The gains provided by the leaf blower are dubious, at best. Remember, we're simply looking at high-end power here, not the overall curve. I'd be willing to bet that part of the gains we're seeing in this video are more closely related to the removal of the stock airbox and filter, and the inherent restrictions in those components. Couple that with the simple fact that the blower is feeding cool air from outside of the hot engine bay, and you've got the explanation for your gains right there. The pressures from the leaf blower simply aren't sufficient to provide any notable gains at all, a HP or two at the most.
Aside from that... Let's assume the leaf blower really DOES work. So, then, let's figure out what it'd take to install a similar system on a car. First of all, you have to provide power to the blower. That means we're looking at a quite powerful electric motor, one with a high RPM capability. That's going to be a large motor. Think of what's in your washing machine, and upsize it. For any sort of reasonably affordable setup, we're looking at a motor which would weigh upwards of 20lb, and be at least 6" or so in diameter, and close to a foot long. So, then, you figure out where to mount it. Now the motor needs electricity. With this motor, the stock alternator's going to last about an hour. So, an upgraded alternator is necessary. That adds bulk, weight, and cost. This upgraded alternator is going to have a greater parasitic loss effect, and will sap at least 5HP, and possibly upwards of 10, from the motor, in all areas of the powerband.
So, you're looking at a probable weight increase of over 50lb, an expenditure on par with most turbo kits, with a maximum increase in power of around 5HP, and that's if you can even fit the system under the hood.
The final verdict: Possible? Yes. Feasable? Barely. Sensible? Not in the least.
Completely pointless? Absolutely.
