Intercooler piping (a series of tubes, like the internet)

Intercoolers take warm, compressed air and cool it before it gets to the engine.  This is good for power and safety.

Intercoolers are essentially a radiator, but in the case of my setup it is air-to-air (no water involved).

Compressed air blows apart piping that isn't well secured, which is why we use T-bolt clamps for it.  Can you see how it got its name?  I had to educate NAPA and Fastenal employees today what these things are, because no one local carries them in stock

Piping can be made of steel, aluminum, silicone, and probably other stuff I haven't encountered.  This is a miata-specific silicone hose made by Flyin Miata for the turbo to intercooler side.  These are very expensive but nice because they are designed to snake around all the stuff in the engine bay that gets in the way.  I got a nice price for this used example on the forum, which is the only reason I have it.

That pipe needs to find it's way from my finger to the green tape.
 

It fits, but will need pieces of rubber tied to it in strategic places to keep from metal objects rubbing holes in the pipe.

 This is taken from the front corner of the car.  The pipe exits the engine bay and wraps around in front of the radiator and AC condenser but still under the nose of the car.

 Ok, this hose is in place - time to tighten it down.

Next is the actual intercooler--27"x6"x2.5" cheap ebay intercooler with 2.5" openings.  I would have normally gone for a higher quality piece but for my power goals this should be sufficient.  Homemade hanging bracket is designed to use the hood latch bolts.  This design may change in the future, but for now that's how it will work.

Hmm, looks crooked, will definitely need adjustment.

The intercooler to intake side will takes three piece of pipe, 2 metal and 1 silicone elbow.  This side also gets the BOV (blow off valve) and IAT (intake air temp) sensor.


BOV - this Turbosmart model can be used for either recirculation or vent to atmo.  It's now set for VTA because I want my car to go "pew, pew, pew" (also I hate running more plumbing than needed and since I'm running a MAP sensor I don't need it to recirculate).  All you do to convert it is to uncrew one of the bosses and replace it with a cap.  Easy.

I had to wire up a used IAT sensor.  I do not like this setup, but it's what is needed with the particular aftermarket ECU I purchased

There was a 3/8" hole drilled in this pipe from the previous owner, most likely for a GM style IAT sensor that is commonly used by megasquirt ECUs.  So I adapted it to serve as a wastegate actuator signal source.  Since it is placed after the intecooler instead of at the turbo, the theory is that the wastegate will always be working to maintain pre-defined boost levels while accounting for pressure loss in the intercooler.  If the signal source was coming before the intercooler, the intercooler would be causing changes in boost that the wastegate doesn't know about. I think this would matter more with a manual boost controller rather than an electronic boost controller...either way I needed to do something with this hole so this works as well as anything.

Water and Oil Lines

Modern turbochargers are water cooled and lubricated with engine oil.  That means making new connections to source and drain these vital fluids between the engine and turbo.

First we need a place for the oil to drain back into the engine once it's gone through the turbo.  That means drilling a hole and tapping threads for a brass fitting in the side of the oil pan.  I probably used about 4 different sized drill bits during the process.  This picture was taken just after I started.

 

One trick I picked up is that while you're drilling holes into the side of your engine, you can use regulated air pressure (~5-10psi) fed into the valve cover and it introduces some positive pressure into the engine, so as you drill, shards of aluminum actually blow out of the engine instead of falling inside.  Most of them anyway.  This picture shows the air compressor hose with a regulator.

 After the hole was done and threads tapped, I JB Welded this fitting into the engine.  It has a 5/8" hose barb fitting on the outboard side for the drain line to slide on.

 

Here is the finished product.  I could have gone with a hard line, or one made of braided stainless steel, but instead I chose a special high-temp silicone hose because basically, it was the cheaper and easier alternative.  It will need to be replaced every 2-3 years, but I don't really track that often so it should hold up fine.

While it might looks like the engine is chugging a cheap beer very fast, this is just the stage where I pour mineral spirits, chased with some engine oil, into the hole I just drilled to flush any remaining aluminum shavings out the oil drain hole.

