Engi-Ninja's Remarkably Unremarkable NB2 Turbo Build
 

So, after a few years of dreaming, I'm going to attempt to turbo my 2003 this summer. She doesn't have the Konigs on her in the picture because they have summer tires on them. She looks much better in triple black.
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I bought her in the spring of 2013 with 23k miles on her. I then proceeded to drive her all over central and southern Indiana for 3.75 years, and now she got about 4 times that many miles. Never had any issues, runs flawlessly.

The plan is to do a straight-forward, pseudo budget, 220HP build. I don't want to have to build the engine at this point, so I don't plan on going for any more power than that in the near future. This will be my daily driver, so I want it to be as reliable as possible.

A couple of weeks ago I installed an MS3 basic and MTX-L, and have been working on the tune since then. For the most part, it's coming along nicely, though there are a few oddities I may need some help with down the road. I also acquired an SR20 T25 from Zilvia, which appears to be in very good shape. I'm planning on working on breaking the turbine housing bolts loose this spring so it's all ready to be clocked when I get the rest of the parts.

The rest of my list is as follows, in roughly chronological order:

IAT: GM from DIY
Injectors: Flow Force 640cc, unless I can find a good deal on something else, like matched rx8 yellow injectors.
Clutch: Either ACT HD with organic disk or FM stage 1, depending on which I can find a good deal on. If I have to buy one brand new, I'll probably get the FM1.
Compressor flanges: Kingawanga from Ebay.
Wastegate snap ring: Garrett from Ebay.

Everything else: FM DIY kit. I know this will cost me a bit more, but right now time is worth more than money, so I would rather all the bits go together with minimal banging of heads into walls and punching of furry woodland creatures.

That's about all I have right now. I'll keep this thread updated when I have any interesting developments. Let me know if you see anything missing or wildly out of line!

It appears you are very local to me. I feel like I have seen this car around with the Konigs on it. Do you plan to do track days/autocross with this car?

Good to see another local! I'm not sure if I'll auto-x or not...I'll see how I'm feeling about it once the turbo is installed and tuned. I have thought about taking her up to Indy for the open drag days too; that would be fun. Do you go to the Columbus auto-x often? I know some guys who go nearly every time; a white MR2 and a green Bullit mustang. One of these days I'm going to tag along with them and check it out.

I've gone quite a few times, and still go periodically to do shake downs, but mostly I do track days. I know the people you are talking about, Xu was my nemesis for a while when I was autocrossing regularly in ES. I would highly encourage going turbo or not, it's a great group of people, it's great fun, and teaches you about your car.

Haha, yeah I heard he was pretty quick! He's working on building a Formula SAE car right now, he plans to autocross that eventually too. I'll have to check it out when the weather gets warm, I'll let you know when I'm going.

Glad to see this build progressing. If you're ever up at the Lucas strip give me a shout, I'm only about 5 miles from it.

Will do man! I'm starting to get excited about it, it's always nice to actually start making progress.

Sooo....after a somewhat long hiatus, time for an update!

After a rather intensive investigation into how to make the world's quietest turbo Miata with a 3" exhaust, I have commissioned the worthy Mr. Shuiend to build me a turbo kit with a custom exhaust. Props to him on a very solid price for a custom setup. He also stopped by on his way up north to drop off some bits that he already had on hand:
https://cimg4.ibsrv.net/gimg/www.mia...43e5221626.jpg

Since the MK Turbo kits use a T3 flange setup, I sold the SR20 T25 to Cameron and Ben, who promptly installed it and boosted the shit out of it.

While waiting for the MK Turbo kit, I have a few things I can work on in the meantime:

1) Install boost gauge (VDO mechanical gauge just arrived today, installing tomorrow)
2) Drill and tap oil pan (maybe tomorrow if I don't chicken out...)
3) Upgrade clutch

I pulled the splash guard off yesterday and realized there's no way in hell my drill is going to fit in there. HF was out of angle drills on sale, so I ordered this from amazon instead:
https://cimg3.ibsrv.net/gimg/www.mia...237a828e83.jpg

Hopefully it'll help me sneak past the power steering lines.

