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Turbocharger install- August 2008

One hurdle that I had to face was the header that the original owner's husband installed. When he installed it, he removed the cat and had a straight pipe bent and welded between the header and the rest of the exhaust. This was fine, but there were exhaust leaks all around the welds, which made the exhaust whistle, pop and make other unpleasant noises.

Due to this I was forced to modify the Greddy downpipe. While I was going to do that, I figured it would be a great time to fab up a 2.5" exhaust also. Here are the parts that I got together for the install. That pipe on the far left is the factory "mid pipe" from an Evo 8. I think I may use at least the first part and the resonator since its 2.5" and has a nice flange on the end.

Before I started on the exhaust, I wanted to get the header out of there. Here's a shot of the header gone and the oil feed line installed. I also installed some new NGK plug wires as the no-name yellow ones that were on the car didn't even fit into the wells correctly.

After looking at (and being unimpressed with) the length and routing of the stock Greddy oil drain hose, I decided to tap the pan. I hunted around and was able to find a 3/8" NPT to 5/8" hose end fitting from NAPA. I also picked up a 3/8" NPT tap and 37/64" drill bit. The job wasn't too bad, but I did lower the steering rack and let it hang by the tie rod ends. This allowed me to get a straight shot at the pan. All told, the job went smoothly. I'll post a pic of the fitting in the pan later.

Here's a shot of the turbo mounted. For those with keen eyes, you'll see that I chose not to use the Greddy oil drain fitting. Being a hardcore Mitsu-head, I had an oil return line from a DSM lying around that I never used. I used the top part of it to bolt to the turbo and cut off the other flanged end and mated it with the 5/8 oil drain hose. I liked this because it got the hose away from the hot turbo and with the flex-section in the tube, I could angle things how I wanted them.

This also came via UPS yesterday. I'm not sure if I'm going to install this right off the bat, but I wanted to have it to start taking measurements and look at pipe routing options.

Here's a shot of the Greddy downpipe with a few modifications. As mentioned above, there was no cat on this car, so in order to better accommodate the transition to 2.5" pipe, I changed the angle of the outlet and welded in a 2.5" adapter. I also wrapped it to try and keep the heat down to a minimum.

Here's the finished downpipe with the flex section and 2.5" flange welded in. The pictures do it no justice, but it's tucked up in there good with plenty of clearance all around.

I know that I mentioned above that I may wait and install the intercooler, but given my experience, I just couldn't imagine not doing this while I had the chance. Here's a shot of it in position (more or less) while I fab up some brackets.

Here's another shot of it in position. I trimmed a little bit off of one side of the hood latch support in order to get this puppy tucked up inside the nose.

I've dealt with some tight engine bays, but space is a premium in these cars with air conditioning and power steering. I needed to see some daylight in order to start running the hot side piping, so I removed the driver's side cooling fan and p.s. reservoir. I may relocate the reservoir, but I'm not sure yet. I'll probably end up going with a slimmer aftermarket cooling fan also.

Here's a picture of the fan I ordered from Summit Racing compared to the stock fan. Replacing the fan wasn't 100% necessary, but it sure did free up room to install the hot side turbo piping.

Below are the upper brackets that I made to mount the intercooler. They are pretty simple, but strong.

The intercooler mounted. You can see the passenger side bracket, but the driver's side is barely noticeable. I used two holes that were already in the factory core support. It's like Mazda stuck 'em in there for this purpose. To get to the bolts, I loosened the four 10mm bolts that hold the condenser in place.

Here's the intercooler piping after being welded up and painted. I've done this on a few cars and found the Miata to be fairly simple. I re-used a 1G DSM blow off valve and flange that I had lying around from another project. The section of hose is Napa truck radiator hose. It is 2.5" and is very tough. It comes in a variety of bends and is affordable compared to the same part in silicone.

Pic of the intercooler piping being test-fitted. You can see how much room is freed up from the slimmer cooling fan. I didn't have to relocate the power steering reservoir thanks to using 2" piping on the hot side.

Pic of the engine bay with the turbo re-clocked and all intercooler piping installed. the lovely orange couplers will be replaced with black ones soon, they're all I had on hand at the time.
Also, I had accidentally overlooked the small throttle body bypass hose, so I welded a little section of pipe to the IC pipe that leads to the throttle body. Also, the blow off valve will be plumbed back into the intake.

I was thrilled that the front end didn't have to be removed for this install. Overall I am happy with how it came out. I'll probably paint the clamps black so they aren't as noticeable. I still need to modify and install the stock plastic under trays, which will require a little trimming here and there.

The last thing I took care of was the Vortech FMU. This was a piece of cake. I still have to plumb the vacuum lines to it and the boost gauge.

It was a perfect day for doing some welding. Unseasonably cool and low humidity made it much nicer to work outside. Here's my setup. It's simple, but I highly recommend a Lincoln if you want a good entry level welder.

I was really flying on this thing, so I didn't take a bunch of pictures throughout the process. Here's a pic of the system finished and waiting for paint. Don't you love my exhaust stand/empty cat tree box?

Here's a shot of the exhaust all finished with a coat of dupli-color low gloss black engine enamel. I always spray my exhaust systems with this to avoid any rust and to make it blend in under the car. For paint out of a can, this stuff is tough and durable. You can also see that I was able to use all of the factory hanger points.

Done! Being able to drop that little brace on the rear is key. In fact, I'd like to hug the Mazda engineer who made that a bolt-in piece. As you can see, the system tucks up in there pretty good and the tip is just a good old piece-o-pipe.

Another shot of the tip. Stealthy, no?

The last thing I did today was whip up a 3" intake pipe out of some pieces I had from a car that I sold. I welded them up and put in a BOV recirc port and nipple for the valve cover vent. The intake isn't complete here, but it should be done tomorrow. On the BOV return, that is a stock return hose from a DSM with another small extension on the end. It's almost like it was made for this car!

It's alive!

Here's a short video of what the exhaust sounds like. I plan to get some better video soon, this was filmed with my camera. The exhaust sounds so much better than I imagined! It's sporty, but not loud or raspy at all. I'm very pleased with it.

I still have some things to do in the short term, (install water injection, heatshield, wideband, etc) but it's to a point where I can drive it easy and break it in for the next few weeks while I tackle each one of these items. Heck, I've even got a full tank of 87 octane that I need to run out.

I am calling this phase 1 and will be developing my plan for more boost and fuel.

Here are a couple pics of the engine bay. I haven't had time to actually detail things under here, so it's still pretty filthy. I hope to get it shined up in the coming weeks.

So how does it run? The video below says it all! This is at 5psi of boost.

Thanks for reading!