does the scottsman give a boost in power over the black muffer
They seem about the same but I have not swapped which engine they are on for comparison.
Mine perform about the same but the Scotsman is about twice as loud (+6dB) over the regular
black which is slightly louder than the stock muffler with the baffle in.
A little off the subject, sorta... Where is a good place to get a dB meter? I've got a few engines and a few exhaust choices and would like to check the noise level..
on the subject: I've heard from a few sources that the Macs black pipe doesnt boost performance much over a stock muffler (generalized statement, sorry). Someone recommended a tower muffler over the Macs.. any reason behind this?
Macs one piece mufflers do help on performance.
After actual testing, the original 6590 (made for the 46AX but fit the 55AX) gave only a few hundred RPM over stock.
The new 6720 and 6724 both give a great performance boost of 1,000 RPM over stock with a 13x4 APC sport or Xoar.
The 6720 and 6724 is very comparable to the tower muffler performance-wise but is lighter.
Most SPL meters are uncalibrated and useless for reading actual SPL. The RS meter is OK for relative levels when comparing two setups.
A real calibratable meter and calibration device will be well over a grand.
The real problem with SPL meters is the way they are used in this hobby. Most of the guys using them have really no clue what they are doing.
Since the inverse square law is in play with sound, the distance from what you measure is critical as well as any boundaries or reflective surfaces.
High frequency is directional and low frequency is not directional.
Also with the meters there is something called weighting that limits what frequencies are being measured is very mis-understood.