Quote:
Originally Posted by xsnapshot
First off, this makes the nerd in me get all excited.  A few quick constructive questions....
Question: If the exhaust is supposed to be reducing drone, of which complaints come from those experiencing it usually at lower RPM's, then why are you comparing the exhaust tone at 5000 RPM? Wouldn't a better test be where you hold the throttle constant at 1500/2000/2500/3000 RPM and then record the differences in decibel level between resonated and non-resonated?
To my ears it did sound less noisy at the very low RPM's and idle, but it was difficult to discern IMO. It would be interesting to take some in car audio samples of a resonator equipped Z cruising at 75mph and likewise with a non-resonator equipped Z. (or any two identical sporty cars for that matter)
Question 2: Underneath "ark performance resonators", the first paragraph:
"The resonator is designed to work best in the frequency range where the engine makes the most noise". Would the engine not make the most noise in the high RPM's at WOT, where the frequencies encountered might differ greatly from those at cruising RPM's? Thus wouldn't it be ideal to design the resonator towards those specific frequencies? I would think the resonator would work best at any RPM dominated by the frequency to which the resonator was designed.
Question 3: Just curious on your correlation of pipe diameter to the given ranges of Hp. I come from the Subaru realm where not much gain is to be had going from a 2.5" pipe to a 3" pipe (below about 400 crank hp), as long as the muffler designs are similar. 3" exhausts with straight through mufflers seem to work well for people all the way up to 600 crank horsepower. Still single exhaust. IMO a 4" exhaust recommendation for someone at 450 Hp seems like it might just add a lot of unnecessary weight and more area for heat transfer to occur.
Overall great presentation. I love the engineering side of it, and can tell your marketing people and your engineers must have a happy relationship. |
Answer 1: We do test it at certain RPMS. However, you must take into account that its easier to hear or notice frequencies at a high range than low. This is because of how combustion engines function. It functions as a pulse. For during low RPM's it the gaps between the pulses are more apart than the pulses between high RPM.
Hopefully when do produce our next video, we will be able to show a picture in picture of the Speedometer.
Answer 2: Adding on to how I explained about the pulsing of the engine, We have to control the variables we have to work with to find the best range in frequencies to eliminate.
Variables . Size in piping, Piping diameter, thickness of pipes, size of perforation, size of chamber, thickness of chamber, placement of chamber, volume of the resonators.
Answer 3: This is subjective. We can only guess how big the piping diameter should be for best performance. You must take into account for where the testing is done as well. There is no best way to measure this. It all comes down to trial and error and the resources that each exhaust manufacturer has