PDQ's MX5 MK3 NC 2.0 DIY Turbo Conversion

  1. My model of MX-5 is: 2007 NC 2.0 RHD Manual 6spd
  2. I’m based near: Kent, England
  3. I’m looking for technical help or recommendations on: components for the DIY conversion.

So having had a great year of track days I have decided to put together a DIY turbo conversion for my MX5 NC. Here is the list of components I have used to help anyone else planning this folly:

The PDQ Component List:

Exhaust & Manifold

  • Kraken MX5 NC MK3 T25 manifold
  • KrakenMX5 NC MK3 Turbo Downpipe
  • Exhaust Manifold Gasket
  • T25/28 Turbo Gasket set (turbo to manifold and turbo to downpipe)
  • M18 x 1.5 O2 Oxygen Lambda Sensor Blanking Bolt if your downpipe has 2 bungs in it.

ECU & Sensors

  • ME442 Wire-in ECU
  • ME442 ME to NC Harness Adapter
  • Bosch LSU 4.9 Wideband Sensor
  • 3 Bar MAP Sensor & Connector
  • Inlet Air Temp Sensor & Connector

Turbo

  • Maxpeeding GT28 0.64AR Turbo
    (this specific turbo comes with none of the screw in adapters you need to fit oil and water lines to it)

Water Feed/Drain for Turbo

  • 2 x 6AN to 3/8 Barbed 80cm lines (if bought from Mamba these come with the 2 x 6AN turbo fittings below included)
  • 2 x M14x1.5 to 6AN turbo fittings

Oil Feed for Turbo

  • 90deg 90cm Turbo oil feed hose (try and get 90degs either end to make fitting a lot easier)
  • Turbo Oil Feed Banjo Bolt M12x1.5 to 4AN > this goes into the turbo and allows the oil feed hose above to connect to it.
  • Oil Switch T piece Adapter with at least 1 1/8NPT port and 1/8 NPT blanking bolts for any ports you don’t use.

Oil Drain from Turbo

  • Billet Oil Drain Return Flange GT30 (T3/T4 flanges do NOT fit)
  • 2x Low Profile M8 x 15mm Titanium Dome Head Bolts
  • Sump Plug Adapter 10AN M14x1.5 for Turbo Oil Drain
  • 10AN 90 Male to Female Adapter (to point oil drain upwards from sump)
  • 60cm of hose for the oil drain
  • 1 x AN10 straight connector (this connects down to the AN fitting pointing up from the sump)
  • 1 x AN10 45deg connector (this is the turbo end)

Intercooler, Pipework & Joiners

  • Side Mount Intercooler 465x280x74mm
  • 2 x 59cm Long 63mm Diameter Intercooler Pipe
  • 2 x 90deg 63mm Silicon hoses
  • 7 x 63mm Hose Clamps
  • 1 x 63mm x 2.5" with M12x1.5 Boss IAT Intercooler Pipe
  • Universal Intercooler Mounting brackets
  • Throttle body 75mm to 63mm reducer 90deg silicon
  • Turbo outlet 51mm to IC piping 63mm reducer 90deg silicon

Misc Parts

  • Remanufactured RX8 450cc Injectors
  • 1m of 1/2” internal diameter Heater Hose (for the expansion tank relocation)
  • 1m of 9.5mm internal diameter rubber hose (for the engine to expansion tank re-route)
  • 5L 5W/50 Oil
  • 1x Oil Filter
  • 1 x 500mm brake fluid (for use when bleeding the clutch)
  • LiON 038 Car Battery Part.No 444770381 - this fits in the engine bay where the washer bottle was

