Dyladjent

My tired greddy td04 is on its last leg. It has developed some shaft play and it seems like it takes a good bit of heat for it to spin freely after a cold start. I'll order a rebuild kit and keep it as a spare but as a precaution I'm about to order a turbo from kinugawa and I have a couple of choices.

I'm 99% sure that the greddy turbo on the car now is a td04h-15g. The only difference in the td04h-15t that they offer would be a variable vane compressor wheel instead of equal length blades. I’m running 12-13psi (190ish kpa in the logs) on what’s supposed to be a 7lb wastegate. The spool and transient response are ok. Running without a boost controller I’m seeing 4 to 5 psi in third gear at 2500 rpm that levels out to 8ish by 3100 and then slowly creeps up to 13lbs by 6500. My guess is that my wastegate can't keep up with the extra flow now that I have a full 3" exhaust from the turbo back.

The easy button would be to order the td04h-15t but I think I could optimize it a bit in regards to my goals.

I have two turbine wheel sizes to choose from a (H) 44.2/52 or (HL) 45.6/52 (exducer/inducer)

and 4 Compressor options (13t) 40.3/56 (15t) 42/56 (19t) 46/58 or (20t) 47/58

I think the 19t and 20t are overkill for what I want out of the turbo and will just hurt my spool for no real gain.
I"m not too sure the exducer size on the H vs the HL is going to be a huge deal. I may be wrong, I haven't really dove into specific compressor maps to see if the smaller compressor wheel will run into issues with the bigger turbine.(not sure if they even exist)

So that leaves me with the choice of the 13t or 15t compressor wheel. A big reason for my indecision is @DNMakinson has a 13t that I have seen VD plots for and he is making a good bit of low end torque. His turbo is a WRX TD04L-13t which is a 40.3/56 compressor wheel and a tiny 41.3/47 turbine. Unfortunately the L doesn't come in an exhaust housing that works with my DP. I have to have at least an H turbine wheel to work with my setup.

I'm kinda leaning toward the 13t just for the spool since I'm not really looking to make more than 230ish. My only concern is the 13t being too small and potentially running into compressor surge since I can't get the smaller turbine wheel.

My problem now: Is the 3.4mm in exducer size going to make a huge difference either way? Should I just go with the smaller one to get less mass for spool or will the bigger one flow more so it won't taper off up top? They offer a billet compressor upgrade for 100$ and a 9 blade turbine upgrade as well. I think I will be getting both of those.

Am I splitting hairs at this point or is one setup going to be significantly better than the other?

I only need this turbo to hold me over until I can start the K swap. My goal right now is to just stay out of rod bending territory and have fun while I gather parts.

I know this is an oddly specific scenario that not a ton of people here have experience with but just looking for some opinions.

Skamba

For most TD04s you can buy the core (CHRA) separately. If it's available, I'd just buy a replacement CHRA for the turbo you already have. Considering you're planning on swapping your engine I'd go for an inexpensive solution.

x_25

The WRX turbo uses diferent flanges.

The Greddy turbo is a TD04H-15g. I would just rebuild it and put it back on. If you want more power, do the 19T upgrade on it, though the CHRA needs to be machined slightly for that. This is what we did on my friend's greddy turbo.

As a side note, the turbo uses a T25 flange on the manifold side but the exhaust side is different. If you have a different flange put on your downpipe you can use any T25 turbo you like. My friend has his TD04H-19T on a kraken t25 manifold with a custom downpipe he made.

Dyladjent

Yeah it's an odd 4 bolt exhaust flange that I just paid a fabricator way too much money for a full 3" downpipe.







It fits perfectly and looks incredible and I think he might kill me if I brought it to him and asked him to put another flange on it haha.

The only options I have are from kinugawa and mamba, they make drop in turbos with the greddy flange. I would have to get a new exhaust housing for my current turbo because the machine shop that I had resurface the flanges took a good bit off and I'm having trouble getting a consistent seal without a gasket. I think the flange is too thin and warping with heat and I'm not 100% sure on if its a h or hl exhaust wheel. The compressor housing says td04h but I've seen people on the internet saying the greddy kit was an hl. Nothing I couldn't measure but by the time I pay 250ish for the new exhaust housing and for the machine work/ new compressor housing and getting the turbo balanced (which there is no one local that would even touch it) and sending it off to have it rebuilt/machined I would just be better off getting the Chinese one for less than 700$ and having a full spare core that I could rebuild at my convenience. Plus the new cores are water cooled as well which is always a plus and I've heard good things about the mambas from the evo/volvo community.

