Seeing my engine on the road from the inside: OEM vs Stage 1 tune ONLY vs Stage 1 tune + SE slip-on exhaust


Why and How:

My 2023 Breakout 117 came to me brand new from the HD dealer. It came with OEM mufflers, OEM tune, and Heavy Breather (The Heavy Breather is OEM on the 2023 Breakout 117).

I purchased a Screamin’ Eagle Street Cannon slip-on mufflers kit pn 64900690, used versus new for a decent price.

I also purchased 2 new exhaust clamps pn 65900012, and 2 new exhaust gaskets pn 65900012.

I also purchased the Screamin’ Eagle Pro Street Bluetooth tuner pn 41001141.

I did all of the above because

• HD’s replies to product Q&As for the tuner consistently say that even without an upgraded exhaust or upgraded air cleaner (i.e. a fully OEM motorcycle), a Stage 1 tune will improve the performance of an HD motorcycle equipped with the tune.
• HD tells buyers who ask that if they install a Stage 1 tune, and later remove the upgraded exhaust and/ or air cleaner, there is no way to return to an “OEM” (i.e. non-Stage 1) tune, because there is no need or desire to do so, since the Stage 1 tune by itself makes the engine run better.
• The tuner installs tunes by you grabbing them from HD online, bringing them to your Bluetooth-equipped mobile device or computer, plugging into the diagnostic port on your bike, and enabling you to install your selected tune via Bluetooth from your device.
• The tuner can be removed after installing a tune, OR it can be left installed, and if left installed, it can send selectable performance sensor values to a “dashboard gauge panel” on your mobile device. These sensor values can include things like current throttle %, engine temperature, engine rpm, etc). HD calls these “Performance Gauges”.
• If the mobile device is mounted on your motorcycle, you can see these gauges show “live” readings while you ride. They include:
  • engine head temperature
  • battery voltage
  • throttle position
  • engine rpm
  • speedometer, and
  • absolute manifold pressure
  • O2 sensor voltage for each cylinder
  • Timing advance for each cylinder

Test methodology:

I actually DID some realistic on-the-roaf testing, using an actual defined, fully repeatable 80.5 km = 50 mile test route that encompassed a mix of city, suburban, and highway mileage, mostly highway.

This route is representative of my typical riding. It is all on VERY low traffic roads. I rode it as close to exactly the same as I could, for each of the tests I did, using a very strongly controlled protocol. That protocol included for example using 95 kph = 59 mph as a consistent highway speed, since that speed was (a) consistently holdable and (b) legal for each highway segment in the route. I could maintain that speed consistently on the highway portions because it was slower than the posted limit of 100 kph, so any vehicles going in my direction passed me, rather than me having to lower my speed because I happen to find myself behind a vehicle going in the same direction.

I used the cruise control set to 95 kph for one long (about 20 km) uninterrupted highway section with a 100 kph speed limit.

I made each run when traffic was almost non-existent compared to normal, and I tried to do it at very similar air temperature and light wind conditions (although wind was not as big a factor since this is a “circle” route).

Since I am interested in how the Stage 1 package affects normal, typical riding, not competitive or aggressive riding. Since HD offers only a limited number of “gauges” to select from, and since I can see only a maximum of 5 live gauges simultaneously with the gauge layout HD offers, I tracked only the following live gauge readings:

• Engine temperature
• Battery voltage
• Engine RPM
• Timing advance for front cylinder
• Timing advance for rear cylinder

The voltage one turned out to be rather dull. The engine maintained a 14.0 volt reading reasonably closely, varying only from a low of 13.8 volts to a high of 14.6 volts throughout the entire 80.5 km route, regardless of speed, and was totally blind to my turning on or turning off my electric vest. Most of the time it was right at 14.0 or within a tenth or 2. No shortage of electrical power on the current Harleys!


What I was looking for:

This posting thread will examine any differences I noted between:

• OEM (i.e. Heavy Breather intake only on my 2023 Breakout 117)
• Stage 1 tune ONLY (No SE slip-ons yet)
• Stage 1 tune + Screamin’ Eagle Street Cannon slip-on mufflers

Note that since my 2023 Breakout 117 came OEM with the Heavy Breather air intake, there is no way for me isolate the effect of the Heavy Breather.



