Fuel Pump Upgrades
For Golf R and GTI and most TFSI engines we offer a fuel pump upgrade using Autotech internals as used and approved by Revotechnik allowing up to 50 %more flow than standard pumps across the midrange, this mod not improves throttle response and overall gains but increases power safely without the risk of running the engine lean which can cause major damage , a fitting service by our workshops is available with a new upgraded pump and or internals.
The low pressure fuel pump, which varies from ~40-95psi, delivers fuel from the fuel tank to the high pressure fuel pump. Then the high pressure, camshaft driven pump pressurises the fuel to upwards of 130bar (almost 1900psi) in order to spray fuel directly into the combustion chamber. Unfortunately on cars that have engine modifications, the stock fuel pump cannot flow enough volume of fuel to maintain the system pressure and the car suffers from the familiar fuel problems that so many modified customers experience.
The limitation of how much volume of fuel the high pressure pump can flow is dependent upon the volume displaced by the pressurising cylinder inside the pump and the number of times the piston reciprocates inside that cylinder. Since the high pressure pump is driven off of the engine camshaft by a three lobe cam the piston of the pump cycles at 1.5 times the engine rpm. (Engine camshaft turns at one-half engine rpm multiplied by three for the number of lobes on the high pressure cam lobe).
Due to this dependency on engine rpm for the high pressure fuel pump output volume, the FSI pump is capable of flowing almost 370hp at 7000 rpm but only 158hp at 3000rpm. The stock pump is insufficient for the output generated by this upgraded maps over stage 2. The only way to address this issue while maintaining a pump that fits in the stock location is to change the volume of the pump’s internal pressurisation chamber.
In order to address the lack of fuel in the midrange, the upgraded fuel pump increases the volume of fuel from the high pressure pump by over 50%. Simplified, this is achieved by modifying some key internal parts within the pump. Changing these components requires precision machining of the new components with special surface treatments as well as enlarged, redesigned seals. Using inferior components on this critical part can lead to many problems from petrol in the engine oil from a bad seal, to complete engine failure from a seized piston in the high pressure pump.
To give an idea of the tolerances involved, the final surface finish on the piston inside the fuel pump is so critical that it can be damaged by touching them with bare hands. The tolerances between the piston and the new barrel the piston rides in can only be measured by a highly refined machine which uses air volumes to measure the part clearances to within microscopic levels.