Hey there, just looking for some input. It sems the walbro 450 pump is the go to option for fuel pump upgrades over stock, but I have read some questioning if it is too much flow (and thus heat, amperage draw, etc) compared to stock without several other changes made to the fuel system. Several vendors sell cheap drop in kits with the Walbro pump, and it looks like SRM makes a phenomenal full kit with growth capacity using a single Walbro pump, but at +$1k it seems to be overkill for my power goals, even if it is very nice. I've read a lot of the great fuel pump upgrade threads on here, but it seems like most are shooting for fuel flow for 700+whp and making major changes to the fuel system (new supply and/or return lines, fuel rails, etc)

From my understanding the stock pump starts running out around 575-600whp, so it would seem the Walbro pump is way overkill to just get to mid 600 or close to 700whp. So through my searching and looking at the kits Radium makes for the Walbro pump to drop in, they also do the same for an AEM 50-1200 fuel pump that flows 340LPH, and their aluminum spacer also fits the Deatshwerks 9-301-1000 Pump referred to as DW300, so both of those appear to flow about 20-25% more than the OEM pump and with the DW300 doing better to keep flow up as fuel line pressure increases than the AEM 50-1200 does. Another plus is the amperage of both of those pumps is less than the Walbro 450 which has been raised as another concern point.

If the assumption of the OEM pump can provide power up to 575-600WHP, then 20% increase would put it right at 700+WHP vs the Walbro being good for closer to 1000hp! If I was going built motor and looking for 850-1000hp, it'd make entire sense to make it a full AN system with an pump (or two) capable of those flow rates.

So questions are:
1) Consensus on if the Walbro 450 is fine to use with no other changes to the fuel system?
2) Does the AEM 50-1200 or DW300 work as a suitable upgrade? Better or worse option than Walbro pump?
3) What other route or upgrades should I consider?
4) What other changes need to occur just to get one of these pumps up and running while not replacing the entire feed line to the engine.

Comparison sheet of fuel pumps

DW300 spec sheet

 

I have the Radium engineering walbro 450 drop in kit. I'm very happy with it. No issues to report. My fuel system is stock aside from the id1050x injectors and the pump.

If I ever need more fuel, I'll add the radium surge tank kit.

 

I made 647whp with a Walbro 450 for a couple of years now with no issues. I did run a -8 line from the hard line below the seat to the engine and I have ID1000s in the car too. I also have a 08 SRT8 Jeep with a 88mm turbo and I just took the 450 out of it and went with Walbro 525 pump. I was seeing fuel pressure drop a few psi when it made over 600wtq. The 525 does require rewiring because of the higher current draw.

 

Will it still require re-wiring on the Porsche as the pump and battery are up front so wiring path is much shorter and less chance of voltage drop than running the pump in the rear and battery up front.

 

I have the SRM brushless with the 3 speed controller box. I have it half installed, working on it...

 

For those that installed a Walbro 450 and didn't make any other changes outside of new lines or larger injectors, do you see high base fuel pressure at idle and and off-boost? If so, do you just accept the higher fuel pressure and adjust the fuel mapping or injector duty cycle to deal with it?

 

Do the protomotive single drop in for stock location

 

Your base pressure will be higher with the 450. Not ideal but the ECU can handle it. The Walbro pumps are PWM. I run the 525 and we operate the pump on an on demand basis based on MAP along with other inputs with which we devised a fuel pump output table. Essentially the pump output is continually variable based on demand.

 

Thanks pwdrhound, that's in line with what I understood. Right now, using the stock FPR, i run about 4.8 bar at idle. I'm working with Todd at Protomotive on the tuning, but before we go too far, I'd like to get the pressure down. If nothing else, for less stress on the system and better controllability at low RPM/coming off throttle. I'm currently testing a modified stock FPR (drilled out to 3 mm) which should allow more flow back to the tank. If that doesn't work, I may need to look into slowing the pump down a bit to bring down the pressure.

With your PWM method, you're essentially controlling the pump based on estimated load (via MAP pressure, speed, etc)?

 

I show 3.2 bar at idle. This is on a 4.0L engine. A 3.6L engine would show about 3.4 bar at idle due to lower vacuum. To control the pump we are not looking at load per we but rather at MAP (post throttle body) along with throttle pedal position. We created a 3D table that is used to send a PWM signal to the pump to continually vary it's output anywhere from 30%-100%. There are also safeties built in which will drive the pump to 100% output if the fuel pressure ever drops below a predetermined level throughout the operating envelope. Everything is handled via Motec solid state PWM controller which makes this seamless.

 

I think getting the SRM system with the 3 speed controller is the best solution. It is wired into the map analog signal from a wire near the ecu. Really clean setup.

 

I haven't looked into the SRM setup closely. Do you run it? Any overall feedback in terms of controlling pressure and functioning reliably?

 

So far so good but I have not pushed it hard just yet.

 

FYI to anyone interested - Yesterday I bored out the stock FPR to 3 mm (from the stock 2 mm). This results in the idle pressure dropping from 4.8 bar to 4.2 bar, due to the increased return flow capability. This is a nice option IMO as it re-uses the stock FPR, return line, etc. I may try opening it up more to get back to 3.8 bar.

 

Any noticeable driving impact from getting the fuel pressure back down close to stock levels?