[Diy_efi] A/F mixture, EGT and engine damage

[Tim Marsteiner]

Great insights. I keep these in mind as I move
forward.

How does one find non-winter formulations? Is it a
regional or perhaps seasonal type of thing? I live in
the Southeast US.

I think someone had some flow bench testing done a
while back and they came up with a port and polish
package including some intake tract modifications. I
will put this on my list to take a closer look.


Thanks,
Tim


--- Adam Wade <espresso_doppio at yahoo.com> wrote:
> --- Tim Marsteiner <tmarstei at yahoo.com> wrote:
> 
> > I get some surging at lower speeds and
> > some pretty high EGTs. A/F seem to be all over the
> > place(~14.5:1 - ~17:1).
> 
> Chances are that you're not getting similarly
> homogenous mixture from cycle to cycle, and that
> this
> accounts for both your surging and your fluctuating
> AFR.  If the fuel is not well-distributed, you'll be
> down on power and get excess O2 in the exhaust, as
> the
> burn will only be in the richer part of the intake
> charge.  V-twins, especially at lower engine speeds,
> are notorious for having poor repeatability in terms
> of intake "tumble"; I suspect that this is what
> you're
> getting.  And then there's the issue of reduced
> intake
> pressure and cylinder filling as the throttle is
> closed in increasing amounts.
> 
> Unfortunately, the only real way to attack that kind
> of a problem, AFAIK, would be changing the design of
> the intake tract and/or the piston crown.  There may
> be some relief from moving the injector, or
> switching
> to an injector that has a better spray pattern or
> finer misting of the fuel.  Using fuel with a lower
> pressure of vaporization should also help in that
> regard (i.e., avoid "winter" fuel formulations,
> avoid
> ethanol, etc.).  You might want to call Russ Collins
> over at RC Engineering and have a chat with him,
> sending him a set of injectors for his evaluation. 
> I'll bet he could help you operate in that AFR range
> with far fewer drivability issues.
> 
> | 82 Honda CX500 Turbo (Cassandra)  90 Kwak Zephyr
> 550 (Daphne) |
> | "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     |
> | M/C Fuel Inj. Hndbk. @ Amazon.com - 
> http://tinyurl.com/6o3ze |
> 
> 
> 		
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