PDQ's MX5 MK3 NC 2.0 DIY Turbo Conversion

Now I am starting to look at where to T into the water feed for the turbo. The coolant hoses that go through the bulkhead look easy candidates.

Does anyone know what diameter they are for ordering a T piece?

I ended up repurposing the water feeds to the Throttle body, i disconnected then from the throttle body and now they feed/drain the turbo.

Installed the ME442 ECU into the NC and she fired up first turn of the key!

At the moment this is a standard NC1 so I thought bedding in the ECU at a basic level first would take out one variable from the turbo install weekend.

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I bought a T25/28 Oil feed and drain kit from eBay for £43

Also I had earlier bought an additional oil feed line that has a 90deg end as I think looking at the turbo this will be better ‘packaging’.

this is a universal kit and I used the fittings only to make the oil drain hose pretty much. The oil drain fitting for the turbo that was contained in this kit didn’t work with my GT28 series turbo.

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I bought a genuine Bosch Wideband Sensor and some extra gaskets for the turbo to manifold.

Injectors arrived 450cc Denso units.

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I have been investigating the MX5 NC Turbo Oil Drain options and it seems that drilling a hole in the block just above the sump might be the way forward? - i think this is going to take some bravery

and seen from the wheel well past the engine mount.

I chose not to drill this block and instead used an AN sump plug adapter with a 90degree bend to point up towards the bottom of the turbo.

Today’s purchase: £89 after discount.

Would have liked a wider one but this will probably do for my intended boost levels.

Perfect fit - I got lucky with my guesswork.

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Arrived and as described, seems a well built intercooler and all I need to do it make a bracket to mount it to the standard holes.

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Todays purchases are sensors & connectors that I will need to use with the ME442

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Really interested in your progress, thanks so much for posting.

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Loving it as well.

Another thing I needed has arrived

£9.99 from ebay

I was pleased when I fitted it to discover it’s a multi-layer metal gasket.

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Ok so this is an interesting one… Over the course of the last 3 weeks I have been searching for the right adapter to tap into the block of the NC 2.0 engine. This was £10 from eBay.

I now have 3 variations of this and the reason is the depth of the thread that will protrude inside the block itself. Also I wanted to use a steel adapter and not an allow one. So now I have a selection.

04-DEC-21 I have decided not to drill the block at this point but to start by draining into the standard sump drain point. I will keep this in case I need it for a later version or end up with an engine swap.

thank you very much for this thread/guide.
it has shown me that this kind of thing is completely beyond my level of mechanical ability!

and so when I upgrade, I shall pay to have it done! and not get my hands dirty!

so thank you, you’ve just possibly saved me from a big mistake!

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I am hoping that by doing the research on parts, sharing the list of parts needed and being open with the costs will help others know DIY conversions, whilst not easy can be done for the NC if your not up against a timeline.

I was very lucky as a 16yr old as I was mentored by a car journalist (Fast Ford / Haynes) who was also an ex engineer at Rolls Royce. He and his son taught me how to work on cars in his back garden. From changing brake pads on MGB GT’s to head gaskets on Rover 214’s and engine swaps on Audi 80’s. I had a few Metro’s as a youngster and all ended up modified with their help. They gave me such a grounding with a ‘give it a go’ mentality it has served me and driven my passion for cars for the last 30years. My day job is IT and my garage is so small I cannot fit the MX5 in it - so this will be a driveway conversion (hence over 1 weekend).

I was also able to spend 5 years with a successful TimeAttack racing team making tea/coffee and helping where needed (holding up gearboxes and turbos frequently!). I learnt so much from them just watching and listening. The biggest thing I learnt was just take your time, drink plenty of tea and it all goes smoother if you get a bunch of mates round to ‘help’. Part of this conversion is just an excuse for me to get a group of like minded car mates over for a couple of days.

Covid prevented the group, but I am ticking over with the conversion between the rain and the day job.

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I’m pretty handy with the socket set myself.
in my early 20s, I basically rebuilt my Opel manta.
changed the shocks n springs and changed all the bushes, changed the engine for a 2.2 Carlton lump.
replaced the rear axle, installed a 1k sound system that had an amp for each pair of speakers, and needed an extra battery in the boot with a split charger.
and that’s just the big stuff I did.

I am going to put a supercharger on my nc2 a but cortenmiller cant do it atm due to supplier issues.
so I had been starting to consider buying a kit and doing part of it myself and having a garage do the bits I cant.

however, today I’m 25 years older, several stone heavier and I now have arthritis in my hands.
I’ve no doubt that I could do the grunt work but I can’t weld, I’m not good at planning and I just don’t have the energy to spend 2 days bending over an engine bay or rolling around on the floor.

so for me, the best thing is to just wait for CM and pay the premium price.

as i said, reading this thread has made me realise that i DO need to have the pros do this for me.

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Today has been a challenging day and ended up under the MX5 NC at a local garage looking at the location for the oil drain.

On an NC the standard downpipe has the CAT in it - this obscures access to the ideal oil drain location. So downpipe needs to come off, but even then you don’t really have space for a right angle drill or a straight shot from the wheel arch to drill the hole in the block as the subframe bracket for the engine mount is in the way.

I am beginning to think that realistically the engine will need to come out to get this drilled - and if it’s coming out then I am asking myself why wouldn’t I swap it for a forged engine (2.0/2.5) at that point?

I would be keen to know what BBR did in terms of oil drain if anyone knows?

BBR drilled the sump about 50mm above the standard sump position.

I’m probably misunderstanding as I’m not at your level what I see on all the forums is people just putting a tap on the standard drain on the bottom of the engine? I think I’m misunderstanding and this is tapping into run off into a cooler? Rather then just easy removal / changing of oil.

Hi - you are not wrong some of the kits sold have used a simple AN fitting adapter into the sump plug of the NC oil pan.

Fab9 show pics of theirs here: NC Turbo

All turbos are usually mounted above that point so the oil from the turbo can drain down into it. Too much oil in the turbo can cause problems with seals in the turbo, so a good drain is needed.

The problem is there is mixed feeling if using one of those simple adapters will end up causing the oil to not drain out of the turbo fast enough as the oil going down the drain tube then hits the mass of existing oil in the sump pan.

I was trying to avoid that potential problem by mounting my drain above the line of the oil in the sump. But it seems the hassle of drilling the block might lead me down the adapter path at least for this engine………

I have taken the simple route and gone adapter into the sump plug. I will accept the consequences if/when they occur.

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Hi, and first off great thread,
I Was contemplating a DIY conversion myself but was worried my skill level/ space in a single garage to throw stuff was not up to the job.
So turned to BBR, the oil drain on my conversion has been located around 2”,(or 50mmish for you tech guys) above the sump plug but still in the sump not the block, I’m assuming that once the engine is hot this location is above or around the oil level?
Can take a quick pic later if wanted,
Great work
Kev

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