Gents:

Purchased my new '19 SG a week ago. Had the dealer install the stage 1 and I'm very disappointed in the results! My seat of the pants tells me I should have left well enough alone! I guess I'm just used to having to go stage 1, at minimum, with the twinkie engine...
I learned that the M8 is a superior engine in many ways over the Twincam. This is evident with the stock M8 performance. Best engine/performance from a stock HD bike. Ever!
If anyone is on the fence about the new M8, don't be afraid to join M8 ownership. This new engine is a performer, even in stock trim. I absolutely love this bike. It's the cat's ****!

Perplexing issue: Long & short, dealer installed Supertrapp Fatshot slip-ons, SE Pro Street Tuner & the stage 1 (SE A/C). I had Supertrapp on two of my former baggers with the TC & was very pleased with the performance/sound. Noticeable improvement over stock, when paired with the TC engine.

The '17-'19 Fatshot slip-ons come with 24 discs for each individual slip-on. The instructions from Supertrapp suggest 22 discs per slip-on, for low end torque, and 24 discs for medium to high end torque. The dealer did the former. Dealer installed 22 discs per slip-on. Not at all satisfied with the results!

I believe I might have to reduce/remove additional discs to get some performance back. Any suggestions on how many discs I should remove in order to gain back the perceived performance I lost?

TYIA/Cheers,

B

 

How much seat time did you have on the new bike before you had the stage 1 installed? If you’ve only had it a week I’m gonna guess not much. Which leads me to question how you could draw a good comparison (seat of the pants) between stock and stage 1?

What were you expecting? Stage 1 is primarily about looks and yields only negligible performance gains.

 

^^^ Experience, son! This ain't my first, second, or third rodeo. I've been around/owned performance bikes and cars for several decades.
If you read and understood my post, you would note that I lost performance ("perceived performance I lost"). I did not expect to lose performance with a stage one. I expected to gain at least some performance, i.e., 5-10% improvement, which is typical of a stage one improvement with the TC.

 

I had the SE Fatshots on my Rushmore 103 with SE AC and dealer ECM calibration and it sounded and ran great, noticeable performance improvement...but the SE Supertrapp versions didn't have the removable discs..maybe you could run some auto tunes with the SEPST or if you know of a reputable dyno operator they could make improvements to it

 

I think you hit the nail on the head. The M8 stock is such a well tuned and running motor, that the conventional wisdom of Stage 1 performance improvements, as was on the TCs, does not apply to the M8. Unless you get it dyno tuned, by an Experienced technician using a non EPA tuner.

 

I've never ran these fatshots, the disc thing seems weird to me but something seems odd if you lost performance. I ran the street tuner on my 2017 SGS with aftermarket exhaust and aftermarket ac and it never ran right no matter what I did. Finally just decided the street tuner did not like my combo of aftermarket accessories. Some run it with no issues but for me it just didnt work.

 

^^^ me thinks I'll have to experiment with removing some discs, and then adjust the SE tuner...
I'll report back after I make some adjustments.
should have left it stock, at this moment, lol.

cheers/b

 

I've not made the leap to the M8 yet, but I have researched many performance sites and the common thread seems to be that there is little gain from a stage 1 on the M8 likely because stock it already runs really well (the twin cams had considerable gain with stage 1). However when a cam is introduced that's a game changer and huge gains can be had.

 

In my experience, stage 1 on M8 did not add a lot. With wrong mufflers it can hurt.
Stage 1 made a big difference for TC, and for EVO, but not for M8.

So I doubled down and went to Stage 2. Even with the SE447 cam and a couple of “auto” tunes, it made noticeable improvement.

 

The stage 1 is nothing more than a precursor to more mods, I can’t see expecting much from it, based on my experience and what I’ve read here the street cannons are hard to beat on the stock M8, everyone seems to be after sound and not performance. I will say you will see a very noticeable gain from the stage 2 cams.