Tomioka Racing Hybrid VF54 Turbo is our newest line of turbo for the 2010 Subaru Legacy GT. This turbo is designed with performance in mind for the Subaru bottom mount turbo set -up. This turbo features a TD05-20G custom billet compressor wheel and upgraded steel wastegate actuator to maintain boost and increase power. IN addition, the hybrid turbo housings are machined to increase ow compared to the factory housing Legacy turbo. This hybrid VF54 will turn your BM/BR Legacy GT in to a racing power house!
Check out the available video and dyno graph on this turbo.
Refundable Core Deposit
A $500 refundable core deposit will be automatically added to your cart for this turbo. The deposit will be fully refunded once your original turbo core is returned. Core return shipping is included within the lower 48 U.S. states.
*** Note: This turbo does not come with turbo oil pan. Customer needs to transfer the original oil pan to the new turbo ****
Turbo Characteristics
| Bearing Type: | Journal | |
| Flange Type: | Standard Legacy 2010 | |
| Compressor Wheel | In: | 52.5 mm |
| Ex: | 68 mm | |
|
Turbine Wheel |
In: | 55.8 mm |
| Ex: | 49.2 mm | |
| Actuator: | 1 Bar / 14 psi | |
| Max. Power: | 450 HP | |
Kit Contents
• Turbocharger
Wastegate actuator spring choice: 1.1 bar vs 1.3 bar (what customers need to know)
What the spring actually controls (and why it matters)
On a pneumatic internal wastegate, the actuator spring sets your gate pressure (often called base boost): the boost level where the wastegate starts to open because boost pressure overcomes spring force. Haltech describes it simply: changing spring pressure changes the default boost pressure, and when boost exceeds spring pressure the valve opens and begins regulating boost.
Choose 1.1 bar (16.1 psi) / Red if:
You want a lower boost map (street/traction/valet) around the mid-teens. Remember: you can’t go under the spring.
Your normal target boost is roughly 18–22 psi and you want good controller authority and flexibility.
You’re building a setup where drivability and multiple boost modes matter (daily + weekend map).
Choose 1.3 bar (19.1 psi) / Silver if:
You will not run low boost—your “low boost” is still ~19 psi or higher. (If you need 15–17 psi sometimes, don’t pick this.)
Your normal target boost is roughly 22–28 psi and you want:
less “work” from the boost control system to hit target, and
typically better resistance to the wastegate being pushed open early (especially in higher load / backpressure situations).
There are two different “maximum boost” questions people ask:
1) Maximum boost your boost control can hold consistently
Using the GFB rule-of-thumb (target boost ≤ ~2× gate pressure) :
With a 1.1 bar / 16.1 psi spring, the “control stability ceiling” is roughly ~32 psi (2 × 16.1).
With a 1.3 bar / 19.1 psi spring, the “control stability ceiling” is roughly ~38 psi (2 × 19.1).
Reality check: that does not mean “safe to run 32–38 psi.” It means beyond ~2× gate pressure, boost control tends to get inconsistent because the actuator isn’t receiving enough meaningful reference signal for correction. GFB explains that once you go beyond double, boost control becomes less stable and more affected by variables like RPM/load/backpressure.
2) Maximum boost your turbo/engine can safely run
That’s not spring-limited. It’s limited by:
turbo efficiency and speed/heat,
fuel quality and knock margin,
intake temps/intercooling,
exhaust backpressure,
engine/clutch/trans limits,
tuner strategy.
FAQ:
Can I run less boost than the spring rating?
No. Spring pressure is the lowest boost level you can reach.
Does a stiffer spring automatically mean higher peak boost?
Not automatically. It mainly raises minimum boost and changes how the wastegate behaves. Boost above spring comes from the control strategy.
Why do people say “don’t exceed 2× the spring”?
Because boost control gets less stable as target boost gets too far above gate pressure; beyond ~double you tend to lose correction authority.
What spring gives the best spool and boost stability?
A spring that puts gate pressure about 10–20% under your target boost is a strong general guideline for best performance.
