[mattkosem]

Wow, that is really loud compared to my DAMPFAHMMER setup. I had to decrease the gain of my headset to 30 % to feel comfortable.

Aww, the idle isn't too bad. I agree, though, still too loud. The last pass was specifically aimed at mitigating unpleasant tones, which it did very well.

Need to focus on overall bulk sound reduction next. Will start with an additional resonator, and revisit the DBX situation if that doesn't seal it.

I will say, under track conditions today it worked great. No unpleasant drone during any of my sessions, just that sweet sweet singing VTEC noise (which, yes, could also be quieter 😁).

--Matt

 

[mattkosem]

Oh, shoot, I see what happened here @LotusElise. These videos aren't possible to compare and the sound levels don't provide any consistent point of reference.

The camera app that recorded these is automatically adjusting the mic gain. Worse yet, "audio zoom" is trying to pick and excenuate certain sounds on top of it. Spectroid eliminated these, but lacks the ability to provide other data points. I guess I'll have to find some more repeatable camera setup after the next round of changes.

--Matt

 

[KBuilt]

Here's idle:

--Matt

Sounds nice and deep 👍

 

[LotusElise]

These videos aren't possible to compare and the sound levels don't provide any consistent point of reference.

Maybe just from a frequency standpoint, a sort of quality comparison ?!

 

[mattkosem]

Maybe just from a frequency standpoint, a sort of quality comparison ?!

Pretty much only that, yeah. 😅

 

[LotusElise]

Beside the amazing interesting exhaust noise investigation you do, what does it put on the table of the dyno? Or did I miss that in your thread?

 

[mattkosem]

Beside the amazing interesting exhaust noise investigation you do, what does it put on the table of the dyno? Or did I miss that in your thread?

I haven't been back on the dyno for before/after investigation. I moved from one restrictive muffler to a different restrictive muffler, so I'd hope it isn't much (if any) different. I don't have immediate plans to dyno again in the near future. The 2.5" straight through vs 3" chambered results are earlier in this thread, that chambered muffler vs this Flowmaster DBX...who knows.

--Matt

 

[LotusElise]

he 2.5" straight through vs 3" chambered results are earlier in this thread, that chambered muffler vs this Flowmaster DBX...who knows.

Load the battery and do a nice WOT line from 1500-8500 rpm in 3rd gear, you will see the effect if there is any change in VE.

 

[mattkosem]

Load the battery and do a nice WOT line from 1500-8500 rpm in 3rd gear, you will see the effect if there is any change in VE.

Can you expand on that? Sounds reasonable, but the "how" part isn't familiar to me. Wouldn't I need "before" data to make such a comparison?

 

[LotusElise]

Wouldn't I need "before" data to make such a comparison?

Not really necessary as your engine calibration acts like an measurement tool. The calibration is fixed but the engine changed. The change in VE one can read from lambda, assuming the car was properly tuned. The point here is if the lambda was before e.g. 0.90 +- 0.01 and is now for instance only from 6-8.5 krpm leaner by 0.03 points, we can assume there is an change in VE. Therefore clean tunes makes life easy.