Side note:

Correct me if I am wrong here but this is my plan:

Now that I have 1000cc injectors and still running a Walbro 255 pump, the pump is now the limiting factor in my system. Therefore I am going to lower my fuel pressure from 52 psi to 43.5 psi because even at 43.5 psi the ID1000's will flow 365 lph so raising the pressure is only going to make the pump run out sooner despite the fact that the injectors flow more at the higher pressure (around 394 lph).

The next step for me would be a DW300 or an Aeromotive 340 and a 10 or 12 gauge wire and a 20A relay to the fuel pump. That should be plenty for 550 whp on pump right?

 

Depending on who you ask the 255 is enough for mid 500's, but the setup you propose to step up to is how I would do it.
I know of a member on here running around those hp levels who lost an engine and consequently dropped the Z by the failing of a 255. Not sure how longevity compares to a 340 or 300 but I assume it's better. That being said a lot of people have various opinions on 255's... Some believe it's only the cheap ones that let go, some believe they only let go after lots of high pressure, I believe they all let go, it's just a matter of time (as with any fuel pump realistically).
Oh and go with 10GA wire in the event you go for a bigger pump setup/more power you won't have to rewire it.

 

DW has great products but I'm not sure of many people using that pump. The users on here with the 340's have good results. Though the 255 will get you low/mid 500's I think it would be wise to use either the 300 or 340 for your power goals as you have stated.

 

Already had the boost a spark, repurposed as a boost a pump. My current set up runs 10.5 volts at idle and 16.5 volts above 4 psi. The Walbro 485 I think is the same as the Walbro 400 E85 version depicted in the chart above (and reportedly flows 6% more than the pump gas version of the Walbro 400).

Why hasn't Injector Dynamics come out with something between their 1000 cc and 2000 cc injectors yet??? I need a bit more injector to be pump limited.

 

Ya, i was just talking in general for those of us without a boost-a-pump already.

ID makes 1300cc injectors for domestics. They would be perfect for our setups but they don't physically fit. I wish they made adapters because ID 2000's are way too big. Even a twin pump setup flows only enough to max out 6 1400cc injectors so 2000's is a waste of injector unless a person has a triple pump.

 

The AeroMotive 340 wasn't enough for me for some weird reason. Had to go with the CJM twin pumps. Every time it got past 10psi (480-500whp) fuel pressure dropped. Twin pumps are in and holding pressure and now waiting on dyno results.

 

I'm thinking that is a rare occurrence. There could have been a defect in the pressure valve of the pump, the connection between pump and basket or an impeller defect.

Even a 255 can push 500 without problems so I think there had to be other problems going on with that specific pump.

 

3-Walbro 255's and 2-AeroMotive 340s were tried and failed above 8-10psi of boost.

I will agree though that my Z had a freak issue as far as fuel pressure. I upgraded to the 340 for added insurance over the 255 and it failed me. However a 340 should be more than enough for a 500-700whp build.

I'm just glad the twin pump solved the problem.

 

voltage issue?

 

Hot wired directly.

 

That's crazy. Was it drop in in the stock fuel bucket?

 

Yes... Both the Walbros and AeroMotives are drop-in pumps. Even swapped baskets.

 

I had fuel issues with my evo. I wanted to run a single pump so I jumped from a 255 to a a couple different 300+ pumps. Let's just say they "slightly" outflowed the 255. and according to my tuner, he has basically seen every one and he says "none of them lived up to the hype".. all of these pumps drop off when you start raising the pressure.

If you are going for more flow on a single pump I would suggest a wally 400

 

this is exactly my experience.

another option is a kennebell BAP for a single

 

Sorta on topic, maybe you know the answer to this question Robert -

If I made the fuel basket modifications to fit the Walbro 255 (shaved down the slots in the clip that holds the pump so it could snap on) will I have any trouble with the DW300 or Aeromotive 340? Are they exactly the same dimensions as the 255? The DW worries me because it is supposed to be "drop in" and if that is true, then it should be the same as the stock pump and therefore would be loose if the clip modification was already done.

 

What is your base fuel pressure set to? 52 psi?

 

I can't speak for the DW but the AeroMotive was a direct swap. And yes fuel pressure was set for 52psi. If I remember correctly, I'm back in Iraq, it went up 1psi for every # of boost. But don't quote me on that since I haven't driven the car since July. LOL It's actually on the dyno right now finishing tuning.

 

This is correct for most standard fuel pressure regulators. There are few that are different rising rates and most state that. If it just says "rising rate" then it's probably is the standard 1:1. The 1:1 only takes away the boost pressure in the manifold to make the injectors work to their standard output. The 7:1 or so that vortech does actually causes and increase in flow from the injectors.

 

Just an update... The twin pumps fixed my fuel issues.