^ Thanks D.

 

Awesome thanks guys!

 

Updated my post describing the fuel pump voltage control table and the EvoScan definition. I modified the EvoScan definition slightly to make the description more accurate. No changes to the table for ECUFlash.

Also, this is for sure the correct table. I adjusted the high voltage load on my Evo tonight, and I've got fuel pressure totally under control. For my custom rewired Walbro 255 that retains the low voltage circuit, setting the high voltage load to match the open loop load resulted in 43 psi across the injectors under virtually all conditions. Using this approach for a Walbro 400 on factory pump wiring will probably work pretty well. For a rewired Walbro 400, I suspect the high voltage load will have to be somewhat higher to keep the fuel pressure consistent under all conditions.

 

Well I picked up one of these puppies up from MAP along with a fuel pressure gauge kit from Ultimate Racing during their xmas sale.



Installed the gauge first and tested on my current pump, DW300 and I was running pump gas:

43-44psi. I was shocked! Unmodified fuel system other than the DW300 and FIC1680's.

Converted back to e85 and pressure dropped at idle to ~40-41psi:


So I decided to forgo punching out the siphon right away and just throw in the new pump and see what I did. I was pretty shocked:

~44psi on the nose.

I'm running a boost-a-pump, and with the 1680's and DW301 pump I've been about at the limit of the fuel system since I converted to e85 in May/June. This pump very obviously flows more up top, time for most boost and more mods I guess?




Mrfred, I may have to fool around with your voltage crossover point, but with my BAP the car is already a tri-voltage setup

 

*Note* both pumps were running at 17.5V via the boost-a-pump. Car is making around 550-575whp dynojet.

 

If fuel pressure at idle is good, then really no need to mess with the crossover. A couple of questions though:

1) The idle fuel pressure measurements were with the FPR disconnected?
2) How is the BAP a tri-voltage setup? Does it have inputs to alter voltage based on rpm or something else?

 

I am guessing tri-voltage because you have the normal dual voltage then the BAP bumps it up further off a hobbs switch I think or something.

 

Idle pressure measurements you see were with the fpr connected, but in all cases I disconnected it and saw less than a 2psi variance in all cases.

Yea I was half joking but low voltage, then stock high voltage, then whenever the Hobbs switch trips the BAP jumps pressure to 17.5. It sits inline with the stock pump wiring.

 

That's a bit odd. When the fpr line is removed, fuel pressure should increase by whatever vacuum level there is in the manifold.

 

^yeah, odd.
my Evoscan tells me i have ~5.5psi vacuum at idle, and sure enough when i clamp the vacuum hose the fuel pressure gauge goes up by 5psi.
Unless his idle is so choppy there's hardly any vacuum?

 

Noted. I'll double-check. Idle is smoove as buttah; kelford -b's.

 

^ what idle rpm and how much timing?

 

around 850rpm and 10-12° of timing.

 

Yea the Kel-B's are hard to even tell you have cams in the car. My favorite cams for the 10.

 

I was hoping the GSC s2's would show a lot of power over the b's but I don't think they are too much better if at all. I know Scheides' car is for sure smoother than mine at idle.