| (original thread is locked, replied here instead) The most effective method to build boost off the line is to use a rev-limiter with an anti-lag feature. There are a couple different ways anti-lag can be done, either by cutting spark or retarding timing. Cutting spark causes unburnt fuel to be dumped into the hot exhaust manifold, where it ignites and spools the turbos up. This is very effective at building boost, but is pretty hard on the turbos. I have tested this on a stock turbo Z32 by adding in ECU code for a spark-cut rev-limiter, and the results were ~15psi of boost at 3500rpm, along with some scary high EGTs (gauges that go up to 1600F were pegged well above that). This was accompanied by some very loud backfiring and flames out the tail pipes... The other method for building boost is to retard timing enough to cause combustion in the manifolds. This results in lower overall EGTs (< 1500F) than spark-cut, and can further be controlled by changing how much the timing is retarded. i.e. More retard = higher EGTs = more boost. I have found that ~10psi of boost can be achieved on stock turbos with a 3500rpm rev limit using this method. The reason I have done this testing is because I have been developing a launch-controller for stock ECUs by writing custom firmware. IMO using the stock ECU has a few advantages over aftermarket launch controllers: - No additional hardware has to be installed, it's all done in firmware via an ECU chip upgrade
- The neutral position switch can be used to activate the launch control and adjust the launch RPM in real-time via the gear shifter
- The Check Engine Light can be used to signal launch control activation
- It can be fine-tuned over the CONSULT port (parameters such as base launch RPM, anti-lag settings, neutral position switch usage, CEL usage, etc...)
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