That would be awesome if you could send them my way! I've never used SendCutSend (if there's a better alternative let me know), but have been wanting to check it out.
One of our local guys also has a CNC I think (same guy who will weld this for me), so if the drawings are already there he might be able to do it for me.

Sent PM.

Dude with CNC could make it. Or you could print them out on paper, glue to 1/4" aluminum and jigsaw out.
or xometry, sendcutsend, whomever else. and just have them show up for probably the same cost as a small plate would cost you to cut them from.

I opted for sendcutsend on mine, even though I have a cnc mill I could have cut them with. material costs made it even, and labor pushed it over the "might as well" threshold for me.

I thought about buying some reinforcements plates online from RTheory because I'm lazy, but figure for less than half the cost I can just make some. I bought a 12"x12" 1/4" thick sheet of Al from amazon for about $20. I'll make some templates out of cardboard and cut em out w/ my bandsaw. Should be fairly straightforward. Napp motorsports did a nice video on welding plates onto the cast housing so I'm going to have my buddy give it a shot.

Went out to tinker last night and I'm pretty sure I know where my front end/steering vibration is coming from.
https://cimg0.ibsrv.net/gimg/www.mia...34f93ce26f.jpg


Shiny! Once the garage warms up to freezing I'll pull the downpipe and add some clearance with the help of a hammer. On the old setup it was super difficult to get the downpipe off without pulling the turbo, so I'm thankful for the V band on the new kit. Ideally I wouldn't have to clearance anything, but nothings perfect I suppose.

Diff reinforcement plates are off to Send Cut Send. I also drew up some fuel rail spacers since I'm trying to sell my old injectors and didn't have a set of spacers to go along with them. $40 for 3 reinforcement plates and 9 fuel rail spacers seems like a good deal to me. SCS has a $40 minimum or I would've just gotten the one plate.

The diff was coated by the PO so I got a wire wheel and cleaned that up a bit.
https://cimg1.ibsrv.net/gimg/www.mia...9f3508861e.jpg


So, waiting on some shifter parts and the clutch (should be grabbing that tonight) for the transmission to go in. Reinforcement plates & welding and then the diff will go in.

After that I just need to dial the tune in a bit, get the boost controller turned up, blow the 6 speed, do a ZF swap, do a K swap and then the car should be done!

Haha, that one got me good.

Good find on the source of the vibration! Sorry if I missed it, but what's the reason for the diff reinforcement? I know spec Miatas use it since they get bumped a lot, but hadn't seen others install them on street cars before.

It’s a tall list. Just remember to break the whole thing down to one step at a time and you will get there!

Sick clearance on the DP. How are the fingernail bushings in your steering shaft? I had just barely more clearance than your DP at one point and I wound up melting said bushings after a track day. Caused some real unnerving play in the steering lol.

My clearance was tight. I snapped a picture, it's in my build thread somewhere but I wanna say it's like 1/4" or so of clearance? Not a lot for sure. This is one of the big reasons I opted to wrap my downpipe from the v band flange to the flex section.

Z, I have no idea what a fingernail bushing is, but I guess I'll have to find out. Heat management is on the list for the future, so I'll keep that in mind when I tackle that.

Redursidae, The diff reinforcement plates are preventative. I personally haven't seen one break, but have seen threads on here where people have broken them by launching the car. It could 100% be overkill for me, but I plan on launching the car regularly and figure that's going to put more stress on that weak point. Again, probably overkill, but more of a, "I don't want to remove this diff again" thing.

I did get the downpipe clearanced. It's hard to tell if this was enough since the vibration was only in certain circumstances, but there was one freeway exit that I felt it on a couple times and I didn't feel it this weekend, so that's promising. I still feel like I haven't really turned the car since last season, and I usually get a bit of exhaust rubbing/vibration at autocross, so I doubt I've see the worst of this.
https://cimg0.ibsrv.net/gimg/www.mia...b23b4f34de.jpg

Nothing like taking a hammer to your fancy new downpipe.

I've been reading around about IAT sensors and heat soak, and had been thinking about heat shielding my IAT sensor. Nothing fancy, just a bit of foil tape and DEI heat sheath that I had leftover from wrapping various lines.

https://cimg8.ibsrv.net/gimg/www.mia...e89260b2b5.jpg

If anything I would say that this just stabilized the temperatures a bit? It didn't seem to prevent the sensor from getting hot, but IATs didn't seem to swing as badly when putting around town. It's a bit hard to compare since it was really cold here this weekend anyway. For now I'm going to leave the sensor wrapped up and observe. It doesn't seem to be hurting anything as far as I can tell and I'd rather keep my temps as stable as possible.

