Hey all,
I'm still mostly an inactive lurker here. A new car means it's time to change that, I guess.

Last year I decided that I was done doing dual duty and started the hunt for a dedicated track car. My black NB has been great, but I've been wanting to convert it back to pure street duty and have 2 cars with less compromise. When the hurricane hit us in NC last fall, a friend of mine needed this car out of their life thanks to their garage flooding - it needed a home or it was going to the scrap yard. Welcome to my life, little blue disaster. This is 10AE #5383/7000.


First move; take the black car to COTA for a final track day, then spend time converting it back to dedicated street duty. The XIDA's and big sway bars got removed and it is now sitting pretty on tecna's and stock bars. 1.95hz wheel frequencies, 2 degrees of roll at 0.8g, and a basic alignment of about -1.8 degrees of camber everywhere. A good street Miata is a recipe for weekend fun while you spend a year or so off the track, working on a new build


Otherwise, the last couple months have been pretty uneventful. Lots of planning, ordering parts, and cleaning. The AE is now stripped interior and has been cleaned. I've found dead rodents, rodent damage, mud in 2 cylinders, transmission overflowing with water (all the gear oil was inside the interior), and a newfound dislike of aftermarket car alarm systems. Thankfully the car is straight, square, and 100% stock. It has no major rust, and is overall in pretty good condition! I've managed to get rid of the funky smell from dirty flood water - think diaper bag mixed with creek mud and gear oil - and the 10AE blue carpets even came out pretty nice! The engine harness and body harness are both out due to rodent damage, so I have some good condition replacement units from a local reseller and will be spending some time gutting out some of the parts I no longer need.





Goals for this money pit:

1. Entertaining track car. "Streetable" track car - inspected, tagged, insured, but predominately a closed course car. Minimal interior, just enough to not be a horrible place to exist for the occasional street drive.
2. Max 5 class, SCCA Time Attack. New rules for 2025+ mean this car can have a built engine (N/A, less than 1.9L) and a min race weight of 2200 lbs. That seems like a fun place to play. It won't be competitive, but that's okay because my driving isn't winning any events on skill anyway.
3. Engineering playground for all the things I refused to do to my black car. Aero, suspension, powertrain, etc., fundamentals are all at play here. I want this to be a project for technical learning in addition to an entertaining hobby.
4. Seat time still matters. Focus on reliability and target a sustainable budget for long term enjoyment.
5. Somehow keep it nice enough to be proud of it in the paddock.

I have been accumulating plenty of parts for this car over the last few months, but no sense listing them all out. I'll continue to update here and include all of them as I go. I'm not sure I plan to add forced induction or do anything nearly as awesome as what I've seen on this forum over the years, but I know this is a community with an appreciation of all technical things Miata.

 

Based on 1) the rats making their home in the cowl, right where the HVAC takes in air and 2) wanting to simplify things and cut some weight, the entire HVAC system came out. Bare minimum requirement is to defrost the windshield on a cold morning in late fall or early spring.

I found this heater unit from Summit and decided to give it a try. Electric 12V heaters don't impress me, so this water-based heater seems reasonable. It will get plumbed in to my bypass loop just like the factory heater core. I scanned the factory HVAC plenum with my phone to know what my space claim was and got to designing parts. It's crude, but it's good enough for free. The mounts are printed in ASA, which should be okay. If needed, I can make an additional leg to brace this on the firewall at the bottom right corner.


This will mate up to the factory HVAC defrost duct and will work as normal, but with much simpler wiring. No temp control, only a 3-speed fan switch.

 

Holy good base for a track build, batman! That 10AE was cursed with an actual flood, which is kinda biblical (if not familiar google the "10AE curse"). I was always afraid mine would be cursed, but I did buy it from the widow of a deceased friend, so yeah maybe it is. Hopefully it got it out of its system, or something.

