Flyin' Miata : Redesigning the turbos

Before you ask...the new turbos will be available when they're done. Due to the nature of development like this, we cannot give solid timelines or availability dates. The first pre-production kits will be shipped to some customers as test units before the end of September.

Flyin' Miata is redesigning their turbo systems. Why? While we had worked to refine the old designs for years, there were still some problems with quality and fit consistency. Using modern CAD technology, we knew we could improve the function of the parts while using much more accurate production techniques and better materials. As an added bonus we should be able to bring the quality and performance up without affecting the pricing. Dan Bond, an experienced aerodynamicist and member of the original Ubercharger design team, is working closely with FM to add his knowledge and expertise to our new designs. There aren't any other companies out there with both our long experience with Miata turbocharging and deep understanding of engine management.

The manifold has been reworked with a close eye to internal airflow. We did all the design work in SolidWorks and then had a plastic version made on the world's coolest 3D printer. When this piece was offered up to a cylinder head, it fit perfectly the first time out and there was enough room to put a box wrench on every nut on the manifold. That's more than we could say for the old parts. It also retains the turbo mounting location we have used for years so it can be retrofitted to existing kits.

The turbine outlet housing has been extensively redesigned but again is backwards compatible with older kits. It looks a little odd, but allows us to have a divorced wastegate exhaust to smooth out airflow at the turbine outlet and keeps the two air streams separated right from the start. There's no complex and error-prone fabrication required, it simply bolts into place. This improves reliability as well as accuracy. As with the manifold, careful attention was paid to ease of installation, so a box wrench can be used on each nut.

Both of these parts will be cast from NiResist. This alloy has extremely good temperature resistance and corrosion properties. In fact, it's the same stuff the hot side of the turbo is made from. The castings are being made using the shell casting technique. This process is so precise the parts will need minimal machining, eliminating another source of potential inaccuracy and installation headaches.

All intercooler piping will be made from CNC mandrel-bent polished stainless steel or custom moulded silicone hoses. We will be offering multiple intercooler designs, all of which will be more efficient than the previous designs. The more conventional ones are long tube design with polished cast end tanks and we have one that will be truly cutting edge. Sorry, no more information there at the moment.

The current status? The intercooler piping is now on the shelf and we're waiting for a few of the production hard pipes to come in. Airboxes should be shipping to us next week. We're fine-tuning some details on the manifolds.

Photos (newest at top):

The 1990-93 throttle body inlet pipe.
The 1994-97 throttle body inlet pipe.
Parts on the shelf! There are several towers of intercoolers in another part of the warehouse. This pile consists of downpipes, IC inlet and outlet hoses and IC mounting brackets.
The intercooler piping at the IC exit. The amount of trimming required is visible here. And yes, we know the clamp is missing!
The view from underneath. The trimming to the stock plastic is minimal and easy to do. Everything is mounted up out of the way and the IC can't be moved by hand. Due to the retention of the stock plastic, there's no extra ducting required.
The intercooler in place on a customer car. It's not obstructed by the nose at all and doesn't hang low. The end tanks and mounting system cause minimal restriction of air to the radiator. The FM stencil is optional.
The hose clamps that will be used on the kits.
A little bit of bragging.
Checking dimensions on the final prototypes.
The final outlet casting.
The turbine outlet casting. This part is in NiResist and the quality of the casting is excellent. In fact, it's arguably better than the turbocharger we bolted it to!
Intercooler and compressor outlet pipe. The pipe is made of Nomex reinforced custom formed silicone hose. Why? Because it insulates the charge from the heat at the exhaust manifold, it's easy to install, it cuts down on the number of potential failure points for the hose to blow apart and it allows full engine movement. 6 clamps and 2 joints are eliminated.
Downpipes! With a shared front section, we have four possible rear sections for 1990-93, 1994-97 and 1999-05. What's the fourth? It lets us use a 1994 catalytic converter on a 1990-93 car to avoid a bottleneck caused by the stock flange size seen on the bottom pipe. There's no need for a flexible section in these pipes due to the accuracy of fit of everything else, eliminating a heavy and expensive point of failure. We've also eliminated 7 welds. These stainless steel prototypes are not polished but the final parts will be.
A raw casting versus a finished unit. The machining is done by CNC to ensure consistency.
From CAD to rapid prototype to metal. A test casting (grey) compared to the plastic version. It was cast using a less accurate process than the final and is not made of NiResist, but the important dimensions are the same. Final pieces will have a much nicer finish and will not be grey!
The final CAD model for the exhaust manifold. The individual runners can be clearly seen.
We paid attention to internal flow.
We also paid attention to installation, ensuring there is room for fasteners wherever necessary.
The CAD modelling process allows us to peek inside the manifold to ensure everything worked well.
The manifold has been designed to allow fitment of an external wastegate if desired.
Our rapid prototypes allow us to ensure the digital models work well with reality.
There are some small details that don't show up well on models. That's why we invested in the rapid prototypes.
The two air channels are carefully managed in the turbine outlet housing.
The protrusion on the housing is to seal the wastegate stream from the turbine outlet. This ensures minimum turbulence and maximum efficiency without the packaging hassles of an oddly-shaped downpipe such as the one we investigated on our racer.
A detail you don't appreciate unless you've tried to install a part without it - clearance for tools.
A peek at the rapid prototype. This was made from an earlier model with a shorter divider.