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-   -   RotorNut's Build Thread (https://www.miataturbo.net/general-miata-chat-9/rotornuts-build-thread-24575/)

Ben 08-09-2008 11:13 AM


Originally Posted by RotorNutFD3S (Post 294253)
Thanks man! LagunaRoadster is selling me the pistons out of his '96 motor. If there is anything wrong with them, which there shouldn't be, I'll give you a call.

At this rate, you need to go ahead and get them, just in case. :giggle:

XxGoKoUxX 08-09-2008 11:27 AM


Originally Posted by RotorNutFD3S (Post 294253)
Thanks man! LagunaRoadster is selling me the pistons out of his '96 motor. If there is anything wrong with them, which there shouldn't be, I'll give you a call.


Eh, figured you'd read the thread and see. But oh well. They are very nice, can't wait to put them to good use! Thanks again!

anytime buddy... hopefully somewhere down the line i'll have some extra cash on the side a few years from now to do a monster miata or a 400RWHP miata.... i know what i need and what i need to do, i just haven't got the monies :(

RotorNutFD3S 08-09-2008 01:34 PM


Originally Posted by Ben (Post 294293)
At this rate, you need to go ahead and get them, just in case. :giggle:

Very funny... :fawk: lol

RotorNutFD3S 08-14-2008 11:19 PM

First part of my update, and this may be common knowledge to some, but for people (like me) who are comparing t25/t28 turbos, this was a good quick reference tool:

Lets break it down.
The GT2871R is known as ....well....the GT2871R
The GT28RS is known as the GT2860R
The GT28R is known as the GT2560R

TURBINE

GT2560R
* Wheel: 53mm w/ 62 trim
* Housing: .64 ar

GT2860R

* Wheel: 53.85mm w/ 76 trim
* Housing: .64 or .86 ar

GT2871R
* Wheel: 53.85mm w/ 76 trim
* Housing: .86 or .64 ar

COMPRESSOR
GT2560R
* Wheel: 60mm w/ 60 trim
* Housing: .60 ar
Flow : 320hp

GT2860R

* Wheel: 60mm w/ 62 trim
* Housing: .60 ar
Flow : 350hp

GT2871R
* Wheel: 71mm w/ 56 trim
* Housing: .60 ar
Flow : 400hp

Anyway, after a day full of research (and one failed attempt at picking up a turbo because of a dishonest or confused seller) I'm trying to find a .64 a/r GT2871R turbo because I think that at 15psi, I'm about at the limits of the 2560R, and the 2871 isn't too big of a turbo for our cars.
I'm just concerned as to if it's a worthwhile move, or if I should be happy with what I have for a mildly built daily driver. Input?

In any case, my ARP head and main studs arrived today. Got a pretty good deal I think at $185/shipped for both.
Still got to get the pistons coated, and then the block and parts can go to a machine shop. Need to test the injectors and make sure that they aren't responsible for this mess. And now I need a passenger side rear brake caliper, because mine seized up and won't release the e-brake unless you reach under and release it manually. No amount of PB Blaster and working it will free it up.

And I'm hoping the GB and actual production of the billet oil pump gears doesn't take much longer, as I'm sure others are as well. I'd like to get them installed at the same time as all the other work instead of having to pause the rebuild to wait for them to arrive.

leatherface24 08-15-2008 01:43 PM

I know for a fact on that car the turbo started to run out of juice after 15psi. If your looking for more power, i say GT2860R

Ben 08-15-2008 02:30 PM


Originally Posted by leatherface24 (Post 296914)
I say GT2860R

Fuck that. The 71 was designed by Garrett to stomp out the 60 (newer, more efficient blade design). ;)

NoiseRacing 08-15-2008 02:37 PM

But how much later will it take for the 71 to spool? Or because of this new blade design is it close to the 60?

Ben 08-15-2008 02:39 PM

No real world difference in spool. As I understand, the upgrades are in the compressor side.

