Electrical Supercharger

[Michael D. Porter]

Steve Meade wrote:
> 
>         I noticed a while back (over a year ago) there was a discussion about
> electrically powered superchargers. I was wondering if anyone actually
> followed through on plans and tried it. To me, there are several advantages
> to electrical power over the traditional crankshaft power:
> 
>         1. Cost (electric motors are less than blowers and don't strain engine as
> much)
>         2. Placement -- the placement isn't dictated by crank positioning.
>         3. Ease of installation -- no need to completely tear apart front of
> engine
>         4. Adjustability of boost -- a simple 2-d rpm and boost mapping system can
> be made
> 
>         However, I was thinking of the extra energy losses by using an electrical
> blower. In a regular system there are only two possibilities for energy
> loss:

Most of these concerns are true. Add to them a cost related to #1 above.
You need the motor _and_ the blower. A crank-powered blower only needs
the correctly-sized pulley and the belt. Saying motors are less than
blowers doesn't address your problem. The motor is not a _substituted_
expense, but rather, an _added_ expense. 

> displacement of 2.5liters) a regular supercharger kit costs around $6K! As
> you can imagine, I would be very willing to accept a fraction of the power
> boost for a small fraction of that cost. Also, designing the system myself
> would be fun.

Hmmm? That cost seems pretty steep. From whom does this kit originate?
How about looking at other electric clutch-controlled units, such as
that for the Buick Nationals, or the Toyota MR2? Such are available at
much lower prices that $6K, though some additional costs could be
incurred for specialty fabrication for hookups. The cost may still be
considerably less.

Last, but not least, nothing is for free. Adding the current draw of an
electric motor adds to losses in efficiency and the cost, but if
installed, would probably require a larger alternator, which would
increase the cost of the installation, and because of the efficiency
losses, would require _more_ horsepower to run than direct crank-drive,
which is a net loss. There would have to be some further compelling
reason to add such a set-up, such driveability or detonation control to
justify the extra work and expense. All this not to discourage, however.
<g>

Cheers. 

-- 
My other Triumph doesn't run, either....