People have been installing just slip on mufflers and not tuning bikes for a long time now. This is not new to the M8 models. Does the ECM have the capability to keep up with just a muffler change? In most areas of the map probably. But if you do a little bit of research there is plenty of evidence that even a bone stock bike can benefit from tuning. The problem I see with all of these tuners being sold is hardly anybody uses them to tune, they load a canned map and ride the bike. The biggest advantage to having one is to be able dial the tune in on your bike. Having said all of that, you need to decide what your comfortable with on your bike. If keeping your warranty intact is your biggest concern then you should follow your installation instructions to a tee, then there is no concern weather it was installed correctly by motor company standards (not gonna debate those here) which should keep your warranty coverage intact. If you're not too concerned about your warranty then it's your bike and do what you damn well please, just educate yourself before making a decision and in my experience on this forum there is more hearsay than fact. Talk to another dealer, talk to a reputable indy, read the actual installation instructions, that is one thing I like about what Harley is doing on their website they provide a lot of the instruction sheets in PDF format. Here it is in black and white, read it and then you will know.

https://serviceinfo.harley-davidson....3?locale=en_US

EDIT: this is on the website but not in the instructions under the FITMENT tab

"Fits ’17-later Touring models. Does not fit Trike models. Installation requires separate purchase of Muffler Clamps P/N 65900012 and 65900015. Requires separate purchase of end caps. All models require ECM calibration with Screamin’ EagleŽ Pro Street Tuner for proper installation. 50-State U.S. EPA compliant."

 

I hated the idea of spending $300 on the SEPST just to have the calibration loaded so I had it dyno tuned which made a significant difference over the canned map..cost more but at least it was utilized to its full potential and the engine benefited from it

 

Is what it is. I guess I'll just do all of it and stay in warranty. Really didn't want to mess with the air cleaner or anything. Honestly, I'm actually happy with the exhaust as is, just want to be able to hear the shift points a little better on the highway over the wind noise. My speed triple was literally just a race cone with no baffle bolted to the header. Im a bit over "stupid loud" lol.

 

forgot to mention the Stage 1 AC will improve the exhaust note/tone/loudness as well..at least with the SE Hi Flow..seems the Heavy Breather adds the sucking intaking noise that some, myself included, find annoying..not sure about the Ventilator

 

No intake noise at all with that one I'm running it.

 

intake noise doesnt bother me. I quite enjoy it on cars, actually. Thanks for the advice guys, I'll just be safe and do it all I guess. Just seemed excessive and wanted to make sure it was factual info. Makes sense with a lean factory tune for emissions I guess.

 

I am using 4" V&H Eliminators, I can do the street cannon base tune and then datalog from there. My biggest problem here is not the $275 dollars for the tuner and cables that I'm going to throw in the garbage when the warranty is up and buy a Powervision, it's the fact that I am forced to do this thanks to yet another government agency that should not exist.

 

For me just slip on's, (Rinehart 45's), killed my low end torque. I had no desire to do stage 1 and still don't think it's a must for the M8 but in order to gain back the lost torque I did full stage 1 and got most of it back. I've since switched to Street Cannons and got all if not more low end back. I see the problem as more the trend for large baffle mufflers that are horrible for these bikes. I believe if you were to carefully select a slip on with baffle 1.75 to no more than 2.0 you'd be fine stock.

 

On most of the 2018 Softail M8 models, the cat is in the muffler. Most of the aftermarket slip-ons are catless, which can really mess up the VE tables and really increase exhaust gas reversion. Performance will drop drastically on the low end of the rpm scale. Baffles can only do so much, the smaller the better but most aftermarkets come with large hole baffles for sound. An SE tuner is not going to fix that, because fueling changes are basically locked and VE change is limited. You need something like TTI's to control the reversion and a PV tuner to fix the fueling.

Same thing would apply to the Touring bikes if the head pipes are changed out for catless or to a lesser extent if big baffle slip-ons are installed on stock or aftermarket catted headpipes (not sure if those exist though).

 

mines a road king, not a soft tail. I believe my cat is in the header? Regardless, I seem to have chosen a pretty solid dealer. Just seemed like an odd thing. I'll let them do all of it and not worry about the warranty. Thanks guys