mousemobile
Member
- Joined
- Mar 13, 2003
bypass regulator
A bypass fuel regulator bleeds off excess fuel pressure and returns excess fuel to the tank. When some of the fuel is bled off, the pressure is reduced. There is a return line to the tank, usually coming from the pressure regulator. This is the scheme that most OEM fuel injected cars use.
These bypass fuel pressure regulators may be vacuum and/or boost referenced. The pressure reference increases or decreases the fuel pressure based on engine demand. i.e. high engine intake vacuum ( low throttle opening) = lower fuel pressure, low engine intake engine vacuum (WOT, NA) = higher fuel pressure, and engine intake pressure (turbo boost) = even more fuel pressure.
Most new cars use a returnless system. The fuel pressure is computer controlled by varying the voltage to the fuel pump.
Other fuel reguation systems simply limit the fuel pressure. Think Holley blue inline pressure regulator. The downside is they somewhat restrict fuel flow. (Definitely did on my Mopar 440).
If you need to use a -8 line as the return line, you probably have way too much fuel pressure and flow.
I might be wrong, since you may be supporting upwards of 1000 horsepower. In that case, at idle and very boost, you may need to bypass a lot of fuel. That may be especially true with an alcohol system where more fuel is required for a given power level.
At 600 horsepower or less a -6 return line should be adequate.
However, as the learned gentleman (V6UnderPressure) said, you can always split the return line flow with a Y-block. A portion will go through the fuel sensor and the rest will go around it. Both flows will return to the tank. Since the fuel is relatively homogeneous at this point, it isn't necessary to read every bit of fuel, only a representative sample.
HTH
A bypass fuel regulator bleeds off excess fuel pressure and returns excess fuel to the tank. When some of the fuel is bled off, the pressure is reduced. There is a return line to the tank, usually coming from the pressure regulator. This is the scheme that most OEM fuel injected cars use.
These bypass fuel pressure regulators may be vacuum and/or boost referenced. The pressure reference increases or decreases the fuel pressure based on engine demand. i.e. high engine intake vacuum ( low throttle opening) = lower fuel pressure, low engine intake engine vacuum (WOT, NA) = higher fuel pressure, and engine intake pressure (turbo boost) = even more fuel pressure.
Most new cars use a returnless system. The fuel pressure is computer controlled by varying the voltage to the fuel pump.
Other fuel reguation systems simply limit the fuel pressure. Think Holley blue inline pressure regulator. The downside is they somewhat restrict fuel flow. (Definitely did on my Mopar 440).
If you need to use a -8 line as the return line, you probably have way too much fuel pressure and flow.
I might be wrong, since you may be supporting upwards of 1000 horsepower. In that case, at idle and very boost, you may need to bypass a lot of fuel. That may be especially true with an alcohol system where more fuel is required for a given power level.
At 600 horsepower or less a -6 return line should be adequate.
However, as the learned gentleman (V6UnderPressure) said, you can always split the return line flow with a Y-block. A portion will go through the fuel sensor and the rest will go around it. Both flows will return to the tank. Since the fuel is relatively homogeneous at this point, it isn't necessary to read every bit of fuel, only a representative sample.
HTH
