PDQ's MX5 MK3 NC 2.0 DIY Turbo Conversion

Work In Progress

I have now got about 35miles into the driving and cured the first serious problem……
The spring that was in the adjustable wastegate actuator was rated for 0.5 bar but I was seeing 12psi spikes …

So I changed the spring this morning and now am seeing the expected 5psi ish of boost I want to start at. I log using the ME442 logging function the use MegaLogViewerHD to make some sense of the data I am seeing.

Another 40min drive tonight with some more logging. It’s quick - like a nippy N/A under 3500 revs then the boost kicks in……… smiles…

So now I will start putting some miles on it and see how reliable and fun it becomes. Clutch is standard as far as I know so will be interesting to see how long it lasts.

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Fantastic. Do you have you word file with all the parts you can share… I think I need to start buying a few bits each month. :slight_smile:

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Email pdq.mx5@gmail.com and I will email it to you.

So the car is running well but I am suffering from the dreaded boost creep and it’s peaking at 13psi of boost.

The problem is well known - I should have watched this video (https://youtu.be/a8kFbTJlpz8 before fitting the turbo……

So now I am going to order a new turbo from the same manufacturer and will port it, then swap them over.

I assume you are already aware of this possibiity with waste gates etc, but just in case not, then are you seeing “spiking” as well?

i love the diy approach i superecharged my mk1
i did absolutly everthing myself including fabricating all the brackets to the electronics to control the bypass valve
all in it cost me £384

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Awesome work, I cannot wait to get mines out - I’m rather jealous!

So this is what I found when I looked at the wastegate aperture on the MAXPeedingRods GT28 turbo……… obviously too small.

I was suffering boost creep but no spikes.

The blue area is paint transferred from the flapper so I can see how much space I can expand the hole to (a little bit less than the diameter of the blue circle.

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Whilst waiting for the Carbide Burr drill bits to arrive I thought I would correct some earlier mistakes…

  1. I have ordered heat wrap for the downpipe to protect the clutch master cylinder.

  2. I have ordered a heat panel to shape to add even more heat support to the abs unit and brake pipes.

  3. I tightened down the joints on the Oil Drain hose with 27mm spanner’s.

  4. I have picked up some 10/40 oil as I feel the 5/30 was probably not ideal for the additional heat and the cold of the U.K.

  5. I am switching in my spare new Wideband sensor and so have ordered another because it’s always good to have a spare if you run a turbo’d car. On the last logging run the Wideband signal stopped logging…. No visible damage to wiring so just swapping it out.

Plan is to aim at 9psi across from 3750 to 7000rpm so also swapping the 0.5 (7psi) actuator spring back in. Hopefully the wastegate porting I am doing will give me the controlled boost that we need.

Before

After

Decided I wanted to only do this once…. So I made it a little bigger but left enough metal to reduce the risk of cracking.

Great work as usual! I think I’m going to try that CXRacing kit I linked, and refer to your guide for assistance. Won’t be for a couple of months though. Will need the same ECU you’re using I think.

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All wrapped up and ready to refit, might slip 1 more tie onto it….

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Managed to spend 30mins on it tonight before it got dark. Added some more metal ties.

Turbo is now back in the engine bay, held on by 2 manifold nuts :crazy_face:

I have fitted the replacement Wideband Sensor and have refitted the water and oil lines to the turbo finger tight.

Tomorrow is connecting the oil drain to the sump, manifold nuts, 2 x exhaust bolts followed by wastegate actuator and a final tighten of everything then we will see if we have cured the boost creep.

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So I relocated the wastegate actuator.

The wrap seems to be in the right places - for how long we will see!

Battery secured:

Clutch to bleed tomorrow and we can go for a drive and see if the boost creep is fixed

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Hurrah - boost is now controlled just needs the duty tuning in the boost controller settings in the ME442z

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Now the DIY MX5 NC Turbo is driving really well she is on her 2nd full tank of 99ron fuel!

I decided to treat myself……: ordered this…

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Where does that mount mate? Are you going to rip the oem dash out?

I have ordered it with a mount that I can use to fit it in front of the stock dash. I plan to use the stock dash fuel gauge so need to keep it in sight :slight_smile:

I also plan to add an oil pressure sensor to monitor the engine health - but that won’t be until we get many more miles of good running under our belts on this 129k engine.

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