gt2871r vs gt3071r - Hyundai Genesis Forum
Engine and Turbos This section is for discussing engine parts (for example, bottom or top end), turbos (upgrades, porting, etc), or other engine related parts or swaps.

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post #1 of 30 Old 04-04-2010, 03:14 PM Thread Starter
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gt2871r vs gt3071r

I decided to start this thread in hopes people will be clearly able to see why the gt3071 is far superior.
First off we have to compare apples to apples and not compare one turbo on one motor and one turbo on another.
The next thing we have to do is present facts.
Here are the facts,Using atp's own numbers that the 2871r gets to 22 psi by 3500 rpm and the 3071r gets to 24 psi by 3800 rpm I was able to do a little reverse engineering to come up with what turbos they are using.
Here they are
gt2871r 71mm,56 trim ,.60 a/r
gt3071r 71mm,56 trim,.50 a/r

Since we already know the gt2871r gets to 22 psi by 3500 rpm which equates to about 280 cfm, we now look at the gt3071r's compressor map and can see it hits 22 psi at just under 3400 which equates to about
270 cfm.
So it spools faster, bigger powerband all while doing it more efficient and with the opportunity to make more horsepower if you wish.

Of course when ever doing reverse calcuations I could be off on what turbos they are using, but that does not take away the fact that the two turbos I have listed above, the 3071r is superior in everyway.

Hope this helps,
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post #2 of 30 Old 04-05-2010, 09:10 AM
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Both are great turbos. The GT28 will peak sooner, obviously, but the GT3071 will give more horsepower and spool, normally, around 500 RPM later. Coming from a Subaru background, the GT3071 is a great quick spooling turbo for the 2.5L power train. The GT3071 on a 2.0L will take longer, as you mentioned. It will be closer to 4K before full boost. So those looking for high HP number, but later boost, the GT3071 is right up your alley.

IMHO, the GT28 is a better "street" turbo for the 2.0T Genesis. The powerband is located in the more usable 2700 - 4500 range most folks sit in when street driving and will not disappoint most drivers. You will be limited to the 300 whp range with the GT28, while the GT30 will push you 350 and higher. Pick the one that works for you. That argument really shouldn't be which turbo is best, but which turbo is best for what you want out of it.
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post #3 of 30 Old 04-05-2010, 12:24 PM
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I want this little Buschur offering for the EVO to be installed on my car eventually; HTA3076

Quote from Buschur site:
"What is a HTA3076 you ask?

One of the most popular of the Garrett Ballistic Concepts Turbochargers has been the GT3076R. This mid-sized roughly 52 lb/min flow rate turbo is widely used in 2.0 - 2.7 litre applications seeking a 400-500whp output level with minimal turbo lag.

The only thing that could make this turbo any better would be a better compressor wheel that delivers decreased spool time and increased max output, and we have just that, the HTA wheel aero. Scaled down to 76mm exducer and 54.8mm inducer this aero flows over 57lb/min without dropping efficiency, and works well to sustain boost pressures above 40psi is needed without compromise.

There optional turbine housings for this turbo, but the recommended default housing is the .82 A/R or .63 A/R T31 style with it's compact 2.5" diameter 4 bolt outlet. We have the corresponding gaskets and flanges for this housing if needed."

Sponsored By: Columbus Body Works / ARK Performance / Modern Automotive Performance / Forged Performance
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post #4 of 30 Old 04-05-2010, 12:49 PM
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A GT3076 on the Genesis would be too much for daily use. Peak boost wouldn't hit until well into the 4500 RPM range and snap the RPMS to the peak so fast you wouldn't be able to use it. High HP and Torque turbo. A GT35R would smack much more, but I seriously doubt a 2.0L would be able to push it high enough. In my experience, GT3076 and GT35 series turbos are better suited for 2.5L and up. I've seen GT35 series turbos push out well north of 500 whp and wheel torque on 2.5L Subarus.

Honestly, I just don't see the Theta being able to push 40psi. I just don't think it's there.
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post #5 of 30 Old 04-05-2010, 03:21 PM
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Quote:
Originally Posted by davisk6 View Post
A GT3076 on the Genesis would be too much for daily use. Peak boost wouldn't hit until well into the 4500 RPM range and snap the RPMS to the peak so fast you wouldn't be able to use it. High HP and Torque turbo. A GT35R would smack much more, but I seriously doubt a 2.0L would be able to push it high enough. In my experience, GT3076 and GT35 series turbos are better suited for 2.5L and up. I've seen GT35 series turbos push out well north of 500 whp and wheel torque on 2.5L Subarus.

Honestly, I just don't see the Theta being able to push 40psi. I just don't think it's there.
When I'm ready to swap turbos completely, the car won't be a DD, but I'm a little concerned about your estimate for hitting boost on the HTA3076 turbo. I was under the impression the HTA3076 spools quicker than the the regular GT3076 & would hit just under 4k & run til about 7200. I think a GT35R may be overkill for my intentions & plan on using a modified version of the stock turbo as a stepping stone. If the Genesis 2.0L won't handle the HTA3076, perhaps stroking the motor is in order.

