Below is the GTX3576r using the custom top mount header I fabricated with the Garrett 1.01a/r vband TS turbine housing. Since I log turbo shaft speed I can tell you it was riding the choke line so definitely maxed out as far as the turbo goes.

 

that hits later than I thought it did, even for the 76!

 

240Z u still going to consider that maxed out if I get around to outdoing that with a .63 SS t3 on a gt no x 3076?

 

The top mount header was definitely super laggy so I swapped back to the short runner manifold. I posted the spool with the GTX3576r using the short runner manifold a few post back, which was 27.3psi @ 3848rpm in 3rd on pump.

Below is the spool comparison of the short runner manifold vs long runner manifold with the GTX3582r, which was 950rpm.

 

When the turbo rides the choke line then it is maxed out. That has nothing to do with your ability to make more power with the same turbo on a different setup. Considering the compressor flows ~64lbs/min my results are inline with what you should expect. I don't put a lot of stock in dyno graphs that show power levels well above what a turbo is capable of supporting.

 

20 at 4k is what kind of torque on a 2.0. We're trying to study up on a good torque making set up, that has a boost threshold similar to a red, but takes advantage of full frame and twin scroll, ultimately with more 93oct hp available. Using a single scroll red for comparison. We're also acruelly using a 2.4 but 2.0 is easy to compare and rough extrapolate from.

 

how do I get the yellow spring everyone is talking about?

 

what is your power goals?
when i had my STi, i went with the Gen 1 GTX3071r .82ar over the 3076r and i couldnt have been happier! I was making 490whp 489wtq 30psi on E85. I hit boost under 2k rpms, and made full boost(29-30psi) by 4400-5000rpms and held all the way to redline(9000RPMS)
The gen1 gtx3076r is a Mis-Matched turbo. I would stay away from it. The gtx3071 almost caught up to it bcuz The flow of the 3076 compressor is just too much for the turbine wheel to handle.
This is why they made the 3576r. It may be 200-400rpms laggier than the 3076, but it makes a tremendously more power than the 3076.
Now if you want super quick spool up and still make 600whp, i would look at the new Gen 2 GTX3071r! The new Gen 2 GTX series Garrets are Insane! I prefer them over PTE anyday!

 

The Turbo Housing is Key here tho!
I doubt the top mount mani had as much to do with the lag as the Big *** Hotside did! you would've been better of with the .82ar as opposed to the 1.01ar! I wouldnt run that 1.01 unless it was attached to at least a gtx40! If tuned right, you will see the same numbers with the .82ar as you did with the big boy, and you would see boost a lot sooner as well!
I was running the tiny .63ar TiAl on the gen 1 gtx3071r, and after replacing the .63ar with the .82ar, and installing BC272 Cams, i was seeing boost just as quick, and of course my top end was a bit more. Supporting Mods play major rolls in the turbos performance
Ive always been curious to see what the gtx3576r would make with the .63ar on it. I bet it would spool crazy fast, but most likely drop off a little early! But the .82ar is a perfect matchup for the 3576, and i believe Garrett makes an .83ar housing that is SS just like the TiAl housings!

 

He was running a Vband TWIN SCROLL 1.01 AR housing. So the AR was completely appropriate, if not maybe even a touch small.

 

I believe that the gen 2 gtx 30's are what is currently available stock frame