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p-p
08-20-2007, 01:50 PM
Hi,

I was told by bshulz that an open end caps flows for 8-10 discs.

I found on the Internet a dyno diagramm where I could see that the power increases a lot with more discs.

http://www.nrhsperformance.com/tech_supertrapp.shtml

http://img156.imageshack.us/img156/678/supertrappdiscs606706czo6.png (http://imageshack.us)

It is ok until now. I understand well !!! But it is always spoken about horsepower and not about torque. I don't know how you ride but what I use the most is the torque at 3000 rpm and not horsepower at 5000 !!!

My questions are :

- what is the difference between 18 discs with a closed end cap and 8 discs with an open end cap in terms of power and torque ?

- Does the open end cap make loose torque at mid range to win power at top end ??

bschultz
08-21-2007, 07:52 AM
Hi,

I was told by bshulz that an open end caps flows for 8-10 discs.

I found on the Internet a dyno diagramm where I could see that the power increases a lot with more discs.

http://www.nrhsperformance.com/tech_supertrapp.shtml

http://img156.imageshack.us/img156/678/supertrappdiscs606706czo6.png (http://imageshack.us)

It is ok until now. I understand well !!! But it is always spoken about horsepower and not about torque. I don't know how you ride but what I use the most is the torque at 3000 rpm and not horsepower at 5000 !!!

My questions are :

- what is the difference between 18 discs with a closed end cap and 8 discs with an open end cap in terms of power and torque ?

- Does the open end cap make loose torque at mid range to win power at top end ??

There is no difference.
No.
In a street application the open end cap offers you more sound and the use of less discs.

p-p
08-21-2007, 01:03 PM
Thanks a lot for this answer ! It was a very good idea to open this forum !

bschultz
08-21-2007, 01:20 PM
Thanks a lot for this answer ! It was a very good idea to open this forum !

Thanks, appreciate the feedback.

CAPTNAVYRET
08-25-2007, 06:46 PM
I am a little confused. I am running a V5 on a 2007 VRSCDX with a dyno'd PCIII. The bike is running well with 12 discs and no endcap. The chromed outside "show piece" gets sooty after 50 to 60 miles indicating a somewhat rich mixture. My question is should I try adding a disc or two? Or leave well enough alone?

bschultz
08-27-2007, 07:53 AM
I am a little confused. I am running a V5 on a 2007 VRSCDX with a dyno'd PCIII. The bike is running well with 12 discs and no endcap. The chromed outside "show piece" gets sooty after 50 to 60 miles indicating a somewhat rich mixture. My question is should I try adding a disc or two? Or leave well enough alone?

Before adding discs we would suggest checking with your tuner regarding mapping. The intake on the V-Rod is pretty restrictive and may cause a rich condition also.

p-p
08-28-2007, 02:32 PM
Another question about open or closed end caps on internal discs systems :

I have the feeling that the response when I open the throttle is slower with the open end caps than with the closed ones..

I am dreaming or is it possible ??

bschultz
08-28-2007, 04:03 PM
Another question about open or closed end caps on internal discs systems :

I have the feeling that the response when I open the throttle is slower with the open end caps than with the closed ones..

I am dreaming or is it possible ??

Yes it's possible, if you are running the same amount of discs.
The open end-cap is equivelent to more discs.
Generally speaking;
More discs, more flow, more sound, more top-end...leaner running
Less discs, less flow, less sound, more low-end...richer running

p-p
08-29-2007, 04:05 PM
No no, I don't have the same amount of discs. I had 21 discs in each muffler with closed end caps and i have now 12 discs with open end caps. I took 9 discs away...

CAPTNAVYRET
08-29-2007, 07:35 PM
Before adding discs we would suggest checking with your tuner regarding mapping. The intake on the V-Rod is pretty restrictive and may cause a rich condition also.

The bike was tuned by an "certified" PC service center. The bike was tuned with no end plate in place. If I leave all 12 plates in place and add the endplate, should I have a very poor running machine...very rich?

bschultz
08-30-2007, 07:54 AM
No no, I don't have the same amount of discs. I had 21 discs in each muffler with closed end caps and i have now 12 discs with open end caps. I took 9 discs away...

