Savington

iTrader: (31)

The compressor map that garrett publishes for the 2871 is deceptive. At least for the 52 or 56 trim turbos, the compressor map is the same as what you get in a 3071r. It just looks thinner because garrett didn't fully flesh the map out.

JasonC SBB

Adding the GT2560 and GT2860RS. All maps arranged from smallest to largest.

GT2560:


GT2860RS

JasonC SBB

FWIW Garret has updated their website

Re:2871
There are 3 GT2871 compressor trims - (48, 52, 56), and 2 a/r's (0.64 and 0.86)

Garret's page now calls the 4 variants of GT2871, by a suffix: (1) (2) (3) and (4)
http://turbobygarrett.com/turbobygarrett/turbochargers

Only "(3)" uses the small 48 trim, and it has both sizes of exhaust a/r available. The small a/r is labeled
Turbo p/n 743347-3 chra p/n 446179-31
(Direct Link doesn't work, gotta go to above link and click "GT2871 (3)" in bottom right.

FWIW Here is an interesting post by my buddy with a 3071 who went driving with me and my 2560. He was shocked how much of an advantage the 2560 had powering out of tight corners, while the 3071 only having a big advantage above 80 mph or more:
http://forum.miata.net/vb/showthread.php?t=435110

JDMPalace

iTrader: (1)

I like to add these two since I'm in the market for new turbo for my built street car and can't decide between GT2871R (56 trim/ .64 or .84/2) and these,

GTX2867R



GTX2863R

aaronc7

iTrader: (8)

2867 looks pretty sweet...now i hate my 2871, thanks lol

Braineack

iTrader: (62)

a smaller wheel that can produce the same power, is more efficient, and will spool faster.

I'd rock it.

JasonC SBB

The GTX2863 map appears to be similar to the small (48 trim) 2871 but is smaller (less inertia) and runs at higher RPM. May be a better speed match in spoolup so it gains a lot of spool without losing topend! Wait, it has even more headroom up top!

TURNS101

iTrader: (10)

I plan to have the 2863 soon.
I am thinking the S6 mani from BEGI, either their intake mani or a custom.
Oh, and Tial vband .86 housing...
I may throw in some cams too. i am looking to keep all of my same power levels and just have a better powerband.

Oh, I may stroke the engine too.

The 2863 really looks like some quality cats *** stuff..

JasonC SBB

More fun with maps. Now with 1.9L engine airflow overlaid. Note that these assume 100% VE. So for stock cams, peak power is the airflow along the 6000 RPM line.
The reason they are for a 1.9L engine is because the dude who made them used 0*C standard air density instead of 20*C. The difference is about 6%. I'm assuming Garrett use 20*C.
So a 1.8L engine will require 7% less flow.

These were created by "mainstayinc" in this VWVORTEX thread:
http://forums.vwvortex.com/showthrea...what-you-think

GT2560:


GT2860RS (disco potato):


small (48) trim GT2871:

JasonC SBB

GTX2863 comparo against 48 (small) trim GT2871, with, and without 1.8L RPM lines.

GTX2863 gets its topend from being able to rev to the moon. It doesn't choke as early with lots of flow, it just keeps revvin'.

Also in this comparo note the slowest speed line is 65k rpm instead of 59k rpm. Should give better spoolup.




Sucker will go to 22 psi and 42 lb/min, while the 48trim 2871 is only good for ~18 psi and 36 lb/min. Despite the quicker spool.

JasonC SBB

I just discovered this. A company called Forced Performance sell a machined billet 68 mm compressor wheel called an HTA 68 mm wheel. It's meant to be mated to a 2860RS compressor housing after some machining. The resulting turbo is called a GT2868 or an HTA2868. They sell both whole turbos, and the upgrade package.

Supposedly spools better than a 2860RS with a better topend (dunno if this is true).

Threads:
http://highboostforum.com/forum/show...on-HTA-wheels.
http://www.audizine.com/forum/showth...iAL-2868-Turbo)

Wheel:


Dyno on a 1.8T (200 ft-lbs at 3400 RPM):


Spool demo on a 1.8T (pretty damn good, 15 psi at 3500 RPM in 3rd)

hustler

iTrader: (6)

That 1.8t is a significantly better flowing engine than what we have though. I owned an AEG at one time.

JasonC SBB

Here you go ladies, GT2860RS vs GTX2863.
Bottom end nearly identical, GTX2863 topend extends waaaay up.

Boost Joose

This is a great comparo thread! I think I'll be going with the gtx2867(also looking at the EFRs) for my power goals but random question for you guys that might know. What's up with these turbo's when they say max out put is, for example, 45lbs/min and they dyno and are putting down like 550? It's not usual but it happens, I've seen a few with e85, some with water/meth injection, some race gas and a few on straight pump gas. How does this happen if max outout is supposed to be 450 and they make more and sometimes signfigantly more?

Savington

iTrader: (31)

It doesn't. People lie.

Boost Joose

I mean I've seen the dyno sheets, you referring to a "corrected" dyno or just lying about the turbo/setup all together?

Edit: One prime example being "Eliminator" on his 50 trim...

http://forum.miata.net/vb/showthread...ght=eliminator

A turbo rated for 450 hp.....somehow managed to push over 600 whp

Boost Joose

Another question, since I'm looking into the 2867. How signifigantly different would this turbo spool from the .64 A/R tial housing to the .86 A/R tial housing? Also, what could I expect as far as differences on the top end power?

Savington

iTrader: (31)

Search. Lots and lots of discussion has happened on .64 vs .86. If you don't want to search, then buy the .86 housing like all of the cool kids do (hustler and me).

Downshift88

What would be the maximum safe boost on a gt2871? I'm about to order my turbo kit when my taxes show up and I've really been leaning towards the gt3071 but recently started lookin at the smaller one... I was think I could still get the same general horse power I want but it would be more responsive... Am I correct in thinking that? I'm shooting for about 325hp daily

aaronc7

iTrader: (8)

325 then 2871 is plenty, no reason to get 3071.

max boost for 2871 around 22-24psi really. after that efficiency starts dropping off