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KB has done a lot for the community and has always been a good source of information. The GTX3576 is an awesome turbo for that "500-550ish whp" range you want. I believe taking a look at Garrett's new G series as well may also be a great option for you. The G30-770 looks like it will give the GTX3576 a run for it's money with both spool and Garrett themselves rate it for more power potential. Then there's the G35-900 which is the same size as the GTX3576.
I agree completely. And I have debated that g30. But I haven’t found many results on it. I know the gtx line is proven to take abuse and hold up. So I’m leaning more towards a gtx.

and yes killer b has done quite a bit for our subaru community for sure. I wish they still made their low mount kit lol
 

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I have really enjoyed my G30-900 so far - I did a data log and I am hitting peak boost at ~4820 rpm btw (forgot to post it this weekend for you sorry!). The place that did my tune also had 2 GD body race cars (I think they do hill climb mostly) one is on the GTX3582 gen 1 was at 539whp/542tq @30psi, and the other is on the G35-900 that was at 640whp/540 @28psi while my G30-900 was 569whp/473 tq @26psi (all on E85) and my Killer B headers helped too :D

The other cars have a larger fuel system than I do plus no AC with shorter piping and different manifolds and probably spool just a little faster than I do, as well as fully stripped and cages compared to mine (full interior with AC!) so they are not apples to apples necessarily but just more data for you to chew on.

I was waffling between a 3076, 3576 when I was planning my build but ended up with the G30-900 which feels like it is maybe between the 3576 and 3582 though I have no hard data to prove that, just butt dyno readings.
 

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Nice build and numbers. I'm currently waiting on my rotated kit with a G30-770. I hope to have some numbers to show in the next couple months.
 

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I was waffling between a 3076, 3576 when I was planning my build but ended up with the G30-900 which feels like it is maybe between the 3576 and 3582 though I have no hard data to prove that, just butt dyno readings.
You're not wrong. Most often than not, when a new turbo gen or design comes out, there can never be an apples to apples comparison. Comparing the GTX to G-Series is about as easy as comparing a G-Series to EFR. Knowing the nuances of the engine design and how best it interacts with a turbocharger is going to net best power. Unfortunately, that just takes time, and lots of resources. This is why a 3076 makes great power on a Honda, EVO, etc... but not so much on a Suby. You have to look at compressor maps and know the Subaru is going to make nowhere near 'ideal', and they LOVE large turbine housings and big A/R.
 

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I have really enjoyed my G30-900 so far - I did a data log and I am hitting peak boost at ~4820 rpm btw (forgot to post it this weekend for you sorry!). The place that did my tune also had 2 GD body race cars (I think they do hill climb mostly) one is on the GTX3582 gen 1 was at 539whp/542tq @30psi, and the other is on the G35-900 that was at 640whp/540 @28psi while my G30-900 was 569whp/473 tq @26psi (all on E85) and my Killer B headers helped too :D

The other cars have a larger fuel system than I do plus no AC with shorter piping and different manifolds and probably spool just a little faster than I do, as well as fully stripped and cages compared to mine (full interior with AC!) so they are not apples to apples necessarily but just more data for you to chew on.

I was waffling between a 3076, 3576 when I was planning my build but ended up with the G30-900 which feels like it is maybe between the 3576 and 3582 though I have no hard data to prove that, just butt dyno readings.
that sounds a bit laggy for my goals. It would only give me about 2k of powerband (not raising rev likit). But they seem to be great turbos. I really want to see what the g30-770 does. On paper that seems like it would be good but you never know.

I’m sure I’d be happy with the 3576 or even the 3076. Im just overthinking lol. My plan here is research, but once, cry once lol
 

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Nice build and numbers. I'm currently waiting on my rotated kit with a G30-770. I hope to have some numbers to show in the next couple months.
I’m anxiously awaiting seeing this. The g30-770 is the one I have my eye on vs the gtx3576 and 3076 gen2s.
 

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@Karlot I'm assuming you saw this post👆

Also see below:

  • 481 whp & 431 ft-lbs @24 psi Q-16 fuel
  • 575 whp & 566 ft-lbs @33.9 psi Q-16 fuel
I have seen those. But the dyno plots are small and very hard for me to read. But at those boost levels if I’m reading it right it seems super similar to what the 3076r gen 2 would do.
 

