Fuel Pump specs

[Munch]

For 97-02 what is the flow rate and pressure of the stock fuel pump? Don't care how much HP someone thinks it's good for, looking for actual manufacturer specs.

Thanks

[Y2Kvert4me]

While the design specs you are looking for may exist, the question ultimately becomes, at what voltage?

The output of the Walbro Gerotor pump (OE in 97-03 C5s - the late C5s switched to a vane style pump) is is directly related to the voltage it receives, and the stock power wiring to the pump is quite undersized, so there is definitely some voltage drop as pump output (and concurrently, amperage draw) increase when the go pedal is pressed.

It's a snowball effect too, the more fuel delivery that is called for (higher flowing injectors, higher injector pulse width or "open time"), the more fuel the pump flows, the more current the pump draws, the greater the voltage drop becomes, the less the pump delivers.

What inevitably happens when the pump can't "keep up", is the regulated fuel pressure (58-60psi) begins to drop, and the engine is no longer receiving the amount of fuel the PCM is prescribing.
This is a problem, because the PCM does not monitor fuel pressure, it assumes there is always 58psi at the rail, and during WOT, there is no feedback loop to inform it it's running lean.

So, the common upgrades for the stock pump are:

1, Upgrading the wire size feeding the pump, which will increase it's output capability by lessening/eliminating the voltage drop. (ie; Racetronix Hotwire kit)

2, The "Boost-a-Pump" amplifiers, which work by increasing the voltage at the pump even more than normally possible, typically providing 17-20 volts.


So although I can't answer your question, this should give you an idea of what you may need if you find fuel pressure falling off at WOT.



:cheers:

[Munch]

I'd rather not find out that my pump is lacking, especially if it means finding out while at WOT doing 6k. If ya know what I mean.

[Y2Kvert4me]

I'd rather not find out that my pump is lacking, especially if it means finding out while at WOT doing 6k. If ya know what I mean.Are you installing a fuel pressure gauge?

With heads/cam, you may find rail pressure is already falling off slightly on the top end/peak power.

That doesn't automatically mean you're starved for fuel or running lean, but the more power you go beyond that, the worse the pressure drop gets, and eventually you reach a point where desired AFR cannot be maintained, and that is when you need to upgrade.

You will "probably" be fine with your proposed 100 shot, but a wiring upgrade to the pump isn't a huge deal if you find you need it.


:cheers:

[Munch]

I hadn't planned on running a FP gauge, trying to keep the gauges to a minimum. I don't want to put a new pump or wiring in but I don't want to have any problems either. Some people say the stock pump is good for 500hp some say 600, I am at 410 now and shooting for just over 500 with the spray. In the back of my mind I want to replace the pump and wiring just to be safe and plus it's something else I can do to the car for fun. I will leave the pump to last after I do all the other stuff for the spray and see how I feel then. Racetronix has the pump and harness for $299 so that's not too bad for piece of mind.

[Y2Kvert4me]

Racetronix has the pump and harness for $299 so that's not too bad for piece of mind.Why not spend $35 (http://www.casperselectronics.com/store2/product_info.php?cPath=27_42_51&products_id=678) and go from there?

I highly doubt you'll need a new pump.


:cheers:

[Munch]

You're a good boy. :cheers:

And yes, I actually ordered it. :yesnod: