Instant throttle response, lots of torque, cooler running and even better fuel mileage are tops on every rider’s wish list. And whether it’s on two-wheels or three (a brief word about those trikes in a minute) the time-honored route to all this always begins with that standard “Stage I” setup, pipes, air filtration, a re-mapped ECM and, ideally, a dyno tune to cap it off. The biggest expense here, and the most important choice, is going to be that first item, the pipes. Getting that right is critical.
Pipe choices for Harleys run the gamut and if you’re just after looks and sound whatever floats your boat is going to make you happy. But getting a noticeable performance boost to go with that is something else entirely. No one system’s going to be perfect for everyone but with a little homework you’ll have a better chance finding what’s right for you, your bike and for how you ride.
“And for everyday street riding, low- to mid-range performance up to around 5,000 RPM or thereabouts, a 2-into-1 system is tough to beat,” Jamie Hanson feels. Years of tuning experience at Speed’s Performance Plus working with every exhaust configuration imaginable backs up that assessment. The reason those 2-into-1 systems work so well, Jamie says, is because they dramatically increase what engine builders call “the area under the curve,” that torque printout on a dyno sheet that builds quickly to its maximum and then stays there, relatively flat across the chart. That’s what you want for the low- to mid-range performance so useful on the street. The problem is not everyone’s in love with the look of a 2-into-1. But there are options, and good ones.
“Lately,” Jamie says, “we’ve been getting great results with those new Kuryakyn Power Cell Crushers, the connected duals for the baggers and connected 2-into-2s for the Softails and Dynas.” The crossover connection on these pipes, he says, makes them work kind of like a 2-into-1. “And the torque numbers get right up there close to what we see with a traditional 2-into-1,” he says. “And it holds. The torque’s broad and flat across the whole powerband.” It should be noted that Kuryakyn isn’t alone offering this connected head pipe configuration. Lots of other suppliers, Vance & Hines and S&S for instance, have similar designs, which should net similar results. Which brings up the second half of this exhaust upgrade, at least for a bagger. It’s the Slip-on mufflers to go with those head pipes (the mufflers in a Softail or Dyna system are generally integral). “Big, free-flowing 4-inchers are a must,” Jamie says. “Kuryakyn has Crusher mufflers to go with that Crusher head pipe, but we’ve used comparably sized mufflers from Vance & Hines and S&S with equally good results.” The final step, as always, is a dyno tune matching those new pipes and mufflers to the specific bike they’re mounted on. And it’s that last step, the dyno tune that brings us to a quick word about those increasingly popular trikes.
That same connected bagger system, at least Kuryakyn’s, will fit right onto a Tri Glide using an accessory extension for the head pipes. The trike, however, won’t fit on the dyno. “But that Crusher Power Cell comes with double-bungs for the O2 sensors,” Jamie points out, both the OE 12mm size and the larger 18mm size for aftermarket wide-band sensors. “And with those 18mm fittings already in the pipe,” Jamie goes on, “it’s easy for us to use those wide-band O2 sensors and AutoTune to dial-up a custom map that’s dyno close and making a real difference.” They’ll first build a base-map in the Power Commander V drawing on their years of tuning experience and know-how as to what works. “And from there,” Jamie says, “we'll turn on the AutoTune and let the guy ride around for a while.” When he comes back all the settings are re-checked, the trim AutoTune’s called for is accepted and any changes needed in the base map are made. “If the trike’s fairly stock,” he explains, “things go fairly easily. If the motor’s been built up a little it might take a few of those ‘accept and adjust’ sessions to get that exact tune.”
The takeaway here? On two wheels or three the right exhaust matters, big time. And for a street-ridden Harley a 2-into-1 with all that “area under the curve” is tough to beat. But it’s not impossible. Stop in and talk with the guys at Speed’s Performance Plus next time they’re local to you. Take a look at all this for yourself.
605-695-1401 – MN
605-695-2272 – SD