I've just got a couple of specific things I see in the calculation sheet that could skew your result. Generally speaking, get the most accurate data you can into the sheet (metric system and mm are your friend here).

It looks like the pad mu could be up to 10% higher than you've entered in the calculation sheet, based upon what I found. That will change the system pressure requirement pretty significantly.
https://www.brakepartsinc.com/raybes...formation.html

Also, for the effective radius of the rotors, it isn't just the outer diameter of the rotor divided by two (assuming you have an 11" BBK). The actual effective radius is the centerline of where the caliper pistons apply pressure to the rotor, so some distance inboard of the OD. The easy way to get in the ballpark for this dimension is to measure the pad height, divide by two, and then subtract that from the full radius of the rotor.

Final piece of feedback is regarding the end goal. Having a target force is good, but just as important is the amount of pedal stroke to get there. With a 5:1 pedal ratio, an MC that's too small will really add a lot of dead stroke to the pedal to achieve your target pressures.

A lot of good points. After fiddling with the calculator more I still decided to stay with my selection of 5/8" front and 3/4" rear. I also went with a 3/4" size for the clutch but admittedly did a lot less research for that. It is the same size that the Wilwood unit included with the Kmiata hydraulic throw out kit is and also Emilio had mentioned that he used a 3/4" clutch master with their twin disc and the same pedal set as me but that was with the stock slave cylinder setup. Both of those pieces of information might be completely useless since both scenarios have variables that are different than mine like pedal ratio, slave cylinder setup, clutch, etc but whatever. I'll find out the hard way.

Now onto all the depressing news.

Progress has slowed way down with the holidays, and the chances of making it to COTA to race in GLTC at Super Lap Battle USA in March seem like they are slim to none at this point... after adding up some big ticket items that are still on the build list, I likely won't be able to keep up this pace of throwing money into the racecar black hole and need to pace myself.

I am STILL waiting on any news of the AiM PDM32 that I ordered. Seeing people on instagram somehow getting them in the US at the same time that AiM is basically ignoring a lot of US dealers with pending orders is beyond frustrating. I also ordered the front BBK like a month ago but Stoptech is backed up too and the initial estimate for shipping the kit is this last week of December but I wouldn't be surprised if it got delayed further.

I don't want to cut any corners on my grand plan for the build so that means I need time to make more money. Covid-19 has reduced my overtime at work significantly compared to last year, usually I'm raking it in as this is our "peak season" but that's just how it goes. Definitely thankful I still have consistent work in what I feel like is a relatively secure position though.

With all that being said, my dad did clean up the diff, got the rubber bushings out, and cleaned up the rear subframe. They got the same treatment as the rest of the underside of the car with the satin black VHT chassis paint. I've always hated the diff sticking out like a sore thumb on cars with a bumper cut so hopefully this helps. Will it affect cooling? Not sure, but it'll probably be fine. It's a tried and true setup so I'm not too worried, and I'm not sure the extra cost of trans and diff temp sensors would be of any actual use to me anyways.


https://cimg3.ibsrv.net/gimg/www.mia...0b1c57db1d.jpg
https://cimg4.ibsrv.net/gimg/www.mia...620fa7c6b8.jpg

Looks good.

Curious if you're planning any reinforcement for the diff arms?

I know of one person who has received their PDM32 order that was placed back in January or February. They said it started smoking when they powered it up for the first time...

I cancelled my Aim order a few months ago and bought a Haltech Nexus instead. I wanted the Aim but decided I trust Haltech more than I trust Aim for such a critical piece of the build.

Did you order through Ravi? It took almost three months for AIM to get him a Smartycam that I ordered, good god.

That's actually a non-turbo FC RX-7 diff cover so it doesn't have the engineered failure point like the Miata ones. Should be good to go.

You can see better from this angle that there's no cutouts along the edge.

https://cimg2.ibsrv.net/gimg/www.mia...c5620cdff1.jpg


That's reassuring... also I've seen like 4 or 5 people posting pictures of them on Instagram now.

No I ordered a bunch of stuff from UMS all at once like ECU, ATI damper etc etc.