While I'm waiting for that to arrive, I went ahead and marked the drill location:
https://cimg1.ibsrv.net/gimg/www.mia...4469ded44c.jpg
https://cimg7.ibsrv.net/gimg/www.mia...d44cb93fc0.jpg
Ignore the squiggle to the left. The star shaped mark was attempting to imitate Savington's photo with the socket butted up against the rearmost rib on the compressor bracket.

Does anyone see any issues with this drill spot? I think it looks pretty close to the other pictures I've seen on here, but I just wanted to double check.

hole
 

make sure it is above oil level

It was recommended to find another flywheel and get it resurfaced prior to upgrading the clutch. I acquired this one from a friend, but I'm concerned about the amount of rust on it. It looks a little more than just surface rust:
https://cimg3.ibsrv.net/gimg/www.mia...47bfb76fe4.jpg
https://cimg4.ibsrv.net/gimg/www.mia...b59523b0bb.jpg
https://cimg5.ibsrv.net/gimg/www.mia...98819f4e10.jpg


My main concern is the rust on the mounting surfaces; it looks like there's some pitting. I'm not sure what's considered an acceptable amount of rust in this case; could someone please advise?

If you're getting it resurfaced, does it matter? From pics it's tough to tell how bad it really is though. If you are still worried about it, you can have mine.

Well the resurfacing will take care of the friction surface, but I don't think it'll touch the rust on the mounting surfaces. It's definitely beyond "minor surface rust" on those surfaces; there's some texture to it. I don't think I'm comfortable with putting something with that must rust damage into the engine, even if the rust itself can be cleaned off.

If you have one that's in good shape and don't need it, that would be awesome!

Tada! Drilled, tapped, and capped:

https://cimg6.ibsrv.net/gimg/www.mia...8c7be60c00.jpg

Also, someone please tell me what the hell is going on here:

https://cimg3.ibsrv.net/gimg/www.mia...da56d9a146.jpg
It's like he was trying to put a snorkel on and got the intake and exhaust mixed up.

I'm pretty sure he's using his exhaust as a rain gauge

Wannabe bosozoku exhaust, single sad pipe. :cry:

At least do the star...
https://s1.cdn.autoevolution.com/ima...s-96473_5.jpg?

Haha, wow...

So you want one of those for your exhaust tip. I got it and will make sure it looks just as badass.

Awesome! I want mine with heat bluing too, cuz that makes it more fasterer.

So Penis shaped exhaust tip, with a blue shine from a propane torch.

Haha, so aerodynamic!

with some round-ish shaped "resonators"?

He's got 2 of these going in; with some re positioning, they'll work:

https://cimg1.ibsrv.net/gimg/www.mia...8b958351f0.jpg

Needs more:

https://cimg2.ibsrv.net/gimg/www.mia...7d0bea5210.jpg

What is going on there? It has a rain cap? What is with these ricer people...I'll never understand them.

Sooo....I need some quick help if possible. Concealer404 and I pulled my transmission out to replace the clutch yesterday, and we saw that the rear main seal is leaking. I'm going to order a replacement, and I would like to just 3D print my own installation tool instead of ordering one from FM. Does anyone have the FM tool to measure the depth of the lip? Or has anyone ever measured the proper installed distance from the crank nose to the seal? The bolt pattern I can get from the flywheel, so that shouldn't be hard.

Already on it, My FM tool is on its way to his house :)

Awesome, thank you!

Small update to what is probably the most boring build thread ever.

I finally got the fuel pump upgraded to a Walbro 255 so I'm not running out of fuel in boost anymore. Lars also sent me a turbo adapter with the correct size wastegate flapper, so no more leaky wastegate. It's still creeping, though, so I'll need to port the wastegate some more.

Here is the list of projects that need tackling, in probable chronological order:

Thermal management - ducting first, then radiator
Tune spark (it's currently really conservative) and then fine tune fuel again
Replace funky fuji LSD with real Torsen
Still creeping so need to port wastegate more
Depower steering
Need new shocks - will enlist Concealer404 for help on Bilstein setup
EBC
Swap VTCS for VICS manifold

I'll try to post pictures of my ducting work when I get a chance to work on it, hopefully in the next few weeks.

