This car had a whole list of things to do, and is going to be a very nicely set up track car that’s also usable on the road.

The main things added were power steering, some serious chassis braces, and a new ignition system that should work better at high boost levels.

I also removed the air conditioning to save some weight, made up an intake heat shield, installed a larger swaybar, race seat, fixed up the two stage boost controller, and sorted out a few cosmetic items.

This is what the engine bay looks like after painting the cam cover, installing the new ignition system, power steering, and the intake heat shield:

Underneath the car there’s a new swaybar, a diff brace, and this rather massive chassis “butterfly brace”

It bolts on over the original chassis rails, then the “wings” link the two. It looks pretty impressive, and being all stainless steel it won’t rust!

The only issue is that it reduces ground clearance a bit, especially in the middle where the brace has to clear the exhaust.

I’ve done a few airboxes for people with exposed “pod” filters - for legality reasons as well as keeping the hot engine bay air out of the engine’s intake.

This one was a bit different because the MX-5’s engine bay is much tighter for space - especially when it has a turbo conversion and a big strut brace across the middle!

I started making up the usual sheet aluminium box, but found that there is not enough width between the headlight motor and the strut tower to fit the filter.

I’ve seen long thin air filters that would do the job, but was unable to source one, so started looking at other options.

The end result was an all stainless steel conical casing that clips on over a base plate, with a 3″ inlet pipe welded in the top. I think it turned out pretty neat, and it matches the rest of the engine bay pretty well.

It’s also easy to service which is nice

Mazda MX5 turbos have a rubber pipe connecting the intercooler outlet to the throttle body.

It’s normally fine, but if you increase the boost it has a habit of blowing up like a balloon and / or splitting the rubber.

Unfortunately there are two other pipes and an air temp sensor mounted on this rubber section - and it changes in diameter from 50mm at the inlet to 65mm at the outlet!

I used a 2.5″ (65mm) 90° mandrel bend, and cut slots in one end so I could reduce it down to 50mm and weld it up again.

Fortunately each of the pipes and the sensor on the original pipe were joined using steel fittings, so I was able to weld those into the new metal elbow and have it all plug in as normal.

The only extra bit needed was some rubber hose to connect between the new pipe and the throttle body.

It ended up looking very factory I think

This was a good job, because it involved driving around in a convertible on a nice sunny

The other part was swapping the factory springs and shocks for Tein and Bilstein items, which is not too difficult on most cars.

The MX5 was a bit of a pain because the front upper wishbones had to be disconnected from the chassis to allow space to get the strut out, and the springs are very long so normal spring compressors are only just usable. There are also a few little brackets in the way of the other suspension bolts which is annoying!

The end result was that the car sits about 25mm lower, has pretty much the same overall feel, but better handling of road bumps. It should handle better when close to the limit now too.