do i have to add..

ubengineering · Post by **ubengineering** » Thu Feb 21, 2008 11:04 pm

when i received my hahn kit instead of a booster pump i had an in tank walbro

when iw as on the big org, people said to use the booster pump because the hahn system relies on it and it puts tremendous stress on the stock pump

i was told a good combination is the booster pump with the in tank walrbo

this true or is the walbro good enuff? im gona call hahn monday to see what they say

Post by **Vinny** » Thu Feb 21, 2008 11:45 pm

Personally I was never a fan of the Hahn fuel system. I would recommend doing the "spoolboy" mod to your Walbro and using a RRFPR over the booster pump. I would not try running it with just the Walbro in an unmodified canister.

DOHCRT · Post by **DOHCRT** » Fri Feb 22, 2008 12:59 am

Since the Hahn kit utilizes the stock injectors, the fuel pressure in boost is tremendous. This is why there is a booster pump, because even most of the Walbro pumps cannot maintain that pressure. The FMU included with the kit is probably around a 10:1 rate of gain. This would put fuel pressure around 130psi at 8psi of boost. If you're not using stock injectors any more, you could probably use just the Walbro because maximum fuel pressure wont be as high.

Remember that the flow rate of the pump will decrease as pressure increases. A Walbro 255lph does not flow 255lph at 130psi.