Hybrid Car – More Fun with Less Gas


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Posted by Stan and Dee Bringer on August 31, 2005, 2:32 am
When I helped my daughter buy her base Tercel (first car!) back in 1994, I
brought it home and put it up on jack stands.  Then I got under it and
applied a good thick coating of asphalt undercoating.  The main benefit of
this undercoating was that road noise was almost non-existent!

I could tell the difference when I drove another 1994 Tercel without this

The question:  Is it possible to do this treatment with a new Prius? Or even


Posted by richard schumacher on August 31, 2005, 2:28 pm

Drive it a little first and decide for yourself.  (For me it's not
needed.)  Otherwise you may go to the trouble, and risk plugging up the
various weep and drain holes, for no sonic benefit.

Posted by Paul Missman on August 31, 2005, 7:55 pm

From what I've been reading, the Prius has a full underpan to protect the
high voltage system, which runs from the high voltage battery to the engine
compartment.  That underpan may quiet things down enough that you won't need
to spray tar under the car.  Also, with the underpan, it may be impossible
to get the tar where you want it.

My Prius isn't here yet, and I've not seen the demonstrator on a lift, so I
can't say anything about the physical extent of the underpan.


P.S. (And off topic)  Has anyone gotten a look at how the high voltage
battery cable is insulated?  If and when that insulation fails, that battery
could certainly deliver lethal energy to anyone unfortunate to grab hold of
it.  It could also start one heck of a fire very quickly.

Posted by Ingenuous on August 31, 2005, 9:32 pm

Crash any vehicle hard enough and it might explode.   The 12V car batteries
store enough power to burn the insulation from a shorted, unprotected wire.
I once reached under the dash of a car and shorted it's 12V battery to
ground through my watch band.  Burned a link out of the band.  I still have
the scar from that stupid move.

Posted by Paul Missman on August 31, 2005, 11:52 pm
What you say about the danger of 12 volt batteries is certainly true, as any
technician who has gotten a metal object accross a hefty 5 volt power supply
can attest.  A gentleman who came to work on a new computer installation for
us in 1978 had gotten his wedding ring accross a 5 volt 200 amp power supply
at another customer site.  Luckily, he had been in a position to trip the
power switch off with his foot.  He had a very nice burn on his ring finger.
After that, he always removed all of his rings and watch before opening the
cabinet door.

However, while a 12 volt car battery at, perhaps 200 amps will deliver quite
a charge, the battery in the Prius will deliver over 200 volts at over 200
amps.  This is more equivalent to removing the cover from the circuit
breaker box in your basement and grabbing hold of the main lines coming in
from the power pole, with the exception that it is DC instead of AC.

Hopefully, the hot lead from the battery has more than a car lifetime's
worth of insulation or it is required to be replaced at specified intervals.
I've also been hoping that everyone who buys a Prius is smart enough not to
pry into the high voltage battery compartment, trying to recharge the
battery with a handy JC Whitney 12v battery charger.  The results there
could only be described as electrifying.


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