As an owner of a 10AE daily/weekend car and a basketcase NB2 to be purposed as a trackrat (with HVAC already gutted), this is super relevant. Subd! And love your black NB btw, it's about perfect for a street car.

 

The wiring harness is now gutted of anything which isn't basic road things (lights, turn signals, horn, etc.), engine, or basic interior requirements (my defrost unit). Here's before/after of the main body harness for example.


This took a hot minute. I went through each page in the factory wiring diagrams, highlighted each individual wire and component I wanted to remove, then traced it and yoinked it. All in, ~7.2 lbs were shed. That's only counting the wires. I neglected to weigh the various tape/loom/etc. because I knew I'd be putting some of that back on. This includes wiring from the body harness, the engine harness, and the rear/tail light harness. The harness is now wrapped nicely in TESA tape and split loom. I printed out a clean copy of the factory diagrams, marked off the removed wiring again so I had a clean version without garage dirt and hand written notes scribbled in, and put them into a binder with protective sleeves for future use. Benefit of stripping the factory harness over starting from scratch with a motorsport-grade harness.

Here's the spaghetti I pulled out during this process:


Items which were removed.

• Automatic trans everything
  • I started with a fresh body harness, turns out it was from an automatic. I know know the magic of the clutch switch, neutral switch, reverse, etc. that manual-conversion owners have to deal with.
• power windows
• power mirrors
• entire sound system
• factory HVAC
• power antenna
• warning beeper
• rear O2
• a few solenoids associated with fumes and exhaust.
• entire AC system
• fog lights
• alarm system & factory power locks
• cruise control system

Things I added while I was doing this:

• leads for my defrost blower
• leads for DAQ and other in-car accessories
• leads for a few bulb locations in the dash for some of the unused slots (more on this later)

I also test-fitted the dash and am quite happy with the fitment of my defrost blower onto the defrost ducting. It's well within range of being sealed with neoprene tape.


You'll also notice the tub is now completely stripped of all sound deadening/head shielding. A couple lbs of dry ice helps this process tremendously, but be prepared to dislike yourself while you do it anyway. I will be adding heat shield to the trans tunnel eventually to avoid hot foot.


Other random items:

• I discovered the tank was completely full when the car was put into storage. I siphoned out about half of it. No water or yuckies to report, I'm slowly adding it to the other vehicles in the fleet to dilute and dispose of.
• I bought some non-powered mirrors from spinnywoosh since I pulled the wiring for the powered units. I also picked up all the parts needed for hand crank windows - door cards, regulators, etc. since I pulled the wiring there as well.
• I picked up some of the big ticket items I've been thinking about
  • Haltech Nexus S3. PnP harness from Boomslang is on the way.
  • I'm slowly accumulating all the pieces for a Mk60E5 retrofit, thanks to wingman's DIY and tips here
  • Keisler Gen4 drop spindles & MR2 front hubs
  • VU Development spherical bushings
  • Walter Motorsport 5-speed with Quaife close ratio gearset (this one is a very long lead item and has been in the works since before I physically had the car, TBD on when it finally gets delivered)
  • 4.77 torsen
  • M2 motorsport 2.5" exhaust from Bofi
  • ESR head (bowls, blending, radius softening, deshrouding, etc. as allowed to max of Spec Miata rules) with BP5A intake camshaft

Mirrors. Look how small they are! Drag reduction, hopefully.


Final big item - I cut the floor out to make way for a Guarino Watson Racing drop floor. I think this is the most complete Miata drop floor solution on the market, despite being a little more complicated than others. As of now, I have the hole cut and trimmed for good fit, the edges are all stripped of paint/degreased/primed with weld-thru primer, and I'm ready for a friend to help me weld sometime soon. I also had to do some surgery on the floor of the car as it was bowed/bent pretty badly. The only thing I have left to do before welding happens is beat my floor box channels ("frame rails") square enough to fit inside the supplied floor reinforcements.

 

This will be a great build thread! Welcome to MT.

