Walbro 460 in r32 gtr

[portaz]

Hi all.

I had to chamge fuel pump due to car sitting for 10.years and went the 460. From memory it had the slightly smaller walbro in it previously. Running bosch 2200 injectors and a turbosmart compact fpr. Problem is no2 I can't get base pressure below 70psi. If I disconnect return line from fpr pressure drops indication restriction. I've inspected.the fuel line and removed the pipe on return line in tank and no chamge. Surely I'm not the only o e using stockings on a 460? Could the fpr be too small to handle the flow of new pump ? I'd like to sort it rather than going back.to smaller pump.

[TurboTapin]

You got your answer when everything was OK after disconnecting your return line from the FPR. Why in the world are you running a 460, 2200CC injectors, etc. on stock 8mm lines? 

Keep the pump, ditch the lines. I used both 8mm lines as my feed and one of my Hicas 10mm lines as return. 

Edited April 19 by TurboTapin

[portaz]

I'm trying to maintain stock appearance . Hicas is still installed (although has lockout kit) did you retain factory fuel pump hat? If so I assume you used a bulkhead fitting or similar ?  I was also trying to avoid a full re design as it was previously dynoed at 426kw atw with same setup but different pump. Changing return line would also mean having to change ethanol sensor and fpr and possibly fuel rail. Not chasing more power in any way just reliability of the setup 

[Duncan]

I've been running a 525 for years with the standard hat and FPR in the stagea (mine has a 32 gtr fuel rail and stagea and 32 hat and tank setup are the same) without an issue with base fuel pressure.

You said when you disconnected the return it is OK, did you do so at the fuel rail or the fuel hat? Either way I'd be looking for blockages or in the case of the tank kinks in the lines downstream

Note I did however have an issue with the current required for the 460 melting the fuel hat.

[Butters]

10 hours ago, TurboTapin said:

 Why in the world are you running a 460, 2200CC injectors, etc. on stock 8mm lines? 

Keep the pump, ditch the lines. I used both 8mm lines as my feed and one of my Hicas 10mm lines as return. 

I run 2 x 525 pumps on factory 8mm fuel lines     ... zero issues, staged of course 

 

Your setup should work fine, all you need to do is find the restriction. A good aftermarket fuel regulator is always a good idea too. If it's not your regulator i'd be suspicious of your fuel tank breather and your tank pressurising. Next would be something with the fuel hat. Then blow out the fuel lines. 

 

[Dose Pipe Sutututu]

I would be cautious with those 2000/2200 CNG injectors, swap them out for a set of 1550 aka 1650 Bosch stainless ones before you take out a motor.

[portaz]

I disconnected before the fuel pump and restriction still there. Disconnected at turbosmart fpr and also after ethanol sensor and pressure dropped. No kinks in line but I found one spot above diff that I can hear the fuel flowing while running so I'm wondering if there is built up corrosion  from 10 years of sitting.  I had injectors cleaned and tested and one was dead but rest were fine. Was never an issue when I owned the car previously but I'll talk to jez about his thoughts on if they should be changed to newer tech. Thx guys at least I know the setup should work again. Pump is wired directly to relay and not using factory plug any  more 

[Dose Pipe Sutututu]

14 minutes ago, portaz said:

Pump is wired directly to relay

And I hope the relay receives the trigger signal from the ECU and not the ignition power.

It should prime and stop if the motor isn't running.

[portaz]

33 minutes ago, Dose Pipe Sutututu said:

And I hope the relay receives the trigger signal from the ECU and not the ignition power.

It should prime and stop if the motor isn't running.

Yep sure does . Comes on primes and cuts off as a factory pump would 

[TurboTapin]

On 4/19/2024 at 7:33 PM, Butters said:

I run 2 x 525 pumps on factory 8mm fuel lines     ... zero issues, staged of course 

 

Your setup should work fine, all you need to do is find the restriction. A good aftermarket fuel regulator is always a good idea too. If it's not your regulator i'd be suspicious of your fuel tank breather and your tank pressurising. Next would be something with the fuel hat. Then blow out the fuel lines. 

 

1x 8mm line cannot flow 525lph, let alone two pumps worth of it. Your first pump isn't being fully utilized and your second pump isn't doing anything at all.