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Similar yes. Garrett rates the G30-770 at 770 crank hp and the GTX3076r gen 2 at crank hp 750 with a bigger compressor wheel. So peak numbers will be similar. However I've never seen a gtx3076r gen 2 hit 300 ft-lbs at 3400rpm on an sti with a similar setup. Also people are raving over the transient response due to the lighter turbine wheel.
This G30 also has the advantage of a smaller compressor wheel and more efficient turbine wheel. When I add everything together it all just makes sense. Slightly better spool, negligible but better peak hp, much better transient response.
 

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Similar yes. Garrett rates the G30-770 at 770 crank hp and the GTX3076r gen 2 at crank hp 750 with a bigger compressor wheel. So peak numbers will be similar. However I've never seen a gtx3076r gen 2 hit 300 ft-lbs at 3400rpm on an sti with a similar setup. Also people are raving over the transient response due to the lighter turbine wheel.
This G30 also has the advantage of a smaller compressor wheel and more efficient turbine wheel. When I add everything together it all just makes sense. Slightly better spool, negligible but better peak hp, much better transient response.
Yeah the g30-770 does look to be a very nice turbo. Honestly when I do get one it’ll be between the gtx3076/3576 and the g30-770 lol.
 

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In all honesty, if you are looking to be an effective time attack car or even participate and are newer, I would suggest seat time over power mods to make up for that lost time.

While the talk of turbo's and stuff is all fine and dandy, if the car handling characteristics are not suited for the power, you would be endangering yourself amd the car more so than anything with the added power range of these turbos you are looking at. I raced on a low boost DOM 1.5XTR at 23psi on 110 octane and in the street class it was fine.

Coming to a stop with the gtx3576R/gtx3076R/g30/g35, whatever the case may be more important than the power itself. I would exhaust every ability to cut down time without adding huge power before going that route. Lightening up the car, dialing in suspension, aero depending on the class, tires, brakes.

I would definitely not be looking to go into these size turbos unless you are a veteran driver racing in an upper level class.

Sent from my SM-G965U using Tapatalk
 

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In all honesty, if you are looking to be an effective time attack car or even participate and are newer, I would suggest seat time over power mods to make up for that lost time.

While the talk of turbo's and stuff is all fine and dandy, if the car handling characteristics are not suited for the power, you would be endangering yourself amd the car more so than anything with the added power range of these turbos you are looking at. I raced on a low boost DOM 1.5XTR at 23psi on 110 octane and in the street class it was fine.

Coming to a stop with the gtx3576R/gtx3076R/g30/g35, whatever the case may be more important than the power itself. I would exhaust every ability to cut down time without adding huge power before going that route. Lightening up the car, dialing in suspension, aero depending on the class, tires, brakes.

I would definitely not be looking to go into these size turbos unless you are a veteran driver racing in an upper level class.

Sent from my SM-G965U using Tapatalk
I am not a veteran driver but I absolutely agree that seat time is the most important thing. And I planned on staying in street class anyway. I just figured I’d get what I really want as as time goes on slowly crank up the boost (one of my best friends is my tuner, so I wouldn’t have to pay for a bunch of tunes to do so). But regardless yes I understand what you’re saying and agree that it’s not a necessity, but seat time sure is
 

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Pretty sure it's more fun to be the fast guy with the small turbo than the slow guy with the big one :)
 
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Pretty sure it's more fun to be the fast guy with the small turbo than the slow guy with the big one :)
You’re not wrong about that haha. I currently have a 20g so it’s still pretty darn fun to track. I just find myself wishing I had more haha. Granted I do need more seat time and to this point i haven’t done anything but improve. My last trackcross day I improved each and every lap.
 

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I don't know if I am the fast guy with the big turbo or the slow guy with the big turbo but I do have a stupidly large smile every time I start or drive my car. 🤓

I wish you luck Karlot - hopefully whatever you decide brings you some smiles too.
 

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I don't know if I am the fast guy with the big turbo or the slow guy with the big turbo but I do have a stupidly large smile every time I start or drive my car. 🤓

I wish you luck Karlot - hopefully whatever you decide brings you some smiles too.
thank you. And I’m sure it will bring smiles haha. I’m definitely on the slower side but I haven’t had an event yet where I’m not either faster every lap or can’t identify why I went slower. Typically that’s when I either brake too early or slide lolololololol. These cars are so much fun to track anything will bring the smiles.
 
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