On the internal disc system, with 3" discs, the open end cap is equal to the flow of 6-7 discs (9-10 on the 4" systems). You may want to try adding a couple of discs (w/open end-cap) and see if the seat of the pants feeling comes back.

bschultz
08-30-2007, 07:57 AM
The bike was tuned by an "certified" PC service center. The bike was tuned with no end plate in place. If I leave all 12 plates in place and add the endplate, should I have a very poor running machine...very rich?

Adding the "closed" end-cap will restrict the exhaust flow and should cause the machine to run richer and will most likely affect performance.

CAPTNAVYRET
08-30-2007, 09:01 AM
Adding the "closed" end-cap will restrict the exhaust flow and should cause the machine to run richer and will most likely affect performance.

As a "rule of thumb," if I need to put the endplate on to i.e. pass state inspection, how many discs should I remove to be equivalent to the open end with 12 discs?

p-p
08-30-2007, 02:24 PM
On the internal disc system, with 3" discs, the open end cap is equal to the flow of 6-7 discs (9-10 on the 4" systems). You may want to try adding a couple of discs (w/open end-cap) and see if the seat of the pants feeling comes back.

Tanks, I will try with 14 or 15 discs and open end cap !

CAPTNAVYRET
08-31-2007, 10:46 AM
Yes it's possible, if you are running the same amount of discs.
The open end-cap is equivelent to more discs.
Generally speaking;
More discs, more flow, more sound, more top-end...leaner running
Less discs, less flow, less sound, more low-end...richer running

What is the equivalent in discs when one uses the endcap? If it is equivalent to 10-12 discs on the 5" system (V5), it would seem to me that if an open system with 12 discs was a tad rich that a closed system (endcap on) with 8-10 discs should work a little better (slightly leaner). Now Sir Guru, am I all wet or ??? :):)

p-p
08-31-2007, 11:42 AM
Tanks, I will try with 14 or 15 discs and open end cap !

I tried with 15 discs and open end caps. It works great !!! I don't know if it is possible to do better, but I won't try !!!

Thanks a lot Bschulz for your help !!

bschultz
08-31-2007, 01:22 PM
What is the equivalent in discs when one uses the endcap? If it is equivalent to 10-12 discs on the 5" system (V5), it would seem to me that if an open system with 12 discs was a tad rich that a closed system (endcap on) with 8-10 discs should work a little better (slightly leaner). Now Sir Guru, am I all wet or ??? :):)

More discs, more flow, more sound...leaner running
Less discs, less flow, less sound...richer running

DavidHD
09-24-2007, 02:33 AM
Hello!:

p.p. your tests is great help for me. But I have one cuestion for Guru. Appears p.p find the best performance with 15 discs and end cap open. Its the same for TC96 on Street Bob? I want in my bike the best torque. I understand the recommended conbination is 12 discs and end cap openned?

Thank you very much.

p-p
09-26-2007, 03:29 PM
More discs, more flow, more sound...leaner running
Less discs, less flow, less sound...richer running

If I understand well :

- more I add discs, bigger should be the main jet ?

- less I have discs, smaller should be the main jet ?

A friend of mine tells that it is the opposite. He tells that if you open the pipes, you have to put a smaller jet... :eek::eek:

bschultz
10-17-2007, 08:21 AM
Most likely.

DavidHD
12-14-2007, 07:57 AM
Hello Guru:

You understand my cuestion? I'm sorry if my language is no good in english.

Please take a minute for response and I have thank to you for the rest of my life.

V's


Original cuestion:

"Hello!:

p.p. your tests is great help for me. But I have one cuestion for Guru. Appears p.p find the best performance with 15 discs and end cap open. Its the same for TC96 on Street Bob? I want in my bike the best torque. I understand the recommended conbination is 12 (24 in too muffers in total) discs and end cap openned?

Thank you very much."

bschultz
12-18-2007, 07:41 AM
Very likely.

DavidHD
12-19-2007, 04:05 AM
Thank you very much.

Best regards.

bschultz
12-26-2007, 07:54 AM
Most likely.