View Full Version : VRSCDX Night Rod with FatShots 2:2 Performance

01-01-2008, 02:29 PM
Hello Everybody.
I’m just new here, I’ve taken a look to some threads over here and I noticed very quickly that this is a great discussion forum…congratulations guys.
First of all sorry for my bad English…I’m from a wonderful Mediterranean Island called Mallorca, If you have a change to visit it….just do it, it is a nice place to ride…
So, let’s start…
I got a 2007 HD VRSCDX Night Rod Special, I have it since last May and four moth ago I decide to replace the originals mufflers because the noise was not as I like it (you know what I mean, right?) so I set up, in my official HD dealer, a Supetrapp FatShots 2:2 #827-71134 mufflers 6 disc each, closed end caps, as well as a ScremEagle air filter covered (not topless).
After install mufflers, HD dealer suggest to me buying the EFI race tuner kid to adjust the bike to the new mufflers set up, they made themselves that adjustment and honestly I get a little disappointed because the sound was not as lauded I expect, as well as I noticed a loose on torque terms. Regarding power I have not had the chance to check it, supposedly should be increased…
My questions are:
Are torque, power and loudness compatibles wit these mufflers?
What I can do to have a good HD sound and SAME torque response as I had with the original mufflers?
Do you thing is because the EFI race tuner configuration can be improved? If yes, do you know where I can find any MAP .mt6 based on my set up?
Applying extra disc or removing some of them can help me to manage?
How about apply open end caps?
That’s it…..so many questions…sorry….
One more time…congratulations…
Thanks in advance:

01-02-2008, 07:50 AM
Sorry, I was wrong...:D:D:D I got 10 disc each muffler, plus closed end cap.
I've attached a pic for better reference.

Any advice will be welcome.


01-02-2008, 08:39 AM
We acheived the best results with 8-10 discs on a stock machine (see attached dyno chart). More air (freer flowing filter) and more fuel (race tuner) should need more exhaust flow (more discs). Check with your tuner, there is much more power there to be had.

Dyno chart to follow.

01-02-2008, 11:32 AM
Thanks bschultz.

Sorry but I cannot see any attached dyno chart...;)


01-02-2008, 12:40 PM
I have made two open caps in an improvised way…I set up them with 9 discs and the result is much more better, I get more or less same torque as the stock ones and also better loud sound, which is great for me.
Do you think removing the cover air filter will even improve?
You also say to encrease fuel, actually before this modification I had some soot, can be it caused because the map already was generously fueled?

01-02-2008, 02:43 PM
Yes and yes, however you do NOT want to get into a lean condition. Your tuner should be able to provide you with your air/fuel ratios at various rpms.