Power boost valves are basically adjustable fuel pressure regulators. Higher rail pressure means more fuel which in turn means more power, but the ignition advance has to be adjusted accordingly to make the best of it and uprated cams would be a bonus too.
This is a quote taken from a website
What is a Power boost valve?
The Power Boost Valve is an Adjustable Fuel Pressure Regulator.
The Power Boost Valve is designed for use on ‘Electric Fuel Injection' engines with a special fuel enrichment facility for acceleration, commonly known as a ‘Rising Fuel Rate'. The enrichment is 1.7 : 1.
How does the power boost valve work?
As standard the original equipment electric fuel pump supplies fuel at a high pressure to the fuel rail and injectors, which is then regulated by a fuel pressure control valve. Typically, the regulator is not adjustable and is pre-set to a 3 bar maximum pressure. At idle the fuel pressure valve reduces it by 0.5 bar approximately to 2.5 bar. When accelerating quickly from standstill the fuel pressure increases at a proportional rate retaining a lean fuel mixture strength as required by the E.E.C. for new vehicles. However, the resultant effects of the standard valve produce:
Lethargic throttle response
Occasional drivability problems at slow traffic speeds
Intermediate performance 'flat spots' when accelerating
However, the FSE Power Boost Valve has an adjustable fuel pressure, effected by the movement of an adjustment screw on the crown of the unit. New Power Boost Valves are pre-set with a maximum fuel pressure of 2.5, 3.0 or 3.5 bar, depending on the vehicle in question, and similarly (to the original valve) the fuel pressure is reduced by 0.5 bar approximately at idle. There the similarities end.
On acceleration from standstill the Power Boost Valve fuel pressure will increase at 1.7 times the standard rate. This will produce a healthy, strong fuel mixture strength, which will instantly improve the drivability of your vehicle. The regulator enhances engine performance on acceleration by enriching the mixture strength. On constant throttle and cruise conditions the valve returns to a normal regulator function.
The benefits of the Power Boost Valve are: -
Suitable for Standard and Tuned Vehicles
Quicker Throttle Response
Faster Acceleration
Throttle Hesitation (in most cases eliminated)
Normal Idle (with adjustment) retained
Normal economy on light throttle
General fitting instructions included
Manufactured to original equipment specs
Basically, the power boost valve DOES make a difference by keeping rail pressure at a constant rate, meaning when you hit the go pedal there is pressure in the rail to react quickly. If I could afford one I would buy it, but with my financial situation right now sadly I can't.
I do think they are a good buy but I don't think they give added power, it's more about eliminating flat spots, smoothing out the power curve and improving throttle response. Combined with a remap they should provide better results than a remap alone, as the pressure is able to be raised/controlled.
Remaps and chips totally not worth £300.
I might spend £10 on one at most really.
Ebay chips are to be honest crap, can and will cause more issues in the end, most of the time they trick the car into running the cold start map all the time.
You get what you pay for. A remap will be done with your car on a dyno, the operator will see where the curve needs smoothing and improving and will map the injectors and ignition advance to a spec required for
YOUR car. An ebay chip has a preset map that won't take vehicle modifications into account and will dump a preset amount of fuel and ignition advance. They can lead to problems as if you have a completely standard car, it might run too rich, and if you have headwork, camshaft and uprated ignition system it might run too lean. Both of the above will end in tears where as with a custom remap, the map is made to work with your modifications and it takes them all into account.
