On my 2008 Street Glide, I just put on a set of Mutazu 4" slip-ons which replaced a set of Python pipes (which were on the bike when I bought it). Thought I would take a chance on these very inexpensive pipes.

Pros:
1. Love the looks, they have black tips.
2. Really love the sound. Deeper than the pythons and perhaps a shade bit softer at highway speeds.
3. Pick up some upper RPM horsepower.

Cons:
1. The pipes must be freer flow than the Pythons, because I have lost a ton of lower RPM torque.

My bike was dialed into the Python pipes, apparently by the previous owner. I could roll on the throttle around 2000 RPM and the bike would take off. NOT NOW.

ISSUE: I like the looks and sounds of the new pies but I WANT MY TORQUE BACK.

I just order a Dynojet Power Vision. Question: With the Dynojet, will I be able to dial back in most or at least some of my low end torque?

In October I will be adding an S&S 107 Big Bore kit and S&S 551 Easystart Cams that will probably resolve any torque issues. But until then, I am hoping to get some torque back. Any suggestions (or maps) to resolve this issue would be appreciated.

 

Take it to a respected tuner. He can bring some of the loss back and make the bike run better for sure.

I don't know anything about the target tune for the PV. Mine was tuned with a TTS. There is no replacement for a proper dyno tune though

 

Mutazu has been selling those knockoff CFR style pipes since CFR began raping folks with them eons ago. There are countless threads about the torque loss, but in the end most folks either love the sound enough to tolerate the power loss, or they switch to a decent exhaust. Torque cones, baffles, inserts..... Take your pick. Personally, sound trumps torque, but that's just me. You CAN have a tuner with a dyno get it as good as it gets.... But in the end, giant megaphone mufflers are never gonna perform like a proper exhaust.

 

Got my Dynojet Power Vision tuner yesterday and today I flashed in a new tuning map that helped regain some of the torque I lost with the new pipes.

I am heading to Sturgis in a couple of weeks, so we will see how everything works on the open road for 2000 miles.

In October, I will begin the big bore rebuild.

 

More info on the Mutazu pipes and the Power Vision flash tune.

I took the bike out for 100+ mile ride this afternoon with the purpose of seeing how the bike responds in a variety of riding situations (rode Ozark twisties and Interstate. I also wanted to see what the gas mileage would be.

The torque was back and very usable from 2000 rpm up. Still not as much roll on power at 70 in 6th, but not horrible. The big plus was gas mileage. Before, with the python slip-ons and the tune that came with them, I was only getting 36-37 mpg in varied road riding. This afternoon, with my Mutazu slip-ons and the new tune from Power Vision, I got 41.5 mpg., which is about a 15% improvement. I can live with that.