Tomioka Racing Hybrid VF54 Turbo is our newest line of turbo for the 2010 Subaru Legacy GT. This turbo is designed with performance in mind for the Subaru bottom mount turbo set -up. This turbo features a TD05-20G custom billet compressor wheel and upgraded steel wastegate actuator to maintain boost and increase power. IN addition, the hybrid turbo housings are machined to increase ow compared to the factory housing Legacy turbo. This hybrid VF54 will turn your BM/BR Legacy GT in to a racing power house!
Check out the available video and dyno graph on this turbo.
Refundable Core Deposit
A $500 refundable core deposit will be automatically added to your cart for this turbo. The deposit will be fully refunded once your original turbo core is returned. Core return shipping is included within the lower 48 U.S. states.
*** Note: This turbo does not come with turbo oil pan. Customer needs to transfer the original oil pan to the new turbo ****
Turbo Characteristics
| Bearing Type: | Journal | |
| Flange Type: | Standard Legacy 2010 | |
| Compressor Wheel | In: | 52.5 mm |
| Ex: | 68 mm | |
|
Turbine Wheel |
In: | 55.8 mm |
| Ex: | 49.2 mm | |
| Actuator: | 1 Bar / 14 psi | |
| Max. Power: | 450 HP | |
Kit Contents
• Turbocharger
Wastegate actuator spring choice: 1.1 bar vs 1.3 bar (what customers need to know)
What the spring actually controls (and why it matters)
On a pneumatic internal wastegate, the actuator spring sets your gate pressure (often called base boost): the boost level where the wastegate starts to open because boost pressure overcomes spring force. Haltech describes it simply: changing spring pressure changes the default boost pressure, and when boost exceeds spring pressure the valve opens and begins regulating boost.
Choose 1.1 bar (16.1 psi) / Red if:
You want a lower boost map (street/traction/valet) around the mid-teens. Remember: you can’t go under the spring.
Your normal target boost is roughly 18–22 psi and you want good controller authority and flexibility.
You’re building a setup where drivability and multiple boost modes matter (daily + weekend map).
Choose 1.3 bar (19.1 psi) / Silver if:
You will not run low boost—your “low boost” is still ~19 psi or higher. (If you need 15–17 psi sometimes, don’t pick this.)
Your normal target boost is roughly 22–28 psi and you want:
less “work” from the boost control system to hit target, and
typically better resistance to the wastegate being pushed open early (especially in higher load / backpressure situations).
There are two different “maximum boost” questions people ask:
1) Maximum boost your boost control can hold consistently
Using the GFB rule-of-thumb (target boost ≤ ~2× gate pressure) :
With a 1.1 bar / 16.1 psi spring, the “control stability ceiling” is roughly ~32 psi (2 × 16.1).
With a 1.3 bar / 19.1 psi spring, the “control stability ceiling” is roughly ~38 psi (2 × 19.1).
Reality check: that does not mean “safe to run 32–38 psi.” It means beyond ~2× gate pressure, boost control tends to get inconsistent because the actuator isn’t receiving enough meaningful reference signal for correction. GFB explains that once you go beyond double, boost control becomes less stable and more affected by variables like RPM/load/backpressure.
2) Maximum boost your turbo/engine can safely run
That’s not spring-limited. It’s limited by:
turbo efficiency and speed/heat,
fuel quality and knock margin,
intake temps/intercooling,
exhaust backpressure,
engine/clutch/trans limits,
tuner strategy.
FAQ:
Can I run less boost than the spring rating?
No. Spring pressure is the lowest boost level you can reach.
Does a stiffer spring automatically mean higher peak boost?
Not automatically. It mainly raises minimum boost and changes how the wastegate behaves. Boost above spring comes from the control strategy.
Why do people say “don’t exceed 2× the spring”?
Because boost control gets less stable as target boost gets too far above gate pressure; beyond ~double you tend to lose correction authority.
What spring gives the best spool and boost stability?
A spring that puts gate pressure about 10–20% under your target boost is a strong general guideline for best performance.