I had a bad experience with Aim on the new Solo2DL, Slow to deliver, and when it arrived, surprise!! The new OS for the Solo2 and some other new dashes etc had to have new protocols written for it to read the ECU - more months waiting. I would not trust them with a new product, ever. Wait 18 months for them to get the bugs fixed and production sorted, and you are probably good to go. Maybe.

Well, switching to anything else now is going to be a boatload more money. That's if I can even cancel my order. Their PDM + Dash kit is stupid cheap for what you're getting...

So, not a lot of progress lately but that's how it goes sometimes. Definitely not making the goal of driving in GLTC at SLB which is this week lol.

My dad has gotten some stuff moving along like getting the seat mounting figured out, welding in the seat mounts, figuring out pedal mounting, and got the engine bay mostly painted and almost ready for clear coat.

That being said, I got a message from UMS Tuning and randomly out of nowhere the PDM showed up. 9 months of waiting but it's finally here. The only thing that kind of sucks is that I could not get the type of GPS antenna that I wanted (flush mount bulkhead) so it came with the standard wire coming out the side type, and apparently they did not make a "race" version of the 10" display so I have a bunch of indicators on it for stuff like turn signals, head lights, high beams, check engine light and other junk. They pretty much told us we get what we get lmao.

UMS Tuning also got the super backordered front brake kit ahead of schedule which was nice. 11" STR-42 Trophy kit to match the rear 10.9" STR-21 Trophy kit.

And one useless impulse buy before I realized I was running out of money came in as well, the smoked Carbon Miata LED tails and LED running lights came in. I just set the tails in there to see what they are like, they're not bolted in or anything but I like the way they look compared to OEM.

I'm headed to Super Lap Battle at COTA this week to spectate with my dad again, I'll try to snap some cool pictures and report back. Hopefully this will be a bit of a motivation booster because I'm definitely burned out on the project. It's been over a year since the old engine came out and this thing is still a bare shell, and it's coming up on 4 years since I've been able to do a full track event. Hopefully it doesn't take me too long to get back up to speed with the driving... bleh.


https://cimg5.ibsrv.net/gimg/www.mia...fd4771f9cb.jpg
https://cimg3.ibsrv.net/gimg/www.mia...06e9bf6274.jpg

I'm almost 3 years into a VVT swap, BRO.

I've been watching pitwalk/trackday vids on YT pretty heavily, I get ideas and motivation from them. That and the guys in the ASR chat keep me going as well. :hs:

Small teaser of some color in the engine bay.

Next step is a high gloss high temp clear coat. The purple is that two stage Metalcast and the white is the VHT chassis and suspension, same as the satin black stuff. The white does not spray well AT ALL. Drips and runs everywhere, even with the lightest coats, crinkles up a ton too. I definitely don't know why it's so much worse than the satin black but I would never buy it again.
https://cimg0.ibsrv.net/gimg/www.mia...7b9b2440b4.jpg
https://cimg1.ibsrv.net/gimg/www.mia...2042b2506e.jpg

Love the paint! Great job masking things off & having such clean lines between the two colors. Must feel great to be finished with the metal and seeing the results in paint!

I had issues with white when using spray cans on my car too. Ended up getting a harbor freight gun for 30 bucks and visiting auto paint store costing about 100 bucks. It ended up going on much easier / thicker and was really easy to do and @ 10 bucks a can, I think same price / cheaper in the end too (I still have some items to paint). All that to say...if you haven't given it thought, its easier and cheaper than you think to go that route and you'll probably be happier with your white paint.

great color choice. I love me some Metalcast paint

Oh man, what a thread... it reads like a good tv show that you don't want to end lol. Looks like we've made some similar decisions, except you took it to a completely different level. I'm trying pace myself and do it incrementally, specially since I don't have nearly as much driving experience. I also took the HPA wiring courses and just finished installing my AiM PDM and rewiring the whole car and it runs again after a long break. I've been looking at Tilton pedals too (although firewall mounted) and it's nice to see the master sizing research you've done as a reference. Looking forward to more updates.

@rdb138 Thanks man. My dad actually had the great idea of using vinyl to basically make a sticker of the exact size and put that on instead of trying to mask a perfect circle with tape. Worked great. Will also keep the HF sprayer in mind but at this point I've already got most of the rattle cans to do the rest of the car.

