A couple of weeks ago we spent two days with an M8 Freewheeler.

Day One was refining several Prototype Stage I Air Cleaners, plus some riding time, gathering temperature info.

Day Two was spent gathering more temperature info in different riding conditions, and then a good part of the day on the Dyno, testing various Stage I air cleaners and some different tunes.



Below is the first batch of charts showing what we saw on the dyno. I'll be sharing more over the next week.






Unlike the Twin Cams, this M8 was NOT running overly lean from factory. When we swapped out the stock air cleaner with one of our true Stage I Air Cleaner Systems, it did amazingly well with NO change to the tune.


This first one shows the improvement in the stock AFR on the M8's. You can see, except for the shift points (which are the peaks) that the blue line is staying between 14.5:1 and 15:1 AFR while cruising thru the gears.

On stock Twin Cams it was normal to see it up in the 16.5:1 to 17:1 range.

The red line in the chart is showing a base "Stock Improved" tune from the Power Vision. It is a tad richer, but not much, since it was already pretty good from the factory as far as AFR.






This next chart shows the difference between the stock tune and the Power Vision "Stock Improved" tune. Nothing was changed other than the tune. The air cleaner and exhaust are stock. The improvement from the tune is modest but very definite.







The next chart shows the stock tune, stock air cleaner, stock exhaust, vs. a Power Vision base tune with a M8 Outlaw 587 Air Cleaner System. The exhaust was Not changed, Nor was any dyno tuning done Nor any auto-tuning.




It is a very nice jump in Horsepower & Torque with just the PV base tune and a True Stage I A/C System. This is the same A/C system in the chart shown in the original post in this thread. The small improvement is from the addition of the PV base tune.





This chart show that at WOT (Wide Open Throttle) the factory AFR is good.






This chart shows that at WOT with the M8 Outlaw 587 A/C System, the factory AFR is Still good!






As I have stated before, I am very impressed with the M8. I will be posting more charts of our experience with the air-cooled M8 soon.

 

Here are a couple more charts-

This first one shows a comparison between completely stock and the M8 Outlaw 606 Air Cleaner System with a base Power Vision tune. The exhaust was Not changed, nor was any dyno or "auto" tuning done.




The 606 gives a slightly better jump in horsepower and Torque over the 587.




This chart shows a comparison between completely stock and the M8 Outlaw 636v Air Cleaner System with a base Power Vision tune. The exhaust was Not changed, nor was any dyno or "auto" tuning done.




This 636v was with the standard oval filter element. We will be posting charts with the shorty element, the monster round element and with no element.

The jump in torque was fantastic. While most folks seem to be pre-occupied with peak Horsepower #'s, our focus is on the peak Torque. This is for a few reasons:

1. Peak horsepower occurs at an RPM that is rarely ridden in daily riding.

2. Peak Torque occurs at RPM's that are in the everyday riding range.

3. Torque is the feeling of "grunt" that most folks really enjoy about their Harley

You can see from the nice bump in Torque, and how long it lasts- breaking 90 ft. lbs. at below 2000 RPM and staying above it til almost 4500 RPM- that this kind of power is a lot of fun to ride with, and is one of the reasons why we are impressed with the M8 and its' potential.

More charts coming soon.

 

Question? I asked my dealer about decatting the exhaust header only, no muffler or air cleaner change. They said I would need a tuner with this, just decatting the head pipe.
Your opinion?

 

I may be missing something, but that does not make sense.

Even with the addition of a free-flowing air cleaner (which would have more effect than decatting the head pipe) the AFR is still really good with the stock tune. MUCH better than the Twin Cams.

 

It didn't to me either, but being it's the new M8 I thought maybe they're right.
I think they're blowing smoke up my skirt and trying to sell the HD tuner.
I decatted my 12 SG without any ill effects. But with the new motor I thought I'd better check with someone smarter than me ( that's not hard to do ).
Just want to do this for heat management. They also suggested the new fan that mounts behind the rear jug.

 

The last of the charts from our day on the Dyno with the M8 Freewheeler.

This chart is a comparison of Completely Stock A/C & tune with the M8 Outlaw 636v Air Cleaner System using the Shorty Oval Filter Element & base Power Vision Tune.

It has just a tad less increase than with the standard oval or Monster Round Elements. But it still kicks the stock A/C's butt, AND it fits on all bikes and trikes that have lower fairings.






This next chart shows the difference between Stock and the 636v A/C with the Monster Round Filter Element.

It give just a touch more performance than the Oval Element, but not enough that it would even be felt in daily riding, so it would just come down to which look is preferred.






This last chart is an interesting one. We get asked all the time "how much air does XYZ air cleaner flow"?

As you can see from the chart below, free flow of air is only one, of many, important aspects to designing and manufacturing a top performing Air Cleaner System.

