In which I turbo a 1.6 and get in over my head
 

I guess I'll start with a little background. I bought my Miata in February 2016 as my first car. 1990, 106,000 miles, and manual of course. Here's a pic of it parked outside my house that day.

https://cimg2.ibsrv.net/gimg/www.mia...5481fd8d9c.jpg

Paint was rough but mechanically it was sound. Over the next 14 months I've upgraded the headlights to Cibies, swapped in a open diff from a '99 after mine blew up, upgraded to a CXRacing radiator, depowered the steering, and just recently did the timing belt myself. Here's how the car sits now.

https://cimg8.ibsrv.net/gimg/www.mia...a76a425d33.jpg
https://cimg0.ibsrv.net/gimg/www.mia...51cd2a2945.jpg

Most of my upgrades have been from replacing broken parts with something better than OEM, and this is mostly because it was my daily and I couldn't really afford to have it off the road for long periods of time. But about two months ago I snatched up an $800 1990 LS400 off Craigslist as my daily driver. It's sitting at 227,000 miles but I know they're bulletproof.

https://cimg3.ibsrv.net/gimg/www.mia...f56f38ec1d.jpg
(I might have a thing about 1990 silver cars.)

So now I can really start working on the Miata and ultimately turbo it. I've spent the last few months researching and I've come up with what I believe to be a fairly comprehensive spreadsheet and plan. Here's a link. Green means I've bought the part, yellow means I'm ready to buy, and red means I need more research. As you can see, I've started to buy parts. So far, I have the turbo, some hardware, and some downpipe parts. I'm still waiting on flanges to come in the mail, and I need to pick up the manifold tubing from Ace.

https://cimg4.ibsrv.net/gimg/www.mia...8d7c9862ae.jpg
https://cimg6.ibsrv.net/gimg/www.mia...11446e9179.jpg

Once I get all the manifold goodies I'll be able to weld it all up and bolt on the turbo. From there I'll fabricate the downpipe. My plan is to purchase a few "sections" of the build every two weeks, then spend that time adding them to the car. Next will likely come exhaust.

Well, that's it for today, I hope you guys enjoyed seeing this and are looking forward to updates.

More parts came today and yesterday. Turns out I ordered the wrong exhaust flange for the turbo. This is what I get when I don't read descriptions. I bought a T3 5-bolt for my T25. Doesn't exactly fit. I guess I'll be returning it and buying the right flange with an oval tube transition. On the plus side, I now have some 2" tubing to practice welding on before I actually fab up the downpipe in 3". 2 3" 4' sections also came from summit. My cutoff wheel came for the miter saw (I know it's not the best idea) as well as a m8x1.25 tap set to clean up the holes on the housing.

How has the LS400 been?

It's pretty good. I bought it with a CEL on, code read too rich/ too lean. Plugs and wires only cleared it for a while, but it's back. Not exactly a priority since it doesn't affect drivability. Other than that, the a/c doesn't work, and that's about it. It's wonderful to drive in - very isolated.

Thinking of one as a daily?

Quick update: Just got some goodies from PRL and Ace Stainless.
https://cimg9.ibsrv.net/gimg/www.mia...a4e65d9737.jpg

I have everything I need for the manifold so I'll probably start fabbing it up tomorrow morning.

On a semi-related note, I tried my hand at welding some 16 gauge tubing I had, and damn, I need a lot more practice before I move on to the downpipe and exhaust.

Welding ain't easy bro.

Nice kit.

Yeup..think of maybe buying it to ride the wheels off = more money for miata

I made some progress on the manifold today. I've been way too busy during the last week with school and making sure I graduate. Now that's out of the way I should be able to put much more time into the build.

I cut the tees and els to size. A cutoff wheel takes a LONG time and really makes me wish I had a band saw. The fitment wasn't too bad overall. I also beveled the edges so I could get good penetration and cleaned everything up with the flap wheel. I tacked it all together and that's where it is now.
https://cimg3.ibsrv.net/gimg/www.mia...8dcc236c45.jpg
https://cimg5.ibsrv.net/gimg/www.mia...4006d7feec.jpg

A gap that wide was a little frightening at first but I'm much more confident in myself after the tacks. I guess a root pass will be easier than I expected.
Also, here's how the back looks. It looks like I'll need to do some porting before I'm done.
https://cimg6.ibsrv.net/gimg/www.mia...b648d0da46.jpg

So all that's left is to backpurge it, weld it all up, then make the cutout for the T2 flange and weld that on. I'd like to accomplish this in a week but we will see.

Do yourself a favor now, get some new weld els and start over. those gaps are going to crack really quickly. There is a good thread going on about the failure of these log type manifolds. starting out with giant gaps to fill is just speeding up the failure. Not being a dick, just trying to prevent you from a lot of wasted work.