A few pre-testing observations:

There is no published official HD dyno chart I could find that shows the Stage 1 effects upon a 117 Milwaukee 8. But there is a graph that shows the Stage 1 effects upon a 114 Milwaukee 8. That tiny graph in the Screamin- Eagle Performance Catalog suggests that the Stage 1 kit improves torque enough to create more horsepower pretty linearly through the rpm range, leading ultimately to “about” a 10% increase in PEAK horsepower. The 117 may differ from this. In my city, I have no local dyno to visit.

The OEM slip-on mufflers weigh = 7.15 lb each x2 = 14.3 lb

The Screamin’ Eagle 64900690 slip-on mufflers weigh = 6.385 lb each x 2 = 12.77 lb

So the Screamin’ Eagle mufflers weigh 1.53 lb less - a negligible weight difference. This makes me wonder about both the OEM and the Street Cannon mufflers: Do they contain some form of catalytic converter or not? I say that because with the pair of Street Cannons I bought used, I can see uninterrupted daylight between the inlet and outlet of each muffler. But I cannot see “through” the OEM mufflers.


Setting up for the testing:

Setting up by following the HD instructions was ridiculously easy. I downloaded the HD iPhone app for the Bluetooth version of the HD tuner (NOT the older non-Bluetooth version). I found the diagnostic cable with its 6-pin receptacle under the left side cover. HD calls its Bluetooth Screamin’ Eagle tuner a “BCI”(short for “Bluetooth Communication Interface”). I plugged the BCI into the diagnostic cable receptacle and followed the HD instruction steps, which were VERY well described, and very easy to do.

I activated the app, selected configure gauges, chose the gauges I listed above, and then just before starting the first test, I activated the “gauges” display. Then I ran the first test.



Test 1: OEM (i.e. Heavy Breather intake only on my 2023 Breakout 117). NO changes

This 80.5 km first test gave me my “baseline” for a completely OEM non-modified 2023 Breakout 117. Here are the significant findings out of all the date captured:

Average engine temperature = 260, but varied, even once warmed up, from 246F to 268F.

Avg Front cylinder timing = 30 degrees BTDC

Avg R timing = 32 degrees BTDC

Fuel mileage was 4.6 L / 100 km = 51 mi / US gal

Warm idle = approx 850

Notes:

This giant 117 cubic inch air cooled V-twin engine ranged in operating temperature over 22 degrees F over the course of the varying speeds and loads within the 50 mile route. Not great.

The rear cylinder consistently ran between 2 to 3 degrees more advance than the front cylinder. The HD engine is programmed to try for the highest advance possible, within each individual cylinder, without getting detonation. So, this shows that the REAR cylinder encountered fewer threats of detonation than the front cylinder. This is contrary to what I expected, since the rear cylinder gets less cooling than the front cylinder, due to it being BEHIND the already hot front cylinder. Also, engine temperatures in the 246 to 268F range will degrade oil faster than more moderate temperatures.

Fuel mileage was 4.6 L / 100 km = 51 mi / US gal on this tightly controlled test route and riding protocols. Note that there is high potential for error at the gas pump when you are adding only enough fuel to restore a full tank after just 80.5 km = 50 miles. I have done my best to refill as consistently as humanly possible, but you should regard any mpg findings with some skepticism.

The warm idle was “approximately” 850 rpm. I say “approximately” because as you M8 owners all know, the M8 displayed idle rpm, particularly in a digital display format, varies a LOT, like 50 or even 75 rpm from lowest displayed reading to highest!

Performance of the engine showed no obvious dislike or concerns, beyond the engine temperature reading. No notable throttle lag or backfiring. And this OEM engine is WAY more powerful and pleasing than my prior 2014 Breakout 103’s performance, even after I added a Stage 4 kit to the 103!

But also, no “tunes”. I have an age related hearing loss that requires hearing aids, but I cannot wear the hearing aids while riding. At cruising speeds, I literally heard only the wind, with no exhaust sound being discernible. That was of course disappointing.



