I have a walbro pump in the tank,will that be enough? can I put an NOS inline pump to help?

 

Might want to mention what year, engine, other mods, etc..... just to avoid any misunderstanding. Assuming you are talking an LT1 or LS1 injected engine.....

Depends on the HP, whether it has a power adder, how well its tuned and which Walbro pump you have (not a lot of info available to answer the question ). But you should be fine. Assuming 500HP (flywheel), 0.50#/HR/HP BSFC, and allowing for at least 20% recycle for pressure control, your pump has to flow 312#/HR = 52 Gal/HR = 197 liter/HR. If the Walbro can really flow 255LPH at 43.5psi, then it shouldn't have any problem supporting your "heads & cam" HP. I run 500HP NA with a 205LPH Bosch pump at 58psi.

Now, assuming your question really was "if I add N2O to my heads & cam car do I need a separate fuel system"..... you need to tell us what HP you are running NA, how big a shot you are planning on running, whether you have a wet or dry system, etc. If your total HP is around 550 with wet nitrous, you might survive with a 255LPH Walbro. Beyond that, or if you use a dry system, you will probably need another pump.

 

I havn't dyno'd the car yet(95 impala ss) I have a ts-227xr cam,ported alum heads,3200 stall and a bunch of other bolt ons,my question is if I make about 390 rwhp can I spray a 175 wet shot without a separate fuel system? Would adding the inline pump help?

 

with a 255 intank you can spray 200hp on top of a heads/cam car no problem. i was doing it with no fuel pressure drop on a HC combo that was already making whatever power it was taking to go 121mph on motor @ 3600lbs. i would also recommend running larger wiring and grounds to the fuel pump, or getting a Racetronix harness. i got by fine using stock wiring at the time, but the extra fuel supply from the higher voltage at the pump would be a good idea. and as always, i would run a fuel pressure safety switch and have a fuel pressure gauge in the car to keep tab on things