from tpr,
HyTech Exhaust - TEST SET 01
At this point, you've already seen the graph on the previous page, and you've probably already done the math. Yes - we're showing a 51.1hp increase. Yes, that's highly unlikely and it made everyone... uncomfortable. We have to note that the HyTech unit is marketed as a "racing" header and will not fit with the power steering and air conditioning compressor intact; these were removed for our testing of the header. Still, our test procedure stayed the same, our test platform stayed the same, and the multiple runs we did were all repeatable to within 3 horsepower of each other, with power curves following the same lines each time. Like the other headers, the HyTech unit increased low-end torque production to such a point as to negate the effects of the "pre-VTEC" dip in the powerband, and it also straightened the graph to make the powerband more linear after that point. Like the other headers, the standard test procedure was followed, with the same extension pipe mounted onto the header. DISCLOSURE: The pipe was provided to us by HyTech as they were concerned about the possibility of a loss of power due to the relatively short runner length from the collector to the header's exhaust gas exit point. Now, one could easily conjecture that the pipe benefited HyTech the most because they designed it, and that would be true. However, that fact doesn't prove that this was an act of collusion; it rather suggests that HyTech might know a little something about header design that we don't know - hence, their polite suggestion that we use the pipe on all the header tests. Given the design of the pipe (essentially a long test pipe or straightpipe) and the fact that the tests were conducted pragmatically and without bias, we wondered if it might be possible that the header wouldn't make as much power if attached to a complete exhaust system. When we brought all of this information and the dyno charts to our peers and a few industry tuners, however, they all had different opinions...
HyTech - Test Set 02
This time around, the HyTech unit made about 3-5 additional horsepower between 3400-4300rpm, then slowly produced more power over stock from about 6300rpm to redline. In all other areas of the graph, the power gain was negligible. Peak power production rose from 160.4hp to 168.5hp
Aside from the revelations we had about "standardized" testing procedures, we also amassed a mountain of data. And, in our current "peak horsepower" world, if a winner was to be chosen from that data by maximum peak horsepower gain alone, the winner in both test sets - as clearly identified by the graphs - is HyTech Exhaust.