Riding a 2020 Street Glide with Rinehart 4 1/2 slip on's. I am wanting to add a set of Rinehart head pipes and a free flow breather. Question is, is a tuner a must? I watched a DK Customs video that says the M8 is capable of running just fine with no tuner. I think they got am additional 1-3% gain with a tuner, but I'm not really interested in that last 1%. Does anyone know where I can find the absolute truth on this question? Link to video attached. Thanks for any help on this.

 

Slip ons alone - you don’t need a tuner.

Slip ons, headers, max flow air cleaner - yes you need a tuner.

R,
Sanjuro

 

A Twin Cam would but these guys are saying an M8 does not. Are you basing your comment on a Twin Cam?

 

Your bike your decision!

It'll run like crap at low end when you get rid of so much back pressure!

 

Is your bike still under warranty? If so, you might want to rethink your plans.

 

Yes, still under warranty and want to keep it that way. I can keep the factory warranty with a Harley tuner if it's really needed. The question is does an M8 need a tuner like the Twin Cam or can the ECU on the M8 make the necessary adjustments itself?

 

The question was answered in post #2.

Slip-ons - No Tuner
Head pipe - Tuner
Free-flow breather - Tuner
Any combination of the above - Tuner

 

I am one of those people who thinks every HD, even a stock one can benefit from a good tuner/dyno session

IMHO to meet EPA standards the engine is tuned too lean... I am a big fan of being in the 13 to 1 A/F ratio range, and I doubt you are getting that from the factory

 

then you'll need the street tuner. don't get a tuner with those mods and you're just leaving yourself wide open for the dealer to deny any warranty claim you may have.

besides, it will run better.

 

In the video they say they are getting a 13/1 AF ratio with no tuner.