The Purpose of the Blip Speed Variable Rate of Gain (Rising Rate or FMU) Regulator
The Blip Speed 2025 VRG regulator, when properly tuned, will maintain the correct air/fuel ratio on modified EFI equipped engines that have a fuel return line. The MaxG 2025 VRG regulator is used in conjunction with the existing OEM fuel regulator.
The Blip Speed 2025 VRG Regulator (FMU) features
- The Blip Speed 2025 VRG fuel pressure regulator provides a fully tunable and proportional means of adding fuel.
- The Blip Speed 2025 VRG fuel pressure regulator WILL NOT upset drivability at any partial throttle use. The regulator functions only when the engine is at or near full throttle.
- All parts in contact with the fuel are metal (Stainless Steel, Aluminum and Brass) allowing use with E85 fuel.
- A stainless steel valve/diaphragm is used to isolate an elastomeric diaphragm from the fuel. This allows the use of E85 in all 2025 VRG regulator models.
- The use of both stainless steel and elastomeric diaphragms on the fuel side of the regulator provides a redundant seal against a fuel leak.
- Both elastomeric diaphragms are fabric reinforced. This greatly reduces the chance of a diaphragm failure.
- The vent for the intermediate diaphragm cavity can be plumbed to a location outside the engine compartment. This reduces the chance of an engine compartment fire in the unlikely event of a fuel leak into the diaphragm cavity.
- The adjusting spring is stainless steel.
- A brass piston is used to connect the lower and upper diaphragms. Brass provides good wear life as well as corrosion resistance.
- Compact design facilitates easier installation. This is especially nice for applications on motorcycles, ATV’s, snowmobiles, etc.
When to use a Blip Speed 2025 VRG Regulator (FMU)
If you change anything on your engine that increases the air flow you will need to make a proportional increase in fuel flow to maintain the correct air fuel ratio. Changes include but are not limited to:
- Lower restriction air intake systems
- Exhaust system changes that reduce back pressure
- Engine breathing modifications like porting, cams, increasing bore, etc.
- Adding forced induction systems like turbocharging or superchargers.
The Blip Speed 2025 VRG fuel pressure regulator can provide additional fuel for each of these cases by tuning the fuel pressure and rate of gain of fuel pressure using the adjustment screws. The Blip Speed 2025 VRG fuel control function is generally tuned to be inactive in lower throttle ranges, thus the fuel flow rates can remain bone stock until the system's overall air flow rates exceed the stock amount.
Models are available for three specific performance applications:
- Modified naturally aspirated engines
- OEM Turbo/Supercharged engines
- Aftermarket Turbo/Supercharged engines
Applications include cars, trucks, motorcycles, ATV, jet skis and snowmobiles. All applications require an EFI system that uses a fuel return line.
How the Blip Speed 2025 VRG Regulator (FMU) works
For a modified naturally aspirated (NA) EFI engine, the regulator delivers a fuel pressure that is inversely proportional to the intake manifold vacuum. As full throttle is approached and manifold vacuum moves toward atmospheric pressure the Blip Speed 2025 VRG Regulator will progressively raise the fuel pressure.
On forced induction engines the regulator will increase the fuel pressure in proportion to the increase in manifold pressure.
The rate at which the Blip speed 2025 VRG Regulator increases the fuel pressure is fully adjustable (Variable Rate of Gain) within the pressure capability of the fuel pump. This scenario allows economical use of the vehicle when not operating at full throttle, yet can accommodate a wide range of engine modifications.
Range of Capability
The Blip Speed 2025 VRG Regulator increase fuel flow rates more than 45% with most stock fuel pumps and stock injectors. If more fuel flow is needed a high pressure fuel pump can either replace or supplement the stock pump. With the additional fuel pressure available flow rate increases of 75% can be achieved. If a supplementary pump is used, it must be replaced or be installed in series with the original fuel pump.
If all components in the fuel system are in good condition they can handle the increased fuel pressure.
It is the installer's responsibility to evaluate the condition of all items in the system that will be subject to the increased pressures.
The Gory Details
Understanding the Relationship between Fuel Pressure and Fuel Flow
The more pressure is pushing on a fluid the more fluid will flow through an orifice or fuel injector. For any fluid to flow through an orifice there must be more pressure on one side than on the other. This difference in pressure is referred to as the delta P. It is this delta P that determines the flow through the orifice or injector.
More "delta P" means more fuel flow.
An example of how the Blip Speed 2025 VRG Regulator (FMU) works
For this example assume the engine is operating at full throttle and all of the benefits of the modifications are in full effect. More air is going through the engine than when it was stock.
The engine needs more fuel to maintain the correct air/fuel ratio. One way to get more fuel is the increase the pressure on the fuel rail which will increase the delta P across the injector there by increasing fuel flow. Enter the Blip Speed 2025 VRG regulator.
The Blip Speed 2025 VRG can increase the fuel pressure and push more fuel through the injector nozzle. However, it must be understood that a 20% increase in fuel pressure will not increase the flow by 20%. Rather, the fuel flow increase brought about by greater pressure will be proportional to the square root of the pressure change.
This example assumes the stock injectors are retained. Let the Horse Power increase be 10% greater than stock. For a 10% increase in HP, the new fuel pressure must be increased by (1+% increase) squared or 1.10 squared. That number would be 1.21. If a given engine's fuel system maintains 36 psi at full throttle, then an increase of pressure to 36 x 1.21 = 44 psi, is required to achieve the 10% greater fuel flow. Just as a HP increase of 25%, must see the fuel pressure increase to (1+.25)=1.25 squared times 36. As a result it will require the fuel pressure to increase to 56 psi to maintain the same air fuel ratio as stock.
It is a common necessity to operate with richer mixtures than stock after such mods as discussed here. The Blip Speed 2025 VRG Regulator can easily account for this situation as well. If a mixture of 12 to 1 is desired rather than 14 to 1. Calculate the ratio percentage change (14/12 = 1.167), then square that number ( 1.167 x 1.167 = 1.36), and the 1.36 then suggests the previous fuel pressure must be increased by 36% to effect that change in the mixture. Therefore the 56 psi in the previous example becomes 56 x 1.36 = 76 psi.
Keep in mind that the regulator is a progressive device and does not affect fuel pressures at idle. Rather the regulator, when set to produce a max of the 81 psi fuel pressure, will not begin altering the fuel pressure until approximately 8 to 10 inches of vacuum. The vacuum range at which the Blip Speed 2025 VRG Regulator becomes active is also adjustable. With the gain ratio fully adjustable (variable rate of gain), as well as the point of onset of gain, the Blip Speed 2025 VRG Regulator offers an enormous range of tuning capability. These characteristics permit stock vehicle driving quality and economy when the engine system is operating at part throttle, yet provide fuel requirements for the air flow increases as the throttle position increases toward fully open.