67ZNISMO

iTrader: (6)

Tony explained this.....the V2 is just as aggressive and loud as the V1 however; the in-cabin drone has been drastically reduced and or eliminated. I think your ready to buy no?

nismonian

iTrader: (11)

thanks for the explanation, thats what i thought. i was just doing my research. and yes im waiting for the V2 to go into production.

rcdash

iTrader: (18)

Having trouble posting... aargh - what is the matter with this site the past few days?

Anyway - tested the other two larger mufflers and they behave about the same as the VQ muffler. The VQ muffler still comes out on top but I haven't had a change to overlay the RTA curves.

The bottom line I think is that the v2 is excellent for drone control. All the other muffler designs generally dampen the noise but only marginally reduce the low frequency drone. A combo of some sort would be ideal for those really wanting a subdued sounding exhaust system.

For those who haven't purchased a MD set up yet, getting the V2 is a no brainer. It just sounds great - around town, not bad at all due to the drone control but certainly not quiet at WOT. If you already have a Motordyne exhaust setup and are looking for something quieter, it's a tough call whether to spring for the v2 and then wait for some possible future combo setup (Gamma+V2) or just wait for the latter... Anyone want a V1 shockwave TDX axle back?

I had to return the v2 to Tony so he could finalize his production pieces , but he has graciously allowed me to continue "testing" the VQ mufflers for a little while longer. (Tony, would it damage the prototypes to put my new tips on those mufflers or can I install them for now?)

gabe3d

iTrader: (8)

Same problem for me, but the strange thing is that it was only on my main laptop and no other computers. Everytime I replied to a thread it would time out. I had to remove all filters and disable certain storage.

Comparing the V1 and V2 shockwave, would you say that the only difference is the drone elimination? Also can you go ahead and plot a chart comparing the two if you have the data.

rcdash

iTrader: (18)

If you delete all temporary files right before posting (including cookies, etc), it seems to allow IE to post. Weird.

Anyway, I need to redo testing with the V1 to get proper overlays (the data I have is all about 6 dB lower than all others, even at high freq, not sure why but I did change various settings in the RTA and have kept them constant since testing the 4 muffler designs - now need to go back to V1 with these settings). I will try to do that in the next day or two.

Here is everything BUT the V1 (all in the range of 1800 rpms, 10-15% throttle, 4th gear - some variation in outside temp, maybe ranging from 35-50 degrees):



LEGEND
-------
GREEN - Perforated core sebring muffler
YELLOW - Louvered core sebring muffler
BLUE - Large VQ muffler (the BEST of the mufflers for overall noise reduction)
ORANGE - V2 Shockwave hemholtz resonator (the BEST drone eliminator)

Looking at the orange V2 curve, check the waveform below 50 Hz - but also look at overall higher frequency noise reduction - weird, though keep in mind this is at low rpm and low throttle trying to induce drone, not a WOT comparison - trust me the V2 is louder at WOT by far than all the other muffler designs. For drone elimination it is amazing - the usual booming 20-30 Hz peak actually inverts! The 50 Hz peak is still there at 1600-1800 but it disappears by 2k rpms. A combo muffler + hemholtz resonator would be Very Quiet indeed

Testing is pretty much wrapping up. I will get the V1 vs V2 plots up and that's about it unless anyone has any requests.

For most sports car enthusiasts looking for something that can be reasonably quiet at low throttle with minimal in-cabin drone, but still puts out a great growl at WOT, the V2 Shockwave is just the ticket. Nice work Tony.

rcdash

iTrader: (18)

My recollection is that the V1 is a bit more aggressive, but that could be because of the droning in my skull with the V1 . I will try to get a V1 video up for direct comparison to the V2 video, with some WOT, as well as the RTA overlays at low throttle to compare the drone.

gabe3d

iTrader: (8)

Thanks again for your great contribution to the community on this matter.

Is 2k the highest RPM testing you did for all of the axlebacks?

rcdash

iTrader: (18)

I have 2500-2600 rpms plots also for all the mufflers that I can overlay - can post up. As I recall only the V1 has signficant drone at that point so there wasn't much point showing it, but when I redo the V1 testing, I will put up idle, 1800 rpm and 2500 rpm overlays. Above 3k rpms, the V1 drone is pretty much gone also so I didn't test higher. I figured above that, you're on a WOT run, and noise becomes less of an issue at that point. Cruising on the highway with any of the mufflers or the V2 is far superior to the V1 because the drone from 2500-3k is so much less.