 

 

Edited April 21 by TurboTapin

[Butters]

6 hours ago, TurboTapin said:

1x 8mm line cannot flow 525lph, let alone two pumps worth of it. Your first pump isn't being fully utilized and your second pump isn't doing anything at all.

 

I've read that before, really good article.

However my ~900hp+ at flywheel, means it can be done.

Also have tested it with one pump on only, does what you'd expect, near 700's flywheel.

No disagreement that i will have horrible pressure drop compared to what it would be on a bigger lines.  

I can also overwhelm the regulator / return line at low HP consumption with both on, but I don't do that, so no issue  

 

So horribly inefficient but it works really well for the 10 seconds or so the second pump is on. 

[joshuaho96]

14 hours ago, Butters said:

I've read that before, really good article.

However my ~900hp+ at flywheel, means it can be done.

Also have tested it with one pump on only, does what you'd expect, near 700's flywheel.

No disagreement that i will have horrible pressure drop compared to what it would be on a bigger lines.  

I can also overwhelm the regulator / return line at low HP consumption with both on, but I don't do that, so no issue  

 

So horribly inefficient but it works really well for the 10 seconds or so the second pump is on. 

I'm actually really impressed that you don't pop a pressure relief valve or find some other weak link in the system. This puts me at ease though, I want to run 5 bar differential at the injectors and flow enough for maybe 500 crank horsepower tops on E85. I'm really hoping that a single Fuelab 496 series pump will work for this.

[portaz]

So I ran a new return line and upgraded in tank wiring to 6mm just in case and pressure is now adjustable thankfully. I may upgrade fuel.system down the  track but as its only 426kw atw that will.do for  now 

[Duncan]

1 hour ago, portaz said:

So I ran a new return line and upgraded in tank wiring to 6mm just in case and pressure is now adjustable thankfully. I may upgrade fuel.system down the  track but as its only 426kw atw that will.do for  now 

what size was the return line?

[portaz]

At the moment still 8mm. 

[Predator1]

On 20/04/2024 at 8:33 AM, Butters said:

I run 2 x 525 pumps on factory 8mm fuel lines     ... zero issues, staged of course 

 

Your setup should work fine, all you need to do is find the restriction. A good aftermarket fuel regulator is always a good idea too. If it's not your regulator i'd be suspicious of your fuel tank breather and your tank pressurising. Next would be something with the fuel hat. Then blow out the fuel lines. 

 

How are you staging yours? I am running these 2.. and my fuel was heating up.. I had to stick a fan assisted cooler on the return.

[Dose Pipe Sutututu]

4 hours ago, Predator1 said:

How are you staging yours? I am running these 2.. and my fuel was heating up.. I had to stick a fan assisted cooler on the return.

It's 2024, just PWM them instead of staging.

If OEMs are PWM, then you should too, especially with all the fancy ECUs on the market.

FWIW even my shit box with a mediocre ECU has PWM fuel pumps set up to ramp up and down with RPM x MAP.

[MBS206]

On 4/22/2024 at 8:35 AM, joshuaho96 said:

I'm actually really impressed that you don't pop a pressure relief valve or find some other weak link in the system. This puts me at ease though, I want to run 5 bar differential at the injectors and flow enough for maybe 500 crank horsepower tops on E85. I'm really hoping that a single Fuelab 496 series pump will work for this.

If both pumps are only on at full tilt, and even better if he reduces the output of one pump with he other off for idle etc, then when both pumps are on for full tilt power, the injectors are diverting the fuel away from the fuel return line to a much nicer location, which will help keep fuel pressure lower as there's not a blockage/build up of liquid.

[Butters]

9 hours ago, Predator1 said:

How are you staging yours? I am running these 2.. and my fuel was heating up.. I had to stick a fan assisted cooler on the return.

using a map with TPS and duty cycle with a slight delay on the off. 

The second pump only really needs to come on when flat out. 

 

5 hours ago, Dose Pipe Sutututu said:

It's 2024, just PWM them instead of staging.

 

PWM is interesting, are you using a solid state relay ?

[Dose Pipe Sutututu]

9 hours ago, Butters said:

PWM is interesting, are you using a solid state relay ?

Correct, I used to run 1x SSR for both pumps, but the inner OCD in me wanted 1x SSR per pump, so here we are  

Flyback diodes built into the harness

 

Here's my DC table