 

The drop floor is welded! A buddy of mine has spent a couple hours on weekends helping me with the welding since I don't weld. Not all of these are pretty, but they are all solid. ...which is impressive because he was fighting with a good deal of seam sealer and paint and A-pillar goo which I wasn't able to remove all of. I have lots more cleanup to do before I can seam seal, prime, and paint.

I'm very impressed with this kit. Not only did it fit 95% perfectly, but it's STOUT now that it's all welded in place.


While we were in there, he also welded the easy-to-reach seam welds around the door sill, the cowl lapped panels, and the rear cabin gussets. Lap belt anchor points are also welded into the trans tunnel. Only anchor points I'll need to add later are for the passenger side sub belts.



After I'm done with cleanup and paint, I don't want to deal with any form of grinder, sawzall, wire brush, etc. for a while.

Unrelated to the build here; I also adjusted the valves on the black car last week. The car runs like a damn sewing machine again. Very happy camper.

 

Nice thread! will be following for sure!

 

While it's this far apart, take the time to replace the under floor pan sheet metal channels with 2x3 square tube welded into the front and rear frame rails and stitch welded to the floors.
it was the most amazing amount of chassis stiffenining I did to my nb. I can literally pick up 3 wheels woth a floor jack woth sway bars connected and the doors open.

 

I thought about this, but the Guarino drop floor pan already comes with bolt on channel reinforcement. The short one pictured is welded to the leading edge of the new floor pan. The full length one gets attached on the passenger side of the car. These are bolted rather than stitch welded, but I should get some of the effect.

 

I needed a break from the floor/chassis for a little bit, so I took a detour on a smaller task. I doodled up an adapter to fit a 65mm DBW throttle body from a 2004+ Ford Crown Vic/F-series/E-series and printed it out of ASA for a test fit. Everything looks pretty good! I can clock this anywhere from about 25 degrees to 65 degrees without any bolt interference. What I have printed is a 35 degree angle - everything clears and I can still reach the adjustment screw for throttle valve closed position (low idle speed adjust). I have also sourced connector pigtails for the motor and TPS to wire it all in. This will be paired with a Honda Fit/Insight APS pedal asm using a K Power Industries mount. When I get there, I'll have to modify my engine harness for 4-wire TPS, 2-wire actuator power, 6-wire APS.

I'm pretty proud of myself for a little modeling trick I used here: I put the factory throttle body gasket on my office printer/copier and scanned it to PDF. Then I imported that image to Fusion and scaled it based on measuring the width. Then I drew mating geometry directly onto that scaled image without needing any guessing or measuring. It fit on the first try! The Miata TB bolt holes are both asymmetric and not centered onto the bore, so this saved a chunk of time modeling.

For those who are wondering, the Ford throttle body bolt pattern is a simple 76x66mm rectangle centered onto a 65mm bore and uses m6 fasteners. I believe they also make mechanical TB's in this size, found commonly on Fox Body Mustangs and New Edge Mustangs. These throttle bodies are readily available at pretty much any Advanced/Oreillys/Autozone or pull-a-part if needed in the future.



I plan to get this eventually machined out of aluminum, but for now this is good enough. I've been looking into more appropriate printed materials like PA6-CF and PA12-CF in the hopes that something with a little compliance would relieve vibration on the throttle body, but both of those seem to have creep issues over time, even with annealing the part after making it, and I don't want to deal with that.

 

The floor is now painted in inoffensive gray. I didn’t need to paint the whole floor pan because most of this will be covered in trim pieces/carpet, but oh well. While I'm in there...



Hopefully this week I can start putting the interior back in the car after the paint has cured. I’d love to clean up some of the mess in the garage, but the interior needs to go in before I am willing to throw things out.

 

Jeeze dude this car is so sick. Big inspiration for my NB build, though nowhere near as extreme as this!