I don't really want to go back to my V1 straight pipes, but I will, one last time, to get some comparable data I guess... I'm hoping the production V2 pieces will be ready before Tony asks for the prototype mufflers back.

EDIT: Don't have access to RTA software at work - so will have to wait till this evening to post 2500 rpm plots.

gabe3d

iTrader: (8)

2500rpm will be good to see since cruising at highway speed, my tach is right around there. With my current setup, I either have to drive faster or drop it to fifth to prevent my brain from shaking out through my ears. Thanks!

UnitedBreaks

Wow. I just read this entire 36 page thread, LOL. To my understanding, the best test pipes / HFC's to adapt with the MD/SW))) are the MD TP's/HFC's? As I don't see MD producing TP's/HFC's , I assume it is the XYZ w/Catalytic Converter or Straight Pipe integrated with Stock cats?

My plan is to get the AAM test pipes or HFC to adapt with the upcoming V2 of the Shockwave if the above statement is incorrect.

Thanks for everyones input, soundclips, R&D, etc!!!

Hydrazine

iTrader: (53)

The MD test pipes should be ready in the later part of January.

rcdash

iTrader: (18)

Ok, switched back to the V1 last night for 30 mins to get more test data.

Here is the V1 (yellow) vs V2 (green) at 1800 rpms:



Here is the V1 (orange) vs V2 (pink) at 2500 rpms:



Note the 20 dB reduction in peak volume with the V2 at 120 Hz! It is important to note that these snapshots do not adequately convey the general impression over a throttle and rpm range that one feels comparing the two systems. The V1 "booms". The V2 is "clean". Those are the best words to describe the difference between them.

Hope the testing with at least some quantitative data has been helpful. I'm glad to be done with the testing - tired of jacking up the car.

TheOtherRob

iTrader: (14)

Yes it has helped with us wanting the v2 to release already!!!!!

rcdash

iTrader: (18)

LOL. I didn't want to give up the V2 prototype I had either. In the above graph at 2500 rpms, the 20 dB increase with the V1 would be perceived as being 400% louder than the V2 (just FYI). At 1800 rpms, it would be twice as loud (10 dB difference in peak volume at 100 Hz). It's so weird that the V2 sounds so good without any kind of muffler on there.

TheOtherRob

iTrader: (14)

Very strange but yesterday my car did not drone all day. Maybe it was the temperature outside or something.

UnitedBreaks

Thank you, Tony

UnitedBreaks

I do believe this can affect tone of sound? What about high/low atmospheric pressure?

rcdash

iTrader: (18)

Drone seems to be worse in colder weather with all exhausts I have had on my car (5AT). I know for a fact that the drone on the FastIntentions exhaust (large Sebring mufflers) was much worse below 50 deg F but tolerable during the summer. There was one warm day running the large MD VQ muffler a couple weeks back and the drone was much less for that also with temps above 60 deg F.

The cold weather these past couple weeks in NC made for good testing conditions from that aspect (to highlight drone when present) but it was certainly unpleasant to be working in the cold to change out parts!

BrianLG35C

iTrader: (2)

Yes, especially too old for my current boomy, droning exhaust. I would love to see/hear the combo as you suggested, but I wonder if there's a big enough market for it.

Thanks again Raj.

rcdash

iTrader: (18)

The V2 does a good job getting rid of the "boom" but it is not quiet when you apply the throttle - not like stock (what I remember of stock). The V2 is MUCH better sounding than the evoTT and also significantly better than the FastIntentions exhaust, both of which have killer drone (worse with the evoTT). The other large MD prototype mufflers actually are similar to the FastIntentions as I recall. They sound good, but still have that nasty low rpm drone, expecially in cold weather.

A combo (V3!) would be ideal for a quiet performance exhaust. Tony hasn't said he will or won't work on a "V3" and I think he is concentrating on the V2 release right now. I will probably order the V2 - it is the ONLY system that minimizes drone that will work well for FI (MD needs to release the 3" primaries also though for the XYZ). If MD comes out with something even quieter, then I will probably buy that also. I think the V2 will resell easily if I buy the combo (V3) design. Not sure about the V1 though - need to find a young kid that likes it super loud.