I need some opinions.

I still have all stock cooling and A/C. My coolant temps while cruising on the interstate are getting up around 220F. When I do a few pulls, it gets up about the same temperature. When I'm in city traffic, it stays around 210F. Idling it goes down to like 205.

My first attempt at test ducting made a small difference; it kept it to about 215 during pulls. All I did was connect the bumper to the OEM splash guard, which is mostly intact. I'm guessing even if I make a sophisticated ducting structure and seal everything up tight, it still won't keep it below 200 under load. Plus, it'll still be over 200 when idling and in stop and go traffic.

So, before I go and buy a new radiator and at least one slim fan (the other stock fan should still fit), I just wanted to do a little sanity check.

A) Are the temperatures described above actually a concern for a street car? Am I making this a bigger deal than it needs to be?
B) Would a robust ducting setup help get the temperature down better than I'm thinking? Should I do that first?
C) Should I stop being a pansy, buy a damn radiator, AND build a robust ducting setup?

I would start with some ducting and a non-stock radiator.
So... C!

Thanks for the input :-) What coolant temperatures do you usually see under high load?

Re-route is the #1 improvement. Do that first!

New Koyo Hyper-V 37mm radiator (I have) or CFS from Supermiata (looks good) and ducting is next.

My build thread shows a fairly simple ducting made with plastic sheet. I did this same time as re-route, so I don't have separate data. However, after my little wreck, I ran a while without the ducting, or a bumper cover and CLT stayed below 210F (by conservative memory, perhaps only 205F). This would be with the Re-route and Koyo radiator.

I must be retarded, I can't find any pictures of the ducting in your build thread. I bought some of that rolled 1/8 inch plastic sheeting for the purpose; I'm trying to decide if I should buy a sheet metal brake to bend it, or cut it up and use angle brackets.

I guess I hadn't planned on doing the reroute because I have an NB2, and based on this discussion, there's some question as to whether or not it's necessary/effective/detrimental with the NB2 head gasket. Thoughts on this?

CFS was the radiator I was planning to go with. I need one low profile fan due to my intercooler return piping, and I was going to get the silicone intakes one because I'm cheap.

The fact that you were still above 200 even with a koyo probably confirms that I need to just do both (rad and ducting) in order to get back to reasonable temperatures.

Latest comments from Emilio is that any year, any head gasket, will be improved by re-route. Look Here

My apology on build thread. I don't have pics. I will see if I have some on phone. NOPE. Dang, I just got it put back together. I do like how it worked, so I'll pull the undertray off this evening and get some shots.

I did a combination of press brake, including making flanges on the side pieces, then used pop rivets made for plastic to join things together. Not real elaborate, but functional. I looped below FMIC by about 1.5" to get more air to the condenser / radiator per Sixshooter and others.

You can also heat with a torch, get it soft, and then form it. In fact, IIRC, some of the angles I put in with the press brake, I set with heat.

EDIT: At idle, you will always get to your fan settings, which, for me, turn on at 205.

Haha, I literally looked through it like 4 times thinking I was just missing the pictures. I'd appreciate some pics, though, if you have a chance to take some!

I stand corrected on the reroute; I daren't contradict Emilio :-) I'll add that to the list.

10-4 on the brake and heat...I don't have a torch, but I could probably pick up a HF heat gun for cheap.

Good point on the coolant fan temp setting; for some reason I was assuming it was set to stock, but given that my base tune came from vtechkiller, it's possible that it's set at 205. I'll check it when I get home.

Thanks for the help!

I am trying to complete some things before my first track day, so I was not willing to take this off the car for better pictures, but I can explain what I did.
First picture is the bottom, and the main event. The lip to the left is at the bottom of the opening of the bumper cover. Then the part goes down, under the FMIC and on back. What is obscured by the under-tray is that there is a 90 bend up such that a flange goes between the A/C condenser and the radiator. It is about 3" tall. It guides the air to the bottom of the Radiator. It does not block any flow, as it does not extend past the bottom tank. It helps position, and also yields rigidity.