Well the thread about weld el manifold failures is far more about absurdflow low mount styles cracking. I don't think a log has the same sort of forces in the same directions. Saying all that I would definitely get 2 new tee's and make those so they are closer when you weld. When I build my manifolds I try to get everything touching, or at least within a millimeter or two. Building 1.6 manifolds are my least favorite since everything needs to be cut.

Multiple valid points.

I also have just about zero formal welding training, so I don't really know what is proper or good. I just know what I have done for the last 40 some manifolds I have made, and what seems to work well for me.

I tried to do exactly what you're doing; weld-els and used T2. Gave up, hit the easy button and bought a Taco log and eBay T3. PLenty of other stuff to spend time on.

I appreciate the advice, but I think I'll just end up welding across the gap. I know fit up is important for more precise tig work, but from what I understand there generally is a purposeful gap to allow penetration when welding pipe in the field. With pipe this thick, I think this will give me the strongest welds.

However IF they crack I will definitely let you guys rub it in.

I considered the easy route - after all, I'm hardly saving any money this way. But at the same time, I'd rather gain experience and pick up some new tools and skills than have someone do it for me.

To each their own I suppose.

You like the flanges from PRL? That 1.6 flange exists because I got them to make it for me. The T3 log flanges that curve over the log are also baller.

I have a few 1.6 setups cut up, I will try to snap a picture or two tonight of how close I try to get mine.

Thanks man, I'm in love with them. I couldn't imagine trying to smash pipe this thick into ovals.

What do you use for the cuts? A band saw? I couldnt imagine you use a chopsaw or cutoff wheel with the number you cut.

I weld, a lot. some gets tested. I can tell you with 100% certainty that the gap is way too big for tig, mig or stick. you are going to introduce huge amounts of stress ( in the 10's of thousands of lbs) in those joints. continue on.

Dont you want a very small gap at the bottom of a v butt weld for best strength?

I use a HF band saw. It is between $200-$250 and word reasonably well. If I could figure out how to properly adjust it to get perfect cuts it would be much better. But every time I do go to adjust it I just make it worse.

It is very hard to tell from the picture. 1/16" gap on that size pipe would be ideal. You may be able to get the center gap together a little by gaping the outside 2 a little more. The way the outlet saddles on this type of manifold is what saves it. Make the best weld joint the one that isn't gusseted with the outlet. You could also pull one of the Tee's out and "butter" up the end if the tee with weld metal and regrind your bevel and fit it up again.
Good Luck.

Thanks for the tips. I think I will pull them out and add some material. Before you mentioned that I really thought my only option was buying some new tees and cutting them and I didn't want to go through all that again.

Just keep everything clean. Spend the time grinding and in fit up your welds will come out much better.

I buy all my weld el's from a local plumbing shop. Call around and you can probably find them locally if you live in a decent sized area.

Luckily enough I live about 30 minutes from Ace Stainless.

In that case I would go buy 2 more tee's and start over just to be on the safe side.

Well, you guys convinced me. I'd rather do it right than do it twice. I'm going to order new tees today and pick them up on Tuesday.

Good choice. Take plenty of time and get the fit perfect with good bevels.

smart.

in this case I would not. I would bevel 75%, then run a hot setting on the welder. I could easily get full penn. Cuts down on having 10,000 wires inside the manifold too. Thats just me.

Got more parts today! I stopped by Ace to pick up the tees and had the ATP Turbo stuff waiting for me when I got home.

https://cimg2.ibsrv.net/gimg/www.mia...b8350f6f9a.jpg

It's nice to have an exhaust flange that actually fits now. It feels like it's good quality, not that I really would know. However, I'm disappointed in the oval transition. Even though ATP says to use it with their flange, it did not fit initially and required some massaging with my vice. Now it sort of squeezes into the relief. And now, thanks to the persuasion it needed to fit, the "round" 3" side is slightly ovaled. Wonderful. I don't think I'm expecting too much for an $18 part. If I did it again, I would much rather crush a 90 into an oval. It would be the same amount of work and save me a weld. Oh well... live and learn.

This is how one of my 1.6 manifolds looks before I bevel it.
Attachment 230193
Attachment 230194

Very helpful, thank you.

Today I cut and beveled the tees. I'm very pleased with how it turned out and can't wait to weld it up.

https://cimg8.ibsrv.net/gimg/www.mia...9c8109026e.jpg
https://cimg9.ibsrv.net/gimg/www.mia...54c43a91e3.jpg

Nice! Looks great, sooo much better than last time.

ladies and gentleman, this is what happens when real friends step in. You started off showing parts than looked like doo doo destination brokenville. We told you it was junk. You came back with nice parts and added skills. Keep going with new standards and this build will be a good one.

nice....be sure you clean the ID of the pipe also a 1/2" back or so from the weld. The first set was worth the money for practice.

