I have a 2000 FXDS-Conv, so far i have a Mikuni HSR45 carb complete with Mikuni intake manifold and air box, S&S 510G cams, Revolution performance big bore kit 98ci 10.5/1 compression forged pistons, Rev stage 2 ported heads. For pipes i have vance and hines short shots that were on it when i bought it. I had a set of baffles specifically made at a local shop and they seem to work good but i dont like the sound. i prefer straight pipe sound. the bike runs great with no baffles but i know with more back pressure it could run better as i feel im probably giving up power at the low end having such short drag pipes.
So would adding torque cones and taking the baffles out be good enough for what im running?
If i got longer drag pipes (vance and hines longshots or similar) and ran no baffles no torque cones would that perform well?
Also if i was gonna go with torque cones is there a difference between ones that cost $20 vs $100?
Thanks for any info you can provide. everybody have a great riding season!

 

After spending that much on engine mods why run a cheesy exhaust? Get a decent 2 into 1. If you like loud a Thunderheader or Fat Cat will give you both power and sound. There are a lot of good ones out there. Those short shots are just not real performance pipes.

 

I agree with Northside. The Thunderheader would probably be a good choice. It's a good 'midrange' and top end pipe, which matches up well with your cam (I have the same cams). They both start working around 3,000 rpm, and the T header has a great deep roar, which is quite loud. Only thing I didn't like about the T header sound is the tendency to "pop" on decel.

 

The short shots were on the bike when i bought it and just have yet to be changed thats all, i like the way they look and the sound is great.
2 into 1 pipes are pretty pricey and i dont think they would look good on my bike, i just have always like drag pipes. Even if im giving up a little power to get the sound/look i want thats ok.
Just wanna know if im gonna have the backpressure i need running longer drag pipes with no baffles or if i should add torque cones?

 

You can also add a 1/4" bolt about an inch or so from the end of the drag pipes. Other term for this is a lollipop done with an eyebolt or a washer welded to the end of a bolt. Creates some backpressure without really diminishing the sound.

 

SuperTrapp SuperMeg.........

 

I have read about the lollipop thing i might give that a try and see what happens. Would it be a good idea to use torque cones?

 

If you're dead set on the 2-2, I would get the v&h big shots. They have that half assed power chamber for a quasi 2-1 yet keep the 2-2 sound and look. The short shots are about the worst pipes for power, if that's your concern.

The supertrapp is great, but if you're into the short shots sound, you will hate it.

I've done lots of dyno testing, the lollipop/bolt trick works to lessen the torque dip around 3k, but what works best is to take the factory baffle and cut it in half.

And you are not trying to create back pressure, you are trying to diffuse the reversion wave that travels back up the pipe. If it hits the exhaust valve at the right time, it pushes air back into the chamber, hurting power.

 

Here is what I am talking about. The graph is a bit cluttered, but it shows you how much of a difference things make. These are Rinehart 2-2 staggared pipes, same bike, same day, same jets, only changing the exhaust baffles. I also put a 2-1 supertrapp on the graph to show you the difference.

 

Thanks mrlexus. Reversion was on the tip of my tounge and I couldn't remember it. I figured if I said backpressure he'd get the idea. A lot of it has to do with the length of the wave, the length of the pipe and the peak torque rpm. I've read a lot about it on nightrider and in a book titled "How to build a Harley torque monster". I tried the lollipop with my old drags. It worked, but I eventually just gave up and went 2-1.