Then I cut the front most flange off the under-tray as the main body of the tray is not at the same level as the duct. 3 holes and push fasteners can be seen, tying the front of the under-tray roughly as it used to be to the stock air director.

You can also see the pop rivets that hold the sides onto the main ducting body.

https://cimg3.ibsrv.net/gimg/www.mia...1c4483db31.jpg

Another shot of the pop rivets. The sides are mirror images of each other. They have flanges bent 90 to be able to mount to the main body. At the rear mounting location, they also have built in flanges (where the stud is that also mounts the under-tray).
https://cimg4.ibsrv.net/gimg/www.mia...33fb0273b3.jpg

(from the other side) The front mount was made with a simple angle piece riveted to each side. I could not find a way to integrate those.I made a little square piece to add thickness for the shoulder bolt that goes in that location (stock bolt).
https://cimg6.ibsrv.net/gimg/www.mia...0330659ea8.jpg

I don't have anything on the top, other than some foam strip to seal the top of the radiator to the cross member. I also stuffed foam along the sides where needed to stop the air from going around the radiator.

That's it.

Dude....you rock! Thank you! That's very helpful. I shall endeavor to replicate your handiwork.

How big of a brake will I need to do this? Is the 30" Harbor Freight one sufficient?

Not familiar with that tool. My FMIC is 27" flange to flange, and the width is just beyond that. I measured, width of main piece is 28".

Ok, thank you!

My stock undertray is kind of mangled from the previous owner, and it doesn't fit well with the intercooler piping anyway, so I think I'm going to make a new one. From what I've seen, it appears that the sidewalls on the undertray section are not necessary, but I can't find anything explicitly stating "sidewall are not necessary for the undertray to work effectively." Anyone care to confirm?

They are necessary. Just cut holes for intercooler piping.

Yeah, thanks; I was a little confused because I had found several examples of people just putting a flat sheet under it, but the more I thought about it, it didn't seem like that would be sufficient. I think I'm just going to try to make the stock tray work with trimming for now/

After several years of not having time to do much of anything on my Miata, I've got a few projects I'm going to work on this spring/summer. My sons are finally old enough to be interested in "helping," so that should make it interesting :-)

First up is to replace the engine mounts; the current ones have been shot for years. @concealer404 can attest to how much we were able to rock the engine around when we did the clutch, and that was years ago! I don't need anything fancy, so I got the Roadstersport competition 70 durometer mounts.

Next, replace my wideband. I currently have an MTX-L, but it's going out. Bought a 14point7 Spartan 2 to replace it. Still debating whether to get a gauge or not...leaning toward not. My tune is currently shit, so having a reliable O2 sensor is the first step toward rectifying that. I've never had much luck tuning it myself, so I may break down and take it somewhere or do a remote tuning.

Then, new coilovers. I don't need anything crazy, and anything will be an improvement over the current springs/dampers, which I think are original. My current plan is to get the V-MAXX classic set from FM.

I may also de-butterfly my intake manifold...we'll see how the first few projects go.

Replaced engine mounts, engine much more solid now. Spartan 2 wired up, need to route cables in engine bay and reinstall downpipe.


https://cimg7.ibsrv.net/gimg/www.mia...1ad233fa80.jpg
Engine mounts definitely worn, engine sits noticeably higher in the bay.
https://cimg6.ibsrv.net/gimg/www.mia...fe576246ea.jpg
Steering column had almost worn a hole in the downpipe. I knew it contacted sometimes, but didn't realize it was this bad. Preliminary fitment with new engine mounts looks like the DP has proper clearance now.

So...hit a couple of snags. The downpipe now has clearance with the steering column, but it's contacting the frame. My plan at this point is to cut some material away on the frame...but if anyone else has any suggestions, I'm open to it. I also haven't fully tightened the v-bands down yet, and it's possible that doing so would pull the pipe away from the frame. I'm going see what happens before I start cutting anything, but I think it's actually going to push it more into the frame, not away. We'll see.