Test 2: Stage 1 tune ONLY (No SE slip-ons yet)

The acquisition and installation of the Stage 1 tune designed by HD for the 117 M8 engine with Stage 1 intake and exhaust was also easy. Once I requested a tune in the app, it used my VIN to identify the correct tune in “The Cloud”, downloaded it, and asked my permission to install it.

It also gave me a peek at one table in the tune that was interesting:







This table is pretty interesting when you actually analyze it.It shows the target air fuel ratio (AFR) that the ECU has been programmed to try to achieve and maintain at any specific rpm and load. The vertical axis shows the rpm. The horizontal axis shows the loading. For each point in the rpm vs load table, the AFR is expressed as a fraction of “Lambda”.

MotorTrend magazine gives us the best description of what Lambda is, and here I have enhanced that description just a bit for more clarity:

“Lambda, which is a Greek letter, represents any fuel's stoichiometric value as 1.00. “Stoichiometric” is the ratio at which there is theoretically exactly enough air to burn all the fuel present. Lean conditions (too much air compared to fuel) would show as a Lambda value higher than 1.00, and rich conditions (too little air to fuel) are lower than one”.

You can see in this table that The “target” AFR that HD has told the ECU to chase is just a tiny bit rich at low rpm and low loads, and is notably more rich at higher rpm and higher loads.

The stoichiometric value for gasoline burning efficiently in air is 14.7 units of air per unit of gasoline. So, at high rpm and/or high loads, the Stage 1 tune for the 117 M8 commands the ECU to get the AFR to about 0.877 x 14.7 = 12.9. In the world of gasoline internal combustion engines, this is very safely rich AFR. In fact, it’s almost good enough to use safely in a supercharged engine!

But even at low rpm and low loads, the HD Stage 1 tune is pretty good, with an AFR = .990 x 14.7 to 994 x 14.7, which is 14.55 to 14.6. Contrary to what many HD riders and tuners claim, that is NOT lean! Lean, by definition, would be a Lambda number greater than 1.

Now what those people claiming this is “lean” really mean is that in OLDER HD engines, these Lambda values would have been, despite their mathematical “richness”, too lean for those older engines. This was because the engines did such a poor job of distributing the air and fuel properly for optimal combustion, and the engines ran too hot because of primitive emissions control systems, so they would get detonation. Extra fuel was needed to help cool the combustion chambers, and so the AFR would have to be deliberately targeting ratios more like 13 versus 14.7!

With today’s superior computerized engine management controls, even engines as difficult as twin cylinder, air-cooled, V-twins with the cylinders being one behind the other, and with a weird relative combustion timing like these big hD engines, can be run VERY close to a Lambda = 1 value safely and very productively from a performance perspective.

So, no, I do NOT think HD tunes too lean. I think they are doing the right things, as evidenced by the fuel mileage you will see below as a result of this actual controlled testing.

The results of the test using this Stage 1 tune gave the following results:

Average engine temperature = 270, but ranging from a low of 264 to a high of 273.

Average front cylinder timing = 33

Average rear cylinder timing = 36

Warm idle is +100 rpm = about 950

MPG = Apparently unchanged from OEM tune

Performance improvement was pretty evident - see notes below

Notes:

The engine temperature ran HOTTER on average with the Stage 1 tune versus OEM tune. This contradicts the common misconception that a Stage 1 tune will cool down the engine.

However . . .

The engine temperature VARIED a LOT less with the Stage 1 tune only installed, varying by only 9 degrees F (versus the 22 degrees with OEM tune). THAT is a substantial benefit all by itself, since it shows greatly improved thermal stability.

Note that the difference in spark advance between front and rear cylinders increased to an average of 3 degrees versus 2 degrees. But, note that BOTH cylinders were able to hold higher advance than OEM, with the rear cylinder gaining 4 degrees on average! This indicates that there was less need to retard timing, DESPITE the higher engine ambient temperature. More timing is always more efficient, so this being possiblr despite a higher engine temperature is a truly important improvement that merits some study going forward.

