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Old 01-27-2011, 02:25 AM   #8
Johnny Danger
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Join Date: Nov 2008
Location: Massachusetts
Posts: 4,810
Garage
Quote:
Originally Posted by Jake Raby
But you'd be amazed at how well they work.. even when adding up to 400ccs of displacement via big bore hotrodding.

Not a single engine of mine received any aftermarket exhaust system in 2010... The data supports my decisions.
Jake,

With all due respect, I experienced a marked improvement in performance over the oem system after I upgraded to a set of custom headers that utilized equal length primaries, a merge style collector, along with a set of 200 cell HJS tri-metal cats, to include deleting the secondary cats and replacing the oem muffler with a custom cat back exhaust. This led to a significant increase in horsepower/torque throughout the entire power spectrum as evidenced through dyno testing. However, there was a substantial price tag attached to all of this, and it involved two very well respected "tuners" in Germany - M&M Exhaust and 9FF. Prior to this, I experimented with all sorts of configurations. For example, deleting the pre-cats and leaving the secondary cats in place, and vice versa . Or, going completely catless and alternating between the oem muffler and an aftermarket catback; so forth and so on. In most cases, my vehicle lost low end and mid range torque. Moreover, all of these approaches proved to be futile in terms of reliability (keeping the vehicle OBDII compliant and avoiding CEL's ect..) and making strides toward better performance. It wasn't until the latter was accomplished that I achieved positive results . In any case, I'll concede that unless someone is willing to commit the time and money necessary to improve the oem system, things are best left intact. Still, I can't help but emphasize the overall restrictive nature of the oem system. Especially, the superfluous function of the secondary cats and the equally inefficient design of the oem headers/pre-cats.
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Last edited by Johnny Danger; 01-27-2011 at 06:54 AM.
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