The powercurves for these turbos are very similar. Im sure transient response might slightly favor the gt28rs, but it seems most people overlook the sc34. which is a few hundred bucks less. very similar curvers, and has the ability to make way more power than the gt28rs. here are some examples:

Car: Integra GSR

Engine: Stock block gsr, edelbrock IM

Mods: Epic Tuning custom turbo kit: Inline pro SS log manifold, gt28rs, 3" dp, 3" exhaust, precision medium intercooler, custom 2.5" charge pipes, tial 38mm wg, tial 50mm bov, dumptube under oil pan, precision 780cc injectors, neptune

Tuning at 10psi on 93 octane:



Car: Ek coupe

Engine: Bone stock JDM gsr swap

Mods: Blox turbo manifold, tial 38mm wg, precision sc34 .63a/r, 2.5 to 3" downpipe, 3" exhaust, 3" high flow cat, 2.5 custom charge pipes, precision medium intercooler, long dumptube, rc 550cc injectors, walboro 255lph pump, neptune

Tuning at 7psi:


Car: 1994 Integra gsr

Engine: Stock block gsr

Mods: Inline pro manifold, tial 38mm wastegate, gt28rs with the atpturbo.com .82a/r t3 drop in housing, 2.5" downpipe, 2.5" exhaust, itr muffler, closed loop wastegate dump, drag ic piping, spearo intercooler, rc 550cc injectors, walboro 255lph fuel pump, neptune

Tuning at 8.5psi:

Car: Eg hatch

Engine: Sleeved/built 9:1 84mm ls/vtec, edelbrock IM, stock tb

Mods: Inline pro manifold, sc34 .63a/r housing, tial 38mm wg, 3" dp, 3" exhaust, dumptube, custom 2.5" charge pipes, precision medium intercooler, RC 1000cc injectors, 3bar map sensor, walboro 255lph fuel pump, manual boost controller, neptune

Tuning at 18psi pump gas:


and as a bonus a t04e 57 trim


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Car: EK hatch

Engine: LS/vtec, 9:1 cp pistons, eagle rods, acl bearings, oem headgasket, GE ls/vtec conversion kit, stock b16a head, b16a cams, b16a intake manifold/tb

Mods: Inline pro cast iron manifold, t3/t4oe 57 trim .63a/r, 2.5" dp, 3" exhaust, custom 2.5" charge pipes, precision intercooler, Rc 550cc injectors, walboro 255lph pump, tial 38mm wg

Tuning at 9psi on pump gas:

 

It really depends on what you're goals are. How much power are you after? What's the rest of your setup like? What kind of driving will the car be subject to, street, strip, autocross, roadracing?

 

i can only speak for myself when i say this:

I appreciate the dyno plots, there is ALOT of usefull/good info, but the comparison between the 2 turbos has inadequate info.

None of them are on the same setups or the same boost level.

If they all had the same mani and DP, i would say its all good, but a blox mani doesnt compare to an Inline pro.

 

how much closer would a small sc50 be to a gt28rs, which still has a higher ceiling than the gt28rs

 

i wouldnt say the sc34 is overlooked. garrett is probably a bit more popular than precision but the t3/to4e 57trim is probably one of the most popular turbos for b-series motors. as far as the comparison i dunno, there are so many variations of the gt28r its hard to say.