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Discussion Starter · #1 ·
HKS supplies two upgraded fuel pumps with their GT600 package while retaining the stock injectors.

They must know that the stock injectors are +/- maxed out at 600hp so presumably the upgrade pumps and regulators give some extra headroom.

This approach doesn't seem very popular in North America, with most people changing to 1000cc injectors and Walbro pumps at the same time.

Why not just use the HKS pumps? Has anyone added the HKS pumps to a non-GT600 car? Does it help?

• Racing Extension Pipes (75mm) • Racing Center Pipe (75mm x2 - 85mm) • Intercooler Pipe Kit (Polished Alum.) • Pre-programmed EVC (JDM Spec) • Pressure Release Computer (PRC) • Super SQV Blow-off Valve Kit • Reinforced Actuators • Super Fire Racing Spark Plugs (M45HL) • Premium Suction Kit • Fuel Pumps x2 • Fuel Pressure Regulator
 

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I used them on my E85 setup with ID1000's.
 

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Discussion Starter · #4 ·
They do add a fuel pressure regulator and it ups the fuel pressure enough that you get some more headroom without touching the ecu.

Sean
But more fuel pressure = retune


How are they doing this without touching the ECU?

Does anyone know how much more fuel pressure the HKS fuel pressure regularor adds?

Maybe HKS won't sell the pumps and regulator separate from the GT600 package so this mightt not be possible.
 

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The HKS pumps are true drop-ins, use them on mine with ID1000 running on E85.
 

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To do it properly, you need to choose your injectors and fuel pressure with regard to your HP target and what fuel.. GT600 setup assumes your targeting 600hp on pump gas so the kit just increases the fuel pressure without changing injectors.. the advantage of this is is you retain full OEM fuel atomization.. which has direct affect your fuel economy in day to day driving... however, its limited to the specified HP.. increasing the fuel pressure more might help increase max HP but at a point you will run into non efficient range of the fuel pump.

If you want more HP you should retain stock fuel pressure and just change injectors and fuel pump for more flow.. injectors also have efficient operating range..choosing the correct injector for your HP target is very important if you want to maintain your fuel economy in day to day driving. keep your injector at 85-90% IDC at your max HP is a nice and balanced tune.

so 1000cc maybe good for 950HP.. and if you target 700HP on pump and use 1000cc you'll be using about 73% IDC which is a bit compromising on day to day economy drives.

if you target 700-800HP pump gas.. using 860cc or 900cc injector is a better balance.

SARD and HKS also have nice injectors for GTRs
 

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Discussion Starter · #10 ·
To do it properly, you need to choose your injectors and fuel pressure with regard to your HP target and what fuel.. GT600 setup assumes your targeting 600hp on pump gas so the kit just increases the fuel pressure without changing injectors.. the advantage of this is is you retain full OEM fuel atomization.. which has direct affect your fuel economy in day to day driving... however, its limited to the specified HP.. increasing the fuel pressure more might help increase max HP but at a point you will run into non efficient range of the fuel pump.
I couldn't agree more. My situation is that my end power goal is just at the edge of the stock fuel system's capability. Let's call this circa 550whp by using catless DPs and a good free-flow exhaust plus 3" intakes. It seems that some GT-R owers can reach this power level on the stock fuel system while others upgrade the injectors and pumps. I want to keep the stock injectors for driveability reasons so if the HKS fuel pumps and regulator can give me +/- 10% more fuel vs the stock set-up this should suit my needs perfectly.

<OT> I do find it odd that HKS insists on changing a lot of parts (GT600 @ $10k) to reach 600hp (crank) while the US tuners only need DPs, mid pipe and a tune for 525-550whp (circa 625 crank HP) at a third of the price. Maybe the Japanese horses are bigger or more reliable, or just underrated? What is peak boost on the GT600 kit? Maybe much lower than the 18psi that other tuners use to reach this power level? No negativity here, just trying to learn.
 

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I couldn't agree more. My situation is that my end power goal is just at the edge of the stock fuel system's capability. Let's call this circa 550whp by using catless DPs and a good free-flow exhaust plus 3" intakes. It seems that some GT-R owers can reach this power level on the stock fuel system while others upgrade the injectors and pumps. I want to keep the stock injectors for driveability reasons so if the HKS fuel pumps and regulator can give me +/- 10% more fuel vs the stock set-up this should suit my needs perfectly.

<OT> I do find it odd that HKS insists on changing a lot of parts (GT600 @ $10k) to reach 600hp (crank) while the US tuners only need DPs, mid pipe and a tune for 525-550whp (circa 625 crank HP) at a third of the price. Maybe the Japanese horses are bigger or more reliable, or just underrated? What is peak boost on the GT600 kit? Maybe much lower than the 18psi that other tuners use to reach this power level? No negativity here, just trying to learn.
The GT570 and 600 kits are a bit antiquated at this point; they were designed back in 2007-2008 when the GT-R first came out. Since then, the aftermarket has been fully developed and the Accessport has taken tuning very far. The US has contributed substantially to the development of the GT-R's aftermarket and have found other workarounds and combinations of parts that improve the car more efficiently.
 

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The GT570 and 600 kits are a bit antiquated at this point; they were designed back in 2007-2008 when the GT-R first came out.
Agreed..

However, still now, the only way to get 600hp without touching the ECU (and injectors) is increasing the fuel pressure and actuators..in addition to intake and exhaust mod..the only other thing that would benefit the engine is Cobb Tune but that would mean touching the ECU.
 
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