On a similar note, I built an intake box out of some of the coroplast I had laying around. I previously did something similar out of embossed aluminum, but it wasn't tall enough and left a fairly large gap to the hood. I thought it would block airflow out of the vent as well (which it probably does worse now), but I'm going to give it another shot.

https://cimg1.ibsrv.net/gimg/www.mia...01c0d15e62.jpg
https://cimg2.ibsrv.net/gimg/www.mia...d6ce0bb73f.jpg
https://cimg3.ibsrv.net/gimg/www.mia...3b7e7b3f10.jpg



I wrapped this in some reflective wrap that I had laying around from previous projects. Mostly to try and keep the coroplast from warping. Again, hard to say exactly how effective this is, but now the air filter is right under the hood vents. Between that and the large hole going into the fender, I think this should help a good deal. Again, hard to compare since it's been so cold here lately, but temps seemed lower and more stable in this configuration.

We also had our awards banquet for autocross this weekend. 1st place in XB by 1 point baby! Its sounding like I'm going to have some new (kinda old) competition. One of our national champion BSP ND's and a K powered NB with a 25-660 are going to be joining XB for at least a bit of next year. Both cars are dialed and both drivers are extremely good. Now that Vitours are legal and these guys can get 305/30/R15's I guess they're interested in checking the class out. Wish me luck!

Slow going around here. Not much to report outside of gathering parts. I think I've got everything to put the shifter together now. Shout out to Tasca Parts for putting a staple through one of my paper gaskets...

I also got the parts from SendCutSend. I'll have to get over to my buddies place to weld up the arm, but I think that's all that is preventing the diff from going in right now.

Still unsure about the clutch. Both of my buddies who drove the SM 4 puck seem to think I should look at getting something else due to streetability concerns. Still, a free clutch is a free clutch.

Going to be busy this weekend and next, soI probably won't make much progress until the end of the month.

https://cimg8.ibsrv.net/gimg/www.mia...e44064362a.jpg
https://cimg1.ibsrv.net/gimg/www.mia...fd32a048fe.jpg
https://cimg2.ibsrv.net/gimg/www.mia...2969604a2e.jpg
Stapled right through it...

Haha, the stapled gasket is priceless. They're gonna replace that for you, right?

Funny your buddies are saying the same thing about the 4-puck. Can't remember, you've driven one of their cars with the clutch in it, right?

My kraken kit did the same, and my solution was the same as yours. It rubbed under hard high load right handers at the track. Never felt it on the street. I hammered it a bit, less than yours, and it was much better but still happened a little. Then I went to a supermiata hybrid motor mount which solved it completely. The hybrid mounts aren't too bad on nvh either, but definitely worse than the mazdacomp pair.

Going to see if I can get a refund on the gasket. It was like $10 and I think the parts from MR came with that gasket anyway. Annoying if nothing else.

I haven't driven that clutch, but I'm really considering going to the FM stage 2 instead or just staying on the FM stage 1 until I go to a bigger turbo. I don't want to pull the trans more than I need to, but I don't really want to sacrifice streetability if I don't have to.

I'm on the IL motorsports mounts, which I think are pretty comparable to the Mazda Motorsports mounts? Thankfully the vibration is gone (for now) after the... modifications to the downpipe.

From my previous research, it sounded like the SM clutch was preferable to the FM clutch in general. IIRC people said the stage 2 FM's were also juttery and the SM clutch had a substantially larger swept area..?

Although after running my 4-puck clutch for some time, I'd have traded the 4-puck chatter for a heavier clutch pedal without a question. Interested to hear your thoughts down the line whichever way you go.

I'm trying not to scope creep too badly right now. I'm honestly tempted to get the diff in there, test it for a bit and then throw the 6 speed in with the current FM1 clutch. I don't want to do another clutch job any time soon, but I think the FM1 should be able to hold the power from the 2560. Assuming 15% drivetrain loss, the FM1 should hold 270 WTQ.

Main reason for sticking with the FM1 for now would be to save some money, maintain street ability and make the install a bit easier since I wouldn't have to do anything with the flywheel. We're 6 weeks away from the season, so not having to break in a clutch would be nice.

I don't imagine I'm going to move on from the 2560 for the season unless this one blows. I likely won't be going to E85 for a while anyway, so I doubt I'm going to be past 270 WHP or torque.

We will see... I think I'll try to get the diff arm welded up and install that next week. Once the diff is confirmed to be working properly then we'll see about the trans. I have other projects planned (throttle body, redoing oil lines, etc...), but those are mostly smaller jobs that I can complete in an afternoon once above freezing.

Got my $2.50 back from Tasca for the gasket. Major win there...

