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We are often asked how well our Conical
Merge Collectors perform on the dyno against traditional,
and much more expensive, welded merge collectors. Many of
our long-time customers have done extensive dyno testing
that showed they performed very well but we didn’t
have hard data to share. Now we do!
We were approached by a long-time customer
that planned to use a set of our collectors for a header
they were designing for a new customer. Their customer wanted
to use a welded merge and wasn’t too concerned about
cost just plain performance. But isn’t that what we
all say until they get the bill? We were requested to prepare
a collector kit that would be comparable to the welded merge
collectors he was given in order to conduct a direct dyno
comparison. His customer just couldn’t believe that
our $50 collector would perform as well as a $350 collector!
In fairness, there are some differences in the collectors
that should be disclosed. First, their collector was finished
and ready to bolt on. Ours was a kit that required some assembly.
It takes about two hours to assemble and weld a pair of collectors
to the header. Slip-on collectors do take slightly longer to
build. And you will need to have some basic fabrication tools
such as a TIG or MIG welder, a hand grinder and a saw, preferably
a metal cutting bandsaw.
How to build a Megs
Conical Merge Collector, click here >> Collector
Assembly Guide
The two different collectors would have to be as similar as
possible in dimensions for the results to be comparable. If
the collectors differed in this regard it would call into question
the results and defeat the purpose of the test. In addition,
the unique nature of the test engine also required some slight
customization of each collector.
Neither we nor the builder of the welded merge collectors
set the collector specifications; these were all set by the
customer. This individual has been building high-performance
and race exhausts for many years. On this project he was working
with a major aftermarket automotive company.
The test engine is a 482 cubic inch big
block Ford V8 with a 4.25” stroke and 4.25” bore. In earlier tests
it generated around 550 horsepower. The base collector they
selected would use 2” primary inlets and a 3.50” diameter
outlet. This would be matched up to a 3.50” x 4.50” x
8.25” length (7 degree) transition cone.
The welded merge collector that our competitor supplied was
a very beautiful part. The welding was top-notch and even the
inside of the collector had a fantastic polished finish! It
was going to be tough to compete against something like this,
but we had to know once and for all how we stacked up!
We supplied our customer a collector kit
that included (2) 2” 4-into-1 304 Stainless Steel collectors,
(8) matching bullet vanes and the fixture tool to assemble
the merge bullets. Also included were a set of transition
cones as previously described. Our customer then assembled
everything, adding additional tubing to fabricate it as a
slip-fit collector. Similar to the welded merge collector,
we generally recommend blending and polishing the bullet
assembly for optimum performance. However in this case, they
were left unfinished.
Now came the moment of truth, back-to-back
dyno pull using the same set of headers….
As you can see from the chart above, the
results were amazingly similar! At certain RPM’s there
are differences. Generally, the Megs collector produced more
HP and Torque up to about 5200 RPM. The competitor pulled
slightly more from 5200 to 6000. When you consider the RPM
that most street-driven vehicles operate at, the results
were astounding! Compare the prices and it could be hard
to justify spending several hundred dollars for gains seen
only in the upper reaches of usability! Now if you are building
a full-bore money-is-no-object racecar, you might be able
to make an argument. And if he had just polished those bullets…
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