BEGi Performance Engineering - Fuel Pressure Regulator Instructions

Purpose and description of the Multi-Role (MR) Rising Rate Regulator

This B.E.G.I. regulator is designed specifically for the multi-role function of controlling EFI fuel pressures under vacuum operation (replacing the factory regulator) and providing additional fuel when under boost from either a supercharger or turbocharger. This is accomplished by using the manifold vacuum/pressure to drive the fuel pressure up at a high rate of gain as the boost rises and offer the one-to-one ratio when off boost. The MR regulator is adjustable on three ways. The base EFI pressure is adjustable in the 20 to 50 psi range. The rising rate function can be adjusted for both onset of gain and rate of gain.

Types of regulators

PN: 2035 Aftermarket turbo and supercharger
PN: 2032 Factory (OEM) turbo and supercharger (not adjustable for onset of gain)

General Information

1. The multi-role regulator fits into the fuel system after the fuel rail. It is necessary to cap off, and remove the original regulator.

2. The regulators can be mounted in any position. For convenience, place the adjustment screws within easy access.

3. “In” is for the fuel line from the fuel rail. This is the only reference to direction of fuel flow.
The unmarked fitting goes back to the fuel tank. The plug, already installed, remains as is or is appropriate for a pressure gauge.

4. Some form of thread sealant is advised. We prefer one drop of Loctite or a small smear of Perma-Tex, per joint. In general, please avoid teflon tape as the residue and debris can get into the fuel system.

5. The threaded bosses on the regulators are strong enough for a zillion ft-lbs of torque, they will not crack. They can be stripped, but neither failure is covered with any warranty.

Pump Requirements
The pump pressures needed to run the rising rate regulators are relatively high. Anticipate the need for pump outputs of approximately 100 psi to operate the typical aftermarket turbo/supercharger system. Checking the pump is discussed later.

Signal Lines
The regulators are powered by manifold vacuum and pressure. The signal must come from the intake manifold, after the throttle plate, and is handled by a single line. These regulators will not work properly if the signal comes from anywhere else. There are two connections for the signal line on the regulator. Assemble a tee from the brass and 5/32 hose. From the cross bar of the tee, place one hose onto the fitting on the top cap that points directly at the center of the regulator. The second hose from the tee goes to the small hose barb on the side of the lower, cylindrical part. Lastly, the third leg of the tee gets routed to the intake manifold.

Check Valves
Two functions are accomplished by the check valve. One, the simple plugging of a small vacuum/boost leak. Second, vacuum is required to pull the pre-load spring under the rising rate center screw away from the valve so thus reverting the regulator control to the one-to-one side. Stock fuel pressures are then achieved under manifold vacuum conditions. The check valve white end attaches to a short segment of vacuum hose, and the hose plugs onto the 5/32 hose barb attached to the needle valve. This allows venting the boost signal for adjustment, but will seal under vacuum. The check valve blows off into the atmosphere, do not hook it to the manifold or anywhere else.

THE CHECK VALVE: White end is closest to the regulator!

The black end of the check valve is not attached to anything!

The Restrictor
On occasion the regulators will not adjust to a sufficiently low rate of gain. In this instance, it is necessary to add the small restrictor to the signal line. This is provided for your convenience. The restrictor is non-directional, it can point either way. Place the restrictor in the signal line at the entry into the R/R side so it affects only that side.

Checking Pump Pressures
A brief check of the maximum fuel pressure available should also be done at idle. This is essentially determining the pump’s pressure capability. None of the regulators can force a pump past it maximum pressure potential. With a pair of pliers, squeeze the fuel line shut that connects our regulator to the original fuel pressure regulator. When squeezed shut, the pump will be forced to maximum output. Make sure the pressure available is consistent with your intentions. In all cases, the pressure must show, in this idle test, to be about 10 psi higher than the desired fuel pressure, as the available pressure under real load conditions will be less than that measured at idle. This test does not actually prove the pump to be adequate under boost, but if it doesn’t pass this test, it is certainly a waste of time to continue with the same pump. In general, we do not recommend exceeding 100/110 psi fuel pressure.

Adjusting the 2035
Three adjustment are necessary with this regulator. NA engines that are subsequently fitted with forced induction often exhibit extreme leanness in the range of 4 inches of vacuum to approximately 3 psi boost. The cause for this is that the turbo/sc can achieve atmospheric pressure in the manifold prior to the throttle being fully open. Without full opening, the throttle position sensor will not send the proper signal to the ECU, hence, a lean condition occurs. To counter this we’ve made the “onset” of fuel pressure rise adjustable. The 2035 can actually start raising the fuel pressure prior to being under boost. This is accomplished by the center screw in the R/R section of the regulator. The actual rate of gain of the fuel pressure rise relative to the boost is under the control of the needle valve at the side of the R/R section. Adjusting the static fuel pressure for normally aspirated operation is the responsibility of the screw at the end of the 1/1 section. In all installations, we urge tuning be aided with an air/fuel ratio meter.

After the regulator is in place, all signal lines attached and the check valve in position, adjustment can begin.

