Unless i'm missing something, wouldn't it make more sense to go with stage II torque instead of HP? unless you spend most of your riding time in the 5-8k rpm you really won't get the benefit of the stage II HP version. but torque version will increase pull in the lower rpms where you feel it most. You won't lose existing hp in the higher either. just wont have more to give at that higher range.

 

You bring up a valid point but exaggerate what the HP cam give you. I really prefer a flat power band and really like the current TQ of a Stock M8 low to mid range.. Don't really need any more down low but don't want to loose any of it over stock.. Looking at the cam timing between the HP and TQ cam, Intake duration on both cams is the same only the HP cam is retarded 7 degrees..

I've started leaning a little more toward the TQ cam mainly because it's a little more conservative in the valve timing.. Might play with a couple simulators and see what they say.

Going to the Tq cam bleeds off 0.15 corrected compression ratio but HP bleeds off 0.3.. Might have to bump the CR to get the TQ back.. That may require parameters beyond what the street tuner can do.

 

Bruce

The link below gives you the results of both the HP and Torque cam. The HP cam only does better than the torque cam above 4600 and losses to it below 4000. It also losses to stock below 3000 RPM. I know you like to run the RPM up but why give up so much for so little gain above 4600?

https://www.hdforums.com/forum/the-d...l#post15492942

The intake event on both is the same as you noted just the HP is retarded 7 deg from the Torque cam. Since you appear to be wanting to keep warranty and use SE parts why not get the best bang for the buck? If your going to change it later after warranty period expires get the best bang for now.

The rain has cleared out for the rest of the week so call me and ride that new one up and I will toss it on the dyno and get you a baseline.

 

I guess it all depends on what type of experience a rider is looking for. Based on HD's statement below, if one rarely goes over 4500 rpm and never comes close to redline, then a stage II power kit seems like a waste of money and time. If you want more power down low, where most riders probably spend more of their time, then the torque version is best. On the cruisers I rarely go over 4500 rpm whether local or highway riding. I don't treat my SGS and rev the crap out of it like I would my sport bike.

Screamin’ Eagle Stage II adds a performance camshaft to achieve the next step up in performance. Harley-Davidson® Genuine Motor Parts & Accessories offers two Stage II camshaft choices to tailor Milwaukee-Eight performance to specific needs.

The Screamin' Eagle Milwaukee-Eight Stage II - Torque Kit features a Screamin' Eagle torque camshaft that delivers on-demand throttle response from low to mid RPM at cruising speed. Installed in the Milwaukee-Eight, this cam produces a 5 percent increase in torque over the stock engine that can be felt immediately off the line and continues to build up to 14 percent more torque at 4500 RPM, an ideal power band for passing slow-moving vehicles without a downshift and compensating for the weight of a passenger and luggage. Kit components include a Screamin' Eagle SE8-447 cam, adjustable pushrods, pushrod covers, O-rings, and a cam cover gasket.
MSRP: $389.95

Riders will get an adrenaline-pumping burst of speed from the Milwaukee-Eight engine by installing the Screamin' Eagle Milwaukee-Eight Stage II – Power Kit with a Screamin' Eagle power camshaft that starts to pile on power at 3000 RPM and continues to build by up to 24 percent more power than the stock engine at redline. This kit is ideal for riders who want to ride the bike aggressively while downshifting to lower gears to keep the engine operating in the higher RPM range. Kit components include a Screamin' Eagle SE8-462 cam, adjustable pushrods, pushrod covers, O-rings, and a cam cover gasket.
MSRP:$389.95

 

Yeah it looks better. HP probably don't get you that much until head pipe flow is increased. I'm wondering what running the stock muffs will do also.. Weather here don't clear out til Friday.

 

Well it's safe to assume the SGS won't rev as high as the sport bike. So you are saying that you don't run the SGS to the redline but do the sportbike?? I ride most of my bikes the same.. Use everything from the bottom to the top.. The only bike I limit RPMs on is my 113ci evo softail and it's mainly cuz parts fall off if I run it much over 5K for any period of time..

 

no i'm saying sport bikes in general are designed to be revved higher.. their power increases over the higher rpm range vs tapering off like it does on the SGS. In order to take advantage of the extra power you do need to live closer to redline on those bikes. Doing so on the SGS gets you nowhere. I would never take my SGS to redline on a regular basis. different bike, different design.

 

Well for me, I ride a little different... I send to do a little spirited ride on everything. All my street bikes have HD motors in them but the 02 RKC I have has the smallest motor and while it still makes over 100hp/tq it sees over 5500 a lot. Flip side the bigger motors tend to not see the higher RPM range because I don't need the power or run out of straight before I run out of Rs..

 

I'm very curious about this too. None of the graphs I'm seeing indicate that changing exhaust is yielding much performance gain. Certainly not just a muffler change. I'm seriously considering Stage II torque cam, SE air cleaner and street tuner to hold me over for 2 years.

 

I'm leaning on the Tq cam, SE AC, and tuner at the first service. No SE mufflers The TQ cam still increases the HP up top over the stock cam. The biggest restriction is the cat in the header.. It's enough that freer flowing mufflers don't make any difference... Bet might see something if you knock the cat out but me wanting to keep the warranty and quiet sounds like a win - win.

if it doesn't work out with the stock mufflers, can always buy aftermarket.. One thing to note is that with the M8 heads flowing so well, the durations of these cams is mighty short and the cat really controls the exhaust flow.. This means that a wide range of exhausts can be used and performance/tune changes very little.