I wish you would read back further in the thread to eliminate the need for reiterating.
Ouch. I apologize if I missed something, but a search of terms nitrous, N2O or anti-lag did not appear in this thread (except mine), so i don't quite know what I missed that you have to reiterate or link back to. You mentioned the trans brake, so I didn't.
When running on a Pro Tree (as in this case) there is only 4 tenths of a second from the last staging light to green light.
When turbocharging we use a “bump box” to get launch boost as you bump into the last staging light.
Yes, power needs to be maximized within 0.4 seconds of staging.
I disagree the purpose of the bump box, and my perspective is that you (minimally) use the trans brake and power against it to build exhaust flow and boost. You could optionally add anti-lag (air, fuel and retard) to increase the effect dramatically. The bump box then is only for moving the car under transbrake for staging with either x-millisecond cuts (bump) or PWM trans-brake modulation for slipping it forward (soft or slider staging).
Most sanctioning bodies do not allow the use of nitrous with turbocharging.
The OP said 300' sand drag. I would appear the ISDA rules allow turbo or supercharger with nitrous. No purging in staging lanes. But N
2O is just one option.
Even though the Procharger is a centrifugal supercharger, it will have a wide enough power band for drag racing when using a high stall torque converter.
The power band width is increased by over running the supercharger but being careful not to run it into the surge zone then clipping the boost at the target pressure with a BOV.
The max rpm band is typically achieved with the correct compressor to fit the flow at pressure ratio, nearing surge, but not hitting choke until after the lights. Same for turbos and other things with compressor maps. Both a turbo and a super can stay in the band with a high-stall converter and cumulative gearing. While every application should use stuff that fits the application best (and that could be the super), an advantage to turbo in this short-drag scenario is the ability to hit full boost immediately, for more efficient and wider range under full boost than the super. While trickier with the super's increasing boost curve, the same can be done to
some degree with the super.
The super could do somewhat similar 'quick boost' with a lazier curve over the map with over-driven boost at the low-end, but will be disadvantaged with excess and hotter air (also needing a wider map range) being bypassed at the top-end. Else, skip the bypass and let it choke.
Not picking winners here (not enough info for that), just stating the general pros and cons of each. The easy trick is using an ECM to control boost and nitrous (and optionally rev-limiting or anti-lag), so it transitions from N2O to boost at the optimal point. Instant power with a boost-level hand-off, and built into a number of ECMs.
Looking at a turbocharger compressor map, a target pressure ratio may cover half of the engines rpm range at best.
A dedicated drag racing turbocharged engine uses A/R turbine housings at 1.00 and above.
Yep, generally true, depending on 101 factors. As we can build boost a number of ways, the AR can then be sized to permit peak boost at peak rpm at reasonable EMAP. Sizing to spool for response is no longer
the (or even a) parameter.
The power bands are not that wide as result and it also takes time and effort to build launch boost.
That’s why the “Bump Box” was created.
OK, but it can build full boost before launch, while the super can't, limited by the super's staged rpm. Do you have to build turbo boost? Of course, and the basis for my last post. And no, the trans brake and anti-lag were developed for building boost for launch. Bump boxes and sliders were created for staging. IMO.
