Hey y'all, I just got a turbo'ed miata!
 

Hello!
My name is Dylan, I'm 27 years old, and I live in minneapolis mn. I have a garage full of nice tools and I kinda know how to use them. I've had about a dozed project cars and bikes, but this is my first turbo(other than a vw tdi). I am comfortable doing just about any job except some that involve internals, but dad (vw mechanic for 30+ years) always helps when I get myself in too deep. My friends dont give a ---- about cars, so I rely on forums for support. I've been lurking here for a few months while waiting for a cheap miata too pop up around here, and I finally found one last night!!! Its a 92 5spd w/116k, its got a greddy kit installed, and the turbo its fried!!! I drove this think home about 10 miles last night and by the time I got her into the garage I thought I was going to blow chunks all over myself and pass out from the fumes! It was awesome!! So, I pulled the turbo(td04h) and sure enough, tons of shaft play. I am extremely stoked to get this thing running, but I am on a very tight budget and I have to find a new turbo. From the little research I've done so far, it seems that this setup is a bit obsolete and I'm not going to find a ebay td04h for a few hundred bucks. So here are a few thoughts/questions:
*I know there are a variety of td04h turbos out there, but how do I know for sure what one this is? (i think its a 15t 15g???? sorry, dont know ---- about turbos!)
*I think the td04h was the stock turbo on some saabs and volvos and others, but are they the same as this one?
*can I find a more common turbo that would be an upgrade and a direct replacement for the td04h? perhaps a td05 or t25?
Basically, I am trying to find a cheap turbo to get this thing back on the road for less then the cost of a rebuild(a few hundred bucks?), if at all possible. If not possible, I'm effed and I'll have to park it for now. Any advice you dudes have for me would be greatly appreciated. here's a few pics. sorry for the poor quality, I'll get some nice ones up soon. Thanks in advance for your input!!!
https://www.miataturbo.net/attachmen...ine=1343169213
https://www.miataturbo.net/attachmen...ine=1343169213
https://www.miataturbo.net/attachmen...ine=1343169213
https://www.miataturbo.net/attachmen...ine=1343169213
https://www.miataturbo.net/attachmen...ine=1343169213

You might tear down the turbo and see if its damaged, if not rebuilding it might be a good option that saves money over another used turbo.

It's a very specific turbo. Nearly identically sized turbos do exist, but with up to 4 different bolt flanges. Remember you have the compressor inlet(air filter) and outlet(intercooler), along with the turbine inlet(manifold) and outlet(downpipe) to match.

A rebuild kit is under $100 from gpopshop.com, I'm 90% sure you can get one from them, they have great customer service, shoot them an email.

can I rebuild a turbo myself? I've heard if you diy it can be unbalanced and not work right. Im also thinking it would be smarter to swap to a more common/better turbo then to put money into this one. I am willing and able to modify my downpipe for a different outlet flange, but what turbo would work well with my setup and bolt up to my t2 greddy manifold?

Yes you can rebuild it yourself, loads of people here and elsewhere have done it at home, myself included. There's a step by step tutorial floating around somewhere, it's easier than it seems.

If you're going to change turbos, you could do any GT25 turbo, the one of an SR20 DET being the cheapest and most easily found, but I'd suggest a rebuild on a used one of those as well, and they're no bigger.

That's the same roll bar I have!

Rebuild kit. I've also rebuilt one and it worked out fine and was still going strong 3+yrs later last I heard. Just pay attention, don't bend any fins, mark alignment with a sharpie, etc.

Welcome to the site bloodnstuff, thanks for joining up!

Alrighty then, rebuild it is! Now, should I take the rebuild cartridge to a turbo shop for balancing after I rebuild, or is that unnecessary? I'm looking on gpopshop and they have a standard and a full rebuild kit. I'm thinking I'll go full, but I need to identify my compressor wheel to buy the full kit. (flatback or superback, 14g or 15t etc.) how do I do that?

My rebuild kit is on the way. I pulled apart the turbo and the shaft is groovy, but I found a new one locally at midwest turbo connection. they can also balance my shaft, so it looks like I should have this beotch done this weekend for about $300 total. Should I worry about the cartridge bearing surfaces being warn out like the shaft was? its very hard to see/feel in there, and judging by the wear I found on the shaft, this poor little guy went through hell.

You'll be replacing the bearings with the included replacements in the rebuild kit.

Yes, I realize that, I guess I worded that question poorly. I meant the surface, or bearing race of the cartridge itself. Or is the bearing in a fixed position in the cartridge?(Doesn't rotate in the cartridge) Sorry for all the basic turbo questions, I'm not retarded and I DO know how to work on cars, I just have NO experience with turbos.

My impression of the Garrett I rebuilt was that the bearing sleeves rotated (or at least could rotate) since they were a drop-in replacement, as opposed to a press-in affair. Not only that, but there were oiling holes through the bearing, which led me to believe that they floated inside the assembly.