I got out into the garage last night and started doing a bit of prep for the transmission and diff.
https://cimg8.ibsrv.net/gimg/www.mia...cffc9aa8bd.jpg
https://cimg9.ibsrv.net/gimg/www.mia...bd2c4a834f.jpg


I don't know if you can tell from the photo, but the fulcrum offset ring that I got from MiataRoadster has the dowels a bit too far out, which prevented the shifter from slotting in. I reached out to Bill about this, so hopefully he'll get back to me today or tomorrow. He's been really helpful so far. I tried to loosen the set screws and adjust the dowels myself, but I guess they're secured with red Loctite, so that's a no go for now.
Edit - Bill told me they can be a snug fit sometimes. I went back out at lunch today and put a bit of force on it and the shifter popped right in. So now the trans is pretty much good to go.

To hopefully prevent headache in the future I also marked off this bolt on the transmission. Apparently if you pull this bolt then something falls into the transmission and you have to pull it completely apart. Overkill I'm sure, but I'd really hate if someone was helping me with the car and pulled it by accident (or if I did that when I was tired).
https://cimg0.ibsrv.net/gimg/www.mia...d21a36ba5f.jpg


Diff plate from @Ironhydroxide lines up great. Hopefully I'll be getting this welded up on Friday or Saturday and installing it this weekend, or early next week. I ordered some new seals and such from Mazda, so those should be here in a day or so. I should've 3d printed the axle seal install tool, but oh well.
https://cimg8.ibsrv.net/gimg/www.mia...8d4d7ed96e.jpg
I'm not sure if this means it's a Torsen 1, 2, or apparently there was one that was kinda in between? Not an open diff at least.

https://cimg9.ibsrv.net/gimg/www.mia...fc23d12e09.jpg

The weather is looking really nice next week. Highs in the 50's and at least one day is sunny. I think I'm going to need to figure out how to pull the hard top with one person and probably build a little stand for it.

One gremlin I'm still chasing is my BOV fluttering. I opted for the cheaper Chinese BOV from Kraken when I ordered my kit and it's fluttering. The weird thing is that it only flutters at higher boost levels. At lower boost levels I get the pshh sound that I'm used to. I've got the spring set to the softest setting, so I'm wondering if the piston on the BOV is bouncing back and forth causing the flutter? I'm not too worried about it, and I've got another BOV I might try out, but I'm curious about what's going on. I love the flutter sound, but I'd rather not stress my turbo more than I need to.

Stopped reading after this. That's closure enough for me.





Stoked to see you guys are getting some warm weather and have been able to tackle some of the big projects you've had in the works for a while now. I was just thinking, it's nuts your build thread is barely over a year old. Thing's come a long way in that time period dude!

https://cimg7.ibsrv.net/gimg/www.mia...557ea2d60b.png

Yeah, I've gone way deeper than I expected to. I probably threw a bit more than I needed to at the car this winter, but fingers crossed it'll alleviate some of my gripes with the car.

Dude, I remember your NA build thread and it felt like you were doing 2x what I've done. Multiple engine's swapped in, transmissions every other week lol. I watched everything you went through with the driveline vibration and have largely swore off the swap because I don't think I'd be able to do half of the troubleshooting you were.

BOV opens when the pressure on the piston overcomes the pressure of the spring plus the "pressure" of the vacuum on the back of the piston.

Snooping in older pics I see this is your setup

https://cimg2.ibsrv.net/gimg/www.mia...e250679e2b.png

As the BOV is fairly close to the throttle body, the pressure builds very quickly when you slap the blade closed.
This pressure wave then opens the BOV, which dumps, and drops the pressure below opening.
But then the cycle starts again as the air has mass and all the volume of air from turbo behind it.

Personally I'd choose a bov location closer to the turbo (before the intercooler), gives the system less mass to act on a resonance.
BUT, you have what you have, so getting that to work is probably better than redoing it all again.
Change the resonance.
I'd suggest either a restrictor pill in the vacuum line. or a stiffer spring.
Restrictor will slow down the rate at which the piston moves,
Stiffer spring will require a higher differential intake to prethrottlebody pressure before initial open, letting the pressure wave pass without blowing the valve back open.

And BTW, those gears ship out this week. had a lot of problems with USPS's website refusing to allow payments.

My old setup had the BOV right after the turbo and I never had issues at any boost levels. This kit (Kraken) puts it towards the throttle body as you picked up on. I tried another BOV I had laying around and I was getting some compressor surge at lower manifold pressure, but decent blow off at higher pressure. The BOV that came with the kit is adjustable, so I assume instead of a stiffer spring I can just adjust the preload on the spring for a similar effect.

I appreciate the knowledge dump. I've been trying to think through this one this weekend. I'm going to keep playing around with it. I'm not too worried about the surge, but I'd rather take care of it sooner than later. I'll read through that a couple times to try to internalize it.

Excited to get those gears, and thanks again! I took the 3.6 out today and thought I got hustled before I realized my speedo was off by 5-10 mph.

