1990-05 Flyin` Miata shock tower brace
Cars with strut suspensions rely on the top of the strut towers to maintain their suspension geometry - and inconveniently, there`s usually an engine between them in the front. So strut tower braces are very popular to improve the handling on those cars.
But a Miata has a double wishbone front suspension. The top of the shock tower is mostly taking vertical loads. But there`s still a big hole in the middle of the engine bay, and that means the structure of the car suffers in this area. Joining the shock towers together with a well-designed brace will improve steering feel and cut down on cowl shake when you hit a bump.
Of course, the brace has to be designed properly. There are a lot of cheap ones that are simply shiny jewelery for the engine bay. The cross bars are very flexible, there`s usually a bolt in just the wrong place that acts as a pivot and the towers are flimsy. Some also "triangulate" to the thin metal at the top of the firewall, but there`s no structure to tie into there.
Mazda knows this. It`s why, when they designed the brace found on many 2001-05 Miatas, they put two vertical bolts on each side with a nearly-straight bar in the middle on top of beefy towers. And it`s why our bar is designed along similar lines. Ours, however, will fit under the hood of a 1990-97 model as well as the later cars.
We didn`t just stop with the design, though. We made the parts out of High Strength Low Alloy steel, which gives more strength for the same weight. This makes the brace even more effective. The bars are finished in wrinkle-coat powdercoat.
1990-05 four cylinder with most turbochargers and superchargers. Not compatible with the M45 supercharger kits, unfortunately.
Does not fit:
air intakes that sit on top of the shock tower, such as Racing Beat
LS engines with an insulated intake manifold
Here`s a comparison of a cheap bar versus the FM unit. You can see the "pivot bolt", the weak tower design and the big bends in the bar.