This shows that without a filter element there is substantially less torque than with a filter element. It also shows that there is less horsepower, all the way up past 4500 RPM, and even after that, it is a very small increase.





Some folks have difficulty understanding how our Air Cleaner Systems can out-perform so many Air Cleaners made by companies larger than us, companies that have much deeper pockets for R&D. I know that HD is constrained by profit factors and the EPA, other companies, I can't say.

At DK we recognized early on, there are many factors that make for a truly exceptional performing Air Cleaner. We design, test, re-design & test some more, (having been granted some patents along the way) and then finally manufacture accordingly.

The next post will outline some other things we observed about the M8.

 

Other interesting info-


Heat & Performance on the Dyno-

The M8 reacted very similar to the Twin Cam on the dyno in regards to heat.

When doing comparative Dyno pulls it is important to have the engine temperature the same with every pull.

On both the Twin Cams and the M8, when the cylinder head temp crosses the 250* line power drops off, significantly.

We always get the engines heat soaked, then use the dyno fans to try and keep the temperature stable. However, just like on the Twin Cams, the M8 will go past the 250* mark very easily, even with the fans on. So there are times when we have to wait for the engine to cool down to get to our 240-245 range for accurate comparative pulls.

The upshot of all this is that the M8, while have less felt heat, still seems to have the same overheating challenges that the Twin Cam does.


Heat on the Road-

We had the M8 for two days, and both days were cool, in the 50's. So all of our testing of temperatures were in relatively cool ambient temps.

We were disappointed to see that the M8, again, while have less felt heat, has some serious temperature challenges.

At 70 MPH cruising, in 54* ambient temps, we saw the Front Cylinder at 290* and the Rear Cylinder at 310*. This was after only 30 minutes in cool temp riding, One-up.


Another 45 minute test, again, one-up and easy riding at 56* ambient temps, showed a front cylinder temp of 288* and a rear cylinder temp of 317*.


Since we already know, from our time on the Dyno, that the ECM is pulling spark (retarding the timing) when it crosses the 250* mark, we know that in everyday riding, even when it is cool out, that the engine is not performing optimally, power-wise AND MPG-wise.

We know that a Twin Cam starts suffering actual damage to the engines metal components at 275* and higher. It is yet unknown if HD has done something different with the metal in an M8 that will allow the engine metal to be 275* and higher and not suffer damage. Only time will tell on that.


Another observation-

The intake manifold on the Twin Cams is made of metal. The intake manifold on the M8's is made of plastic.

Since Intake Air Temperature (IAT) is a big variable in performance, our thought was that the plastic may hold less heat and enable the M8 to have an overall lower IAT, resulting in a benefit to performance.

In the little testing we've been able to do, there is no significant difference in IAT between a Twin Cam with a metal intake manifold and the M8 with a plastic one.

However, we have not been able to do an all day test in warm or hot weather.

When we do, we may see some differences.

All that said, we are very pleased with the potential we see in the M8 for producing great, usable power with a Stage I upgrade.

While it has some, and maybe all, of the heat challenges that the Twin Cam does, the known & proven strategies for dealing with it on a Twin Cam should also work equally well on the M8.

Again, a Big Thank You to Jack for letting us use his M8 for some testing!

 

What would DK recommend as the best and most cost effective performance upgrade for 2017 Freewheeler?

 

Man, I wish we could tell you. We do not have enough time spent with an M8 to know what the best & most cost effective performance upgrade is with absolute certainty.

From what we've seen, a good air cleaner system is a very good bump in power per $ spent.

I doubt that exhaust will give that much of a bump, plus the exhaust can cost Much More.

The tuner is more than the cost of a good air cleaner system, and it does not yield anywhere near the performance improvement. (see chart above)

The probability is high that there is no better performance increase per $ spent than one of the Outlaw A/C systems. (see charts above)

The other thing we know for sure about the M8's and performance, they need to be cooled down. There is no one silver bullet for accomplishing that, rather quite a few little things, that each contribute, and cumulatively result in a significant cool down.

This is a REPORT that talks about cooling down the Twin Cam. From what we have seen, and Customers have reported back, it all applies to the M8 also.

How is cooling related to performance? Just like on the Twin Cam, when the ET hits 250* M8 power begins dropping. As we've seen, the M8 hits 250* and just keeps going up...and it is NOT because it is too lean. So it definitely needs help there. I don't know that it is the most cost effective, but something, in my opinion, that is necessary.

 

After talking to they guy that tuned our 2016 this is my plan for the 2017.

SE air filter kit
Decat the header
Dyno With PV tuner

Everything else remains stock, including mufflers. He advised this will make the TG run better and cooler. I'm not looking for goons of performance, more heat management