Also, the harness on the LSU from 14Point7 is super short! It's nowhere near getting into the engine bay from where the O2 sensor is in the exhaust pipe. I do have an old LSU from my MTX-L that broke when I removed it from the pipe (note to self: don't use an impact wrench to remove oxygen sensors), and I have the cable from the MTX-L itself, which died anyway, so I'm going to splice them together to make a jumper.

https://cimg6.ibsrv.net/gimg/www.mia...1f16aaba13.jpg
Downpipe touching frame now...
https://cimg2.ibsrv.net/gimg/www.mia...54f52518b7.jpg
But it's not touching the steering column anymore!
https://cimg0.ibsrv.net/gimg/www.mia...ece35d2eaa.jpg
LSU cable way too short
https://cimg5.ibsrv.net/gimg/www.mia...f0d640e782.jpg
The controller has no extension from the plug, and I don't want to try to hang it in the transmission well...
https://cimg5.ibsrv.net/gimg/www.mia...028f702636.jpg
So these 2 guys are going to have a whole new type of relationship

Jumper harness complete, overall I'm pretty happy with it. I checked continuity at the end and everything checks out

https://cimg9.ibsrv.net/gimg/www.mia...109706940f.jpg
To make sure I spliced the right wires, I inserted the connectors and used an ohmmeter to check continuity. I was surprised, none on the colors matched. Not even red and black!

https://cimg0.ibsrv.net/gimg/www.mia...54a8327e8c.jpg
Twisted the wires together

https://cimg1.ibsrv.net/gimg/www.mia...e2b74f0cbf.jpg
Soldered

https://cimg2.ibsrv.net/gimg/www.mia...e5abddd62d.jpg
Oops! I let the wires heat up too much and activated the heat shrink...had to cut the ends to slide them over the splices.

https://cimg4.ibsrv.net/gimg/www.mia...997202da51.jpg
Individually heat-shrinked

https://cimg5.ibsrv.net/gimg/www.mia...a6bf2bea69.jpg
Overall heat-shrink, connecting the original sheathing.

https://cimg1.ibsrv.net/gimg/www.mia...2c5d51ffdd.jpg
Installed a couple of these in the garage too...tired of needing a flashlight for everything

https://cimg2.ibsrv.net/gimg/www.mia...5946d02e5e.jpg
Before - the camera is compensating, it was much more dim than this

https://cimg9.ibsrv.net/gimg/www.mia...a96026ebc0.jpg
Threads into normal light bulb socket

https://cimg0.ibsrv.net/gimg/www.mia...666ddf8771.jpg
Much better :-)

So I decided to depower the steering rack. Got the pump out and the rack off, though I may or may not have screwed the splines on the steering shaft in the process....

https://cimg9.ibsrv.net/gimg/www.mia...c1a8a0d76d.jpg
Bye bye power steering pump

https://cimg0.ibsrv.net/gimg/www.mia...2b07b17705.jpg
So much room!

https://cimg1.ibsrv.net/gimg/www.mia...dd70c18342.jpg
Tiny mechanics

https://cimg2.ibsrv.net/gimg/www.mia...439cac77ce.jpg
I got a little over-enthusiastic while encouraging the steering rack to "get the **** off the ****ing steering ****ing shaft!!!!" I'm really hoping I won't have to replace the steering shaft as a result...

Making slow progress on the steering depower. When I pulled the universal joint off, the splines on the pinion were super rusty, to the point where they're losing some shape in places. Has anyone seen this before? Should I consider replacing it? If I can re-use it, would it make sense to put anti-seize on this joint to help mitigate further rust?

Also, the tension adjuster came off with the locknut...which explains why it was so hard to get off. It didn't help that the only thing I had large enough to get a grip on the lock nut was a pair of channel locks. The locknut and adjuster were seized together and the top few threads on the adjust were pretty rusty. I'm soaking them in POR15 rust remover to try to clean it up, we'll see how it turns out. I think I may try to soak the pinion splines too to clean them up a bit too.