The vacuum control of 1/1 regulation has been set by BEGI to 36 psi at atmospheric pressure (zero manifold). The engine should start and idle properly. Start the engine and inspect for fuel leaks. Correct any leaks before proceeding further.

First adjustment:

Check the idle fuel pressure. It will be less than 36 psi due to the manifold vacuum of idle RPM. Verify the 36 psi setting by pulling the signal line from the 1/1 side of the regulator. It is necessary to pinch or plug shut the removed signal line to read the fuel pressure, as the vac leak will upset the R/R part of the regulator. If the gauge reading is not 36 psi, trim it to 36 with the 1/1 screw. Then snug the jam nut and replace the vac signal line.

Second adjustment:

The second adjustment of fuel pressure is the onset of gain. This represents the fuel pressure as the manifold conditions cross from vac into boost. This is done at idle. To simulate passing through the zero point, the vacuum line must be removed from the R/R side. The regulator then sees atmospheric pressure as a signal, the same as zero on the boost gauge. Control of the fuel pressure at the zero point is by the Allen screw in the center of the R/R side of the regulator. Clockwise on the screw will raise the pressure. Once adjusted, plug the vacuum line back onto the regulator and observe the fuel pressure drop back to the stock figure. A suggested starting point pressure 48 to 50 psi. Please understand, this will vary from engine to engine, and is not a magic number. The “magic” number is whatever pressure your vehicle requires to pass thru the boost onset without the lean flat spot. It is not unusual to see pressure anywhere from 40 psi to 55 psi. Use whatever works best.

Third adjustment:

Adjust the R/R needle valve when testing under boost.

The maximum fuel pressure is controlled by the needle valve and must be determined while driving the car under boost. Start with the needle valve closed, which is fully clockwise.

Pressure calculation:
The fuel pressure required increases with the square of the boost pressure ratio:

Example: 6 psi boost is a pressure ratio of 1.41. With stock fuel pressure of 36 at zero boost, than:

Needed fuel pressure = ( PR2 x 36) + boost = (1.412 x 36) + 6 = 77.5 psi

The second adjustment, the needle valve, controls the rate of gain of fuel pressure versus boost pressure. The lowest rate of gain is with the needle valve fully open, the highest, fully closed. Clockwise closes the needle valve. Figure 2025 offers a typical guide to fuel pressure versus boost pressure. Caution: There is a vague limit that exists with regard to the maximum possible fuel pressure. The industry Barbara S (BS) of injectors jamming at 50 psi and the flow not increasing with pressure is not correct. It is possible for a very large injector (90 + lbs/hr) to jam at 100+ psi of fuel pressure. At anything less than that, jamming is not going to happen.

Figure 2035

120 *

100 *

80 *

Fuel 60 *

Pressure *

0 1 2 3 4 5 6 7 8 9 10

Boost Pressure

Trouble Shooting

1. Jams at maximum fuel pressure:
    The regulator is installed backwards.
    The center screw in bottomed out inside and must be backed off.
    The fuel return line to the tank is plugged or crimped.

2. Pressure doesn’t rise:
    No signal
    Signal is blocked.
    Pump won’t make any more than that pressure, squeeze the fuel line shut and check the deadhead              pressure.

3. Pressure rises, but not enough:
    Close the needle valve.
    Increase the center screw (static) adjustment.
    Check the pump again, but remember, it will have less pressure at high loads, than at idle.
    Remove the restrictor.

4. Pressure rises, but too high:
    Open the needle valve further.
    Back off the center screw somewhat.
    Add the restrictor.
    Check Valve installed backwards.

5. Fuel pressure won’t return to stock at idle:
    No check valve.
    Check valve installed backwards.

6. Fuel pressure oscillates:
    A slow oscillation of about one hertz can also result from the regulator being hooked up backwards.
    A faster oscillation, more like a buzz, but without the noise, is usually induced by a rapid pulsation
from the fuel pump. Not much can fix it short of a different brand of pump or a pulse damper. The
    condition is not harmful at boost pressures of 8 psi or less.

If buzzing, turn the center screw a 1/4 of a revolution, and it usually ceases.

7. Regulator buzzes under boost:
    This fault occurs occasionally when fuel pump and manifold pressure oscillations overlap to reinforce
     each other. Usually, it can be quieted by turning the center screw one or two flats. If it cannot be
   quieted   in this way, return the regulator to us for an overhaulor replacement.

The B.E.G.I. Regulators are individually tested through the full range of pressures prior to shipment. If none of the above prove effective in tuning the regulator, call 830-438-2890. If needed, call us to return the regulator to BEGi for service.

Warranty:
1. The regulators are warranted for workmanship and function for one year from the date of shipment form our facility. No open threads, user installed threaded items, or adjustable threads are warranted in any way.

2. If problems arise from using teflon tape, B.E.G.I. reserves the right to refuse warranty coverage for damages caused to the regulator.

3. BEGI will not warranty any FMU purchased thru an online auction that is not purchased from an authorized dealer. The customer must be able to provide proof of purchase for any warranty repairs.