It was a little while since I worked on the car since my last post. In the past two days, I really got to work and finished the manifold, the 5 bolt adapter, and I fabbed a small bracket for the wastegate.

https://cimg2.ibsrv.net/gimg/www.mia...1d67130414.jpg
https://cimg3.ibsrv.net/gimg/www.mia...e426e60b21.jpg
https://cimg4.ibsrv.net/gimg/www.mia...c5604e7556.jpg
https://cimg5.ibsrv.net/gimg/www.mia...c114e09461.jpg
https://cimg6.ibsrv.net/gimg/www.mia...8026136ea7.jpg
https://cimg7.ibsrv.net/gimg/www.mia...4d75ea7a26.jpg
https://cimg8.ibsrv.net/gimg/www.mia...382c092f75.jpg

My welds ARE getting better but still look shitty.

Update for today: I was a dumbass and bent the compressor wheel from moving around the housing carelessly. I think I'll end up buying a new wheel or just wait and buy a genuine 2554 or 2560. Or maybe another chinacharger. I don't know for sure yet, and I still have a while to go before I can get to a point where I would make boost.
https://cimg2.ibsrv.net/gimg/www.mia...861e14541f.jpg

I also fitted the manifold to the head after making the holes slightly bigger. I still need to do a little grinding so the nuts will all fit. I'm happy with how it looks.

https://cimg5.ibsrv.net/gimg/www.mia...d4c26ccea7.jpg

Yep lower cornet nuts are always tight on the 1.6 manifolds. I have not figured out a good solution for that yet.

Skip the chinacharger and get a SR20 T25. I've gone through two chinachargers, and they've both been junky on different levels. You can pick up an extremely decent SR20 T25 for 250$-300$, and you'll be perfect for the future. I suggest going on zilvia.net and post a WTB post. I had a response within a day.
The SR20 turbos are garret journal bearings. You get OEM quality, at a chinacharger price.

bend blades back, call it a day. that's what I'd do at least...

Today I did a mini coolant reroute, mostly because I needed more room for the downpipe. I bought 2' of 5/8" heater hose, a 1' 5/8' copper coupling, and a few 15/16" spring clamps. In total, I spent about $15. I'm pleased with how it turned out. It should do a little to keep temps down until I start making boost. Now, I can finally start on the downpipe and exhaust. I really wish I made a bottom mount manifold because it would be a hell of a lot easier. Oh well.
https://cimg8.ibsrv.net/gimg/www.mia...f4d61dbd1a.jpg

I also bent back the blades per Braineack's advice.
https://cimg7.ibsrv.net/gimg/www.mia...2630ebe552.jpg

I started on the downpipe today. I decided to make pie cuts because 1) there's no way a mandrel bend will fit in there, and 2) it'll give me a lot of practice welding thin gauge material, which I really need to get better with. I'm probably not going to calculate the exact angles I need and instead I'll make lots of pie cuts and use them for the complex angles I'll need.
Here's the first 90 I made. I ended up eyeballing the size of the middle pieces after I set the center line radius to 1" in the calculator and realized that wouldn't work after I started cutting. Also it doesn't quite reach 90 degrees - and I'm not exactly sure why.
https://cimg6.ibsrv.net/gimg/www.mia...6b2a501bf8.jpg

Here's a quick comparison to a 90 with a 3" CLR from Summit. Much tighter as you can see. I did the math and my pie cut has a CLR of about 2.3".
https://cimg7.ibsrv.net/gimg/www.mia...abf1ce7b4d.jpg

Here's my second pie cut 90. Much better than before. This time I cut it correctly for a 2" CLR. I added one more middle section to make it smoother and a little more aesthetically pleasing.
https://cimg8.ibsrv.net/gimg/www.mia...a23c14c183.jpg

Here's the new one compared to my first. Even tighter.
https://cimg9.ibsrv.net/gimg/www.mia...9f0ca37c99.jpg

The smallest sections are a little thicker than a quarter inch, with the edges being a little under. After welding all these up I'm either going to be wayyy better at tigging small stuff or never want to see a tig torch again. Hopefully its the former.
https://cimg0.ibsrv.net/gimg/www.mia...825d913c51.jpg

what turbo are you running, and why did he advise you to bend the blads?

how are you bending them? Were the tops bent before, and you bent the vanes straight?

wouldnt that negatively change the balance? I cant imagine you could bend them all perfectly and have balance past 100,000rpm

thanks

It's some t25 chinacharger. I think they were mostly straight before but I guess it'll work if they're all straight after. Yeah the balance is probably off but it's better than when they were bent.

Oh ok, I missed his post on the mobile site.

I thought it was some performance gain lol