Matt's hairdresser spec Mazda of lame.

[mjrstar]

Finally weather was ok(ish) in my paint booth. I did have to shift around the side of the shed to apply the clear as the wind got up a bit. Added bonus that none of the bits blew away, but they were threatening to.

Will my 15 year old slightly yellow clear coat with mismatched hardener work? Who knows,  but I guess I'll find out.

The bits that were white and green are now a vaguely similar shade of red to one of the many reds on the car.

Probably should have just rollered the paint on and skipped the clear coat as that would have been a better visual match.

 

I also spent way too much money having the radiator recored it's basically un-used but is 15 years old and developed a number of tube leaks due to corrosion. 

[mjrstar]

As expected the newly redded red bits are red, in fact much redder than the top of the windscreen and right rear guard. Similar(ish) to to the front left guard and the boot lid though

[kws]

With the catches on the bonnet up, it looks like an RC car

[mjrstar]

Should add some boot catches and buggy whip aerial you reckon?

[mjrstar]

A bit of surface rust removal underneath where the welder has made touchdown for certain things like seat mounts, cage footing plates the box-out for passenger seat.

Plus of course the speed bump induced gouging of the floor stiffeners which seems prevalent across MX5's even at stock ride height.

No show quality under there just a bit of wire wheel, rust kill, brush on prime and a bit of whatever black I can find once this is dry. 

Oh wow that gearbox mount sure isn't the prettiest thing.

[mjrstar]

On 30/12/2025 at 12:25, kws said:

With the catches on the bonnet up, it looks like an RC car

I reckon this thing also has a bit of the RC car vibe going on.

[mjrstar]

I've been back and forward on the front suspension setup, for sure the easy option would be some willwood kit adapted to the standard Mazda gear.

But simple and I don't seem to get along when it comes to this car for whatever reason.

These was a loose plan to use fd rx7 stuff but the steering arm was a no go.

The other idea was a set of the gto 4 pots, but these are ultra hungry for spoke clearance and I noped out due to disc selection constraints. 

 

I spied a setup that had merit on my mates 2J converted MA70. So because this era toyota is so plentiful I decided to have a crack.

 

Am I happy with this, well for a race car it ticks a few boxes, the bearings are nice and strong, on its current configuration the bump steer measurements are very good, and it packages what I'd consider enough brake rotor under a 15 inch wheel.

What I'm slightly less stoked with:

- The steering arm dropper has the mounting arrangement with some bending motion through the top cap screw.

- The upper arm to knuckle interface is kinda weird and not very serviceable. 

 

It is however all reversible if I decide this isn't the setup for me.

 

[mjrstar]

I took this for a short trip to Mexico yesterday. It's got great boost response, and is shifting gears nicely the steering is perhaps a little too responsive (will try my bigger steering wheel) and spring rates are a little heavy.

Haven't bedded the brakes yet but I think it'll have plenty of stopping power.

 

The fuel map is decent enough, afr is 11.9 at 7 psi boost and settles at 10.7 at 22psi. Pretty safe and comparable to a stock evo.

I haven't yet explored passed about 5500 rpm or 70% throttle as the boost controller must need looked at as the only thing holding the boost back was my right toe.

The other thing not working well is the speed sensor, it's OK up to about 90kph then loses it shit, fixing this may be above my pay grade.

I will also need to devise a way to stop the roof ballooning out at the front edge in the centre. I don't think it's from the wind catching the front edge, but is maybe from pressurising the cabin.

But yeah makes wooshy evo type sounds as it should. 

 

 

[mjrstar]

So I was wondering when I set the boost controller to hold 15psi on the gauge it was sweet as, then when I checked back at the ecu logs it was reaching 22 and a bit psi. 

 

Puts glasses on, oh that's not 15psi on the gauge. I'll probably set up spring pressure, a setting at 1bar and higher boost at the current 1.5 bar.

Anyway it goes pretty good, and power down grip is impressive,  compared to my old starlet.

i changed to my slightly bus spec steering wheel, fitted my harness which has the crotch belt, as the 4 point just felt weird, and epoxy is setting on my additional roof mounting. 

 

 

[mjrstar]

Proof that this hodge podge of second hand parts actually goes..

 

Maybe I'll do something interesting in it one day like motorsporting.

 

https://youtu.be/CZP_rIdCIVw?si=VkaT5GhUNq_t8ZKN

[mjrstar]

Thanks to @gibbon for testing and cleaning my mix and match injectors I now have the best four in the car, a couple of spares and a cou6of do-not use.