Sponsored By: Columbus Body Works / ARK Performance / Modern Automotive Performance / Forged Performance
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post #6 of 30 Old 04-05-2010, 03:28 PM
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Quote:
Originally Posted by Tufast View Post
When I'm ready to swap turbos completely, the car won't be a DD, but I'm a little concerned about your estimate for hitting boost on the HTA3076 turbo. I was under the impression the HTA3076 spools quicker than the the regular GT3076 & would hit just under 4k & run til about 7200. I think a GT35R may be overkill for my intentions & plan on using a modified version of the stock turbo as a stepping stone. If the Genesis 2.0L won't handle the HTA3076, perhaps stroking the motor is in order.
+1 on that. I dont think the Theta will handle a GT35R, I was at a standstill between the GT30R and GT35R, but I've finally decided the GT30R will suffice considering Lovefab has been running it for quite a while with no issues, and it's at a decent HP range that I'm looking at setting my Coupe in. Now perhaps after it's paid off and I decide to buy another newer model later down the line then I might consider toying with the GT35R.

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post #7 of 30 Old 04-05-2010, 03:42 PM
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I think they are both awesome turbos... I ran on my mazdaspeed miata the GT2871R after doing a bore on my block to 85mm and 85mm stroke (taking it from a 1.8L to about a 2.0L) But I personally picked the GT28 for the spool speed on my block over the GT30. It made amazing power at extremly low RPM.

The facts you put down was for PSI and RPMs I would like to know the Boost at the same RPMs would make it a little more interesting...

HP and TQ lines on the same motor should be pretty much the same for both turbos only the GT should do everything a few 100 RPM later then the GT28 which gives you the slightly bigger top end on the GT30.

But both turbos can get you deep into the 400whp numbers which is more then enough if your buidling a gencoupe IMO
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post #8 of 30 Old 04-05-2010, 04:12 PM
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I was thinking gt30 first but when I found out It needed rods after just north of 350whp I figured what the hell if its built lets give it a built engine sized turbo GT35R. So I am building it for a 35r as we speak.

7ism td05 turbo, 7ism equal length tubular manifold, 7ism FMIC and hard pipes, 7ism catless race downpipe, Tial 50mm BOV, Poweraxel flash module (7500rpm redline) and custom tune, Grimmspeed BCS, Grimmspeed manifold spacer, Grimmspeed 160 degree thermo, water weter replacement, Agency Power 3" exhaust, Electric cutout, Rc750cc injectors, autometer boost gauge, HID fog lights, tinted fogs and tail lights, wieght reduction stg1.

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post #9 of 30 Old 04-05-2010, 05:29 PM
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Quote:
Originally Posted by Tufast View Post
When I'm ready to swap turbos completely, the car won't be a DD, but I'm a little concerned about your estimate for hitting boost on the HTA3076 turbo. I was under the impression the HTA3076 spools quicker than the the regular GT3076 & would hit just under 4k & run til about 7200. I think a GT35R may be overkill for my intentions & plan on using a modified version of the stock turbo as a stepping stone. If the Genesis 2.0L won't handle the HTA3076, perhaps stroking the motor is in order.
The bigger the number, the bigger the turbo. So a GT3071 is smaller than a GT3076 which is smaller than a GT35. In most applications I've seen, the GT3071 spools about 500 RPM sooner than a GT3076. Both turbos are so close in power, so you can't go wrong with either. If you want an "insta-spool" turbo on the Theta, stick with the GT28 or the "Disco Potato" GT28RS. Great spool at 2800 RPM and awesome street power. If your goal is 350+, you must go with a GT3x series. The GT28 won't get you there on a 2.0L motor.
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post #10 of 30 Old 04-05-2010, 05:53 PM Thread Starter
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Quote:
Originally Posted by davisk6 View Post
The bigger the number, the bigger the turbo. So a GT3071 is smaller than a GT3076 which is smaller than a GT35. In most applications I've seen, the GT3071 spools about 500 RPM sooner than a GT3076. Both turbos are so close in power, so you can't go wrong with either. If you want an "insta-spool" turbo on the Theta, stick with the GT28 or the "Disco Potato" GT28RS. Great spool at 2800 RPM and awesome street power. If your goal is 350+, you must go with a GT3x series. The GT28 won't get you there on a 2.0L motor.
you just cant say because the number is bigger the turbo is bigger.You have to know wheel size for both turbine and compressor, exducer and inducer sizes of both wheel and A/r.Once you take all the numbers into account you can determine which flows more cfm and which spools better.
Max boost is not how you determine how fast a turbo spools up.When dealing with similar turbos you compare how fast a turbo spools to cetain psi.Most tuners choose 20 psi as a good gauge.
So to sum it up the two turbos I used in the OP, the 3071 will get to 22 psi quicker and more efficient.
Reason being smaller A/R.
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