Eric, you know you can get that local 71 and change exhaust housings right? I mean, if it's cheap enough.

RotorNutFD3S 08-15-2008 04:56 PM

Yeah, I know. It wasn't that great of a price though. And the guy was a dumbass.

RotorNutFD3S 08-18-2008 06:27 PM

Well, finding a nice, used 2871 for a decent price has proved almost impossible. I'm beginning to just think it might be a wiser idea to stick with the 2560 I have, go with BEGi's new manifold, and be happy with it since the car is going to be a daily driver.

leatherface24 08-18-2008 08:59 PM

the turbo never did you wrong dude. even though id like to have it again, i think you should keep and put the new manifold on.

Ben 08-19-2008 08:26 AM

or just have the old manifold cleaned up on the inside

wildfire0310 08-19-2008 11:21 AM


Originally Posted by Ben (Post 298183)
or just have the old manifold cleaned up on the inside

I am with Ben on this one, just sit down and clean up the old manifold.

RotorNutFD3S 08-19-2008 05:45 PM

I might look into that. Just sit down with the Dremel and go at it. I have plenty of the attachments to get it done.
On the other hand, I'm pretty sure no matter what I do, it will never be as efficient as the newer design.

pschmidt 08-20-2008 09:15 AM

Would you happen to have the torque specs for the bottom end? (Rods, mains, clearances) I cannot find them anywhere?

RotorNutFD3S 08-20-2008 08:08 PM

Nope, sure don't. Leaving that to the machine shop.

RotorNutFD3S 09-02-2008 05:47 PM

OK, noob question time.
The OEM rods have pressed-in wrist pin bushings. Do the CAT rods require bushings for the wrist pin, or just machining to make them fit?
Just as a side note, my wrist pins fit perfectly into the CAT rods, which is why I ask.

RotorNutFD3S 09-08-2008 09:29 PM

1 Attachment(s)
So I got some seals, gaskets, belts, pumps, pulleys, and bearings from Finishline to rebuild the engine and trans. Oh, and the Workshop Manual too since they are on sale.
Not from Finishline are my ARP head and main studs and the pulley/bracket for adding a/c without power steering.

Attachment 211141

And while I was at it, I snagged a set of MSM pedals and an oil cap, not exactly needed, but oh well.

Now, it's time to take the pistons to get ceramic coated and the rods cryo treated.
Then, to the machine shop.

Anyone have an answer to my question in the post above?

RotorNutFD3S 09-22-2008 09:56 PM

5 Attachment(s)
So today ended on a good note, this showed up on the doorstep:

56 Trim GT2871R (743347-2) - .60/.64
Hopefully will be a nice bump in power! And of course, I took it apart, but I needed to because the turbine housing is going off to get ported, fit for 10mm studs, have the cast-in divider (which is a nice feature) finished, and ceramic coated by BEGi along with the new manifold.

Pictures of course:
Attachment 210918
Attachment 210919
Attachment 210920
Attachment 210921
Attachment 210922

RotorNutFD3S 10-08-2008 07:22 PM

9 Attachment(s)
Been busy as far as acquiring parts go.
A couple weeks ago, I got my 3" Enthuza dual outlet exhaust, gently used, and got a great deal too:

Attachment 210641

Got my internals and valve cover back today. The valve cover is powdercoated, the pistons have a ceramic coated dome, dry film lubricant on the skirts, and an oil shedding coating on the undersides. The rods were simply cryo-treated.

Attachment 210642
Attachment 210643
Attachment 210644
Attachment 210645
Attachment 210646
Attachment 210647

Also have these stock sized Supertech valves thanks to Neogenesis:

Attachment 210648

Unrelated to the engine build, I snagged these Tein SS coilovers w/ NB tophats and FM front sway bar (with new bushings).

Attachment 210649

Within the next week or so I will have a '99 head, 6-speed transmission, and a set of new 3.636 gears.

I can't wait until this car is on the road again.


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