 

I moved on to tweaking the idle stability,  i don't have anything in the way of iacv,so was limited to some ignition trickery, so I out in a target table to improve stability.

 

then I thought hey I could add a sectable second table for idle instability because who doesnt like being able to turn on choppy cam noises.. 

With those dialled in I worked through a bit of cold compensation as an assist on first start. So now I've got it happy enough to idle from cold without the hot idle being crazy high.. 

 

It seems to like a bit more base timing than i was expecting but I don't really have an explanation for that yet.

 

Video is garbage sound on my phone due to lack of bass, but makes correct noises via headphones. 

 

https://youtube.com/shorts/E9g4cweMnm0?si=lab_Xx-eGIflzYQP

[mjrstar]

Back to speed sensor woes, it's a hodge podge (of course it is) it needs to work better. Clint's suggestion had me thinking is the issue torque related with twist in the drive train messing with the air gap. Because it seemed to lose it's shit at higher speed.

This snip is an accelerate to 6th gear (legally of course) and then maintain speed with a bit of full throttle run holding the speed on the brakes.

So if it was working properly the top white line would be a tabletop but really the oy bits that are representing correctly are the ramp up in speed and then the deceleration at the end.

It's also interesting that off throttle at higher speed it comes right (kind of anyway)

 

Maybe I need a proper mount, an actual tone wheel and an automotive sensor rather than my industrial one?

[mjrstar]

So the internet suggests that too much air gap can lead to poor signal performance..... so I reduced the gap and took it for another road test. That resulted in it losing its shit at even less speed.. it turned to haywire at around 50kph. So there is something in that..

 

next up I tinkered around with more air gap on the hoist to get the smoothest slow speed signal then sent it in 5th gear on the hoist. ( no need for 6th gear on this test)

 

its cleaner but not perfect , maybe this is because its basically not producing any torque I'll need to put it down the road to confirm..

i also need to look deeper into this slip yoke bushing..

[mjrstar]

Still on this speedometer thing... the oem cluster is cable driven and the nissan gearbox certainly doesn't have provision for any sort if speed output cable or electron based...

 

So cluster wise there us a few options from aftermarket digital dash from link or haltech or some form of whizzing thing that turns the stock cable input..

Naturally I took neither of these simple(ish) options...

 I've opted for a cluster retrofit of an NB mx5.

This will be hours of work and the result will be a cluster that looks pretty much the same as the original at first glance.

I am however no stranger to a cluster retrofit after fitting an EP3 type R cluster to my pos civic to get a tacho capable of displaying the RPM it now sees..

I'm a little sad that the original odometer won't get to clock up any more miles. And maybe the og cluster is slightly cooler looking with its chrome rings...

 

One bonus i guess is the new cluster has a full tank of gas.

[mjrstar]

So should be a simple re-wire and bang it in..

Well no of course..  the mounting provisions are pretty close so some strategic trimming and filing got it sitting decent enough.

Next was the oil pressure gauge swap.. but why?

The NB cluster although it has a needle is just a pressure switch operated deal that wangs the needle to the centre once the switch is met.

The NA gauge actually has some movement based on pressure from a sender so time for some more punishment. 

The 2 look similar but.....mounting, depth, terminal arrangement and even the pointer drive diameter are all significantly different.. 

I found a thread that outlined plonking the complete na gauge in. But this didn't take my fancy as the faces are a fair bit different. 

So I hogged out as much material from the cluster to gain any space I could. I considered setting up in the mill but the caveman in me took over so I hit it with the powerfile which was quick and effective.

Then modified the light stand to take the na gauge driver and took some height out of that.  I also trimmed the back side of the bezel. 

In the pursuit of reducing overall gauge depth I removed the connector standoffs and made up some low profile terminal nuts.

 

[mjrstar]

I ummed and aahed over the wiring situation for a bit, so if you are electrically inclined look away now.. 

at first it looked like there may have been an option to make some threaded adapters to connect up the terminals in the conventional screw in from the back deal.. but that was going to take depth I simply didn't have..

I settled in using the light well for the airbag warning and sending the leads inside to connect up.

And there you have it...

 

it looks almost exactly the same, although the gauge face sits ~1.5mm forward from stock but as the 3 smaller gauges all sit back from the tach and speedo it's not something you'd be likely to notice..

 

Does it work.. well who knows, I've got cluster plugs and pig tails en route from ebay USA.