The warm idle went up by “about” 100 rpm, from 850 to 950. This is a “tune setting” made by HD, not a result of any engine improvement. I do not know why HD increased the idle speed, particularly since Donny Peterson (Hells Angel member who was brilliant in his knowledge of HD bikes and engines) said that most HD riders want a slow idle that accentuates the “lope” inherent in the weird crnakshaft timing of an HD engine.

And yes, the engine performance DID improve notably with just the tune: the two words that describe it best are “eager” and “smoother”. BOTH attributes were rather noticeable. The engine felt eager to run at rpm / speed combination were before it seemed “ok but not exciting”. And the increase in smoothness of operation (engine smoothness, not vibration) was quite noticeable. So, yes, HD seems correct in saying that if you are running a Stage 1 total package tune (tune, intake, and exhaust), and decide to remove the combination of high flow air intake and higher flow exhaust, you should still keep the Stage 1 tune itself. In fact, their newest tuner, the Bluetooth tuner, will not even enable you to go back to the OEM tune.



Test 3: Stage 1 tune + Screamin’ Eagle Street Cannon slip-on mufflers

There is a fair bit of confusion in the HD marketplace about what is the actual configuration of a Srceamin’ Eagle Street Cannon slip-on muffler. Does it contain a cat or not? The part numbers of the Screamin’ Eagle Street Cannons kit I bought used are:

Overall kit: 64900690

Top muffler: 64900693

Bottom muffler: 64900694

The installation of the mufflers was fast and easy. It took me 90 minutes only because I am very detail-oriented (e.g. I wore plastic gloves to avoid creating fingerprints that would manifest as stains once the mufflers got hot the first time, but then I also washed each muffler and each heat shield with Mineral Spirits as well, even stopping to wash portions that would later be covered).

The results of this test with a full Stage 1 (Heavy Breather + tune + slip-on mufflers) were:

Average engine temperature = 268

Average front cylinder timing = 33

Average rear cylinder timing = 33.6

Warm idle = 950

Slightly improved mpg: 50 to 53

WAY NICER sound especially on shifting up between gears

Even BETTER performance on both part throttle response and especially on hard acceleration.

Notes:

Average engine temperature = 268, but got as high as 275, so NOT cooler than before the mufflers were added, so no, the SE mufflers do NOT reduce engine temperature. In fact, they resulted in engine cruise temperature varying from a low of 261 to a high of 275! That’s a 14 degree spread, compared to the Stage 1 tune with the OEM mufflers spread of 9 degrees F, but still far better than the OEM tune’s 22 degrees spread. I do not know why this is so.

Note that the spark advance timing remained the same for the front cylinder, but FELL from 36 degrees average to just 33.6 degrees average for the rear cylinder. I have no idea why this happened.

Note that the rear cylinder timing and the front cylinder timing are now on average only 0.6 degrees different. I have no idea why this happened.

Warm idle of course stays the same since that is setting controlled rigidly by the programmed tune.

Fuel mileage is hard to measure reliably when using only less than a gallon in each entire 80.5 km - 50 mile test. But depsite the potential for inherent error, I should at least report the finding. The bike delivered 53 miles / US gallon with this state of tune. That’s 6% better than the pure OEM tune. So, apparently, at a minimum, installing a Stage 1 tune, and running the bike conservatively versus aggressively, does nOT reduce your mpg, and seems to instead improve it, because the engine is running notably more efficiently.

Finally, even without benefit of a dyno, I can readily believe the HD implied claim of 8 to 10% more power with a complete Stage 1 package. Really. The front end comes up notably more and quicker than it did under hard acceleration from a standing stop.



The Last test remaining to be done

The HD Bluetooth tuner offers a built-in app called “Smart Tune” that you can activate whenver you choose to, and you can activate it repeatedly.

When you activate Smart Tune, the BCM feeds instantaneous sensor readings from the engine to your phone, and stores the readings as a “recording”. The recording process can be short or long, but longer of course is better, as that gives the app more data points and more information.

