Quote:
Originally Posted by ZCP M3
Okay, let me drop a bit of knowledge here. It's all about power under the curve and thus the ability to generate lots of torque at all RPMs. Twincharging is only advantageous if the turbos are overly large and take a long time to spool up.
Take a look at a 135/335/1M dyno graph. Max torque is available almost anywhere in the rev range and damn near down to idle.
Now take a look at a Supra dyno graph with a turbo that is very large. It clearly doesn't spool, even under load from the dyno (which will make it spool faster), until about 4000rpm. This is where twincharging would help.
You want the supercharger to provide low end torque until the turbos are up to speed. The N54 has the turbos up to speed at around 1500rpm. If we say the supercharger makes 7PSI boost at 7k RPM, you will have less than 1.5PSI of boost until the turbos are pushing out all 14.5PSI or whatever they provide. So 99.9999% of the time, the supercharger would actually cost you horsepower due to parasitic drag. You'd see a benefit from idle to 1500rpm in first gear.
Now the follow up argument is that the supercharger will increase throttle response and to a point it will. But with MDM enabled, the N54 uses the wastegate to keep the turbos spooled up for quick response.
Unless you plan on increasing the turbo size and introducing more lag into the system (and can't utilize the MDM wastegate tuning), the s/c isn't going to pay off for the added complexity. And the same thing applies, once the turbos are spooled the charger provides little benefit. |
Dang! I scrolled through the car pics and missed this one in the middle. Sorry man... you had already said it exactly, thank you! Beautifully done!