[Diy_efi] RE: Diy_efi digest, Vol 1 #413 - 12 msgs

[Adam Wade]

--- William Shurvinton <shurvinton at orange.net> wrote:

> Car overheats. Even with the fan. For whatever
> reason ( and I haven't investigated it) you cannot
> shift the KW when stationary.

Well, once again, I've not worked with cars.  However,
I can't imagine it being substantially more difficult
than with portbikes putting out 190+ BHP with
radiators half the size of that of a Honda Civic.  I
know it works well with bikes, even extremely powerful
sportbikes (based on both coolant temperature sensors
and infrared temperature checking of endine components
and coolant hoses).

Having a very large (or better, several very large)
exhaust fans is critical, as is a good source of cool
air.  Building a good dyno room that is useful, when
talking about a chassis dyno, is not a trivial feat.

> If your dyno was in a wind tunnel you might get away
> with it as the pressure zones on the car would be
> the same.

Given a modern car, there may well be something to
using low pressure under the car to extract hot air
that has traveled through the radiator.  That WOULD be
extremely hard to duplicate in a dyno room, I will
agree.

> See answer to A) I have limited dyno experience, but
> do know someone who has pulled over 3000 engines,
> which is where the 30 seconds comes from.

And when it comes to bikes, I've seen bikes run at
load for over a minute at a time, with about a
five-second cycle time to the next pull.  And that was
a two-stroke with near-ideal ignition advance and
jetted for best power (read: as lean as safely
possible).

I believe we're seeing differences between cars and
bikes, as well as some practical limitations of
affordable dyno room design.  I'm sure it would be
possible to make his dyno room safe for longer
operation (not that it should be necessary,
practically), but it might not be cost-effective for
the results obtained.

I would be interested in gathering more data about the
requirements of cooling automobiles on chassis dynos.

=====
| Adam Wade                       1990 Kwak Zephyr 550 (Daphne) |
|   http://y42.photos.yahoo.com/bc/espresso_doppio/lst?.dir=/   |
| "It was like an emergency ward after a great catastrophe; it  |
|   didn't matter what race or class the victims belonged to.   |
|  They were all given the same miracle drug, which was coffee. |
|   The catastrophe in this case, of course, was that the sun   |
|     had come up again."                    -Kurt Vonnegut     |

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