Stock ATS-V fuel system consists of a low pressure electrical pump in the fuel tank, and a high pressure mechanical pump on the driver’s side exhaust cam. Stock ATS-V fuel systems are already starting to have difficulty keeping up by 17 pounds of boost and 500 whp. This problem occurs when boost is brought in quickly and torque starts to peak. It is also exacerbated in the overdrive gears, and engines have been lost for this reason. We see the high pressure drop off on every ATS-V we tune, as soon as boost is increased. The more boost we add, the worse the problem gets.
Here are some estimated performance capability numbers using Tapout fuel system solutions. The fuel system components themselves won’t produce this much power. These are just estimates of what each fuel system upgrade should be able to support safely.
- 500 whp (gasoline) stock LPFP and stock HPFP
- 600 whp (gasoline) Xtreme-DI OEM fuel cam
- 700/585/475 whp (gasoline/E47/E85) Xtreme-DI HPFP (E85 capable)
- 800/675/550 whp (gasoline/E47/E85) Xtreme-DI HPFP and Xtreme-DI fuel cam (E85 capable)
- 1,000/850/700 whp (gasoline/E47/E85) Tapout LPFP, Xtreme-DI HPFP and Xtreme-DI fuel cam (E85 capable)
The Tapout LPFP can be added to any of the above to provide a little extra padding or safety margin.
This is a factory GM ACDelco camshaft with modified HPFP lobe. The XDI Team Modified the cam to 6.35mm lift instead OEM 5.25mm. This is the maximum possible within the hardened depth area of the OEM camshaft. At 6.25mm this results in 21% more HPFP volume capacity compared to OEM Hitachi HPFP. No custom ECM tuning is required for this fuel cam by itself.
We recommend using a timing chain retention tool (part number EN-48313) to hold the timing chain in place during your camshaft swap. This tool is readily available online for approximately $200.