I've decided on this turbo from mamba. It's a greddy exhaust flanged tdo4hl-13t so the smallest compressor and the biggest turbine. I'm going with the 11 blade exhaust wheel and billet compressor wheel and it should be a spool monster. The 11 blade turbine should spool faster than the 9 blade but not flow as much up top. I'm not trying to make anything over 230ish I just want it as soon as possible. The biggest exhaust wheel should flow enough with my 3 inch dp to make the power I want and it comes with 2 or three wastegate springs with an adjustable .6-1.2 bar spring installed. This turbo also has an integrated bov that I can use if I want to simplify my system a bit. I'm happy with the one I have now so I may just cap/block it off but it will give me more options if I want them. It also comes with water lines pre made so I will just have to plumb them into my system when I have the engine/trans out for the clutch/ coolant reroute install.

I'm ok with upgrading this system because I can always swap it over to my 1.8 swapped 91 when I put the K in my 95.

Pacattack

I'm running a td04hl-15t off a saab viggen, Powerband feels really natural pretty similar to most t28s. It has a different turbine outlet though from yours and I am not sure If you could just slap a different housing on it. Might be another easily found option though.

Dyladjent

Yeah the turbine housings are all interchangeable assuming mine really is an HL exhaust wheel. That turbo is very similar to the one I'm running now the only difference being a variable vane compressor wheel. I'm quite happy with how this turbo feels now, I just think for my goals I could get a bit more out of a slightly smaller compressor.

I'm waiting on this td04hl-13t to get here from Taiwan now. I'll throw it on with my new clutch and report my findings. I think for a sub 250hp setup this will be perfect for a 1.8. It's got the biggest turbine wheel so in theory boost shouldn't taper off like the td04l that the subaru turbos have with the smallest compressor wheel/housing for all of the spool. We'll see. If this works out it should be the most baller overkill 230whp td04 on here haha. It should get me through this year and part of next year while I save up for the K24z3 at least. And I should have a solid setup that will bolt on to my other car when I get the K up and running. That way I can have two unreliable turbo shitboxes.

I will say for anyone reading this, that it is 100% not the way to go. Just get a t25 side mount and a gt2560 and be done haha. Dealing with any topmount manifold at this point means custom work and I've gone through tons of trouble just trying to make it work where it would have been easy mode if I would have just waited for a side/bottom mount. I knew that going in and I'm just living with my decisions at this point.

Dyladjent

An update to the madness that is the family of Td04 turbos.

I placed the order for the td04hl-13t early last Monday. I received an e-mail from Mambatek Friday asking if it was ok to replace the 13t that I ordered with a 16t. After emailing back and forth (Mambatek was very quick to reply with solid information every time) I've learned that they have discontinued the billet 13t wheel and compressor housing. I was a bit disappointed and almost cancelled my order. However in researching the 16t, which is almost exactly the same dimensionally as the 15g wheel just with a different blade design with extended tips similar to the EFR stuff, I came across something I hadn't considered.

There are 2 ar sizes in the td04 family, a 6cm which is near a .41 in garret terminology and a 8.5 cm that's close to a .64 ar garret. I always assumed the Greddy td04hl-15g used a 6cm housing, the 8.5cm housings were normally used on evo/dsm fitments and allowed more top end flow for the larger displacement engines. However that is not the case. The Greddy turbo uses the 8.5cm housing and that contributes to the difference in the 13t with the 6cm housing the wrx turbos use. So the 13t wheel would theoretically be less mass to spool but I think even more the larger ar contributed to the slower response (not that it's bad with the 8.5cm housing just not as good as it could be).

So now FOR SCIENCE I have a Td04hl-16t with a 6cm housing and billet compressor wheel replacing my Td04hl-15g with a 8.5cm housing and cast compressor wheel. I'll make sure to take logs of WOT pulls with my current setup and see how much the new setup changes everything. My theory is that it should gain a good bit of spool while still flowing a well up top because of the slightly larger/lighter and better designed compressor wheel. I don't think that the smaller 6cm housing is going to be a restriction at the power I will be running at seeing what others here have made with the WRX 13t with the smaller housing. And the 16t wheel should be big enough to get out of it's own way at higher rpms. We'll see. It may or may not make a huge difference but I'm doing it so no one else has to.

Could I have done it cheaper? Yes. But I'm one to over think and over do everything. My builds usually end up being meticulous about stuff that doesn't even matter and I'm ok with that. I know a ton more about turbos than I did before. And after everything is done I should have a decent water-cooled setup that will be ok to put a ton of miles on and not have to worry about with a solid backup if something catastrophic happens.

Dyladjent

It's here. TD04HL-16t with a 6cm turbine housing. As far as ordering through Mambatek, 100% would order again. Their customer service was fantastic, quickly replying to emails updating on every step of the process. Once the package left Taiwan it was here in 4 days.

