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

[Adam Wade]

--- bill.shurvinton at nokia.com wrote:

> The dyno can set a constant load of 8HP (once you
> have taken frictional loss differences due to 2
> contact patches etc into account). However at what
> throttle setting you should have 8 HP?

I don't tihnk there's any "should" about it.  At a
given throttle opening and rpm, an engine will deliver
a certain amount of power (assuming the same air
density, and the car is warmed up).  If it takes more
power than that to maintain speed, you'll decelerate;
less and you'll accelerate.  Exactly that much? 
You'll cruise.

> Given you have the curve of BSFC vs Power depending
> on the engine there are a range of throttle openings
> corresponding to the same 'load'.

Assuming different fueling.  I presume you meant to
say "same rpm" in there somewhere, since obviously if
you vary the rpm, there will be different load/speed
sites that make the same power, even when tuned for
the same goal.

> Tuning the whole map on a dyno for best power or
> best BSFC is obvious, but the blend between those
> would appear, at least to my inexperienced eyes, to
> be a challenge.

If you were so inclined, it seems to be simple enough
to average the fuel numbers on your map.  I'm not sure
what goial would be achieved by picking a particular
value between the two.

=====
| 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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