Dual Exhaust or 2 into 1 pipe on my Harley RoadKing
I have a 2001 HD Road King that I am very fond of but I would like more power out of it. A few of my friends have said that a 2 into 1 type pipe setup is the ticket for more power but I've never heard that before.
I am an old school hot rodder and you always put dual exhaust on your hot rod for more power so I figured I would ask you guys. Will a 2 into 1 exhaust increase the power on my Harley? What are the Pros and Cons? Does it increase torque and horse power??
Experienced replies encouraged....please no magazine experts.
Our Answer
Hey Rocky..love the Road King....incredible ride on that bike and definitely old school cool. I will tackle your question the best I can but still be succinct about it.
A 2 into 1 exhaust pipe setup will typically show stronger torque gains at a lower RPM than 2 into 2 pipes without losing any power on the top end. If you're a hot rodder then if I were to say the torque curve is typically broader and flatter with more area under it on a 2 into 1 pipe setup than a 2 into 2. It is a very common misconception that dual pipes are the best thing for power, but it simply isn't true.
Now...that isn't ALWAYS the case. So much will depend on the tune and the build of the Harley but typically in my experience, 95% plus of the time, a 2 into 1 will outperform a 2 into 2 pipe in the torque department. Too many guys get hung up on horsepower, but a strong torque curve makes your bike a joy to ride. You can skip downshifts that other guys have to make and it just gets out of the hole and handles two up riding much, much better than stock bikes.
If horsepower is a consideration then my experience shows me that you have nothing to worry about. I will say that in the lower RPM ranges, the 2 into 2 will keep pace with the 2 into 2 and typically outperform it a small amount. When the RPM gets up to 4.5k to 5k RPMs plus, then the pipes power output tends to come together and the variation is not that different.
So to summarize...better power and torque in the low to mid range with no loss of horsepower on the top end power band is what you can expect from a typical 2 into 1 Harley pipe. I can't say enough that the tune and build can change things, but not typically and we are speaking in generalities. Me personally, I LOVE the 2 into 1 pipe setup. I am a power junkie and I love being able to walk my buddies from a stop light. That alone makes it worth it.
If you are considering a 2 into 1 for your Road King then I would give the D&D Fat Cat pipe a look, it looks great on a cruiser and performs awesome. It also happens to be the pipe that I have currently on my 2007 Nightrain with a 107" ported and cammed build. I know that it works and works well. Good Luck
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January 1st, 2009 at 2:26 pm
i would say leave the stock pipes on the bike because all that loud pipes do is piss people off.
January 4th, 2009 at 4:51 pm
I’ve always known bikes to be faster w/ dual exhaust!!!
January 5th, 2009 at 1:27 pm
truly dual exhaust is best creates more horsepower/ more fuel efficient and better sounding from 4th generation mechanic/ase certified
January 8th, 2009 at 3:57 am
two into one will help evacuate the exhaust out of the cylinder to get more good air fuel in. there for making more power. it this bike is efi you will have to get a program er to adjust for this.
January 11th, 2009 at 5:59 am
true duels will boost performance but due to decrease in back pressure will requier remapping of your fuel curve . two into 1 looks kick ass and will also open up exhaust and gonna requier remapping almost any after market exhaust means you gotta remapp
January 13th, 2009 at 6:25 pm
Go two into one for performance. The author is right…..most people think Dual exhaust are the deal because of what they think they know from the automotive world but it isn’t the same. Even in the hot rod world, those in the know, use a crossover pipe on the duals to boost low end and mid range torque.
Your bike is huge and heavy and if you ride two up then you NEED TORQUE. A 2 into 1 won’t hurt the horsepower and will improve the torque dramatically.
January 14th, 2009 at 8:58 pm
The 2-1 exhausts like the Thunderheader or the Hooker Header produce the most H.P. of the pipes available. Both torque and H.P. are increased. I run the Hooker because it has a feature that is pretty cool, adjustable back pressure. What this does is allow you to tailor the tuning to the way you ride. P.S keep in mind you’ll need to play with jetting/ computor to adjust the fuel mixture to match the pipe.
January 16th, 2009 at 2:39 pm
i have the 2 into 1 python on my harley .better performance with
the 2 into 1 way better.
January 19th, 2009 at 8:00 pm
Do the 2-into-1 for best results with your FLHR, the D&D is the best one available, grab that and a Power Commander (if you’re EFI) and you’ll be ready to rock…
I just don’t like the true duals b-cuz of that extra looped piece of pipe (its ugly, and a waste of space… and why send exhaust thru that whole extra curve anyways..)
January 20th, 2009 at 6:13 pm
You really oughta consider taking it to an experienced mechanic and checking into a Power Commander. If I wouldn’t have been fired I would’ve done it on my 2005 Harley Road King at work, but I had a feeling the Chief of Police would’ve been ticked off.
Everybody I know with a Power Commander raves about the power, check it out with some people, I don’t think you’ll be disappointed.
Any mods and exhausts changes you make will be better with this add-on too in my humble opinion.
http://discountmotorcyclepipes.com/fuel-systems/dynojet-power-commander/
January 21st, 2009 at 11:12 am
Get a 2-1 with a power commander III for the best performance. This will make a noticable difference in the way your bike performs and both are easy to install yourself or you can have it done.
You can find a great deal on the Power Commander Here.
http://discountmotorcyclepipes.com/fuel-systems/dynojet-power-commander/