I did not have my CHRA balanced. I left the turbine wheel on the shaft, and marked the nut/shaft/wheel on the compressor side, reassembling as close to those marks as humanly possible.

The turbo is back in the car! The rebuild went great(i think), there was really nothing to it. Total cost for parts and balancing was about 300 so I'm happy I went that route, thanks for pushing me in that direction. However, this car is no where near ready to be driven regularly. I have to track down the source of the massive pool of oil the thing dumped on my garage floor, and I think its running extremely rich. My air/fuel gauge is ALWAYS in the green (even at idle!) unless I unplug my inline fuel pump,(I dont thing its even supposed to have an inline fuel pump?) then it at least bounces to red a little during cruising and at idle. After boost when shifting gears, it blows a huge cloud of smoke/vapor which I think/hope is unburnt fuel. The longer I'm in boost, the bigger the cloud. It does not smell like oil or coolant although I have not completely ruled that out 100%. If it was oil or coolant and not fuel, then why would it only blow smoke after boost? Oh and btw, I'm running a vortech fmu, stock injectors, and apparently an inline fuel pump. I'm tempted to just get a cheapo manual boost controller, plug the inline pump back in, check the timing, crank the boost up to 7-8psi (it makes 5psi now) and see what happens. I believe its dumping enough fuel for more boost, and I dont have any other discs for the fmu, so this seems logical right?

If the cost of a turbo originally almost made you part out the car, then turning up the boost and blowing a motor will be well over your budget. I highly suggest that you do not touch the amount of boost and track down and fix all the other problems first.

yeah, you are right. This thing is just so SLOW at 5psi. If I can get it to run right with this setup then maybe it will quicken up a little. At some point I will go megasquirt and big injectors, but for now I am stuck with 5psi so I may as well make the most of it. Any thoughts on my huge after boost smoke cloud? And i mean HUGE, after a 4th gear pull from 3.5k to 6k on the freeway, all 3 lanes of cars behind me DISAPPEARED behind the cloud. It was not cool.

I am going to verify that it is not a bad head gasket and that its not burning oil, but I really dont see how those could be the problem when the heavy smoke only happens after boost. I know what burning oil and burning coolant smell like and this smell is not either of those, its is almost odorless. I know its not water vapor because there is coolant in the cooling system and not just water. is there any reason why oil or coolant could be burned only after boost? is it possible for my fuel system to continue to dump so much fuel after boost that I get a mushroom cloud of unburned fuel?

I see you have a maf, do you have an open air bov?

With a system that meters the air, if you release a bunch of air you get super rich right after.
Not sure that would cause a cloud of smoke like that. But it will run stupid rich for a second after.

have you done a compression test & leak down yet to determine the health of your engine? before you get too impatient about turning up boost give your care some tune up action.

akazero- yes it is a open air bov, and I see what you're getting at, maybe I need to recirculate. good point.
krissetsfire- The previous owner just rebuilt the bottom end before blowing the turbo and says the compression is perfect. I would like to verify that though, because craigslist is anarchy. and I'm not going to turn up the boost. I was just a little frustrated when I typed that because I was hoping this thing to be at least fast-ish.
I tracked one of the oil leaks to the bov, so I pulled some boost pipes and found a shocking amount of oil inside. I'm fairly sure its just leftover from the turbo blowing; I've only driven it 8 miles since rebuilding the turbo. But on my valve cover where I would expect there to be a breather, it is vented to my intake pipe right before my turbo. I found a good amount of oil in that pipe too, and thats before the turbo. again, it could be leftover oil, but why is that vented that way? seems questionable, and like a potential source of oil going into the boost pipes to me.

sooo if the rings didn't seat during rebuild or it wans't done well you could have a lot of blowby. i'd test compression but i'd check the leak down. it'll tell you your heads condition as well.

oil from the breather valve would indicate blowby to me i hope it's not!

unless you are racing or putting your motor under extreme pressure little to no oil should make it through there. it's just to relieve pressure.

I never figured out why companies design their turbo kits like this. Why would you want turbo inlet (vacuum) to pull crankcase vapor through your intake tract and back into your engine? I call this CGR (crankcase gas recirculation) because it reminds me of the same thing as EGR (exhaust gas recirculation). I understand the need for the crankcase to have vacuum assistance, but why plumb it to a turbo inlet?

results of compression test::crx:

dry wet
90 105
70 105
175 220
165 240

I'd really like to believe that its the the head, but with my luck, its rings. Although, the wet test helped on the good cylinders by roughly the same percentage as the bad. so maybe my luck has changed and its the head? or both? F, idk, im a shitty mechanic. either way, there is no easy way out of this one. opinions?

Well, so far I have had two heads with bent valves and only one thrown rod. No piston blow-by to speak of. So from my stats head is much more likely....