We've taken our crossflow radiator back into the shop to see if it could be even better than it already was. The filler cap is no longer on a neck, it's now right on top of the tank - which gives much faster filling than having it cantilevered out off the tank. It's a cleaner look and better fitment (especially on MSMs). It also has an honest drain, not a small drain squeezed into a compromised location.
For manufacturing, we worked with Koyo, who brings well over half a century of experience to the table, to see what could be made better. Working with Koyo means that the latest version of our crossflow is manufactured by Koyo (not a third-party), has beautiful TIG welds, micro-welded O tubes (stronger and more reliable than B tubes), and NOCOLOK brazing for maximum durability and anticorrosion protection. We then use Koyo's Hypercore, which increases the effective surface area - i.e., the radiator's ability to shed heat. Finally, each radiator is individually leak tested three separate times to ensure no issues. To top it off, we back it up with an exceptional two-year warranty.
But even though we're taking advantage of Koyo's manufacturing, it's nothing like the generic Koyo radiator you find elsewhere. The crossflow design, the drain, the core selection and the unique mounting setup in the car all set it apart.
Now that you know why the new crossflow is the best one over, why do you want a crossflow in the first place? In short, dramatically improved cooling. The coolant flows side-to-side instead of top-to-bottom, which means that it's in the radiator core (and shedding heat) for longer. Not only is the layout much better, the core itself is special - in our extensive testing (read more about it here), not only did we find that generic upright aluminum radiators weren't much better than stock, we also found that dense tube and fin counts, as well as narrow fin widths, cooled best. So that's what this radiator uses. We also found that while a thicker than stock radiator is better, there's absolutely such a thing as too thick - eventually, the thicker core just means more resistance to air flowing through the core, plus the air is so hot by the time it gets to the back of the core it's not doing any good anyway. A thicker radiator makes a better heatsink, but you're not looking for something to absorb the heat, you're looking for something to shed it. Ours hits the middle ground nicely at 36mm / 1.4" thick. You won't find a radiator that's better at shedding heat than this one. Mate it with our FM coolant reroute and our Stage 2 V2 brushless fan kit, and you'll have the ultimate cooling setup.
We also designed the radiator to fit all 1990-05 Miatas, with the only difference being some brackets. There is no modification required to install the radiator in the car - the factory mounts are used in NAs, new upper mounts (with stock lower mounts) are required on an NB. A new high pressure (16 psi) radiator cap is included, and you can use any cap designed for a Miata.
If you choose to retain the stock fans, you'll need to make modifications to their shrouding. We highly recommend using one of our Airflow Kits for multiple reasons. May not fit with all intake systems - please call us to confirm. Does NOT fit with a TDR intercooler on a supercharger.
NB cars will need our upper bracket kit (not necessary for NAs). NB cars using stock fans will need our NB fan bracket kit as well. If you're not using a reroute, you'll need a crossflow-specific upper radiator hose - this radiator fits really, really well with our reroute kit, though.