Sam I am

pa944red is correct. Increasing pressure will increase flow regardless of any regulators or small diameter orfices. However, regulators and small diameter orfices will decrease flow as in the pinching hose example, seperate from any other factor such as pressure.

nine-44

The pump has a certain mechanical ability and is basicly bench rated at a specific pressure. Ok, so what I'm hearing is that it will pump 90 lph with 0psi and none more, also it will flow the same at elevated pressure? I'm not talking restriction to raise the pressure, (however that is how it is done by the FPR and backed up against the injectors to raise the psi) but it's actual mechanical limits due to the size of the vane or whatever style pump it is. I'm also not saying there is no leeway for bumping the pressure a bit either. I was talking about an NA pump in a turbo car. When I was working on turboing my NA car, I was told by multiple people on Rennlist that the NA pump will not support a turbo(aftermarket) or stock 951 motor. Sorry, I must have been misinformed. I do know that there are different pumps for the 944 NA, early, late, the 2.5L 16V and the turbo, the Turbo S ran the 951 pump tho. I figured Porsche did this for a reason? Man, think of how much money they wasted when they could have just used the same ole pump. I'm not chanceing it or the 4.5mm jumper line on the late fuel rail(which I was flamed about also). The stock 951 pump will support a bit more I agree. Normally with fuel injection, they program in or design for 25-30% more power than the expected output. Going from 140hp to 220hp is waay too iffy for me. I bought the Lindsey Huge Bosch pump and an AFPR. I'd say the original post should have specified a rough HP # they are shooting for. I probably wouldn't go past 180HP on an NA pump to be safe. Rich is bad, lean is worse.

eman930

The reseon I asked about the pump is because Im doing a NA build Pistons eveyrthing and also have a direct port nitrous kit gonna run about a 75hp shot just wanted to see if the stock NA fuel pump can handle it but I think Im gonna bump up to a 951 fuel pump just to be on the safe side

Andre

So i should probably run my turbo motor with basically no boost until i get a larger fuel pump huh? Is there a way of knowing whether it is running leane while driving it?

eman930

No the turbo pump can handle up to 350HP you should be fine unless you go over

nine-44

fast, Andre has swapped a 951 motor into an NA and is using the NA fuel pump still. If you have an A/F meter it should show if you are lean, I'm not sure if narrow band will do it tho, it should. Lean makes more power, but is dangerous to the engine. Also an EGT guage will show higher temps as you get lean. A fuel pressure guage will show if the pressure is dropping off higher in the revs also.

As far as Nitrous, I'd do a post or ask around, I know there has been a few ppl that did it. One I know of is Fishey on his S2. I'm not sure how much additional fuel you would need for a "wet" shot. I'd say the HP increace is only partially the fuel and more so the NO2. The fuel actually "dampers" the nitrous to make it a little more controllable and safe. There is a little more to be gained by the same size "dry" shot from what I know, but is considerably more risky.