Had to order some Torx wrenches from the ol' Amazonians to get the pinion assembly off. They'll be here tomorrow.

https://cimg5.ibsrv.net/gimg/www.mia...8bc0204a03.jpg
Rack out

https://cimg7.ibsrv.net/gimg/www.mia...2930160e53.jpg
Super funky...mildly concerned about the integrity of the splines

https://cimg8.ibsrv.net/gimg/www.mia...c78d1530ac.jpg
These 2 came off as one piece

https://cimg9.ibsrv.net/gimg/www.mia...dd1ec54557.jpg
https://cimg0.ibsrv.net/gimg/www.mia...c3159d4543.jpg
Had to put it into a vice and use an impact wrench to get them apart

So, I'm not sure anyone's actually reading this thread, but I have a question about the PS depower. I've read just about every thread I can find about welding the pinion, and it appears to me that welding the pinion is important mostly to avoid wearing out the spline joint, which was designed to function in the context of pressurized hydraulic fluid, and will experience rapidly accelerated wear without that fluid.

Also, I've seen it mentioned several places that you could theoretically fill the splines with gap filler loctite, but I've not been able to find anyone having actually done this if it worked.

So my questions are:
1. Would the loctite method help support the joint and prevent accelerated wear? Or would it only take out the slop? If I'm thinking about it correctly, the accelerated wear comes from the relative motion between the splined components, so if you stop that by filling the gaps with loctite, it would address the wear concern...thoughts?
2. Does anyone from Indiana have any local welding shops they can recommend?

Thanks!

I can't answer your specific question, but MiataSource is where I bought my depowered rack. The following quote gives their reasoning for welding the pinion shaft. https://miata-source.com/blogs/tech-...-steering-rack
Edit: looks like they offer a TIG welding service for this pinion too

Thanks, I appreciate the response! It's interesting, from what I've seen, a lot of people say welding makes a significant difference in the responsiveness, but a lot of other people who didn't weld theirs say they notice no "slop" at all. I think this apparently discrepancy comes from the behavior of the torsion bar that connects the two components. People expect "slop" to be a binary effect, but in the torsion bar effectively smooths it to the point that you don't really notice when the splines come in contact.

Given this, I'm not as concerned about the initial "slop" factor, since it's a street car and I'm not going to be doing anything extreme in it. However, I've seen the wear related concern in a couple of places, and that seems concerning enough to warrant welding. I believe @hustler 's experience was that the "slop" got worse over time, and eventually had to be welded anyway.

I don’t think I’d use the loctite. I could be wrong, but I don’t think it would be strong enough. Can’t help with a shop in Indiana, but I just drove down the street to a welding shop I found online that was close to me. They spent maybe 5 minutes to TIG it and charged me $40 cash, which I’m fairly sure the guy just stuck in his own pocket for beer money later that night.

I haven't welded either of the 2 manual steering swaps that I have done. Never has any issues.

I am now installing EPS so take my opinion with a grain of salt.

Thank you for the link, I'll probably just use these guys if I can't find anyone local.

You're probably right...I'm always tempted to try things I can do myself, but in this case, it probably doesn't make sense. I worry about taking it to a random shop; it seems like it's a 50/50 chance that it'll get ruined...I'll probably end up sending it somewhere with a proven track record.

Thanks for chiming in Lars! I'm glad to see the business is still going well. What's motivating you to get EPS?

Very small update. Slow progress due to only having 30 minutes or so here and there to work on things. I got some of the rust cleaned up with a combination of POR15 rust remover and a brass wire brush on a power drill. I stopped at this point because I was starting to see marks on the clean metal, and I didn't want to damage the splines or threads.

https://cimg9.ibsrv.net/gimg/www.mia...d28366bf8a.jpg
https://cimg2.ibsrv.net/gimg/www.mia...b2cae6af5d.jpg

I got old and lazy. Really the manual steering is a bit tougher then I liked when driving in parking lots and such. I drove a friends car with the EPS and was happy with it. So while I am in swapping over to DBW and a new ECU, I decided to go with the EPS on top of it all.

Haha, old and lazy; we're not that old! :-)