Quote:
Originally Posted by niky
10 Kw of electric motor equals 10 Kw of assist going to the ground.
10 Kw of electric motor spinning a turbo equals more than double that.
The only issue is the specialized high speed heat resistant motor you need to turn the turbine.
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Where do you prefer the power in a daily driver? 20kw at high rpm and very little below 2000, or 10kw from a dead stop, with built-in ability to auto-stop, silently restart the engine, and creep along on electricity alone in traffic?
Adding boost requires changes to an engine which make it less efficient while out of boost. I'd take a high compression N/A engine with electric assist over an electrically supercharged one for a DD any day of the week. On a track or for racing purposes it might be another story, of course.
An anecdote, a Honda Insight weighs in at ~1850lbs, has a ~66hp gas engine with tall gearing, and takes around 10.5 seconds to 60 with a healthy engine and battery. Without electric assist, 0-60 time is closer to 13.5 seconds, with most of the additional time happening in the 0-30mph range. Torque is improved from around 55ft-lbs to 90ft-lbs at 2000rpm with assist, even though peak HP at 6000rpm only improves from 66 to 73.
How much boost would it take to improve torque at 2000rpm from 55ft-lbs to 90ft-lbs? In an engine with a nearly 11:1 compression ratio, how much would compression need to be reduced? How much boost would it take to match electric assist's 0-30mph time?