What do ya know about this?, Horizontal electric for 914 engines? Options

[JPB]

Aircooledclassics has an electric horizontal fan set up for 914 engines. My question is has anyone ever seen one in use or used one? It looks like a good idea but wonder if it would be good for street applications since they imply for "racing". 1200 cfms is not much wind compared to stronger fans on the market that can even push 3500+CFMs. If it does save HP from the power plant, then its worth it and it will give the engine a stead air stream compared to the belt/fan deal which will only supply higher CFMs at higher REVs. (IMG:http://www.914world.com/bbs2/html/emoticons/popcorn[1].gif)

[lapuwali]

QUOTE (alpha434 @ Mar 26 2006, 11:26 PM)

QUOTE (lapuwali @ Mar 26 2006, 11:19 PM) Energy in = energy out - unavoidable thermal losses.  Plain, simple thermodynamics. If pushing a fixed amount of air, then you have to expend a fixed amount of energy to push it.   If you use a system with a fan that's attached directly to the crank, or you use a system that has to drive an alternator through a v-belt (small power loss), then the alternator has to convert this to electricity (big power loss), then you have to convert the electricity back to mechanical energy with a motor (another big power loss), which one is going to end up drawing more power from the engine to deliver that fixed amount of energy? But with an electrical fan, you have constant output at all rpms. Unless you want to change that. The advantage would be at high revs, where the attached fan has the most power loss, and is borderline starving all the time. With a properly setup electrical fan, the hp cost would be constant, since the fan will always need the same amount of energy to turn the same speed.

High RPM also generates more friction, so requires more cooling, so more airflow is needed, so the fan has to be spun faster.

As Brant says, if you run the car and an electric fan off batteries in total-loss mode, as is commonly done when racing, then you'll see a significant benefit, as you get to recover both the fan and alternator losses. This beneift only lasts as long as the battery does, and that's likely to be little more than an hour per charge. Perfectly fine for many racing uses, pretty useless on the street.

One *could* devise a setup where the alternator is clutched out of the system at WOT, and just run off the battery (or batteries) during full throttle. This may even work on the street.