Once you stop recording, the app uses the sensor data from many different rpm and load / throttle conditions to “refine” and “optimize” the tune. It then asks you if you want to alter your installed tune to incorporate this new data. If you say yes, it will run a process that alters your installed tune, and makes note of there now being TWO tunes available: the original factory-provided Stage 1 tune from The Cloud, and the newer more refined tune created by integrating your recorded data.

I intend to do that Smart Tune process, but will do so when I have my next opportunity for a 275 to 300 km, or even possibly a 400 km, ride. Such a ride will give me MANY data points if I make a point of changing rpm and throttle as much as possible.

This is NOT a substitute for a dyno tune or a wideband O2 sensor based tune. But it is FREE, and I want to see if it makes a notable difference or not.

Stay tuned for a future Smart Tune posting.



I hope this thread will help others as they wonder if the Stage 1 tune, partial or complete, is worth doing. My vote is Hell, yes.

Jim G

 

Just ran a similar set up on my 23 FXLRS. I had previously installed the VH eliminator mufflers, with cats and the S1 HD tune. I didn’t run the “smart tune” with the initial setup. Bike ran great, with a bit more growl. I did not log or monitor the bike before or after and to me the difference was mainly sound.

Yesterday, I installed the SE wedge air cleaner and ran the smart tune. Rode my standard loop at my normal early morning pace and tried to vary the load including some triple digit speeds. Updated the standard S1 with my recording and I’m happy with the results.

Under full load the induction sound is reminiscent of Mom’s 77 Oldsmobile Cutlass, after I flipped the air cleaner on the Q-jet. Aaww-wahhhhhhhh.

Really didn’t notice any discernible performance improvement other than the fully scientific- awww-wahhhhh.


Good times

 

That thing HD calls a tuner is not really.

 

I don’t believe the HD claim of 10% power increase with this EPA Stage 1. I could be wrong but I think it is marketing speak.

Here is a bone stock dyno of the 2023 Breakout done by Cycle World…


Jim, if your 103 Stage IV didn’t have more power than this, I suspect you didn’t have a good combination of parts. The cams, heads, pipes, air cleaner, injector size, etc. all have to be selected with everything else in mind to achieve good results. A good 103 Stage IV should produce at least 103 HP and could easily produce more and still be reliable. The 117 has way more potential of course and the M8 in general has way more power potential than a Twin Cam.

 

I remember adding a "B" to that ... Baaww-wahhhhhhhh

 

Stratplexi, you are simultaneously theoretically right and practically wrong. Let me explain:

Here is the actual dyno chart from my 2014 Breakout with its Twin Cam 103 cubic inch engine with Stage 4 kit i nstalled by the best mechanic at Cowboy HD in Austin, Texas, and dynoed on Cowboy's honest and properly calibrated dyno:



Note that this was in fact an almost ideal run, as the correction factor was only 1.01 to get the raw data to std SAE conditions. And it was an honest run that used the more conservative SAE versus STD correction factor (SAE would have shown 3 or 4% more power and torque).

BUT, note that the torque curve is very weak below about 2800 rpm, and so of course HP, which = Torque x RPM / 5250, is also very weak. So, while the PEAK power was great at 103 rwhp at about 6150 rpm (which I seldom ever run at), the power available at typical riding rpm was rather poor until you hit at LEAST 3200 rpm. Yes the cam did its job, and the compression was high enough to read in the region of 225 psi in a compression test, but the basic engine architecture was poor and so you could have great power ONLY if you sacrificed low and mid range power.

My Breakout was also in fact later tuned again personally by Mike Lozano of Lozano Brothers, who are recognized as THE motorcycle and car engine tuners (Porsche even had them build their race engines for them). Mike was unable to raise that peak power hardly at all, but did improve the low end rpm a bit, while tellimg me that HD blew it on their cam timing by holding the exhaust valve open unnecessarily long.

Now the 2023 Screamin' Eagle I managed to get from my current HD dealer in Canada shows Screamin' Eagle dyno charts for the M8 107 engine that include Stage 1 dyno results. But the 114 dyno charts jump straight from stock to Satge TWO, and the 117 dyno charts only cover the touring models (Presumably because the 2023 Breakout 117 was apparently too late an arrival to make the 2023 catalog print date) AND also jump straight to Stage 2.

