This car was already running an aftermarket air filter with a heat shield partition that sealed against the bonnet when closed - but having a full cover makes it street legal and avoids hassles.

It’s made from 1.6mm aluminium sheet, and attaches to the existing partition and a headlight bolt. There is also a hole for the air filter mounting, replacing the original bracket.

Here’s a photo from a nice angle. The Silvia on the left is waiting for an engine and a few other jobs, and will hopefully be on the road soon!

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.

One thing people tend to add to modified engines is a catch can, which separates oil droplets from the crankcase ventilation hose to stop them being fed back into the air intake and burned.

Most catch cans are just a can, which fills up over time and needs periodic draining, which is messy and annoying - especially when it happens quite frequently on race engines!

Some engines actually have a catch can setup from the factory that returns the oil to the sump. This one came from a turbo diesel engine.

The oil return needed somewhere to go, so I made up a T fitting into the turbo oil return line.

This setup is still a bit experimental, but it will be interesting to see how it goes. The main concern is that if there is too much oil in the turbo oil return it could cause a restriction and force some oil past the turbine oil seal.

In theory there will be no difference in pressure in the system, but if there is too much flow from the catch can it could potentially cause problems.

Aftermarket exhaust systems often put a lot of stress on turbo and manifold gaskets because they add extra weight and are much more rigid than the small diameter factory piping.

Hard use, especially on the track, can shorten turbo gasket life to hours!

This exhaust already had an ugly join where smaller diameter pipe had been used to lengthen it in the past, so I was able to cut that section out and replace it with a stainless steel flex joint. This should allow the rear half of the exhaust to move a bit without levering on the turbo.

A nice quick job, just a pair of aluminium brackets for a race seat.

This car is running a 2L turbo Cosworth engine, and the old exhaust had proven to be a bit too restrictive for the desired power output.

I made up a 3″ stainless pipe and a custom 3″ straight through muffler. The casing is 0.6mm thick stainless steel so save weight (most mufflers are 1.6mm or so) and it’s a lot longer than a normal muffler, to keep the noise levels down.

The front end cap is riveted on, so it can be removed to repack the muffler with new insulation material if necessary in future.

This time it’s a set of GTR Brembo brakes on an S15 Silvia (200SX).

It’s the same story as the handbrake cable adapter plate I’ve made before for S13s (180SX / Silvia) but it turned out that there are some differences in the handbrake cable mount areas on the car.

Fortunately I didn’t just make one from my previous measurements!

This is the adapter plate. The studs on the plate hold the brake lines, and the slotted holes at the bottom of the picture mount on the original studs in the car.

Note the slight bend in the middle, necessary to line it up with the shape of the car chassis.

This is the plate installed:

The brakes were shuddering a bit on this car, so while the rest of the work was being done I sent the brake discs off for machining.

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

One common issue with aftermarket exhaust systems is that they don’t tend to be as flexible as the factory ones (a side effect of larger diameter pipes) so they are more prone to cracking - especially if they hang lower than standard and hit the occasional driveway or speedbump.

This one had cracked most of the way around the separate wastegate pipe, and partly around the main pipe. I gave the cracked area a good clean up, welded it back together, and added a bit of reinforcing on the outside - which will hopefully stop it cracking again for a while

A common modification when turning a street car into a race car is to move the battery out of the engine bay and install it somewhere further back.
It helps with weight distribution, and frees up space under the bonnet.

The process is pretty simple, with the main hassle being installing a long cable from the engine bay to the new battery location. It needs to be protected from damage and not get in the way of any moving parts.
The owner of this car (a 180SX) had already run the cable through the chassis rail and into the boot, so I just had to mount the battery and finish the connections.
I also installed a battery isolator switch, which makes it easy to disconnect the power in an emergency or to stop it running flat if left parked for an extended period.

The battery needs to be very strongly restrained, especially if it’s inside the cabin - and usually should be a sealed type.
This one is a 40Ah sealed lead acid battery. The mounting strap is 25×33mm steel with 8mm bolts holding it in.