 

I appreciate the kind words, but I'm keeping my expectations low - keep it simple, fit within the ruleset for TT, and have fun

 

That's what a miata is for! This is just such a cool platform, being a 10ae, for a track build. Stripping it down and building it up right. You are gonna have a lot of fun with this one.

 

It's been a minute since the last update - I have been making steady progress on a lot of small items and haven't felt any individual item has been worthy of an update for a while. But this weekend I did a big thing - the front half of the roller skate is out! This means an update is due.

The plan is to go through this engine with the basics required for a durable track engine (oil pump, water pump/timing belt, valve springs, crank damper, reroute, intake/exhaust, etc.) and get all sensors sorted to get it running on the haltech.
I have my concerns about if it's really salvageable... if it is, great. If not, I'll skip this engine and move to my plan for something with a little more oomph.


Lots of interior work has happened

• Carpet is fitted and trimmed around my floor.
• Wiring harnesses are fitted and routed along the fire wall/door sill/dash with P clamps.
• doors are re-hung on the car
• Windows have all been replaced with used units because this car had tinted windows and that tint completely separated/degraded.
• Conversion to manual windows since the door wiring is removed.
• Doors have new vapor barrier and sealer.
• ABS pump and yaw sensor are mounted (ABS pump mount will need revised, yaw sensor is final)
• Honda Fit/Insight electric pedal is mounted with K Power mount. TBH this mount works and fits, but it *really* could use some development. This thing is *thiccccc* and unnecessarily fiddly considering the price point... it could be plastic and it could be 1/3 of the weight. Oh well, it's in.
• cleaned/re-lubed/rebuilt the brake and clutch mounts, hacked off the gas pedal mount.
• all relays have been replaced with new OEM, exception here is the turn signal flasher. I used an LED flasher unit from FM.
• Added OEM grommets for the throttle cable & AC lines

Items in progress but not finished:

• I designed firewall passthrough/closeout panels for the heater core hoses, former HVAC inlet, and a pair of Deutsch bulkhead fittings (1 for engine harness, 1 for ABS/instrumentation/other). I got these laser cut from 0.050" aluminum and plan to rivet/seam seal them to the firewall. This will completely close the fire wall.
• ECU mount incoming. It will be mounted where the passenger airbag used to be, clamped direct to the dash bar.
• Extension wires done for extending the body harness 22-pin ECU connector across the fire wall, thanks to boomslang. I will get the 16-pin connector and 26-pin connector when I do the engine harness. Plenty of wire length available in those.

Still lots of cleaning every time I touch a new part of the car.

 

Great updates, it's coming along nicely. It's a shitload of work to go through a car like this, sometimes you put in so many hours and feel like there's little to show. But I can see it!

A little more oomph, aye? What do you have in mind if the BP doesn't work out?

 

Nothing crazy - no swaps or forced induction for me for now.

Plan A is to use this flooded BP for a while to get the car shaken down and knock some rust off my driving. Then take my time building a BP for the typical 150-160whp.
Plan B if I discover the flooded BP isn't worth saving is to go straight into building that BP this winter.

The BP build plan looks like the following. The hope is this makes somewhere around 160whp and is robust. I'd be thrilled if it makes anything north of 150.

• East Street Racing ported/skimmed head and BP5A camshaft. I already have this head and it's in fantastic shape with low hours.
• Swap in some stiffer valve springs. I have some Volvo springs in hand, also looking at Cat Cams springs from Bofi, as they say they've moved away from the manufacturer of their problematic VS855 springs.
• JDM BP6D (or is it called a BPZE over there?) bottom end - the VVT engine from '01-'05 with the 10.5:1 everywhere-but-North-America pistons.
• thin head gasket to bump up to something near 11:1 compression
• boundary NB2 oil pump gears
• fluidampr pulley
• redline somewhere around 7200-7400rpm. This should be safe with stock lifters/shims and stock camshaft base circle (I hope).
• 93 octane with E85 tune and GM flex fuel sensor
• square top & RB header & 2.5" M2 catless midpipe/muffler
• reroute

I'm debating buying the JDM engine sooner rather than later. I need an alternator and starter to replace the flooded units on the car and I plan to buy a square top anyway. If I can find a fully dressed engine, that's ~$700 worth of stuff I can use now - I can leave the rest of the engine sit waiting for the right time to do the build.

