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Complete Upgrade! Part One. July 2010

If you've read through the site and the previous updates, you'll see that I've enjoyed all that a turbocharged Miata can offer. But as the title suggests, I needed more! I really enjoyed the car with the old turbo setup and drove it all the time, rarely missing an opportunity to tap into the extra (and much needed) power. But as many of you can relate to, work got much busier, the family was growing and in January 2009 I decided to sell all of my turbo stuff. I sold it all because I planned to sell the car. What can I say? As you get older, a weekend toy car like this just seems impractical and a luxury that I could do without.

I posted it for sale locally and had great offers, but something told me I'd regret it years from now. At the 11th hour I decided to keep it. I still drove it often, but the stock 1.6 was just a terrible soul-sucking horsepower void that could no longer be tolerated.

I'm now re-turboing it with a setup that has much more room to grow than the old Greddy turbo and manifold that I had before. That turbo was great for modest low-end power, but given the unique manifold/turbine inlet, there were no upgrade options. Bummer. So I put together a plan that would give me great flexibility in turbo selection, excellent performance, solid reliability and low cost. Sounds impossible, right? Well, it can be done and the Miata is an excellent platform to make it happen.

Let it begin! The first hard part I got my hands on was a new cast iron turbo manifold. I found this unit on Ebay, and although you have to be wary of auto parts found there, this is a solid manifold with many happy users who've logged a bunch of miles. It uses the standard T3 flange, which means the turbo combinations are practically limitless. Miata turbo manifold

Here it is mounted, with relief cuts in place. The fit is perfect! Far better than I expected. miata turbo manifold installed

The next part I got my hands on was the turbocharger. Given my strict budget, I decided to try an Ebay turbo. I was wary, but I chose this completely based on the positive feedback that others have shared on the miataturbo.net forums. I also went a little bigger than I originally planned, but the low cost of this turbo means that I now have room in my budget for something smaller if this is too big and laggy. I am going to give it a try and see how I like it. That's the beauty of this manifold - a million affordable (and not-so-affordable) options are out there.

I chose to start off with an internal wastegate turbo for budget reasons, but will likely end up with an external wastegate setup in the future. As you can see below, this turbo features a handy V-band outlet which makes removing the exhaust for maintenance or turbo swaps very simple. This turbo was advertised as a .60 A/R Compressor and a .63 A/R turbine. Not tiny, that's for sure.



After pulling the turbo out of its box, I made a few tweaks before bolting it up. First off, I decided to check out the internal wastegate mechanism and saw some room for improvement. An old DSM trick is giving the flapper arm more room to travel/open. Here's how it looks out of the box - not much angle there.

So by grinding out a little divot in the wastegate housing...

The flapper can now open at a much wider angle.

I've never met an internal wastegate port I liked. This one was no exception.

It's hard to capture this kind of thing on camera, but here's the port after enlarging it and smoothing it out. On the internal wastegate DSM turbos I've modified in the past, I really concentrate on the flow from the turbine inlet into the wastegate port. It is now opened WAY up.

Here's the turbo mounted up and clocked. This manifold places the turbo in a great spot in the engine bay with plenty of room for a nice downpipe setup. I will say that the compressor outlet piping is going to need a couple bends, as the power steering reservoir and headlight motor are fairly in the way. I'd have more clocking freedom without the internal wastegate actuator, but I'm going to give it a try like this.





I got the downpipe completed. It wasn't bad at all, it's 2.5" piping and the v-band makes it so nice! I'll definitely go the v-band route on everything I build from here on out. In this update, I included some pictures of me doing this stuff, I thought y'all would enjoy it. I gotta tell ya, a weekend in the garage taking on a project like this is as good as it gets for me.

Once I picked the right spot for the 02 sensor, I drilled into it a few times until I got the hole the right size. downpipe fabrication

Here's the 02 bung mounted and ready to be welded. This was from Summit Racing and has a nice step to hold it in place. o2 sensor bung

Here I am welding the 02 bung in the downpipe. God, I love throwin' fire! If you don't yet have a welder go get (a decent) one today, you won't regret it.

Here's the downpipe completed and sprayed with some high heat ceramic low gloss black. I am doing a slip fit at the end of it.

All done! I wrapped it in some black header wrap and secured it with hose clamps. I've tried the metal zip tie things that are made for this, but they are a huge pain in the butt - in my humble opinion.

See how it all turns out - check out Part Two of the build!

Thanks for reading!

-Tom