I have a Supertrapp 2 into 1 system on my 1994 FLHTC U.

It's fitted with 12 discs and a closed end cap.

Seems to me that that give quite some backpressure and therefor possibly some unwanted heat?

I can fit and open endcap and do away with the discs alltogether.

Yes it will make more noise but if I adjust the carb to suit, I imagine it will run cooler?

Is that right?

And will I notice a difference in performance, be it good or bad?

Your vieuws are greatly appreciated!

 

Hi from across the North Sea! I also have a Supertrapp, which you can see in my sigpic - it's an excellent choice and can give great performance. I have a closed end cap plus all the discs it came with (I've never counted them), but I also have an S&S 107" engine. Yes the closed cap will be giving some back pressure, which is good. It's unlikely to be causing any problems whatever as far as 'heat' is concerned.

The only adjustments should be done on a dyno IMHO, where the effect of any changes can be seen. Frankly I would leave it alone. Your neighbours will not take kindly to you fitting an open end cap, nor will your ears!

 

I had the Supertrap on a Yamaha sport bike. It's designed for CV type carbs that need a little back pressure as I understand it. I rode it hard for a few years and heat was never an issue. To get the best power you probably need to get the bike on a dyno. It seems to me to be a waste of the benefits of the Supertrapp to pull those disk out. Supertrapp is a great exhaust system for certain applications. Also, on the Yamaha, the sound was the same disk in or disk out due to some baffles in the pipe.

 

http://www.supertrapp.com/resource/faqs.asp

Lots of good info.

 

An open end cap is worth about 10 discs so in theory you should basically be in the same position that your currently in. I run the 2-2 system and have 10 discs + an open end cap on each pipe.

 

I have had this 2/1 on my FXRp since 1990.

the 80" FXRP has milled heads and a cam.

CV carb

My bike is lighter than yours, but geared 15% higher ( 61T rear pulley).

my usual disk count is 18 closed cap...which is about equal to 8 disks and a 1.5" open cap.


The beauty of the Supertrapp is that you can change disks your self and feel the difference.

as ST suggests, try changing 3 disks ( add or subtract) at a time until you find the "right" response...then fine tune within that range.


on my touring bike ( 09 with ST's ) I will add a couple of disks when touring ( more HP) , & take them back out when back home and city riding ( more torque)



mike