**Approx Parts Total: £2350

CONVERSION HANDS-ON TIME TRACKER - Total: 23.5hrs
29-12-21 - 1 Hour (bolted turbo, manifold & downpipe together
31-12-21 - 2 Hours (started to strip the OE parts off the car)
02-01-22 - 4 hours (removed bumper fitted intercooler, removed OE cat and manifold, cut hole for intercooler)
03-01-22 - 3 hours (intercooler adjustment, removed clutch master cylinder, test fitted bumper, clearanced downpipe to bulkhead, made oil drain hose 60cm)
06–1-22 - 1 hours (refitted throttle body and fitted inlet intercooler piping on that side)
08-01-22 - 30mins (made template for the wastegate actuator bracket)
14-01-22 - 4hrs (turbo wastegate actuator bracket and shortened oil drain - final install of manifold and exhaust.)
15-01-22 - 4.5hrs (putting it back together and fitting the oil feed to the standard oil pressure switch location.
16-01-22 - 3hrs in total ( battery relocation, washer bottle mounting, engine to expansion pipe coolant pipe fitting)
17-01-22 - 30mins (battery measurements, oil pressure check to make sure it was pumping oil up the turbo feed)

Parts still to source:

  • Upgraded organic clutch.

>Note: Original plan was a single weekend install. However, due to getting COVID & weather I am just going to do bits on it when I can and record the hours taken. It’s in my driveway and not weather protected

5 Likes

Weekend???
Must be one efficient worker…

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Might have a big S on his undercrackers !!! :laughing:

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Be fair, he has two months of prep ahead of the power burst, all ducks lined up in a row.
If you watch Wheeler Dealers or Car Rescue, you’ve seen it’s possible.
:grinning:

2 Likes

I have done it over a weekend on other non turbo cars and completed many engine swaps in the past etc.

The ecu mapping won’t be done admittedly but I don’t see why I won’t have it started and idling.

Edit: Clutch will be done in advance……

4 Likes

Interested to follow, as the turbos or supercharger packages are all 5k plus. Must be a cheaper diy option

I think the choice of turbo, ECU and mapper will be the variables in the list - I think the other parts are pretty much a defined cost.

My aim is 4K (not including the clutch)

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Injectors purchased Deatschwerks 550cc £250 new from a friend in Germany.

these were not used in the end and resold. Other injectors have been purchased later in this thread.

You need a spreadsheet with the parts all listed :slight_smile: OK you don’t really but the rest of us do so we can borrow your list and see what’s involved :slight_smile:

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ECU Confirmed as the NC version of the ME442 with an adapter harness. Ready to go :slight_smile:

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This weeks task is to work out the oil drain from the turbo back into the sump.

Has anyone any suggestions for the NC?

I found 3 possible options. Option 1 Use an AN10 M14x1.5 Adapter into the OEM sump plug location like Fab9 do. Option 2 drill a hole in the sump a few cm above the standard sump plug location like BBR do. Option 3 drill a hole in the block and drain into that just below the 2.0L stamping on the block.

I went with Option 1 above

I see BOFI racing now have an NC they are going to turbo as a YouTube series.

Be interesting to see what issues they uncover that I can try and learn from.

I contacted Bofi but it seems my conversion will be finished before they get into theirs. Maybe this thread will help them instead.

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Parts arrived….manifold & downpipe.

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Turbo arrived has arrived:

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Seems it’s really hard to find in depth conversion guides for the NC…. Will document the install process when I have cobbled together all the parts.

This was useful: DIY Turbo Build: My Journey - MX-5 Miata Forum

So it seems he drilled and tapped the sump for the oil drain - I suspected as much but wasn’t sure. I am hoping I can get away with one of these kind of things instead, ideally replace the sump plug with one but then I wasn’t sure the turbo would actually drain properly into it?

I did not buy this or use it in the end.

2 Likes

Cheers great thread

I found another helpful blog post :

https://forum.miata.net/vb/showthread.php?t=678241

Nice box arrived from Motorsport Electronics today with the updated ME442 for the NC and the NC specific harness adapter.

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Turbo Oil Feed

I have been thinking about this and it seems the best option is to get an Oil Pressure switch adapter with the additional port.

Ideally something that allows the T-piece section to be mounted up where I can get to it to monitor leaks etc

Then run the turbo oil feed from that. So now I need to work out what thread etc that adapter needs to be and how long the turbo feed line needs to be. Any info welcome.

Update: 1/4" x 18 NPTF

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Today the adapter arrived that goes between the stock oil pressure sensor and the block. £12 approx

I have now ordered a 90cm braided hose to connect to that adapter and bring oil up to the turbo. £25 approx