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I can't believe I don't already have a build thread here, but I guess I never felt my Miata was interesting enough to merit a thread. Now I think it will be.
This is my Miata. It's currently running a VVT motor using a Megasquirt 3. It puts down around 138 horses to the wheels on 91. It has some good torques too.
By day, I'm an engineer at a medical device company in the Bay Area. I write software of all kinds and chase those insidious little problems that **** off our test engineers. I also try and prevent those errors before they happen. You have to be a little crazy to stay in this job as long as I have. I've never worn both a belt and suspenders at the same time, but you get the idea.
The goal for this build is to have a dead-reliable HPDE or TT car that slots nicely into the pointy end of NASA ST/TT4. I've chosen 4 because I've already installed the MK60 ABS, which is freaking amazing, and puts me in no less than 4. I'm leaving my mind open to go into ST, but I don't think I'll be doing that right away.
The car as it sits today, with me and about 3/4 tank of fuel, weighs 2300lb. With NASA-template <266mm, 100TW tires, that will allow me 205 "max average horsepower" with about a quarter tank of gas (rough projection). I hope this engine will get me there.
I've placed an order for all the KPower parts, as well as the trick SuperMiata clutch and flywheel. My bank account hurts.
While wasting away a COVID evening (who am I kidding, it's not like I'd have been doing anything different if things weren't shut down), I came across a low-mile engine at a wrecker in San Francisco. 2012 TSX wagon that was smashed at both ends. I bought it the next day and had it delivered. At $536 delivered, plus a tip for the delivery guy, it's the cheapest part I've bought so far. I'm glad I jumped on it - it looks very clean inside and it has a Honda brand oil filter. I'm hoping that means it was dealer-serviced, which I would think might mean it was actually maintained.
The last NASA event of the season is the first weekend in October. I'm hoping to be there with the car in its current configuration. I'm currently screwed in the "getting to the track" department because I typically rent a truck through Enterprise and CalFire currently has every single one of their pickups rented. I tried a U-Haul pickup for the last event and won't do that again. The truck was the bottom-of-the-barrel kind of stripper you'd only find in Atlantic City. It didn't even have trailer brakes, which made hauling my 20' enclosed trailer up to Sonoma probably one of the dumber and more dangerous things I've done lately. Never again.
In the meantime, I'll be planning. I'm a big fan of proper wiring harnesses and data-logging. I also have a Daniels crimper and TH1A turret just itching to be used.
The Numbers I Don't Want To See
$1,864.08 SuperMiata RaceTwin clutch Never reached production
$4,916.71 KPower
Flywheel Bolt Set
Type S Oil Pump Upgrade for K24Z3
Karcepts K Series Fuel Rail
FUELAB Fuel Pressure Regulator -6 AN
3" Race Exhaust System for NA/NB Miata - NA
K Series Heater Port Adapter
K24Z3 Miata Race Swap Package - Miata 6-speed
$536.13 ENGINE 2012 ACURA TSX 4 CYL USED
$45.10 Bishko OEM Digital Repair Maintenance Shop Manual CD for Acura TSX L4 - Sedan & Sport Wagon 2011 - 2012
$207.58 Honda Accord Starter & Alternator, eBay reman by rr_alternators-starters
$69.92 TSX starting/charging harness
$178.85 Maintenance(ish) parts
Small upper timing chain guide for modified valve cover
Pretty much what I'm doing too, which is building for TT/ST4 and GLTC, and I'm gearing up to do the Teves Mk60 ABS as well, you should definitely have a post about that install and the results in here at some point.
Wow, thanks for all the subscribes and cats, I'm honored!
All the MK60 info is in the thread on that subject. I should add a few more pictures, but it's really not a big deal once you get the sensor mounting sorted out. You're going to love it.
After I made this post last night, I found an amazing piece of software that I've just got to share. It's called RapidHarness and it's perfect for designing wiring harnesses. It has a database of connectors, knows the number of pins/cavities in each connector, and helps you to track basically all of the things you'd track while making a harness. There's a good tutorial here - https://www.youtube.com/watch?reload...ature=youtu.be
You can see some of my progress so far - I'm creating placeholder connectors and making connections between them. My first pass is to create all the connectors I'll use, with the correct number of cavities in each connector. Once my TSX factory service manual arrives on Friday, I'll have an authoritative source for identifying the pins in each Honda connector.
I've decided to use the Haltech 1500 Elite as the ECU - I'm uninterested in the KPro half-answer, and I have not found confirmation of anyone running a K24Z3 on Megasquirt, using stock sensors. The Haltech is popular with Honda owners and there's rumor of a Z3 base map.
What I haven't figured out yet is power distribution. CAN-driven power management is a very attractive idea, but it is far from cheap. There are some options, but the current draw of the MK60 is in question - the documents I've found suggest that it uses a 30A circuit - what I don't know is if it needs all of those 30A or if there are other loads on that circuit. 30A is quite a bit of power for solid-state drivers.
