You see, as unused fuel cycles back to the tank and continually moves through the system, it heats up, and if it’s a warm day outside, you can expect even greater heating of the fuel over time.
“What happens is, let’s say you’re making 1,000 horsepower on the street, you need 140 gph … but that’s at 80 psi. Let’s back up the flow curve, and you’re at base pressure of 40 or 50 psi, now you’re moving 200-some gph through the system as soon as you turn the fuel pump on. You don’t need that on the street,” Craig explains.
This is where a fuel pump controller comes into play, as it can be programmed to slow the pump volume down, thereby drawing less fuel from the tank when it’s not needed, and increasing it when it does.
“If you’re in traffic, you don’t need that pump operating at full speed. When it is, you’re pumping at that pump’s maximum volume. When it does, that fuel starts to get warm, and pretty soon the tank is beginning to get warm, the fuel can begin to boil, and you get into vapor-lock and other assorted issues,” Craig continues.
It takes a lot of fittings, swivels, and adapters to plumb a fuel system. Seen here is the wide assortment of pieces needed to plumb True SStreet, all from the folks at Russell Performance.
Craig recommends with any of their electric pumps (with the exception of their in-line pumps) the use of a fuel pump controller for street use, without question.
“There are other ways we’re skinning that proverbial cat now, where guys are making over 1,000 horsepower, and they’re keeping their stock tanks and pumps and then utilizing a secondary, auxiliary pump when they need it.”
To Overbuild or Not?
Back on the topic of matching a fuel system to your current and future needs, Craig said he always asks, “what is your plan? What are you going to do with this thing? Is it is a true street car, or are you going to convert it specifically into a racecar. What’s your power adder? Take a look at all of that and you can get an idea of where you need to be.”
This decision, as noted previously, is an important one, because if you were to oversize the system to allow for wide-open-throttle track use, but you’re only going to the track on rare occasion but mostly daily-driving the car, you’ll quickly drift into scenarios of overheated fuel and vapor-lock.
“A guy may never take his car to the track, but you can’t just size the fuel system for that. You have to take into account that he may take it to the track once, and you don’t want to burn the motor up because you don’t have a big enough pump,” Craig says. “But on the other side of the coin, you could go in with a large fuel pump to grow into, but if you go too big the heat problems will come sooner rather than later. Then the customer has more failure due to that, and it’ll be pump failures, because it’s cavitation and all kinds of gyrations within the fuel system. That’s where we have problems.”
Fuel choice, again, comes into play on this topic; many racers will tend to switch fuels from the street to the strip, and the fuel can greatly alter fuel system demands.