[Diy_efi] Importance of TPS with lightweight cars

[Adam Wade]

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

> Well I did some research of my own on the 'plugs up'
> list, which is specifically for rotary engined
> planes. There they suggested that you can
> run even leaner than is normal, due to lack of
> valves to burn. The problem with going too far is
> recovering again when you open it up. Fly by wire
> throttles allow this, but without that......

...you whack the mixture control to your takeoff climb
power setting and adjust spark and throttle(s) to
match.  ;)

EGT has a peak about halfway between best power and
best BSFC on many 4-strokes I have seen.  CHT seems to
roughly follow power output at a given rpm, based on
mixture.  So going substantually LOP will give you
nice low numbers; best BSFC should give you roughly
the same EGT as peak power, and  a much lower CHT. 
You can go leaner than best BSFC and get even lower
temps from both CHT and EGT.

See http://www.avweb.com/news/columns/182084-1.html
and http://www.avweb.com/news/columns/182085-1.html
speak to the issue quite nicely.  So does
http://www.avweb.com/news/columns/182045-1.html with
some nice practical examples.

Unfortunately AvWeb is changing servers and formats,
so the one article I wanted to share is not here; it
has data from a twin-engine normally-aspirated piston
prop with one engine at lower manifold pressure and
running a given rpm, set lean, and another engine with
a higher manifold pressure and a richer mixture (SOP),
with the EGT and fuel consumption figures.  The gauges
don't lie...

=====
| 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     |

__________________________________________________
Do you Yahoo!?
Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
http://mailplus.yahoo.com

_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi