barron64

Looking for a little advice...Purchased a NA 90 model last year from a friend who had thrown quite a bit of $$ into the car with a Greddy turbo kit, FM intercooler, Racing Beat body kit, paint, cloth top, suspension, wheels etc...I have been sorting out the details over the last year and had the car running fairly strong at 10psi of boost while still running the band aid fuel controls he had. Then this past weekend I hear a significant exhaust leak and discovered the expected cracked Greddy manifold and 2 broken bolts.

Question is...Is the Greddy/Mitsu TD04 worth building around using the ARTech custom manifold and down pipe, or should I cut my losses and go ahead and convert to a T25 turbo system from FM or BEGI? Cost and ease of installment says use the ARTech manifold/downpipe but am I just throwing $$ at an odd ball turbo setup? The ARTech parts sure look sweet and look like they could really free up some flow...But, I would hate to invest $800+ and then have the TD04 crap out on me. The TD04 looks and feels fine. Probably only has 15K miles on it also. Thoughts?

Fireindc

iTrader: (13)

Find a new or used greddy manifold. If you want to go custom setup like a artech setup, do it around a t25 footprint or something that gives you an upgrade path.

matthewdesigns

iTrader: (8)

Which TD04 turbo comes with the Greddy kit? What are your goals?

ssmith

iTrader: (10)

15g but you could upgrade the compressor wheel to a 19t.

matthewdesigns

iTrader: (8)

Well I'm going to say stick with it. If the turbo is in good shape just get a new mani made with a 7cm^2 flange so you can bump up to a larger Mitsu turbo in the future if you desire. There are plenty of Mitsu-footprint turbos available that can meet damn near any goal you'd have with the car.

Although, not sure if the Greddy kit uses the standard Mitsu turbine outlet flange, so you may also need a new dp if/when you ever swap turbos.

ssmith

iTrader: (10)

The greddy turbo uses a t25 footprint for a manifold, and a wierd almost one off downpipe flange, so essentially you could change out for any other t25 as long as you got a custom downpipe to match.

IIRC artech was doing the greddy downpipes with an option of a different flange so you could do such a project.

curly

iTrader: (25)

I actually just made this upgrade. I had a greddy setup, and artech offered to make a manifold and downpipe around my turbo.

I choose to go with a SR20 turbo for $65 that I rebuilt for $90. I had a stuck stud that cost me $70 at a machine shop, but $225 I'm extremely happy. 5-bolt DP flange, upgrade options, water cooling, and about 300-500rpms of earlier spool. Other than that the turbos are very closely sized.

If you can find an SR20 turbo cheap like I did, I'd say go for it, but if yours is in good shape and you're smart with your money, I'd probably build around it. Just change the setup to a side or bottom mount, they're more difficult to install and bolt up, but the downpipe routing is straighter and cleaner. That also gives you better spool.

He might offer you a stud kit, buy it.

barron64

Thanks for all the input guys. My goals are to eventually have a reliable 225rwhp on 93 octane for a daily driver. Engine is fresh with a set of +1mm J&E pistons but stock rods. I have a MSPNP waiting on the bench along with a Torsen 4.1 1.8L diff...But I still need cv shafts, drive shaft and a FM clutch to allow the drivetrain to survive. 10psi is cheap at the moment as that is all the clutch and fuel enrichment can deal with.

So let me get this straight...The Greddy/Mitsu TD04H turbo uses the same turbo inlet flange as the T25 Garrett? If so, I could keep my current TD04, use an Artech, FM or BEGI side mount manifold which would allow me to change to a T25 in the future if needed. I assume the sidemount design flows better than the top mount Greddy design, correct? Then I would need a custom DP from Artech made so I could use my current Mitsu turbo.

Looking at the FM, BEGI and Artech sidemount manifolds...Who has the best design for flow? Any issues with cracking with these 3?

curly

iTrader: (25)

Very rarely do they crack, all three are great choices. The side mount itself isn't the largest benefit, the reduced bends in downpipe is. Although the side mount does get rid of one 90* bend just from the internal design, I don't think it's as detrimental to the spool as the crappy ? shaped designed required with a top mount.

And as far as I know, yes, you can use the manifolds, but not the downpipes.

Edit: P.S. If you want to combine this with a Artech DP and/or manifold, order now, it can take a while, 6ish weeks.

barron64

Ok...Starting to get a plan together here with having a few options on the manifold. I have seen the cast iron side mounts from BEGI and FM, both around $400 and both look stout, but does anyone have a pic of the side mount that ARTech builds? I see a pic of the replacement Greddy top mount on the site, $500, and it really looks sweet.

curly

iTrader: (25)

Post #109
https://www.miataturbo.net/showthrea...t=63204&page=6

The difficult part I had was that with the greddy manifold, I could easily unbolt the turbo and with that off, I could remove the downpipe.

With Artech's setup, you need to put the giant 3" downpipe first, then the manifold, and then struggle like mad to bolt the turbo on.

If you're smart, you'd install the turbo on the manifold first, then install it as a unit. I think that's possible.

barron64

Curly,
Great thread and thanks for all the input. Abe at ARTech sent a pic of his side mount for the TD04 and it is incredible! At just $100 more than the FM & BEGI I think this is a no brainer. He can also do a 3" DP for this setup as well. Just need to find some spare $$ to get the ball rolling now.

Looks like I still have the 8mm studs in the head...Do I need to replace these with 10mm's?

curly

iTrader: (25)

In the head? You don't touch the head studs. You drill and tap the manifold for 10mm studs. Ask Abe about his stud kit, he also has flanges pre-drilled for them.

barron64

OK...Just read too many posts and thought I saw this somewhere. Here are some pics of the manifold:

curly

iTrader: (25)

Yeah, that's a high side mount, to try and clear bigger turbos from hitting the rest of the engine bay. My little SR20 and "poorly" flowing manifold design (same as BEGI and FM though) didn't require me to cut anything for clearance. With that collector and the higher design, Artech might charge you more. Mine was less than FM's DIY package, that one probably wouldn't be.

It also looks like the turbo flange is tilted to angle the downpipe towards the ground. Nice. Wouldn't go too far due to the oil drain's pickyness.

barron64

ARTech wants $500 for the manifold and $415 for the 3" DP.