All of the above was for the oil drain line.  The oil supply line is completely different.  This time I did go with a stainless steel braided line because this line is under pressure.  It is visible on the right side of the turbo in this photo.  The oil is actually sourced from an unused port available on miata engines from 90-95.  This was a relic from when these engines were turbocharged from the factory in the 323GTX.

Onto the water lines.  I had to reroute the lower radiator hose to make room for the intercooler piping but still keep space available for A/C and power steering components.  I ended up buying a 1 piece hose that was designed for a second generation miata, and trimming about 5.5" off the top to make it fit in the new arrangement without bunching up and kinking.  The ratchet extension is pointing toward the subject hose.

The two lines laying over the power steering bracket are the water feed and return lines for the turbo.  I'm not crazy about how they sit right now and will slip a larger hose over them to protect them from abrasion damage from that bracket.

Turbo/Manifold/Outlet Assembly

Whoops, these studs, this manifold, and this turbo were not engineered to go together so some modification is needed\

offending stud has been cut shorter

Stage 8 locking hardware, keeps the studs from backing out

Installing studs using two nut method

I had to tap new holes in the compressor housing to utilize the stock wastegate actuator bracket in new orientation for the miata build.  Also threaded and shortened actuator rod to account for new arrangement.  This is because when this turbo was on a Nissan, the three rotating parts of it were oriented in completely different ways because it was mounted differently on the engine and the compressed air shot up, instead of down, towards the engine.

I had to "oval" out one hole on the cast outlet to have it fit over the nissan T25 exhaust flange

turbo with cast outlet all mounted on exhaust manifold

 Sacrificed banjo fittings from a stock Nissan hard water line for my application

showing water lines and oil drain line attached to turbo

above assembly mounted on the side of the engine.  the oil feed line is wrapped in a bag until it gets hooked up to the turbo

Supporting mods

I've done a few other side jobs "while I was in there".  I don't have any pictures of any of it, but I changed the stock oil pressure sending unit and gauge.  That's because in 1995 Mazda decided to start using a "dummy" gauge that basically only knew "off" or "on" and didn't act like a real guage that measured pressure.  1990-1994 miata's had real oil pressure gauges, so I picked up the parts from a salvage car and installed them.

Here's what stock motor mounts look like.  I replace them with Mazda Competition mounts, which are a little stiffer.

 
I'm also changing out the horrible stock steering wheel with a Nardi leather steering wheel and airbag from a salvage 1999 miata.  This photo also shows the new gauge panel that houses a boost, wideband O2, and oil temp gauges.

You can see the oil pressure gauge in the dash has graduations on it - that's the "new" gauge, the stock 1995 gauge had meaningless hash marks

Top Gear Top Tips

Top Tip #1 -when disassembling car components, first visit your local amish/mennonite bent 'n dent grocery store and pick up a box of 50 plastic bags for 25 cents.  Hardware from each major component gets stored in it's own bag.  For best results, scrawl the labels so that you're the only one that can read what it says, leaving you in charge of the project.

Top Tip #2 - When taking apart rusty bolts, some will snap.  Don't get frustrated, get even and purchase power tools to exact your revenge. 

The Dremel isn't new, but the right angle attachment is

Turbo!

Since there is a handful of people interested in my turbo build, I thought I would just awaken this blog platform and put up some pictures.  If you're not interested, that's ok, no worries.

First, a disclaimer.  You may see shoddy workmanship, or the signs of a person that doesn't really know anything about installing a turbo system in his miata.  That's just how it goes - I'm learning as I go with this thing.

If you are interested but don't know much about what a turbo does or why it's such a great thing for a fun but slow car like a miata, this article is a pretty easy read.

Generally speaking I'm following the turbo system installation instructions found on Flyin' Miata's website, but since I'm using a mixture of parts from various sources it's just a guide.  I probably won't take time to explain how it all works and what each piece does, but I'm happy to answer any questions if you have them.

Figuring out how to make a bunch of parts work together to double the horsepower and torque of an engine can get complicated.  The hardware choices can get tricky enough, when you add changing out the vehicle ECU and programming it for a range of air/fuel mixtures throughout the RPM range, that's all together new territory.

Let's get to work!