@Padlock Word. Only drawback is that since it's kind of a candy finish the shade can change a lot depending on how much you spray. I like the darker purple look though, looks way better in person.

@tadeuzagallo Thanks! Also do you have any tips or pictures of your PDM install? That's probably the part I'm dreading the most.




Also I took some pictures of some rough progress for the pedal mounts. It's not easy and really cramped in there. Ended up cutting an access hole through the cowl tray to gain access to make some welds as well, just to get them stuck together with the mig. Will probably just pulse over the top of those with the tig machine to make sure everything got full penetration.

https://cimg9.ibsrv.net/gimg/www.mia...7d12e61010.jpg
https://cimg0.ibsrv.net/gimg/www.mia...573ed1c613.jpg

That looks really good, might just be the motivation I need to pull the trigger and order my pedals already. I deleted my booster and pedal feels great, but the effort is a bit higher than I'd like.

As for the PDM, I was dreading it a little too, but it wasn't too bad. The tips I have are:
- My PDM only came with the 16-18AWG terminals, which made it harder to crimp the smaller wires (e.g. 24AWG wires for the CAN bus and analog channels), if I was to do it again I'd order some of the smaller terminals (3-1447221-5 for 20 AWG and 3-1447221-5 for 22 AWG).
- I mounted my PDM on the trans tunnel (I added a picture below), but if I was do it over again I'd make a wiring board for all that stuff (I think that's the name, just a panel to mount stuff). Also, not critical, but right now the PDM expects to be mount in a specific direction, so my accelerometer is completely messed up, but they said they'll add some functionality to calibrate it to RS3 soon.
- This is not specifically about the PDM, but one hard lesson I learned is that leaving the wires too long is just as bad as too short... I left the main trunk a few inches too long and had to make another firewall hole because I couldn't bend it :facepalm:

I barely know what I'm doing, but if you have any questions I'm happy to share what I learned so far. I'll probably have a do over when I do the K swap, planning on going with a Link FuryX ecu and doing a proper twisted harness this time around.


https://cimg8.ibsrv.net/gimg/www.mia...35110d856.jpeg
https://cimg7.ibsrv.net/gimg/www.mia...79f0ee34b.jpeg
https://cimg4.ibsrv.net/gimg/www.mia...cc1ff886f.jpeg

I just made it through the build thread. Subscribed. You weren't exaggerating when you said your Miata was down for a rebuild. The work here is massively inspiring, excellent job all around.

Why did you patch all of the holes in the engine bay? Is that just for looks, or is there a functional reason for that. It looks great, just curious.

@tadeuzagallo thanks for the insight and pictures. I'll probably end up mounting it in about the same spot as well.


Thanks man. I patched all the holes in the engine bay just for looks. I've always loved the way shaved/tucked show car bays looked so figured while I'm in there doing all this metal work and welding already, why not go the extra mile. Who knows, maybe someday down the road it could open up a few opportunities with partnerships with companies and ease the racing budget a little. Plus it'll be something that sets the car apart from all the other track builds following basically the same recipe as I am.

What a journey man! This has been an awesome build to read through. Gives me some inspiration for my build. You picked up the welding pretty hardcore and it probably has already paid for itself.

I have a couple quick questions.
1) If you could do the cage over now that you have your welding would have tried to tackle the installation if you picked up a kit from MiataCage?
2) How do you plan to adapt the axels to the RX7 diff housing? My buddy has a space NA RX7 diff and has offered it to me but I wasn't sure how to adapt the Mazdaspeed Miata axels. Any insight would be great.

Looking forward to future updates!

Cheers,
BA

Well I don't think there's much about my cage that I would change now that I've got everything the way that I want it. The fabricator that did the original work did a really good job of getting everything as tight as possible to the hard top and other sections and making sure I had enough room everywhere. That being said I feel like I would do just fine if I had to weld in a prefabbed cage kit.

The RX-7 diff cover is just the cover. The carrier, ring and pinion and LSD are all Miata parts so there's nothing special that needs to happen when you put axles in.

Hopefully I'll get back to working on this thing soon and have some more updates. I'd like to have it done before October gets here.