What mods are out there to get the last bit of flow & pressure out of a 255 lph walbro fuel pump?

i have heard of tweaking some relief spring...but thats about the extent of it......i dont know the details & / or merits if any...

TIA

 

I heard it rumored that Buschur knew.

 

Something about pushing said relief spring in with a ball point pen... a search with that should get you the answer. I personally don't recall the procedure. However, I do recall it being a significant difference.

 

If you do a search on the Buschur modified Walbro 255HP, you'll find that the only difference was that the pressure relief valve was punched down so that it no longer relieved any pressure. Presto, more pump pressure at 70 PSI and above.

It takes 10 seconds or so to do this complicated procedure.

 

thank you, that is awesome information, and also saves like 50 dollars

 

http://www.driven2modify.com/showthread.php?t=11702

 

Is this mod worth doing if you are not boosting 30+psi?

 

awesome link

 

Someone, on here...Mellon or someone(?) was using a KenneBell Boost-A-PumP to increase voltage to the pump at WOT. I am not sure if this is the same as what is called a pump hotwire kit, which uses 12 gauge wire directly from the alternator to the pump.

 

The pump performance is not affected until the PSI level at which the pump's bypass circuit would operate -- about 75 PSI, so below 30 lbs of boost, the pump operation is identical.

 

Not the same. Google the boost-a-pump and you'll see it can provide higher than battery voltage. http://www.kennebell.net/accessories...boostapump.htm

The wiring upgrade just provides a clean path for the voltage your car already has...

 

actually I just cut the power wire to the pump in half, run one end into the BAP and one end back out to the pump. The BAP steps up the voltage.

 

I attempted the hotwire mod (learned from the 3000GT VR4 days) and it failed car ran .5 leaner thru out than before. I also removed 1 of the 2 relays with no change.

If you are running 30-31 psi, is it recomended to run something other than just the 255?

 

depends on HP, not boost.

30psi on a stock head/shorty + hks 280 = 500awhp and a single walbro was at 108% IDC with 1000 injectors

30psi on a buschur head/shorth + bf272 = 600awhp and required twin walbros with the 1000cc injectors I have and i'm currently seeing 92% IDC

 

I have 30psi on a 2.3 bottom, stock head BC280 cams. DDL is 430 single walbro