For far too long tuners have been implementing launch control on diesels by simply limiting the RPM of the engine, say 3500RPM. With no load on the engine, this results in only 10-12mg/str of diesel being injected which is insufficient to spool the turbo and hence the resulting “launch” is with the engine not at it’s peak performance.
Our goal at Tangent is to have the best of everything. As soon as the issue was identified, we devised a new strategy for an improved launch.
The best way we figured was to:
1. Close the turbo vanes/wastegate fully(100% N75 dutycycle)
2. Retard injection timing, causing excess exhaust gas buildup, further spooling up the turbo
Since this was to be implemented for diesels, there was no way to have an ignition cut based launch.
We reverse engineered the firmware on BMW/VAG EDC15/16/17 and identified code that handled injection timing and turbo vanes and inserted our own patch on a number of test cars. The result was an enormous spike in turbo boost at launch. The small turbo on our Skoda Octavia(Garrett VNT15) made 1.95bar(28.3psi)! We had to dial back the injection timing, as it was far too retarded, resulting in a lot of smoke. Next we tested it on a BMW 330d, here’s the video(CAUTION: Greenpeace activists are advised to not click on play button):