James C. writes:
< snip >
> The crankcase breather assembly has no adverse effect on
>performance, and may even improve it, since it reduces the buildup of
>sludge in the crankcase. It's been in use since 1963, even on
>European-spec cars. I doubt if most people complain about this device,
>but it probably gets removed along with the other equipment.
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No most people leave this alone because it doesn’t affect performance and
most people don't like a stinky car -
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> The EGR valve has been blamed for poor performance and fuel
>economy. I don't know if it actually has those effects,
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Well yes it can, it dilutes the incoming charge by adding unburned gas
(inert to combustion)into the combustion chamber although when working
properly, only during high vacuum conditions i.e. when you don't floor it.
so the performance reduction isn't there. If malfunctioning then you will
lose performance because of the reduction in intake charge.
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> It is entirely possible that air injection is a factor in reduced
>performance, since it does consist of a rather large pump that runs off
>the engine. On the other hand, since it blows directly into the exhaust,
>it may improve exhaust flow. However, this improved flow is probably
>outbalanced by the air pump. Nevertheless, I doubt whether it reduces
>power significantly.
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This device probably more than any other of the add on devices contributes
more to poor fuel economy and performance by virtue of it's function. It
has nothing to do with increasing exhaust flow, and in fact part of the
control is a slightly restrictive exhaust. The idea is to promote exhaust
burning outside the combustion chamber, inside the exhaust pipe. In order
to due this more effectively, fuel systems are actually set to run more
fuel (richer) so that some unburned fuel is in the exhaust pipe during the
exhaust stroke. When the air is injected into this exhaust stream there is
something to burn, the unburned fuel from the incomplete combustion. The
restrictive exhaust (smaller dia pipe, restrictive muffler) helps keep it
there longer for more complete burning. The advantage of doing this inside
the exhaust pipe is that the process is no longer "under compression
pressure" and burns differently (more completely)
These factors, running richer, restrictive exhaust, contribute quite
effectively to poorer performance and poorer fuel economy. Turning the
pump requires hp also, but not a whole heck of a lot is lost there.
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> Why is it that people who complain about emissions controls seldom
>look to the biggest drain on power in early emission-controlled engines,
>the low compression ratio?
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Well, because increasing compression directly increases certian emissions,
and if one were to do this one would probably not pass testing, is not
reversible, and requires much more extensive work to accomplish. All of
the emission controls described above are done as band-aid fixes, applied
with the available technology of the time and as such must be in perfect
working order to function properly. Believe me, if the manufacturers could
have used higher compression and still maintained emission levels they
would have done it!
Most people you hear complaining about emission testing (including me) are
complaining about an unreasonable testing procedure, and requiring cars to
pass tests that these cars were never designed to pass in the first place.
I would be the first to applaud a hook it to the pipe and if it meets the
requirements for my year of car then you pass type of system! I have
absolutely no problem with that! I DO have a problem with someone required
to look under my hood and tell me what I have and have to have without even
testing my car. Or saying nope can't test that, see the ref while my car
may (and it does) actually run cleaner than most cars of it’s era!
Obviously, in this scenario it really has nothing to do with clean air,
does it, as the tail pipe emissions would be the overriding factor wouldn't
it?
Sorry I don't usually get into these arguments, but untill you've had to go
through all th b**ls**t and hassle of trying to get your car through one of
these tests, designed to fail your old car, knowing FULL WELL that your car
is clean or cleaner that it has to be if it were to meet the requirnments
of the car when it was new, you really don't understand the frustration of
going through it. Talk to anyone that has to test cars in Calif. Most
that I've talked to say pretty much any car with a carb will fail Smog test
II. That seams like a test that the car was never designed for to me!
Barry Schwartz in San Diego, CA
Bschwartz@encad.com
72-V6/5sp Spitfire ( daily driver )
70 GT6+ ( when I don't drive the Spitfire )
70 (sorta) Spitfire ( project )
73 Ford Courier ( parts hauler )
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