But, take a look at this dyno chart for the 107 Softail that was shown in this published catalog. Since it was published, HD could be sued by a buyer if these results could not actually be proven:



Compare the power output at 2500 rpm for the twin cam dyno chart and the M8 dyno chart. Dramatically different. The twin cam Stage 4 doesn't even want to BE at 2500 rpm.

I realize the scaling on this chart makes it hard to read accurately, but if you print it out to cover an entire 8.5 x 11" page like I did, you will be able to measure the hp accurately at each point to compare the stock engine to the Stage 1 engine, and you will see that stock had peak power of 77.5 rwhp, while the Stage 1 had peak power of 85 rwhp.

That means HD did get 85/77.5 = 109.7% power out of the Stage 1 versus the stock engine. 9.7% is pretty damn close to 10% in my book.

And again, I repeat, my 2023 Breakout 117 with the now full Stage 1 setup DOES feel dramatically stronger when I hit the throttle hard from a standing stop to a highway speed in the 110 to 120 kph range. The front end rises a LOT compared to stock, and the gear changes now feel violent. And, I should point out that my entire local area here east of the Rocky mountains is a praire at over 3000 feet elevation, where engine power is limited by notably low air density. So, while I don't have any nearby dyno to check the actual power output, but my seat of the pants experience strongly suggests the HD claim might be true, as it SHOULD for a PUBLISHED catalog chart that HD has to be able to defend if challenged.

But since I rarely accelerate THAT hard, the biggest pluses for me are the eagerness and smoothness that the engine now exhibits comapred to before, and the TUNES, which are now fantastic, especially during gear shifts at even very moderate rpm and throttle.

Jim G

 

It's amzing how much your throttle hand can vary your HD fuel mileage. This morning, I went out speifically to enjoy the new exhaust sound and power, and on a route where I would normally get 50 miles / US gallon, I quickly achieved just 45 miles per gallon!

 

I ran into an issue with the HD Bluetooth tuner phone app today, when I tried to initiate a "Smart Tune". The app is falsely declaring that the bike's battery volatge is too low (i.e. below the 11.9 volt lower limit below which the app will not proceed with any tuning, as a low battery voltage could result in corruption of the ECU's programming).

I know this is false, since the bike was brand new 5 months ago, has a Lithium battery with the correct HD specs that is even newer than the bike itself, and the bike starts effortlessly and runs with zero issues, and declares a 14 volt actual reading on the Tuner's "Performance Gauges" display when running.

So, I posted a separate thread here on the forum asking if any other HD Bluetooth tuner user has encountered this issue. This is the first and only glitch so far that I have encountered with this tuner.

Jim G

 

EDIT: I was wrong about that sheet!

 

Just affirming what NorthWestern what referencing: All the HD dyno charts, like all normally found aftermarket dyno charts, show hp at the rear wheel (RWHP), NOT at the crankshaft.

Also, although HD does not say so, they are corrected via the "SAE" correction factor formula, not the "STD" correction formula. The SAE correction produces a 3 to 4% lower rwhp than the STD correction does. STD was used in the past by some tuners who wanted their dyno charts to look "better" than other tuners' charts, but fortunately that sleezy trick has just about disappeared. The correction factor is normally shown either at the top right corner of a dyno chart, or in the text that shows the rwhp and rw torque. If the correction factor is more than about 1.04 or 1.05, the dyno run should not be considered valid, as the correction facotr formulas start to produce erroneous results above 1.04 or 1.05.

Remember too that normal dyno charts show the FULL THROTTLE performance capabilities of the vehicle. They do not show how clean or sloppy the part throttle response is. To most of us who are not racers, the part throttle response is more important.

Interesting confirmation of the M8 117's power: The HD dyno chart in the SE catalog shows the TOURING bikes with the 117 produce about 94 rwhp at peak. Cuycle World's dyno test of the Breakout 117 indeed shows the same 94 rwhp figure. So, the touring engine / intake / exhaust configuration is overall the same efficiency as the Softail engine / intake / exhaust configuration, despite any exterior physical differences.

Jim G

Jim G