I've decided to use the Haltech 1500 Elite as the ECU - I'm uninterested in the KPro half-answer, and I have not found confirmation of anyone running a K24Z3 on Megasquirt, using stock sensors. The Haltech is popular with Honda owners and there's rumor of a Z3 base map.
Please post up if you find that rumor to be true. I was looking to use Haltech as well, but making sure it works with all the stock sensors and without the changes needed to use KPro is my only hold-up. If there is a basemap for the Z3 that would be amazing.
Please post up if you find that rumor to be true. I was looking to use Haltech as well, but making sure it works with all the stock sensors and without the changes needed to use KPro is my only hold-up. If there is a basemap for the Z3 that would be amazing.
There are two Z3's running Haltechs here locally using stock sensors. It definitely works. I'm not sure if there's a base map or if they started from a generic map though.
As mentioned in the thread Emilio referenced above, I've been farting around with the Haltech software. I'm surprised at how quickly I have used up the available IO pins. The assigned pins have the empty checkboxes next to them - I guess you're supposed to print this page out and use it to wire everything up. I'd really prefer to get it in a spreadsheet format, but this is better than nothing by far.
I'm planning on using the Haltech CAN wideband module, which saves me an analog voltage input. I could probably get away without alternator control, but I figure I may as well use it.
Here's a little progress on the harnesses. I'm really liking the ability to capture info like connector part numbers and wire gauge and length. It will make sharing this info easier. I don't actually plan to use the Ballenger parts for all these connectors - I have many from the cut harness that came with my motor. But there's that neurosis - I enjoy the completeness of identifying the necessary connectors.
I'm planning on running the Bosch 74mm DBW throttle that "everyone" uses. I think I knew the part numbers for that connector at one point, but I may have misplaced it. I'll figure it out again I'm sure.
I still haven't settled on whether I'll use a fancy race PDM or just a decent wiring block. AIM has a model called "AiM EPM Power Distribution Interface" that was supposed to come out at the end of August. It seems to be a cheaper version of their PDM-08. I need to reach out to them to ask for more info.
That software looks awesome, great work so far. If you feel like sharing that file when you're done it would definitely save me some time haha.
The only thing that I saw about the trial version is that it has a limit on how many connectors you can have or something like that? Has that given you any issues?
Side note, this thread is already living up to the title. In a good way.
Dammit, I edited out the bit about the software cost and limitations. Yes, the “30 connection” limit has bit me in the ***. That’s essentially a 30 wire limit, which is why I only have a partial sub-harness defined. I would happily pay something to remove that limit, but I can’t afford even their most basic paid plan. I may reach out to them, but in the meantime I have sub-harnesses. This would be fine if I could alias the main ECU and power connectors across all sub-harnesses, but I haven’t figured out how to do that yet, if it’s even possible. So I have copies.
I’d be happy to share the files. Until I get things more nailed down though, the connection spreadsheet images I’ve put up are probably the most useful.
When I worry that I’m worrying too much about some detail on a project like this, I head over to Blog | Tom Yang's Ferrari Restoration and read about vintage Ferrari projects. It gives the engineer and skeptic inside me (and maybe my not-so-inner *******-ness) a feeling of superiority. Man, those cars are slapped-together, poorly-designed, and overanalyzed. The fastidiousness of restoring and maintaining them is amazing, especially when you consider that this level of attention was clearly not the norm at the factory when they were produced. Hey, this software is expensive, but at least I’m not chrome plating anything or worrying about the direction the cotter pin is facing...
I just discovered that Toyota Prius throttle pedals currently sell for about $25 on fleabay. That's about the same as a VW throttle pedal goes for, but it obviously has more acceleration. I'm sorely, sorely tempted to use one as my loud pedal, just for shiggles. I mean, a resistor is a resistor, right?
That would be a bit funny. RX-8 units are cheap on ebay too, that's what I'm going to use. Looks nicer and has kind of an angled edge for downshifting.
My factory service manual arrived today. I'm going to add pinouts for the relevant engine connectors to this post. This post will be edited several times as I find and consolidate the data.
Honda identifies the pins on each connector as they are viewed from the wire side of the connector.
As you can see, they are numbered from left to right. The only two-row connector in this chart has its own diagram (alternator).
On the subject of grounds...
I have identified the two sensor grounds for your convenience. These are directly from the Acura manual.
The three pulse sensors use what Honda identifies as "Logic Ground - Ground circuit for ECM/PCM". I take this to mean something other than a dirty nasty power ground. YMMV.
CMP Sensor B (Exhaust Cam Sensor)
1. ECU
2. Ground
3. 12V Injectors
1. 12V
2. ECU Coils
1. ECU
2. Ground
3. 12V Alternator
1. 12V
2. C - Alternator control by ECU. Tie to ground to turn off charging.
3. L - Lamp - voltage regulator ties to ground to indicate a fault
4. FR - Alternator load indication
09-20-2020, 09:41 PM
A neurotic over-engineer does a K24Z swap
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