Coming in late after a busy weekend to close out this thread ...
Ron Porter wrote:
>> Opening up the exhaust system n a small /a engine like the SHO will
probably always show a peak HP increase on a dyno, but it will be at the
expense of killing the torque below that point. And you can't get this back
with EEC tuning. <<
Since a properly-designed and properly-tuned exhaust system (speaking in terms
of pipe diameter and geometry only) will ALWAYS help contribute to maximum
engine power output and should always show an overall gain when compared to
the original factory system, I have to disagree with you on both of those
points. Furthermore, as Bill pointed out in an earlier post, recent advances
in EEC tuning have made it possible to "tune out" many of the exhaust system
faux pas that were previously and harmfully irreparable.
In short, Ian was correct when he recapped my previous posts by stating that
a) backpressure is NOT necessary when it comes to making power, b) in MANY
cases, the torque losses that are normally observed from a catless Y-pipe or
other exhaust modification can be gained back with some degree of EEC
retuning, and c) it is important to consider the ENTIRE exhaust system (and
not just one component - e.g. the Y-pipe) when considering, designing and
implementing exhaust system changes.
Rick Glass wrote:
>> I did true dual 2" pipes all the way back (to what resembled mufflers with
a pipe straight through them) on my '94 and it had NO TORQUE, was the worst
running SHO I have ever had the misfortune of driving. I took it the next day
and had the stock system pieced back together and re-installed. What a great
way to waste almost $700. <<
Out of curiosity, how were the pipes configured (e.g. where and how many
bends, did you utilize a crossover pipe, etc.)? As I noted earlier, a
properly-designed true dual exhaust system will always show gains across the
board, even with a vehicle like the SHO and it's transversely-mounted V6
engine. Granted, achieving the most "optimal" design and configuration for a
given setup is not always easy, and there are a couple of different ways to go
about it (as proven by Ted Breaux and a couple other members of the
community); however, given enough time and effort, an optimal system is
attainable.
Adam
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