[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: rich vs. lean

joseph edward morgan wrote:
> Before I had the IC on the Pinto, I was switching back and forth between a
> Merkur box and the SVO one.  The SVO box would leave a trail of black
> smoke at WOT, the Merkur box didn't. Same parts, different box.

Hmmm...well, that's more hard facts than I have...

> I would think that the IC box would be richer, all other thing being
> equal...it's supposed to be burning more fuel to make more power, right?

Along with that much more air...so there goes the whole "rich" thing.
I don't know...all I KNOW is that there is an ideal ratio for maximum
power, somewhere in the 13:1 region?  We can't run at that ratio for
very long because EGTs get too high, so we add more fuel to cool things
down a little.  This extra fuel gets in the way of maximum power, but
it's a necessary evil to avoid burning up parts.  So, since temperatures
are lower when the air charge is cooler, we shouldn't need to be so
over-rich when we have an IC.  I'd always heard that the non-IC boxes
aimed for a high 9.xx:1 ratio at WOT, and the IC boxes were in the
high 10s.  Of course, this was from people like Mike Wesley, so you
(and I), of course have to take everything I say with a grain of salt.
It makes enough sense to me as an engineer, though, that I'll need
hard facts to change my mind...;-)