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Old 06-07-2007, 12:24 AM   #1
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Default What would you do? Compressor related.

What would you do?

What I have:

T3/T4 Chinacharger Compressor

2.25" Inducer
3.00" Exducer
.50 A/R Housing 2.50" inlet

T70 Chinacharger Compressor

2.07" Inducer
3.00" Exducer
.70 A/R Housing 4.00" inlet


Would you open the inlet on the T70 compressor housing and run the 2.25" compressor wheel? Run the T70 compressor wheel as is? Run the 2.25" compressor wheel with the .50 A/R housing?

Personally I am leaning towards running the T70 compressor housing with the 2.25" compressor wheel. Any experts here see an upside or downside to any of the configurations.

I will be running the T70 turbine, which is a rather large T3 turbine with a .84 A/R divided tang housing. It makes the previous .63 A/R housing look tight and restrictive. As a matter of fact the turbine wheel won't fit in the .63 housing.

Mark
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Old 06-07-2007, 01:52 AM   #2
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No one has an opinion... Well I did a little research. Seems that the Chinacharger T70 has basically a 46 trim wheel vs the T3/T4's 57 trim wheel.

Surprisingly enough, large A/R's on the compressor side do little to effect much other than low vs high boost performance and are largely irrelevant. They will not affect compressor air flow much. Inducer and Exducer sizes are much more important.

Obviously higher trim wheels flow more air, but how much more?

Well looking at Garrett's website, the Chinacharger T70 compressor is a clone of the 76 series compressors. The GT2876R compressor in the 48 trim with a .70 A/R to be exact.

http://www.turbobygarrett.com/turbob...R_705330_1.htm

Garrett claims this compressor is good for 480 HP.

The Chinacharger T3/T4 57 Trim is very close in specs with the GT3076R 56 trim with a .60 A/R and since A/R on the compressor side is not much of a factor I am going to trust that map. Garrett claims that the 56 Trim 76 series compressor is good for 525 HP and below is a map for that. Roughly a 45 HP difference in compressors.

http://www.turbobygarrett.com/turbob..._700382_12.htm

Mark

Last edited by Markp; 06-07-2007 at 09:05 AM.
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Old 06-07-2007, 10:09 AM   #3
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What are you aiming to achieve with the change? Sounds like you're wanting more top end power (given the rpms you spin). I'd stick with t4 compressor and wheel if you're doing the t70 hot side - assuming you're buying another complete turbo. See what that does for the top end, and what's loss in lower rpm. Then if you want more you can swap the cold side stuff on the manifold.
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Old 06-07-2007, 10:18 AM   #4
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Originally Posted by m2cupcar View Post
What are you aiming to achieve with the change? Sounds like you're wanting more top end power (given the rpms you spin). I'd stick with t4 compressor and wheel if you're doing the t70 hot side - assuming you're buying another complete turbo. See what that does for the top end, and what's loss in lower rpm. Then if you want more you can swap the cold side stuff on the manifold.
I think I will stick with the compressor on the T-70 initially, if I want to install the larger compressor it's pretty trivial even if I want to change the impeller and retain the housing for the .70 A/R and the nice tapered 4" inlet. I just wish it had a bigger inducer but that's the luck you get when you run a chinese turbo. Not exactly honest advertising, but we'll see what she does.

Mark
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Old 06-07-2007, 10:36 AM   #5
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I missed your point regarding the t70s compressor/trim. The straight swap would be an interesting comparison. My guess is the t70 turbine is going to give the room you need over 6500 to keep the hp up.
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Old 06-07-2007, 10:56 AM   #6
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what's your mass airflow and how much are you going to boost with it? the smaller wheel looks the best at around 18-19psi and 35 lb/min, the larger wheel is a bit more efficent with more PR, but looks to be designed for more Mass Flow as the shape is a little wider....
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Old 06-07-2007, 11:40 AM   #7
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Believe it or not, I considered a GT3076R when I picked up my 2876R... but for now I'm happy. I think more would just mean lag, not top end.

I mean 230-240 rwhp at under 10psi is pretty ok.
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Old 06-07-2007, 12:07 PM   #8
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Quote:
Originally Posted by Braineack View Post
what's your mass airflow and how much are you going to boost with it? the smaller wheel looks the best at around 18-19psi and 35 lb/min, the larger wheel is a bit more efficent with more PR, but looks to be designed for more Mass Flow as the shape is a little wider....
I am hoping to be at around 40+ Lbs/min at around 26-28 PSI. I expect my low boost setting to be in the 15 PSI range.

Mark
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Old 06-07-2007, 12:11 PM   #9
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goddamn dude. enough said.


....but then the 3076 wheel does look a bit better suited...on paper, but they are both close in that area. fwiw, you've reached the end of my input/knowledge.
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Old 06-07-2007, 05:10 PM   #10
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goddamn dude. enough said.


....but then the 3076 wheel does look a bit better suited...on paper, but they are both close in that area. fwiw, you've reached the end of my input/knowledge.
Precisely why I am on the fence, they both look pretty decent. We'll see. I think that if I am unhappy I will put a bigger compressor on it.

Mark
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