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

21K views 15 replies 3 participants last post by  pzr2874 
#1 ·
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:

How to Read Compressor Maps... - CICENetwork - Forums

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 |



"


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. Compressor Maps | Turbobygarrett

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


John
ph: 866-922-3059

web | blog | facebook | twitter | youtube"
 
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#2 ·
The factory turbo is a very small unit(that's what she said joke in there somewhere). It tapers off because after 5500 it is just a flamethrower tossing hotter air into the engine and it then goes beyond it's effect range for the factory tmic as well. I believe Cobb does well with trying to keep their products safe for everyone, so to me that's just good business.
 
#3 · (Edited)
Interesting, Kieth.

It sounds like the OEM top-mounted intercooler would be a better fit with an upgraded turbo running within its efficiency range instead, because the intake charge wouldn't be heated as much.

When I asked BuiltEJ about a suitable OEM replacement turbo for the same Stage 2 power levels they said:

"I am going to "assume" a 1k US budget for this turbo and say the Blouch 16G XT with a 7cm turbine housing. The turbo has the MHI (Mitsu) 5H turbine wheel and performs amazingly well. On a well tuned 2.0l WRX you would hardly notice any drop off in low end performance. From 3000 rpm's to redline it will make 15-20% more power and TQ at low to moderate boost levels. If you decide to "turn it up" in the future and have the fuel system to keep up it will make even more power."

This same turbo was suggested to me by others before, but I was hoping to avoid a turbo replacement if possible.
 
#4 ·
Well you could get a ported stock turbo, and Blouch has a 19T upgrade for the stock turbo as well. The basically install a larger compressor wheel and housing and I believe they port the clip the turbine wheel as well. It would flow into a higher rpm range and would still be suitable for the stock tmic.
 
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#5 · (Edited)
Thanks Kieth, I'll look into that as an option. I'm not in the market for it right now, so it'll give me time to do this research.

It's time to take a break from spending on this machine. Ha ha.

However, if you were offering a 19T upgrade for my TD04 then I'd definitely take you up on that. :D
 
#12 ·
Glad I could help. From what I recall it is a compressor wheel from a 3000gt that they fit into the housing via machining. The video Blouch has on there site is pretty cool to watch. I use to do that type of work back in my younger days at my dad's shop...
 
#13 ·
And I suspect that the TD04-19T upgrade runs closer to it's ideal efficiency with Stage 2 power as well, which heats up the intake charge less above 5500rpm.

I'll find out, but this would be good. :)
 
#14 ·
Well if they "clip" the turbine wheel the turbo will effectively be able to flow more air up in the higher rpm range. You'd still need a good tune for that turbo since it does basically change the amount of air flowing into the engine...
 
#15 · (Edited)
Cherry Turbos wants 525 - 675 $CAD to rebuild a TD04 turbo.

Add to that a 19T upgrade kit at 153 $CAD plus tax and shipping,

Mitsubishi Upgrade TD04 19T Compressor Housing Wheel [e-Bay]
Mitsubishi Upgrade TD04 19T Compressor Housing Wheel | eBay

It's still looking like a new- or refurbished TD05-16G turbo is the better overall value approach to a turbo upgrade.
 
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