J&P Community

 I posted this question first on the wrong forum.  Sorry.  Challk it up to my being a newby on this forum.

 Could someone add specific details as to what the ECM changes are with the Stage 1 and Stage 2 downloads?  I have searched the internet and the HD web site to no avail.  I have even talked with the techs at a couple HD dealers, and they mostly view it as magic, which is dissappointing.  Either they don't know or they don't want to say.

Here is why I am interested.  I have a 2006 FLSTC with quite a few mods.  Bored to 95".  HD 10.25:1 pistons.  Ported and polished heads with increased valve size.  (The Iowa dealer that sent the heads in didn't really know what the modifiers did, but another dealer who uses the same company in Cedar Falls says that they often plane the heads which further increases the compression, so it is probably 10:5:1 or so.)  S&S gear drive 585 cams.  Rinehart 2 into 1 pipes.  HD heavy breather air cleaner.  I had them install a Power Commander so it could be dyno tunes.

The bike runs great.  Makes about 100 HP and 98 ft-lb torque on the dyno. Starts and idles great, as long as I remember to push in the compression releases.  However, I have a bit of knock betweem 55 and 70 mph in 5th gear when I slightly increase the throttle.  If I open it wide open, the knock goes away.  Under normal conditions, at these cruising speeds, there is no knock.  But when I just slightly increase the throttle to accelerate, go up a hill, or if I am driving into a head wind, the darned thing rattles.  It is worse on hot days, as you would expect.  Two different dealers have put  it on the dyno to try to fix this.  They have added fuel to make ti run richer.  I can verify this because the fuel mileage went from about 42 mpg to about 34 mpg.  But it had absolutely no effect on the knock.  I also added a oil cooler to reduce head temp, but it didn't affect the rattle.   I suspect that the timing needs to be retarded a degree or two in this rpm range, but the dealers don't really want to mess with that part of the PC set-up.   The local guy want to put in a race tuner and then tune it, which seems to be a lot of money and a lot more complication.  So I wonder if the Stage 2 download would change the timing, since it would be designed for a higher performance engine.  They could put in the download, and then redo the Power Commander adjutments on the dyno. I could get some fuel mileage back since it probably doesn't need to run as rich as it currrently does.

I can hear you say, just kick it down a gear and live with it.  But that is what I do now, and it is a pain in the rear.

First and most obvious be sure you're running the best highest octane gas you can get.

55 mph in 5th gear is around 2000 revs (I think).  It's conceivable that a 10.5:1 compression is going to produce detonation using the current pump gas.  That might be a fact of life.

Second, the dealer won't touch the timing tables on the Power Commander software, but they are willing to charge you a bundle of cash to switch over to the S.E. Race tuner and THEN they'd be willing to adjust the timing charts?  That seems, ummm, odd...

I think the stage one or two downloads will be a waste of money - they will change the baseline that your current (paid for) dyno tune builds on and you'll be all the way back to square one.  Mo' money, mo' money, mo' money...

Have you plugged into the Power Commander yourself using the PC software and USB cable?  If you've done this, then you probably have seen that the throttle position can be set and read in the software.  Use some tape to mark your throttle in 10 percent increments using the PC-3's throttle position readout.  I'm assuming you have a tach on the bike also.  Go for a ride, get the bike warmed up.  Find a highway and roll on the throttle.  Make note of the RPM's and Throttle Position (TP) where you hear the ping.  Go home, plug the computer into the PC, go into the timing tables in your map and put a "-2" in the boxes that best match the RPM and TP where your ping happened.  Take a ride and see if it's any better.  Adjust again and test ride.  If you seem to be making too many scattered or large changes in the table, you're probably off track and might want to undo some of it.

If all the "hook it up to your computer" stuff is not your bag, you can still make notes about the RPM and TP where the ping happens and ask your local tuner to get in there and adjust the timing.  You already own the power commander - seems like the map just needs a little touch up.

Or you could downshift...

Thanks for the input.  I always run the highest octane gas the pump claims to have available.  I have also tried using the Lucas Oil additive, which claims to increase octane, but doesn't say how much.  Doesn't really seem to have any effect.  Which of course it wouldn't, if the spark plug is really firing a bit earlier than necessary for the air/fuel charge I have.  Octane increase should only affect temperature and compression related detonation.

And the deal that really makes me convinced it is timing, is that I can make the detonation go away by opening the throttle up all the way.  Obviously, that will allow more air and more fuel in, so the total pressure should go up, making the problem worse.  But it doesn't.  Of course, it could also just be a lot richer at wide open throttle, but the fact that my fuel mileage went down as far as it did tells me that they really did add a lot of richness.

I agree, the dealer response seems a bit odd.  Actually, a whole lot odd.  Of course, even though they have a sign saying that they are an authorized PC tuner, they are still a HD dealer, and probably want to push the home grown product.  Can't completely blame them for that, but it is a bit frustrating.

Unfortunately, I do NOT have a tach on the bike.  That is one of the items that is still on the wish list.  And I realize that the actual rotation of the throttle does not exactly match the percent readout on the PC.  Bu this set-up makes enough power that it is barely off the idle position, so it is probably about 10% of the allowable rotation.

Another work around that I have considered is to go to the six speed overdrive tranny (put in the gear set) and then change the primary ratio so that most of the sixth is only slightly taller geared than the current five, which would give me a little more flexibility in selecting a gear that doesn't detonate.  Let's face it, cruising at 70 is not a lot of fun in 4th gear.  But again, this is a whole lot of Mo' money.  But since the engine makes its power in the top end of the rpm range, having a slightly lower set of gears wouldn't be all bad.

 The Stage I and Stage II downloads are for specific combinations of Harley Screaming Eagle parts. The Stage I is for HD Screaming Eagle Slipons and Screaming Eagle Aircleaner. It uses a different set of initial values than a non-flashed ECM. Another feature of the Stage I is it raises the RPM limit the module can turn to. When tuning a Power Commander, you need to know what flash the ECM has so it knows where to start from when it adds or subtracts fuel. The new USB PC III allows the reprograming of the ignition curves and rev limit so unless you are useing that specific combination of parts, the Stage I download is usless in my opinion. The Stage II is a more radical fuel map (once again for a specific combination of Screaming Eagle parts) that the PC III must know to have a baseline to add and subtract fuel from.