An 8-port injection system with elite control features, it has served well in the USRT R&D fleet. This Audi S4 V8 Turbo (B7) has led to many design insights and set up wisdoms. All are now implemented in our full production kits. But, as a trip back to 2019, here's what we first proposed:
Dual inlets were set up with each to directly attach RACE* valve prototypes. We learned right away that this produced superior control but only within a narrow RPM band. The goal was to achieve "radical improvements in tuning capability and ease" and this initial performance was a promising start. Taking this advanced control mainstream would require the same control across a wide power band.
*(Rapid Acting Control Element)
This generally requires a single RACE valve per pair of cylinders (vs per four). Most all subsequent USRT "DPR" direct port water/meth kits have been configured this way. The notable exception is 5-cylinder engines whichy may still utilize two valves. For key example, see our Audi RS3/TTRS DPR5+1 kit.
One super-important technique is to keep each connection very short (and not like what's shown here). Longer lines dull control response. A feature that's been kept consistent, however, is smaller diameter 3/16" (4.76mm) tubing for each nozzle run. This enhances accuracy and makes tuning easier.
Have you got an interesting project car and need help configuring it with a DPR system? Shoot us an email. Drop us a line. Be informed.