Rebuilding the DF exhaust system

jirwin

Goblin Guru
I held the ZZP ultra quiet resonator up to the end of my system and it noticeably quieted it down. Nothing super duper dramatic, but noticeable. Seemed to get rid of some of the deeper tones. I wasn't able to rev it and hold it there to fully test it, but I'm confident it will at least quiet it down from where it is now.

Also did some tests with a spectrum analyzer app on my phone about 5 feet from the exhaust. Its interesting to see the difference:

No ZZP
46856


ZZP
46857
 

Dsteinhorst

Well-Known Member
Josh, that does sound good!

There's another user here that did something similar, but I'm in the middle of mockup for my new system.

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I'm going for quietness, so I have a second stage as well.
 

Rttoys

Goblin Guru
That does sound good jirwin. Nice low tone. Drove to a coffee and cars last weekend. The flow master is a good bit quieter and a better tone. :cool:
 

Rttoys

Goblin Guru
Autocross got cancelled last month (stupid 6” of rain), so I’ll have to wait till next weekend for an official db level, but the new exhaust is much quieter. Even if it’s not much quieter in actual db, the tone is lower and more soothing. :cool:Plus, it burned in nicely
47416
 

Rttoys

Goblin Guru
I need to find my db meter so I can test all the combinations. Unless this one is a noticeable difference in tone and volume, I’m going to run the flowmaster one at autocross first. I mostly want the straight one just to be different than others. Gotta be different
 

Rttoys

Goblin Guru
Quieter, but hard to tell how much without real numbers and my stock Df one has been broken apart internally for over a year now, so I have gotten use to the sound. The tone is deeper and driving down the road, it’s much less noticeable than stock. Next autocross I should have real numbers for you. Currently, near full throttle or full throttle, it’s reading 103db as per SCCA measuring. I hope to have a number on the flowmaster at the next autocross in a couple of weeks.
 

Rttoys

Goblin Guru
I really need shorter shift cables. It looks good though. 4# lighter than stock, but 6db louder too.
IMG_8693.jpeg
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