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"TSR" Switch Fuel System, save money, drive on pump gas!
TSR MAX BOOST FUEL DELIVERY #1
The T.R. Fuel system is a loop. The in tank fuel pump, feed line with filter, engine fuel rail, fuel pressure regulator and return line.
The fuel rail is U shaped, with the feed line coming in the passenger side front. The regulator and return line are at the other end. This other end is the exit end at the driver's side front. This end also has a Schrader valve fitting covered with a screw on cap. The fuel rail runs above the injectors and connects with them at their tops. The injectors are fitted to the intake manifold at their bottoms.
In order for the engine to make its full potential power, fuel delivery must be adequate. More importantly, the lean condition that could result from inadequate fuel delivery might result in engine damage.
The fuel pump must deliver an adequate amount of fuel to maintain the rail pressure. This is approximately 43 psi at idle and up to 75 psi at WOT.
In order to be able to monitor fuel pressure at the rail, you must have a gauge. Preferably one that has a length of line long enough to reach the viewing area of the windshield. This line will have to be a braided steel covered one, in order to comply with NHRA rules. These can be purchased from aftermarket suppliers. These are easily installed to the fitting at the front of the rail(Schrader Valve).
An adjustable fuel pressure regulator is another worth-wile component. It will allow you to select the base fuel pressure setting. This setting will affect the final fuel pressure at WOT and boost. These are also easily installed and available from many aftermarket suppliers.
The Vacuum/boost line connects the intake manifold to the fuel pressure regulator. The vacuum/boost line conveys vacuum at idle which reduces the fuel pressure at idle. This is why the reference of connected or disconnected is common. The vacuum at idle will result in a lowering of the fuel pressure by 5-8 psi. The vac/boost reference line when connected will allow the fuel pressure regulator to raise the fuel pressure by approximately 1 psi for each psi of boost. This vac./boost reference is a component to the fuel delivery trim, less fuel at idle and more at boost.
(Base) usually refers to the temporary line disconnect, and therefore no change to fuel pressure in reference to manifold pressure.
(Base idle pressure settings usually ranges between 40-50 psi.) Add this (base) pressure to the (boost) that you are running, (boost pressure usually ranges between 15-25 psi.)Base + boost = range of 55-75 psi.
Your fuel pump must be able to supply at that pressure, the volume of fuel that horsepower output requires. If the supply is not adequate then a lean condition will result.
Here is a simple test. Secure the fuel rail pressure gauge to your windshield. Observe the fuel pressure at W.O.T. and high boost at the top of 3rd gear. If you are able to maintain 60-70 psi, you are probably OK in the pump department. If you come up short, you may want to consider upgrading. There are several possibilities including a different in tank pump or an in-line helper pump.
If you have not changed out your in-line fuel filter recently, this should be done prior to making this full throttle pressure test. The filter, if dirty, could cause restriction to fuel flow.
There are in-tank pumps available that are capable of adequately supplying your needs without a second or helper pump. This would be the logical choice if your in-tank pump has to be replaced. The practice of using a helper pump is becoming less common as the high performance in-tank pumps are readily available. Every combination has its merits and usually will be determined by compatibility with your specific setup. Inline helper pumps are usually mounted in the area vacated by the original stock cross-flow muffler.
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