A tale of two turbos -- OR -- Sneak peak HTA2868 vs GTX2867

[bananas]

-- OR --
The "Little Big Turbo" faceoff
-- OR --
How I learned To Stop Worrying and Love the Boost.

On the left, a HTA2868 (47lb/min) with a chipped turbine blade.
On the right, a GTX2867 (47lb/min) freshly shipped to my door.




GTX2867 nameplate



GTX2867 Exducer, at base (67.82mm)



GTX2867 Exducer, widest point (69.53mm)



HTA2868 Exducer, at base (67.96mm)



GTX2867 Inducer (49.56mm)



HTA2868 Inducer Measurement 1 (48.00mm) (7 blades; no way to measure exactly)



HTA2868 Inducer Measurement 2 (48.80mm) (7 blades; no way to measure exactly)



GTX2868 Compressor Height
Assembly Height (12.58mm)


Highest point (37.67mm)




HTA2868 Compressor Height
Assembly height (12.64mm)


Lowest point (35.89mm minus 12.64mm)


Highest point (approx 41.59mm minus 12.64mm)




GTX2867 Detail


















HTA2868 Detail

[bananas]

Side By Side (HTA2868 on left, GTX2867 on right)











GTX2867 ported compressor cover fitted over HTA2868 compressor.
The GTX2867 fit over the HTA2868 wheel. The HTA wheel spun freely.
There was an obvious small gap between the wheel and the compressor cover.


HTA2868 wheel spinning under the GTX2867 cover.


GTX2867 Anti-Surge Compressor cover
Pictures from inside the cover looking out towards the inlet




Pictures from the inlet looking down towards where the compressor would be




Picture from inlet to GTX2867 compressor


GTX2867 cover and compressor from above


GTX2867 cover and compressor close-up







GTX2867 cover on HTA2868 from inlet to compressor for comparison


Showing gap when GTX2867 cover is put on HTA2868


Blurry pic showing gap when GTX2867 cover is put on HTA2868




HTA2868 with HTA2868 cover with 2.5" inlet (non-standard)


HTA2868 cover and compressor closeup




HTA2868 and GTX2867 side-by-side







The entire IMGUR album this post is based on

[Turbwhistle]

That gtx2867 looks beautiful.

[jeffrey146]

Damn can you say picture heavy? Very good job on the pictures. Wish everyone would take such a load of pictures.

[bedes]

does that turbo require built bottom end? at least pistons?

[Bische]

Nice!

very interesting thread

[mrbacardi35]

does that turbo require built bottom end? at least pistons?

i would say at least drop-in rods.

[EErie B6]

does that turbo require built bottom end? at least pistons?

Drop in rods, yes. Pistons, no. Rods are the weak point. Pistons aren't really needed unless the user intends to change displacement or compression ratio. As for sizing, this turbo is going to be larger than a GT2871 but not as large as a GT3076.

Bananas,
What claimed the turbine wheel of the HTA?

[A4SoftWalker]

Nice pics I personally know how hard it is to take pics of shiny metal parts.
U probably took 3 times the number of pics u posted.
Would like to see what the car does on the dyno with the new components installed. Keep up the good work sharing ur progress.

[SleeperAvant]

Chris, finally you get to put that new GTX turbo on!

John, last year Chris' motor ate a spark plug ceramic and chewed through the turbine of the HTA.

[AudiA4_20T]

GTX are the bomb

[EErie B6]

Thanks for the background Steve.

...somehow I missed that. That sucks to hear.

On the bright side, this is going to be an awesome back-to-back comparison. Its about as perfect of an HTA vs GTX as you can get.

[dougyfresh]

[Sales@RAI]

I can't wait to see how this turns out

[bananas]

A few notes:

The GTX 2867 exducer blades are much taller than the HTA 2868 blades. They are also slightly wider.

I'm a little surprised that the 2867 compressor is marginally larger overall than the 2868 considering the stated exducer sizes in their product names (2867mm and 2868mm).

The machining work on the 2867 is much finer than that on the 2868. It feels much smoother to the touch compared to the machining ridges on the 2868.

I'll be getting the 2868 rebuilt by FP and hope to do back-to-back dyno comparisons of the two turbos to compare spool and power.

I put the 2867 cover on the 2868 just to see if it would fit or if it would be an option for 2868 owners. The gap is less than a millimeter, but obviously tolerances here are very important. If I'm REALLY bored, I might try running the 2868 with the 2867 anti-surge cover at some point.

