[tigwelder06]

i want to build a custom exhaust for my bike, im wondering if there are different types of torque cones and if they are always needed if i dont put any baffles in...

[SPORSTERBOY]

Cones Are A Must If Your Run'n Strait Pipes, They Create The Extra Back Preasure You Need. Wraping Your Pipes Is Also Good For Extra Horse Power. They Don't Come In Differn't Sizes, Pretty Much A Universal Piece For Big Twins ,and Sportys. I Run Cones In Mine And Can Tell The Difference. DON'T FORGET TO POST SOME PIC'S OF YOUR WORK.

[tigwelder06]

i will once i can scrounge some money for em, i got an 81 harley FXS with drag bars and an edlebrock carb and im trying to think of a good design on them, im thinking something short and simple... still working on a good design tho, im definetly thinking of going with the black look on em, i know its a dumb question but what makes the pipes black? i like the look of black pipes wrapped up. also where could i get some exhaust flanges for em?

[SPORSTERBOY]

J&p Sells The Rap For Like 45 Bucks For 50', If You Want Cheap Paint, Go To Wally-world, They Sell High Temp Black For About $2 A Can. If You Have The Old Pipes Just Re-use The Old Flanges. Prob. Be Cheaper To Go To The Muffler Shop And Get Some Bent Up Pieces. Buying A Kit To Do It You Could Just Buy New Pipes For The Same Price. You Could Also Just Hack Up The Old Pipes. DON'T FORGET THAT YOU'LL HAVE TO RE-JET RUN'N OPEN PIPES YOU CAN ALSO LOOK AT DEMON'S CYCLE INC. ONLINE THEY HAVE THOSE CONES FOR 9.99. I'VE GOTTEN ALOT OF STUFF FROM THEM ONLINE. 110% SATISFIED.

[ringo912]

Torque cones as they are commonly called, are really Anti-Reversion Cones. In the theory they are designed to reduce the amount of reversion in a straight drag pipe. Many things are going on inside an exhaust system and manufactures have spent millions on R&D to fine tune exhuast systems.

Reversion is when the exhaust gases are sucked back into the engine on the intake stroke. The piston comes up to TDC on the exhaust stroke pushing the exhaust gases out. The piston then starts back down for the intake stroke. At this point the exhaust valve is closing, but before it is totally closed the intake valve is starting to open. Cam overlap controls the length of time and the amount both valves are open. So for a split second both valves are slightly open. This is when reversion happens and the exhaust is sucked back into the cylinder to mix with the fresh fuel and air.

As I said many things are going on in an exhaust system. Sonic pulse is a big contributor to reversion. Sonic pulse works just like the shock wave from a bomb. You've seen videos of a bomb going off and you see the shock wave traveling outward at a high rate of speed from the center of the explosion.
The smoke or exhaust gas from the bomb travels upward at a lower rate of speed. This is what happpens in your exhaust, but becasue there is only one exit point, the exhaust port, the gases have to follow the sonic pulse to escape.

When the engine fires and the exhaust valve opens you get a soonic pulse that travels at 1300-1500 feet/second down the pipe. This is followed by the exhaust gases traveling at 300-400 feet/second. When the sonic pulse exits the pipe it starts to swirl and curl back towards the open end of the pipe, kinda like the turbulance on the wing tip of a plane. Becuase it is traveling much faster than the exhaust gases, it pushes the exhaust gases back towards the engine.

The only way to considerably reduce reversion is to disrupt the flow of the sonic pulse and slow it down. The only way to do this is with some type of baffle. In theory, the ARC is designed to accelerate the speed of the exhaust gases when they exit and to stop them re-entering the engine when the sonic pulse pushes them back. They are not designed to create back pressure. You might get a little increase, but not enough to notice when you ride. I have used them on two different sets of drag pipes and couldn't tell a difference with or without them. But that's just me.

If you dead set on drag pipes, I would install a set oF Big City Thunder baffles. You will get the sound of a wide open pipe along with a nice increase in performance. Or you can go old school and weld a washer to the end of a bolt, drill a hole in the bottom of the pipe and bolt it in. You can rotate the washer and bolt to adjust the amount of back pressure.

Hope this helps and post some pics when you get the pipes done.

[whacker]

I put some AR cones on my 75 sportty,I have baffled drag pipes,and I noticed the differance...what an improvment,I highly recommend them....

[ringo912]

I would agree they work better with a baffle, but I didn't notice much difference if any using them without a baffle. The baffle is the key to creating back pressure. The AR cones reduce the reversion which reduces the amount of exhaust gases that re-enter the cylinder. Less exhaust gases mixing with the fresh fuel and air allows for a cleaner and more efficient burn on the next power stroke. JMHO

[hotroadking]

If you are not going to run a baffle in the pipes then consider putting in a lollypop which is a screw with a flat washer welded to the end of it double nutted One inside one outside through the hole a baffle would mount itwill create the backpressure you need to keep power up on the bottom

[SPORSTERBOY]

everybody keeps talkin about these lolly pops, guess I'll make some up and give 'em a spin and let ya know.

[voodoochild]

I'm sure they'd be a snap for you considering your talent.....