Stage 2 Within an OEM TD04 turbo's Efficiency Range?

[LaszloT]

I asked COBB about the stock turbo's efficiency with Stage 2 power:

"With Stage 2's 16.5 psi boost (plus 14.7 atmosphere) is a 2.12 pressure ratio, and air flow rate is estimated to be at 017 m^3/sec from the How to Read Compressor Map link below.

How to Read Compressor Map:

http://www.cicenet.net/showthread.php?t=1019

Is the OEM TD04-13T turbo approaching it's efficiency range in a standard Stage 2 application, or operating beyond it?

I know less efficiency means more heat, and I suspect COBB would've designed Stage 2 to be within a practical operating range of the OEM turbo.
Any insight you have would be helpful.

Thanks,

Laszlo Toth, P.Eng. | Associate Manager, Fuel Pricing & Rewards | Fuels Marketing |

http://i.imgur.com/k6KdLlw.jpg

http://i.imgur.com/GmJPjhu.jpg "


And they say that with their maps boost tapers off in the upper rpm range intentially, because of efficiency.

"John (COBB Support)

Sep 12 04:02 PM

Hello Laszlo,

This is the main reason we design our maps to taper down towards redline to prevent the turbo from becoming a heat pump. You will still be good on our OTS maps.

Here is a good link. http://www.turbobygarrett.com/turbobygarrett/compressor_maps

Please let us know if you have any other questions.
Thank you,


John
ph: 866-922-3059

web | blog | facebook | twitter | youtube"

[BryceD]

And practically, you can see what happens if you do multiple runs on a dyno, with different boost maps. You'll find that tapering boost at high RPMs reduces air temps, while still making same or better power, compared to maintaining a high amount of boost.

[LaszloT]

I need to upgrade to a TD05-16G XT turbo to keep the compressor in it's efficiency range even with the Stage 2 boost levels I am running.

With the turbo upgrade we can tune to have power build past 5500 rpm instead of the mid-range power bulge of the OTS COBB maps, designed for the constraints of the OEM turbo [TD04-13T].