I have done lots of reading on these threads and others, as well as talked to the service people at my closest HD dealer. I have 4" Rineharts with stock headers, high flow air intake and remap. I am still not getting the sound I want, and I'm leaning more towards changing the headers than cutting out the cat converter from the stock headers. I have read that true duals causes some loss of power in the low end due to lack of back pressure, so if I was going to get the Rinehart headers that would lead me to get the slims rather than the true dual setup. Is this thinking correct? Have others noticed this power loss when switching to true duals? I don't think I will ever go as far as to start going into the engine to change cams, pistons, etc.

 

I did the freeze plug mod on my 06 ultra stock exhaust and did not notice any massive low end power loss. I could not feel any difference in the seat of my pants. I do have a Power Commander V with autotune. The difference in sound was incredible though. Awesome at idle and even better through the rev range.

I ended up buying Cobra true dual headers because the 90deg bend on the rear cylinder bothered me. I couldn't tell any performance difference with the radius bends either. They look better too.

Exhaust mods are easily reversible if you decide they're not for you.

 

Doubt it'll be enough for you to notice

 

If all you do is stage 1's (non-racing) from stock you will not notice. The Heritage comes with the true duals and I put on the Rush slips and a dyno tune, I not only did not notice but would say I got more, no doubt more from the tune.

Even in my car days going true dual straight pipes in cars I never noticed, however they were more for racing setups.

I doubt no matter what you do you would notice, maybe you would see it on a before and after dyno tune, but even then with a slightly different than stock I still doubt it would show.

 

Have true duals on my 02...no noticable difference.

I have the same setup on my 12 RK (Rineharts and SE intake)....going to the de-catted head pipes.

I do have a fuelmoto micro-tuner with 2 extra maps installed. One I am using now for the present setup and one for future de-catted head pipes. (probably not much difference in the tunes) Have to unplug the o2 sensors.

runs great...looking forward to the head pipe swap. Not expecting much of a change as far as bottom end is concerned.

 

Put true duals on my 07 street glide after the rear exhaust manifold cracked.

Noticed I needed to slip my clutch more when getting underway.

Did not notice a big difference in power, as the true duals were much louder and it sounded more powerful, but did notice a reduction in torque when pulling away from a stop.

 

true duals can help with power at 6000 rpms.

what rpm range do you spend most of your time in.

the reason why a 2/1/2 or 2/1 provides better power is scavenging- which you can look up, the internet explains it better than I have time.

I guarantee you the post above about cars the guy didnt have a separate exhaust pipe for each cylinder- and every v8 out there not only has the 4 cylinders connected on each side, for scavenging- and all stock v8's have the cylinder banks connect down by the tranny.

interesting comment above about the Heritage- i don;t know my way around softail models very well- but I do know that some models use(d) a hidden interconnect to allow scavenging- part number 66737-10A- it looks like a brace, but carries exhaust gasses. International models may have a valve on this, similar to the valve on int'l touring models to make the pipe a 2/1 under certain conditions



Mike

 

I have the dresser duals on my CVO currently and true duals are a mod that I have done on the five bikes that I had before it. Never noticed a loss of power and got better sound with all of them. I did have tuners on them.

 

The reason most people don't notice it, is that when people go from stock to a stage 1 with true duals, they still get an increase, but just less of an increase at the lower end than with other options.

So its not so much a loss, as less gain.

I think if you went from a well tuned stage 1 with a 2-1, and changed to true duals, you'd notice the lost low end, but people rarely go that way.

 

"I think if you went from a well tuned stage 1 with a 2-1, and changed to true duals, you'd notice the lost low end, but people rarely go that way."


I shy away from true duals for this reason, the most power and efficiency is going to be had with 2 into 1, X pipe with duals, or at least connecting duals someplace before the mufflers like many factory exhausts did.


I will say that true duals certainly sound different, and most set-ups I've heard have treat "authority" to the exhaust note. This doesn't mean they make the most power. Well tuned 2 into 1 systems are the hot ticket there, at least from what I've seen with these things......Cliff