3.6 Install
 

Had a beautiful day up on the local ski hill last week. Always a nice way to get some exercise in after work.

https://cimg9.ibsrv.net/gimg/www.mia...a8bb428ad5.jpg


I dropped off the new diff with a buddy on Friday to have it welded up. He was able to get it reinforced the next day so I ran over to pick it up. Thanks again to @Ironhydroxide for the reinforcement plate designs/drawings.

The cooling fins got chipped a bit due to a slipped grip during the welding process, but I don't imagine it'll make much of a difference.
https://cimg8.ibsrv.net/gimg/www.mia...6ab7153410.jpg
It's like it was meant to go there.

Hit it with a quick blast of paint for good measure, not great, but it matches the rest of the diff a bit better.


https://cimg9.ibsrv.net/gimg/www.mia...c774f6cdd9.jpg


I ran over to harbor freight to grab a pry bar this morning which turned out to be little to no help for the job. I assume it was a pretty typical diff swap. This was the first time I've had to do anything with the diff surprisingly. Being in my own garage means I'm missing a couple tools here and there but I figured out a nail will work to unstake the axle nuts.
https://cimg5.ibsrv.net/gimg/www.mia...52653b04c9.jpg

Having done the job now, I'm pretty sure it would go way smoother next time, but it got a bit messy/hectic for a first timer.
https://cimg6.ibsrv.net/gimg/www.mia...a76b764267.jpg

Probably the worst part of the job was getting the diff and PPF separated. I was using a deadblow for a bunch of it which wasn't working. Once I went to a metal claw hammer things came apart a bit easier. The stupid insert in the bottom of the PPF was a pain. All of the spacers/nuts/inserts went back into their homes with a good bit of antiseize paste on them.
https://cimg7.ibsrv.net/gimg/www.mia...410d955907.jpg

The old diff seemed to be in decent shape, The drain bolt didn't have too many metal shavings stuck to it.

https://cimg0.ibsrv.net/gimg/www.mia...1bb0c9c390.jpg

I sent off a 3d print for an axle seal installer. Turns out you can just use the old seal to tap the new one in. The seals stack over each other and a deadblow will set them into their home.

https://cimg9.ibsrv.net/gimg/www.mia...bd019140db.jpg

It took me longer than expected, but overall it was a pretty straightforward job. I decided to give the lightweight shockproof a shot for the fluid. It's a nice cotton candy blue color.
https://cimg8.ibsrv.net/gimg/www.mia...a6e241ce25.jpg

I'd be curious to get feedback on this one, but I've had some difficulty getting V-Bands to separate from my exhaust. I decided to try coating the inside of the vband in antiseize to hopefully keep it from binding up. I'm not sure how this will work, but I think It'll be beneficial when I need to disconnect the exhaust sometime next year or two.

https://cimg3.ibsrv.net/gimg/www.mia...30eca0ed8f.jpg


Got everything bolted back up and it's looking pretty good.

There are two major differences here compared to my old diff, aside from the ratio. First, poly bushings, and second, the new diff had the damper near the driveshaft flange removed. I would expect this to be a major NVH hit, but in actuality it doesn't seem to be too bad.

Once everything was back together I took it out for a shakedown. There seems to be less front to rear slop in the drivetrain (not surprising given the poly bushings). It's most noticeable when going from on to off throttle. There are some new noises and vibrations but nothing extreme, and to be fair I didn't do anything special to align the PPF/diff. I'm interested to see how the lack of damper goes. I might add some sound damper mat in depending on how the car is feeling. It's more weight, but I also want the car to be enjoyable to roadtrip.

I was concerned that the ratio was wrong because of my gauges, but quickly realized that my speedo was just off due to the new ratio. I'll get the new gear installed once it shows up and the 6 speed goes in, which should sort that out.

On the side, I got some battery terminal covers and replace the one for my battery and an exposed alternator post. I broke the plastic cover a while back and am just finally getting around to patching it up.
https://cimg6.ibsrv.net/gimg/www.mia...c6eba28d7b.jpg
https://cimg7.ibsrv.net/gimg/www.mia...ca9d536415.jpg



It was a full day of work, but I wasn't trying to rush through it. This is where it ended up. I did pull the air filter after since it was due for a cleaning.
https://cimg0.ibsrv.net/gimg/www.mia...495703c82a.jpg
https://cimg2.ibsrv.net/gimg/www.mia...abb3cedb7b.jpg



Movie list for the day was Drumline, Good Will Hunting and The Breakfast Club (thanks for the free movies YouTube). Overall just a solid day chilling in the garage and spinning some wrenches. I've got a skiing trip planned for next weekend, so the 6 speed will likely get installed during this week and/or the weekend after. First event of the season is about 3 weeks away!