The castings for the turbine and compressor housings are good. The Turbine housing feels the same as the greddy. The 6cm housing at first glance doesn't appear dimensionally different on the outside I'll have to take side by side comparison pictures.The compressor housing is shaped very differently because of the integrated bov and the inlet is much longer than the greddy's.

The kit itself is pretty comprehensive. It has 2 10ish inch long braided lines to -AN banjo fittings to get the rubber water lines away from the turbo. All the studs have the tiny hex heads on top. (we'll see how the stainless hardware holds up or if I need to upgrade to inconel) It came with a brass t fitting and a couple different fittings for the oil feed. A full -4AN oil feed line that I think will be long enough if the pre 96 oil feed on the block is used. It even came with the vacuum line that goes between the barb on the turbo and wastegate and two of the tiniest spring clamps to hold it on.

They also sent 3 wastegate springs with the kit. The listing for the turbo says that a .6bar (8.7psi) spring is already installed but it feels quite a bit stiffer than the 6 or 7 psi spring in the greddy turbo. I believe that the other springs are a1.5bar (18 or 22psi) spring and a 1 bar(14.5ish psi) spring. I'll get a pressure tester and verify what's in it before the install. I think they would have sent a different combination of wastegate springs but I forgot to ask in their follow up email. I think they will send anywhere from .4-1.5 bar springs upon request.

They also didn't have one of their billet blow off valves in stock at the time so they sent an "oem style". We'll see if its as bad as the ones on the efr. If its terrible I'll probably end up getting a block off plate and just using my current bov that's on the car now.

I'm waiting on a SM clutch now. After that arrives I'm going to pull the engine for some cleaning/maintenance and install the turbo along with my coolant reroute so it will be a week or two before I get everything together and get some results then. I'll post before and after data logs when I can get them.

Dyladjent

I got everything installed and quickly realized in my first couple of pulls that the new turbos waste gate can't flow enough to keep the boost low enough as it is. I hit 207 kpa at 4800 rpm at less than 50% throttle. It spools much more quickly than my old 15g. It feels much more punchy below 3k even at less than 50% throttle.



I thought it might have been the wastegate spring that was installed but after testing it we found out it was opening at less than 15psi. The preload is set correctly. I also switched between running the wastegate vacuum signal from the cold side charge piping to the nipple on the compressor housing just in case the long line was pinching closed. No luck. I will be taking everything apart this week to install some maintenance stuff and will port the wg opening and see if I can't get it down to a more reasonable level.

In other news the integrated bov sounds... interesting ... it has the whole dying seal noise at partial throttle sometimes but I have had 0 compressor surge, even at very light throttle and it doesn't leak at idle so its ok I guess. I'm still going to order a block off plate in the event that I get tired of how it sounds haha.

Dyladjent

I'm dumb and didn't get before pictures and it's not pretty but I took the sharp leading edge off of the waste gate port and smoothed the lip on the bottom side of where the flapper seals. I used a dremel with a dull carbide cutting bit and some polishing stones/sanding wheels so not exactly the best tools for the task. Despite it looking like I hacked it out with a chisel it eliminated my insane spike/creep. With the yellow spring installed it held 7 psi all the way to redline. With the black spring installed and the gate referenced from the nipple on the compressor it holds 12ish. Over 6k in third I saw closer to 190ish kpa so I may still have some creep but it's now 100% manageable.




The turbo even on spring pressure is so responsive. The transient response is great. It feels much better than the old tired Greddy 15g. I haven't got a good 4th gear log because my clutch is not too happy over 12 psi. My supermiata clutch is going on next week and I will get logs. Even now rolling into 3rd I'm easily at 180kpa by 3500 RPM at 75-80% tps. Rolling into 5th at freeway speeds immediately jumps right up to 12 psi before the clutch ***** itself.

This way was a tad overkill for what little power I'm making but so far it's been great. Hopefully I'll be able to get to a dyno soon and get some concrete numbers.

der_vierte

Good documentation!

I would install the 7psi spring, put an on/off switch in the cabin for the solenoid and let EBC do the rest, if you don't plan to go over twice the pressure the wastegate spring provides, no more boost creep.
At 7psi you have a nice low boost/power setup for trackdays, rain and so on

emilio700

iTrader: (3)

If its a puck, only minimal break in is needed. If its the organic, drive it gently a few days without the boosts before leaning on it. Organic must be broken in to reach full torque capacity.

Just FYI

mx5newbie

iTrader: (1)

Old but great thread and write up. I too chose to go with a Mamba TD04-13T to replace the slower spooking Greddy on my 1.6. I ran a 2.5” Downpipe, but this weekend I swapped out the 1.6 for a BP4W. I still plan to run the 13T, but I do have a 16T I could use. I think I’ll like the 13T better, especially going to a 3” Downpipe and exhaust. I may drop down to the 7 psi spring as well.