I have a supertrapp supermeg 2:1 on my '16 low rider S - 110se motor. I was dyno tuned and only got 88/106 out of it. I am seeing many reports of people with other pipes getting upwards of 100/120 (some unusual cases, more) so I feel like I'm leaving a lot on the table.

Unfortunately the tuner(s) - I've been to two - never messed with the number of discs. The benefit of the supertrapp is you can adjust it for maximum power.

I've also heard conflicting comments on the pipe, that it's excellent on the 110, and another said its a lower performer on the 110.

Right now it's running closed end at and 20 discs.

Any experience with this pipe and larger motors? Should I try added information or removing discs? I know it'll have to be a butt dyno test until I can get it retuned if I feel any real improvement.

Or am I better off just tossing it and getting a Bassani RR2 R1?

Thanks.

 

I have a Supermeg on my S&S 107" and am getting just over 100/100, plus a wonderfully smooth wide torque curve. It has all the discs it came with and a closed end cap, is reasonably civilised for noise. I'm a very happy bunny! You're not so very far from HDF sponsor Scott of Hillside Cycle. I suggest you give him a call. If he can't release the potential in your engine, there is no hope for mankind!

 

I've been running SuperTrapp type exhausts for years. I currently have a Fuel Moto E Series 2-1 on my FXDLS. 20 Discs sounds like a lot. Is that what it was shipped with? When you add discs you basically lower torque and raise the sound level and top end and visa versa. My E Series came with 14 discs and that was plenty enough to get 123 hp and 125 ft lbs of torque, but then again I run a 117 ci motor. I woudn't get too wrapped up in numbers on a piece of paper, some dynos are "happy" as they say and some not. I would go more by the seat of the pants dyno, does it run well? Does it idle well? Is the acceleration smooth up to the limited or does it fall flat at some RPM?

 

Shoulda' gone with a D&D. Kaboom!

 

I've had the D&D Fat Cat, good exhaust but that one can't be tuned. I also prefer the sound of the disc style mufflers over it.

 

I spoke to FM about that. The E series has a wider output (oval - more surface area) then the supermeg, so each disc allows more flow. So its unfortunately not an apples to apples comparison when it comes to disc count. Supermeg said 20 is where it should be with the discs on my motor. But then again they said the same thing about my 103...

I agree on the happy dynos, but 10 ftlbs is a little too much to give up on imo.

Re the curve: its pretty good, just a little lacking imo. See below.

Problem with the fat cat is that it will supposedly fit the further forward controls on the S, but there are a fair number of instances of it not. So It's a gamble I didn't want to take.

 

Yes the E Series went to Eliptical discs and I'm sure that effects the flow. The SuperTrapp Fatshots came with 10 discs and an open end cap. The open end cap was worth 10 more discs for your 20 total I'd surmise. The is also normally a 10% error on the upper end of the dyno charts I'm often told which would add 10% more to your numbers. That's why I go more toward the seat of the pants dyno more than numbers on the paper.

 

True enough about the error factor, but I am seeing the vast majority over my results, and only one with a couple less. So I am still leaning towards having room for improvement. I was hoping to do some experimenting this weekend, but its f'n raining both days. So hopefully Monday.

 

When I had my 12 RGU, it was tuned by Doc. Granted it's a 103, but he went up to 27 discs before the torque fell off. The hp was really didn't change to much from 22 disks up, maybe 1 to 2 hp. I wouldn't get caught up with the numbers game. Doc went back to 26 disks, and called it good. Every bike is different, I believe they ship with 18 disks. Pull a couple of plates out and try it, or add a couple, you'll feel a difference. It's up to you how you want the bike/motor to respond vs noise levels. Don't forget to lube the bolts with ant-seize. Adding a lot of discs will lean out the tune, you may consider that also.

 

Plus 1 on this. I always made sure those long skinny allen heads had a good share of anti-seize.