View Single Post
Old 11-07-2009, 04:56 AM   #3 (permalink)
MR JAS
Generous to a fault
 
MR JAS's Avatar
 
Join Date: Apr 2009
Location: hamilton new zealand
Posts: 720
Thanks: 19
Thanked 17 Times in 16 Posts





oh my god please tell me your not stupid enough to think you can get free horse power from a fan

ok quick lesson
electric fans are good for volume not pressure
if you want an electric supercharger setup you need a positive displacement pump
lets look at an engine as if it was an air pump when you add a supercharger that robs 50kw of energy it would be adding around 30kw of air energy to the engine at best (i.e. makes engine run better as its forcing air through) now as you can imagine this would be loosing power as its using 50kw to gain 30kw
however when you factor in fuel ratios the 50kw of energy used by the supercharger its putting 30kw of air back into the engine but also allowing an extra 100kw of fuel to be utilized hence it gains hence giving a net gain of 80kw

while not being as specific as normal energy gain needs (such as needing a specific amount of energy to lift 1kg by 1m) due to varying adiabatic conditions compressing a certain volume of air to a specific pressure always requires a relatively similar amount of energy depending on the efficiency of the system

what that basically means is if a normal supercharger requires 50 kw of energy to run you would need relatively close to the same energy input into your fan to get the same gains so a 10 watt i.e. 0.01 kw fan would have little effect

to prove this put a vacuum cleaner which is normally around 1.5kw onto blow mode and put your hand over the pipe and you will be able to stop air coming out now try the same with a turbo or supercharger and there is no way of doing it this proves the positive displacement pump concept (electric fans cant build pressure)

in theory you can run a supercharger electrically and by having ideal speeds it would run much more efficiently but a 50kw electric motor weighs as much as a mk1

as far as putting this in your intake i would fairly say you would lose power due to intake restriction and turbulence caused by fan spinning at a constant speed in an inconstant air stream also with vibration etc i would suspect it would quickly lose blades which would have buttsecks with your valves

holy crap that was a long rant i better have passed my thermofluids paper just for remembering a word like adiabatic
MR JAS is offline   Reply With Quote
 
Page generated in 0.24203 seconds with 16 queries