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Old 12-01-2006, 10:01 PM   #1
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Default GT3271 with smaller A/R turbine housing

After seeing Andy's results, I've decided to ditch the 2560 and get a GT3271.
I went to Garrett's site and saw the the 3271 comes with either a .78 or .69 AR turbine housing. Sadly, the smaller AR only comes with a suspect looking internal gate.
Anyone have any idea how much faster the smaller AR turbine would spool?
Or would the benifits be negated by the internal gate?
FWIW, I'd be happy with 300WHP on a dynojet at 15 psi or so, and want the best response.

Any guesses?
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Old 12-01-2006, 10:12 PM   #2
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Quote:
Originally Posted by lukydvll View Post
After seeing Andy's results, I've decided to ditch the 2560 and get a GT3271.
I went to Garrett's site and saw the the 3271 comes with either a .78 or .69 AR turbine housing. Sadly, the smaller AR only comes with a suspect looking internal gate.
Anyone have any idea how much faster the smaller AR turbine would spool?
Or would the benifits be negated by the internal gate?
FWIW, I'd be happy with 300WHP on a dynojet at 15 psi or so, and want the best response.

Any guesses?

That internal gate on the .69 a/r version is shady and has been known to have issues with boost spikes. I also think it is some absurd spring pressure ( I want to say 15psi ) but dont quote me on that. The .78 a/r turbine on the GT3271 is more similar to a .48 a/r T3 hotside as far as boost response is concerned. The turbine on the GT32 flows well in both housings, and I wouldnt expect the .69a/r to really spool much faster...maybe 100-300rpms if I was guessing.

I was getting 12psi @ 4000rpm on the dyno and seeing right @ 200ft/lb at 4000rpm. Thats not bad for a turbo that can flow 43lbs from its compressor and it has a turbine that is more than capable of keeping up with the compressor clocking in at 21lb/min. Generally you want the turbine to flow about 1/2 of what the compressor can flow to have an optimum setup...the GT3271 is optimum for 400whp. I would stick with the .78a/r housing and get an external gate since it will just be better in the long run.
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Old 12-01-2006, 10:15 PM   #3
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Now there are also other options if you want to keep the T2 footprint. You could use a GT3071R since it retains the T2 hotside and has a really nice compressor section thats just a little higher flowing than the GT3271. I would expect boost reponse between the two turbos to be about the same.
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Old 12-02-2006, 12:55 AM   #4
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Thanks for the reply, Andy
The GT3071 is my dream turbo, but there are two things preventing me from getting one.
The first is cost. I'm trying to keep costs to a minimum. I have a JGS log, so slapping on a T3 flange would be a piece of cake. I've even got a flange laying around.
The second reason I'm shying away from the 3071 is that I'm running stock internals. I figure if I chunk my engine, there's a good chance it'll destroy the turbine wheel. I'd rather mess up a $700 turbo than a $1300 turbo.
All said, I could have a GT3071 on the car for about $800, while the 3071 would be closer to $1300.
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Old 12-02-2006, 01:13 AM   #5
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Quote:
Originally Posted by lukydvll View Post
Thanks for the reply, Andy
The GT3071 is my dream turbo, but there are two things preventing me from getting one.
The first is cost. I'm trying to keep costs to a minimum. I have a JGS log, so slapping on a T3 flange would be a piece of cake. I've even got a flange laying around.
The second reason I'm shying away from the 3071 is that I'm running stock internals. I figure if I chunk my engine, there's a good chance it'll destroy the turbine wheel. I'd rather mess up a $700 turbo than a $1300 turbo.
All said, I could have a GT3071 on the car for about $800, while the 3071 would be closer to $1300.
Then just go with the standard GT3271 .78a/r. I think youll be happy. Talk to wideopentuning he can get you deals from ATP turbo.
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Old 12-02-2006, 06:04 PM   #6
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Originally Posted by cccpull View Post
The standard GT3271 .78a/r is available with an internal or external wastegate.
http://www.turbobygarrett.com/turbob...1_452203_1.htm

right, we werent debating that. He was asking about the internal WG version and how decent the internal WG is on a GT3271. I personally have no experience with the internal wg, but have read somewhere that it was not any good.
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Old 12-02-2006, 06:49 PM   #7
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That is Holy **** Cheap. You got a hell of a deal.
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Old 12-02-2006, 07:27 PM   #8
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I'd love to try out a GT3071R on my car. I have a feeling the trans (or the engine) wouldn't last long though.

Are you worried about making 300hp on a junkyard motor? I'm really interested to see how far you can take it.
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Old 12-03-2006, 02:01 AM   #9
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Originally Posted by cccpull View Post
That's what I'm running. My manifold is set up for external and I'm using a block off plate. Now, the reason I'm using the internal wastegate is I purchased the GT3271 .78 a/r, brand new, with the internal wastegate, ceramic coated turbine and the oil feed/drain flange,gaskets etc, for $540 shipped to my door. I thought it was a fair deal.
Why would it be no good? (except for turbulance/flow).
The actuator without a boost controller allows 14 psi with no boost creep. I use the mbc to raise the boost to 16-17 psi, a few times 20 psi and it holds steady.
I'm ok with it, so far.

PS I don't know if you can run 6,8,10 psi by changing the actuator without boost creep, but I'm also not running real low boost numbers.
ahhh, never knew you had the internal wastegate my apoligies. I just remember reading somewhere that it was bad about creep, but I was wrong apparently. Im glad its working out for you. Now go get to a dyno so we can see what its making to the wheels
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Old 12-03-2006, 02:16 AM   #10
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Quote:
Originally Posted by cccpull View Post
The standard GT3271 .78a/r is available with an internal or external wastegate.
http://www.turbobygarrett.com/turbob...1_452203_1.htm
I was asking about the .69 AR version.
The .69 only comes with the internal gate.
Good to hear the internal is working well for you.

Cheers
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Old 12-11-2006, 01:03 PM   #11
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So weld/clamp the IWG shut and run an external off the manifold.

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