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Technical Forums => Twin Cam => Topic started by: Finn on March 18, 2020, 10:19:05 PM

Title: 103 Supertrapp Supermeg 2-1 - amount of discs?
Post by: Finn on March 18, 2020, 10:19:05 PM
What is the amount of discs you typically use on a 103? This is with closed end cap.

If I recall correctly Supermeg is delivered with 20 discs and I would need to know if I need more for approaching workshop and dyno session.
Title: Re: 103 Supertrapp Supermeg 2-1 - amount of discs?
Post by: Hillside Motorcycle on March 19, 2020, 04:08:13 AM
Bring extra with you.
We have seen even our High Output 80" Evo's in the 28-30 plate zone
Title: Re: 103 Supertrapp Supermeg 2-1 - amount of discs?
Post by: Finn on March 19, 2020, 04:27:56 AM
I'll tell them to order an extra 12-pack of discs to start with. Thanks!  :beer:
Title: Re: 103 Supertrapp Supermeg 2-1 - amount of discs?
Post by: scoopfraser on March 19, 2020, 05:10:20 AM
It might be worth having an extra closed end cap that can be drilled for the air/fuel probe as well.  If you end up running more than ~26 discs you'll need some longer screws (#12-24 aka 3/16-24 cap screws).
Title: Re: 103 Supertrapp Supermeg 2-1 - amount of discs?
Post by: kd on March 19, 2020, 05:58:03 AM
It will also depend on the size of the discs (3", 4" or more ?).  SuperTrapp's "tuning manual" states that the open end cap has a value of 8 to 12 discs. I suspect that would depend on engine displacement, cams and compression effect.  A while back (2 years?) someone on this site mentioned that their testing or measurements gave a value of 3 discs to a 3/16 " lock washer between the discs.  The spacing is very close between the discs when mounted as directed by SuperTrapp.  I was hoping to do some dyno testing with my Burns pipe fixture but that's on hold now with this virus epidemic. I wouldn't go to the dyno without enough components to go the full distance if necessary.
Title: Re: 103 Supertrapp Supermeg 2-1 - amount of discs?
Post by: Deye76 on March 19, 2020, 08:35:12 AM
The 2004 bagger I had, 113", 10.5:1 CR, 13 discs open end cap.
Title: Re: 103 Supertrapp Supermeg 2-1 - amount of discs?
Post by: Hillside Motorcycle on March 20, 2020, 04:31:59 AM
In some cases, an open end cap is needed.
Yeeears ago, Supertrapp shared their drawings with us for the XR baffles.
We replicated those on a couple bikes.
Low end torque loss, but exposed the hidden hp, for which was the intent of their design.
Title: Re: 103 Supertrapp Supermeg 2-1 - amount of discs?
Post by: Deye76 on March 20, 2020, 05:38:44 AM
I was surprised, this one I referred to, didn't do to bad for the cam used (not considered a TQ cam) was only 186psi CCC. Broke 100tq around 2250rpm. Was in a bagger. The ST did better than the Thunder Header that was on it. The SAE version was 2 tq & 3 hp less.
Title: Re: 103 Supertrapp Supermeg 2-1 - amount of discs?
Post by: Hillside Motorcycle on March 23, 2020, 04:34:22 AM
Quote from: Deye76 on March 20, 2020, 05:38:44 AM
I was surprised, this one I referred to, didn't do to bad for the cam used (not considered a TQ cam) was only 186psi CCC. Broke 100tq around 2250rpm. Was in a bagger. The ST did better than the Thunder Header that was on it. The SAE version was 2 tq & 3 hp less.

SAE averages at best that. :up: :up:
Not the 15-20% of Greek mythology/sewing circle lore.
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