- MK6 GTI (2010-2014) (CBFA/CCTA)
Dyno graph sponsorship results:
*Horsepower and Torque numbers are approximate and can vary significantly depending on numerous factors including what supporting upgrades are done to the vehicle, ambient temperature, elevation, road surface, tire selection & condition, fuel octane and quality, vehicle weight, and more. The advertised numbers herein are based on optimal conditions and utilizing proper supporting modifications. Your results may vary.
Frequently ask questions:
Q: Why do your numbers say I will make less horsepower on E85 than 93 octane?
A: Great question! The numbers we list in the product descriptions are similar to the numbers a turbo charger lists for air flow. The numbers are the "fuel system capacity to generate power" regardless of the other engine system limitations (air handling, mechanical limitations, knock propensity). Essentially the numbers are calculated assuming "sufficiently large air flow", "sufficiently capable mechanical assemblies" and disregarding knock limits. The equation uses actual observed engine volumetric efficiency (when available from sponsorship vehicles) and fuel capacity (including target pressures) to calculate power. Gasoline has more energy per mass volume than E85. So the higher fuel flow capacity will mathematically generate higher power potential for a gasoline than a high ethanol content fuel. The other variables (air flow, spark, rotating assembly strength, charge cooling, mechanical assembly strength) are highly variable from build to build. This is why we state horsepower capacity for the fuel system – representing the potential of the fuel system if you have all the other aspects of your build addressed!
Q: Why don't I see horsepower gains with just a pump?
A: Fundamentally we have to look at the entire fueling system and "where" in the rpm range the limits are. DI fuel systems in stock trim are often pump limited at middle rpm (peak torque) and injector limited at high rpm (peak power). This is due to engine speed. HPFPs are mechanically driven pumps (driven by the camshaft pump lobe spinning at ½ crank speed) and are RPM (engine speed) dependent. Many of the quoted flow increases in the aftermarket are purely displacement based comparisons: where by example the big bore pump has a piston diameter X% larger than the "stock" pump or the swept displacement ((3.14*(radius)^2)*(stroke))of the pump Y% larger than the stock pump. The larger displacement of the pump really shines in low rpm, where the fuel injector has plenty of time (crank angle degrees) to inject fuel. As the engines starts to approach peak power the engine speed starts to become quite short and is limiting the injection duration (crank angle degrees) for the injection event (which is another reason why we like to increase fuel pressure up high!).
