At 07:00 PM 7/16/98 -0400, you wrote:
>
>----------
>> From: Rader <rlr@rtp-bosch.com>
>> To: dakota-truck@buffnet.net
>> Subject: DML: Shorty vs. Long-tube headers
>> Date: Thursday, July 16, 1998 9:33 AM
>[snip]
>>
>> > I'll put on some good, long headers (not the junky shorties that
>> > people are signing on to buy now).
>>
>> I'm curious about this comment. Why do you feel this way? Objective
>> evidence is, of course, most convincing.
>>
>> Ron
>
>I figured I'd hear back about this. Maybe "junky" was too strong a word.
>
>Anyway, shorty style headers are a definite improvement over cast iron
>manifolds. But, I figure regular long style headers are going to cost me
>just as much, and they DO provide more power.
>
[...]
>
>BTW, I'm a mechanical engineer that specialized in compressible fluid
>mechanics, so this is my specialty. However, I'm no expert so I'm sure that
>someone at hooker headers or similar might be able to give us more info if
>we wanted it.
>
>Aside from the logical explanation above, I could further prove that longer
>headers are better through example. Go to the dragstrip and see how long
>the headers are on the faster cars. If they use longer headers, it must be
>better, right? But obviously there's some optimal header length, otherwise
>I'm sure someone would build a header with the collector at the rear
>bumper.
>
I'm even less of an expert than Mike. :-) Figured I'd throw my $.02
in here though...
Mike's right about the exhaust scavenging. If you want to see something
really funky, take a look at a set of headers that has been built for
optimum scavenging and perfomance. Some of the pipes have to run over
to the opposite banks of headers, etc. There's more tubes there than
in the NYC sewer system! These are the kinds of systems that you might
see on something like an Indy car; something where they're trying to drag
every last ounce of horsepower out of that engine, no matter what the
cost.
The equal length headers are a good compromise for most budgets
though. If you're the type that goes for the headers mentioned
above, you're probably also one of those folks that drills holes in
your gas pedal to save weight. :-) Given the price difference, the
bank seperated equal length headers are generally the way to go. However,
they have problems too. They're usually more money of course, and
the install is generally more difficult. The shorty headers will make
only slightly less power than the equal length.
In fact, I was talking with a guy at the track who just put JBAs on his
Dakota. In talking with JBA, they told him they got a set of equal length
headers with the crossover pipe and everything. They dyno'd them vs the
shorties and the shorties made only 3-4hp less power. I was hoping
to see some dragstrip before/after results (on this guy's JBA shorties)
but unfortunately he changed his tires too, and they wouldn't hook; he
was burning them up in all 4 gears. He's coming back with slicks. :-)
-Jon-
.--- stei0302@cs.fredonia.edu ------------------------------------.
| Affiliations: DoD, EAA, MP Race Team, NMA, SPA, USUA. RP-SEL |
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