when it came out.
Thanks for making great parts, Flyin Miata!