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Old 09-22-2011, 06:42 PM   #1
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Default Any experience with small trim (48) GT2871?

There are 3 trims, 48, 52, and 56.

I think most everyone's used the 52 (?).

The 48 trim compressor appears to fill the gap between the GT2860RS compressor and the 52 trim '2871 ...
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Old 09-22-2011, 07:29 PM   #2
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I believe the 56 is generally considered the 'standard' trim for the 2871....that's what mine is.

the 48 doesn't really seem that common
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Old 09-22-2011, 07:34 PM   #3
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Serious question: what is your fascination with small trim?
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Old 09-22-2011, 07:43 PM   #4
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(Posting from my phone.)

Sounds like a shitty combo.
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Old 09-22-2011, 07:48 PM   #5
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small housings + large wheels usually results in failaids. You don't get the lowend response or the topend flow that you "theoretically" should
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Old 09-22-2011, 07:50 PM   #6
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I went with the .56 trim.
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Old 09-22-2011, 11:17 PM   #7
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Quote:
Originally Posted by 18psi View Post
small housings + large wheels usually results in failaids. You don't get the lowend response or the topend flow that you "theoretically" should
?? small trim is a different wheel, right, not just a different housing?

Also, I thought Sav had the middle size trim (52), not the big one.
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Old 09-22-2011, 11:29 PM   #8
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I have a 52.
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Old 09-23-2011, 11:38 AM   #9
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yes, trim describes the size of the wheel.....not the housing (that's A/R)

heres all the maps.... would be cool to see an overlay of all 3, but i haz no skillz





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Any experience with small trim (48) GT2871?-48.jpg   Any experience with small trim (48) GT2871?-52.jpg   Any experience with small trim (48) GT2871?-56.jpg  
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Old 09-23-2011, 11:45 AM   #10
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You're right. My bad. Somehow thought this was about ar
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Old 09-23-2011, 12:09 PM   #11
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Quote:
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Serious question: what is your fascination with small trim?
Because street car.
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Old 09-23-2011, 12:17 PM   #12
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I think your current powerband is perfect for a street car. If you fix the few issues it has it should get even more responsive and widen the powerband to the left a little as well.
Or consider the little twin scroll snail out of a MINI: full boost by 1800

Anyways back on topic
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Old 09-23-2011, 12:44 PM   #13
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Just like all of you other obsessive fools, I'm always thinking "what if I tweak this or that". Also, my thinking about the wee 2871 is not just for myself, but for other fools considering the 2871.

But yes, I'll see if I can get back my missing 200 RPM or so of spool. If I then go "ohmygod this is so much better", then I'll stick to my wee 2560. If I go "meh", then I'm a gonna be bigger turbo dreamin'.
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Old 09-23-2011, 12:59 PM   #14
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street cars work best with big laggy turbos.

because hypermiler.
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Old 09-23-2011, 01:11 PM   #15
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Hypermilers with small turbos can open the wastegate in cruise a la BMW 335i.
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Old 09-23-2011, 01:15 PM   #16
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Quote:
Originally Posted by y8s View Post
street cars work best with big laggy turbos.

because hypermiler.
Depends on your definition of "street car" but Id have to agree (even though I'm not sure if you're sarcastic or not lol)
On my "street car" the only time I opened it up was on the freeway or a freeway onramp. I had plenty of lowend and response down low to not hate life and get decent mileage. When I wanted to haul *** it was just a downshift away.

In Jasons case though, (going off what he's posted in previous threads) he likes auto-x type driving, twisties, etc....So response and lowend grunt is thuper duper important to him, and I think I understand what he's going for here.

Do you have e85 there Jason? You're in the bay right? Cause with e85 you would not only get a little better spool, but be able to seriously push that little snail of yours to its limits.
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Old 09-23-2011, 01:54 PM   #17
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Quote:
Originally Posted by JasonC SBB View Post
Hypermilers with small turbos can open the wastegate in cruise a la BMW 335i.
I could open mine too BUT my wastegate port is teenie and probably not the most efficient passage for exhaust gas.
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Old 09-23-2011, 02:27 PM   #18
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i just dont see the point of the 71mm wheel over the 60mm wheel when we talking about gaining only 5 more lb/min capacity and going from a short fat efficiency map to a thin tall one...meaning it's a better turbo for higher boost but lower flow rates.
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Old 09-23-2011, 04:19 PM   #19
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You're comparing the 2860RS and the small-trim 2871?
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Old 09-23-2011, 07:46 PM   #20
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(Posting from my phone.)

Yeah. 35 lb/min vs. 40



On a 60mm wheel vs. 71mm

I guess I don\'t see what the gain would be. The shorter fatter island of the 60mm lends itself to lower boost and higher flowrates. The 71mm is tall and skinny so its made for high boost levels but not a lot of flow considering.

Last edited by Braineack; 09-23-2011 at 07:49 PM.
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