 

Sounds just like my dream budget build for my N/A nb track beast. Though like you I'm hoping to get away with the stock motor for a bit. Glad you are sticking with the BP!!

 

Small stuff this week.
With the engine out, I spent some time cleaning engine bay and trans tunnel. Both were gross and simple green is fabulous. I found another rodent nest, this time in my frame rail just in front of the shock mount. No rust to speak of, just a lot of fluff and turds. Yummy.


I mentioned my firewall closeout panels in my previous post. I got those installed. On the right, I installed for the defroster coolant loop. Inboard left side is where the engine harness used to pass through with its giant rubber grommet. This is being replaced by a so the engine harness can be more easily disconnected in the future. This one required grinding down the dimple/bead around the edge of the hole so my panel would sit flat. The new hole furthest left is for a second deutsch bulkhead connector - this one for ABS and instrumentation wiring. In the cowl, I closed off the old HVAC inlet hole - I'm debating a cowl/randall intake on this car, so closing that off felt important.

All panels are rivetted and seam sealed. Some folks are willing to 3D print bulkhead panels out of basic materials like ABS for this purpose. That may be okay, but it doesn't give me a warm fuzzy feeling. Aluminum worked well.

 

I've been slow since the last update, but there's been progress. Our weather has made my garage really cold the last few weeks and it's not been easy to convince myself to spend time out there. Also my job has been taking a lot of my brain power/mental battery lately and I haven't been eager to spend more time thinking in my spare time.

Anyway. I tore into the flooded engine. When I started out, my plan was to just pop the head off, clean some mud out, and slap it back together. Once I got in there, did some teardown/inspection... that plan didn't last long. The rings were packed with mud, 2 cylinders were full of gunk, 1 main bearing was scratched up, and 1 rod bearing was pretty destroyed. I spent a couple weeks cleaning mud, varnish, sludge, etc. off of everything I could get my hands on. I measured crank journals, installed new bearings and measured installed bearing bores and end play, etc. New rings and hone, cleaned as best as I can without a machine shop, and slapped the whole thing back together. New water pump, new NB2 oil pump (primed with some assembly lube), repaired oil drain threads, added oil pan baffles, new half moon seals, new RMS, etc., and resealed everything with Yamabond. It's not perfect. I don't claim to be an esteemed engine builder. It's going to get a few rapid fire oil changes to deal with whatever subpar cleaning I did - it is what it is.

Consider this a finished bottom end of my "sloppy refresh".


Here's how the cylinders started


Oil pan



Some other small stuff has happened also. Heat shielding on the trans tunnel


Cowl rust cleanup/paint. I also relocated the washer fluid up here with the FM aluminum washer bottle. Silly and fancy for a race car, but... it needs washer fluid if I'm still going to call it a "street car" in good faith.


Also in this time, I've scrapped almost 300lbs of take-off crap from the car. This isn't all removed weight, as some components were removed for replacement but still, that's promising. I'm still targeting class min weight of 2200lbs with driver.

On top of that, I've put a stock radiator back into the black street car. My Supermiata rad developed a leak. It will be sent back for warranty when I stop being lazy, and its replacement will go into this car. Thanks @turbofan.

EDIT: I forgot to add - I've officially now had this car in my possession now for a year! Progress is slow compared to some of the incredible work I've seen on this forum from some of you VERY dedicated racers and tinkerers, but I have other hobbies and I'm really enjoying taking my time on this thing. I think I'll probably try to get the black street car out for some casual AX this year, just to keep my head in the game a little.