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Discussion Starter · #1 ·
Dynomax VT's = Drone killers!

I'm looking for the quietest mufflers to work with my obnoxious o/r x-pipe (BBK) & using the original cat-back routing being FlowMaster American Thunder...then I direct swapped in Borla ProXS mufflers....seemed better at first but still not good enough for the boss. I noticed the VT's are 2" longer(16") and 1/4" deeper (4.5") than the Borlas (14"/4.25")....does it make sense to buy the whole cat back or just swap the mufflers AND modify the pipe inlet? I see they also offer a 14" long but only center/offset. Wonder about install difficulty between the two applications. Maybe third times a charm...I'm sure that's what my neighbors are thinking, too.
I really think the frickin bbk o/r X is to blame...but I'm committed to no smog. Not doing cats.
Also, not sure of the diff between the Dynomax VT #17159 & #17959? Like to get them ordered from Summit ASAP.

Edit: pulled the trigger on the 17159s since I have a pretty mild cam...so I'll have them running next weekend.
 

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Discussion Starter · #3 ·
difference is in flow

its clear on their website, no?
Sort of...17959 are for single exhaust over 4.0L (some with big cams use them because of stronger flapper spring to stop lope rattle/not my situation).
The 17159 are for dual exhaust...this will be my third attempt since the O/R X-Pipe was put on and all smog gutted. I'll have em tomorrow and install Saturday. 2" longer than my Borla ProXS's which only have a few thousand miles.
 

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Discussion Starter · #6 ·
Please report back when you get them installed, I would like to hear your opinion on how they sound, and how they fit. I am also curious to know if they help will drone at highway speeds.
Oh, you know I will. I think I'll do the decibel app on my phone for a before and after. I had to cut my tailpipes between the x-pipe rear joint (which was welded to the original American Thunder Cat-Back) and the Borlas just to get my Aod out...then I used Holley couplers to mend them. I think it will be pretty easy to remove 2" there. I just need to make sure the routing over the axles stays same as stock because I still have the MM Panhard Bar to install.
 

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I'm looking for the quietest mufflers to work with my obnoxious o/r x-pipe (BBK) & using the original cat-back routing being FlowMaster American Thunder...then I direct swapped in Borla ProXS mufflers....seemed better at first but still not good enough for the boss. I noticed the VT's are 2" longer(16") and 1/4" deeper (4.5") than the Borlas (14"/4.25")....does it make sense to buy the whole cat back or just swap the mufflers AND modify the pipe inlet? I see they also offer a 14" long but only center/offset. Wonder about install difficulty between the two applications. Maybe third times a charm...I'm sure that's what my neighbors are thinking, too.
I really think the frickin bbk o/r X is to blame...but I'm committed to no smog. Not doing cats.
Also, not sure of the diff between the Dynomax VT #17159 & #17959? Like to get them ordered from Summit ASAP.

Edit: pulled the trigger on the 17159s since I have a pretty mild cam...so I'll have them running next weekend.
I'm running dynomax ultraflow with bbk off road x, doesn't seem loud to me that's with a stage 1 cam. my friend cobra sounds Hella loud compared to my car with Flowmaster 44.
 

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I have the Dynomax VT 17159's on my vert with BBK shorty headers, off road H-pipe with high flow cats welded in. There is ZERO drone on the freeway. I'm talking NONE. With the flowmasters I had before I could not hear my passengers talking to me or the stereo. Now I can carry on a normal conversation in the car on the freeway at 60 or 70MPH with no problems.

Chris
 

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I have shorty headers, off road h-pipe, full tailpipes and switched from dynomax super turbos to dynamax VT's. The drone cruising is gone, idle volume is about the same, pretty quiet, the VT's are louder when you get on it.
 

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Discussion Starter · #10 ·
Last cruise decibel reading before swap.

So tomorrow morning I'm going to have the Borla ProXSs out and replaced either DynoMax VT's...went for a drive with the DB meter app and anything in the drone zone is measuring mid 90's with peak readings near 100db...convertible's suck loudly ?. This is with the windows up and top secured in coupe mode (always felt the car was quieter with the top down), lower rpms in the 80's range which to me is tolerable...don't care how accurate the reading is, just want to compare to the same scale...to be continued...
 

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Discussion Starter · #11 ·
Couldn't be happier!

The verdict is in and I think this swap may have been the best thing I've done to the car. I swear the drone zone 2k-2.5k rpm is now quieter than the previous quiet rpm zones.
Borla ProXS sound range measured: 89db to 98db (mostly 94-97db).

DynoMax VT's sound range measured: 66db to 79db (mostly 70-74db).

ZERO DRONE BUT NOT QUIET...Very healthy sounding. Maybe not such a big deal with a notch or hatch, but this convertible owner is very happy!



h
 

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Discussion Starter · #13 ·
Thank you for following through and taking the time to get actual data.
That is a pretty serious drop in interior sound.

And....where did you get that diff cover?
Cover was bought @ LMR for $146 less our forum 6% discount...part #M4033K...Steeda sells it too. It's the GT500 model through 2014 I believe. Back to the DynoMax VT's, it may have saved my marriage LOL. I just wrapped up a Wide Ratio AOD with a good higher stall converter and made the Borlas way worse. The VT's are real loud when getting on it, too...but only when I want it loud.
 
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