Thanks Doug, for getting the reference

[bedes]

looking forward to seeing results

[dougyfresh]

Thanks Doug, for getting the reference

No problem. Was stoked to see the reference so I had to provide.

Will you be tweaking your softwere for each turbo on back-to-back dyno runs or keep the software alone but switch turbos? I prefer the later. Less variables the better story the data tells...

[bananas]

Will you be tweaking your softwere for each turbo on back-to-back dyno runs or keep the software alone but switch turbos? I prefer the later. Less variables the better story the data tells...

I plan to run the same software, but there will probably be at least a day between dyno runs to allow time to swap the turbo correctly. I suspect the two dynos will be very similar.

[SleeperAvant]

How much boost are you planning to run?

[Sales@RAI]

All the boost.

[Sales@RAI]

Stanley Kubrick films kill it.

[bananas]

I'll probably dyno each turbo at each of: 20, 25, 30psi

[AudiA4_20T]

I'll probably dyno each turbo at each of: 20, 25, 30psi

You old sailor you! That info will be passed around on a bunch of forums, it's going to be extremely useful

[dougyfresh]

I plan to run the same software, but there will probably be at least a day between dyno runs to allow time to swap the turbo correctly. I suspect the two dynos will be very similar.

What manifold are you using now-a-days?

[bananas]

What manifold are you using now-a-days?

Still running the cast iron T25 Treadstone (unfortunately still M8 too)

[dougyfresh]

Still running the cast iron T25 Treadstone (unfortunately still M8 too)

Oh

Yeah, that T25 is not quick to swap. I can probably swap my Treadstone T3 within an hour (once cool) because you don't have to remove the T3 from the car.

[MmmBoost]

Still running the cast iron T25 Treadstone (unfortunately still M8 too)

M10 that shit! ASAP!

[nein-reis]

M10 that shit! ASAP!

This.

[RudeJude518]

In for results!!!!

[bananas]

M10 that shit! ASAP!

I failed miserably. Don't have a press, so I tried using a hand drill. I ended up drilling each hole at a slight angle (maybe 3 degrees off). I suspect this will stress the studs enough that they'll break off.

I ordered a Treadstone Stainless Steel T3 flange, which are pre-tapped for M10. I'll be porting my T25 exhaust housing a bit to better match the T3 manifold outlet. Sigh, more money down the drain.

On a side note, I was shocked at how easy it was to tap cast iron.

[SleeperAvant]

Damn, hand drill?

[bananas]

Also, got an email from FP today. The HTA2868 is rebuilt and on its way back to me with a new turbine wheel. Total charge $500.

[Nateness]

Have you set a dyno date yet? I'm really looking forward to seeing the data.... The question of HTA2868 vs. GTX2867R has been on my mind for a long time!

[Bische]

Im also very interesting in your comparation, I would LOVE to see a log from the dyno pull(s).

These two turbos are in my opinion the best matches to the 1.8t(along with the smaller framed EFR's, but those arent really attainable).

[DCarver75]

Im planning on running bigger turbo eventually i have the ko4 upgrade from the k03 what else would be necessary besides rods?

[AudiA4_20T]

Im planning on running bigger turbo eventually i have the ko4 upgrade from the k03 what else would be necessary besides rods?

Everything else?

[Nateness]

Im also very interesting in your comparation, I would LOVE to see a log from the dyno pull(s).

These two turbos are in my opinion the best matches to the 1.8t(along with the smaller framed EFR's, but those arent really attainable).

+1 Data logs would be fantastic. EGT, mass airflow, charge air temp, etc. (all data normalized to Dyno RPM would also be a huge plus) kind of a lot for us to ask for, but it would be damn interesting to see.

[dougyfresh]

I ordered a Treadstone Stainless Steel T3 flange, which are pre-tapped for M10. I'll be porting my T25 exhaust housing a bit to better match the T3 manifold outlet. Sigh, more money down the drain.

Have a machine shop face the T3 flange and the exhaust manifold flange.

Then do something like this: http://www.audizine.com/forum/showthread.php/422519

and if you have a 38mm MVS w/g then weld on this adapter: http://www.atpturbo.com/mm5/merchant...egory_Code=WGT

[EBG 18T]

Im planning on running bigger turbo eventually i have the ko4 upgrade from the k03 what else would be necessary besides rods?

A deep checkbook.

[koskotas]

If you interesting on anti-surge housing for 2868 let me know ! is a company in uk that can do it for you ! ! i manage and take one :)