Us Dave’s get asked about this popular product a lot, so here’s a look at what it’s all about.
Yes – and probably more than you’d think. For the cooling system to work correctly there must be air travelling through it, removing the heat from the fins on the radiator’s core. To do this efficiently the air must be ducted in a way that it can’t escape around the side of the radiator. Air will always take the path of least resistance, and it’ll want to go anywhere it can before it goes through those tiny fins on your radiator.
It’s no secret that Mazda did a pretty good job of this by designing a plastic moulded under tray that very neatly ducts most of the air through the radiator from the opening in the front bumper.
But I’ve got this awesome under tray that was designed by Mazda, why do I need anything else?
So you’ve ducted the sides, and the underneath of the radiator works pretty good for normal day to day driving, but what about on a track? And some extra horses?
Okay Dave, we get it – there’s a gap at the front of the engine bay where air is escaping and if I cover it up there’s absolutely no escape for it. That’ll increase the efficiency of my cooling system.
I’m still not sure, other cars don’t have cooling panels? Why does my Mazda need one?
If you look in front of the radiator on many other cars, they have a rubber ‘dam’ like you’d get on a door or boot lid seal in a strip along the front of the slam panel. This is an excellent way to prevent air from escaping over the top of the radiator, provided the seal is in good condition. It also weighs very little, these car designers are pretty good! Typically, a car with this kind of seal will benefit very little (if at all) from a slam panel cover other than for aesthetics.
The MX5 doesn’t have this strip, as the bonnet seals against the front bumper, exposing a large gap.
I’ve got a cooling panel on my very late MX5, it’s designed by Mazda and made of thin plastic – I don’t need your aluminium panel!
We also had an OEM very late model plastic panel. They are very soft with several cuts for different vehicle options, such as the large hole for the washer bottle fill position on ABS cars.
On our original prototype we used the OEM plastic fasteners, because they’re super light, and they work great. Or so we thought. One day we opened the bonnet after a spirited drive and to our surprise the aluminium panel had pulled every single fastener out of the slam panel. We changed the design to bolts. During back-to-back data logs on the same day, the same car saw peak temperatures drop by 11 Degrees C. These days, we only supply quality stainless fasteners with every kit for this very reason.