[DML] Re: Performance Exhaust

["content22207" <brobertson@xxxxxxxxxxxx>]

Because of valve overlap, there is a brief period of time in which the
exhaust side is either at static pressure or even in a vacuum
(converse is true on the intake side BTW). Of course RPM's affect
this. The big theory of "scavaging" is that the momentum of outgoing
gasses will compensate for this. Libraries could be filled with the
debates that have raged over backpessure and scavaging.

In the DeLorean world, no matter your position on the above, it must
be admitted that the stock exhaust set-up is very restrictive and
counter-productive to efficient flow.

I modified mine not for performance, but for access. The stock set-up
is an impediment to maintenance. Easy to install on the factory floor,
but an obstruction in the driveway.

Bill Robertson
#5939

>--- In dmcnews@xxxxxxxxxxxxxxx, "Steve" <p2freak@xxxx> wrote:
> Gang,
> 
> In the archive, someone mentioned PJ Grady had setup a "green machine"
> with performance suspension and exhaust.  I saw the performance
> suspension on PJ's website, but is the performance exhaust available?
>  Is it a special item that you have to call and order in advance?
> 
> 
> Off the topic.
> From my readings, a real performance exhaust would be no exhaust
> headers or pipes at all.  Just discharge the exhaust gas straight out
> of the engine.  But... that wouldn't be street legal at some places,
> not to mention loud as hell.  Therefore the catalyst converter,
> muffler setup.
> 
> Avoid back pressure like plague, because back pressure essentially
> keeps some exhaust gas mixture in the cylinders, preventing  fresh
> fuel-air mixture from filling up the cylinders.  Unless, you can do
> some fancy valve timing work and piping the exhaust gas around like
> Honda cars. 
> 
> 
> Steve
> VIN#04421







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