ECT Timing Mod

[pancho]

I performed the ECT timing modification on my bike a couple of days ago,, it is hands down the most bang for the four dollars I spent of anything I have done to the bike. I ran a tank of gas through it yesterday riding secondary roads, 95% between 2 and 3 K RPM. The drive-ability is much better at those RPM's with more ready torque and power availability. The bike is smoother, I get no pinging running 87 corn gas, and while I usually don't need to downshift once in fifth, I certainly don't need to now, the exhaust note with cobras seems to be a bit mellower, and it even shifts better!!?

The gas mileage in my most conservative way of riding, went from 39MPG to 38 MPG,, I can handle that.

There are a couple of things I would like to point out,, in the instructions, it says  

"The pot was selected and customized (adding the 3.9kohm Resistor) to give you approximately half of that advance when the pot is turned half way up.  The pot was selected and customized (adding the 3.9kohm Resistor) to give you approximately half of that advance when the pot is turned half way up.  The very beginning and the very end of the adjustment will not do anything."

While the values of the components selected are correct, the description is a bit misleading. a 3.9K resistor in parallel with the two terminals of the 10K pot as shown gives a full off value of 0 ohms and full on value of about 2.8 K ohm (ohms law of parallel resistance) which is enough to give the full 10 degrees advance. So, where it says that,   "The very beginning and the very end of the adjustment will not do anything." , that is not correct as one end of the adjustment will give 0 advance from the modification, and the other end of the adjustment will give full advance,, as it says, the middle of the adjustment provides about half of the advance. The empirical proof of this is that when the pot is all the way on (clockwise), the RPM will increase when dropped into gear,, and will not when the pot is all the way off (counterclockwise).

I purchased the components from eBay from sellers in China and paid 99 cents for a package of 20 each of the diodes and resistors (how can the Chinese send a package to this country through our postal service and still make money when selling it at 99 cents with free shipping??? I think about how much it would cost me to send something to them??) Anyhow, I waited 10 days or so, but so what, I wasn't waiting on it...  I bought one of these (linear taper for incremental advance adjustment) for the specified audio taper pot as it has a plastic dust cover on it to keep water and dust out of it. I guess I should have taken a couple of pictures, to show that it can be done very neatly with minimal disturbance. I did use about 8 inches of wire between the connectors and the pot so nothing is tight when removing the neck cover, and the wiring tucks away when installed.

http://www.ebay.com/itm/201061916008?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Bottom line,,, GREAT modification for the type of riding I do,,      the best!



 

[big poppa pump]

Did the ECT Mod on my bike as well, but wanted to keep it simple. I already had an I/S ICM on the bike before I decided to do the ECT Mod. Since the I/S ICM already has an advance of 2 degrees built into it, I did not want the full 10 degrees advance made available by doing this mod. As such, I ended up using a 1K Ohm resistor and did the simple ECT Mod. I believe with the 1K Ohm resistor you get about 5-6 degree advance.

[Tx Bohemian]

There are a couple of things I would like to point out,, in the instructions, it says 

"The pot was selected and customized (adding the 3.9kohm Resistor) to give you approximately half of that advance when the pot is turned half way up.  The pot was selected and customized (adding the 3.9kohm Resistor) to give you approximately half of that advance when the pot is turned half way up.  The very beginning and the very end of the adjustment will not do anything."

Ok, this is making my head spin!  Do the instructions actually say this twice? or is there something here I'm missing?

And did you check the timing with a timing light or just kinda guessing with the way it's running?

[pancho]

Not sure what you are asking Tx Bohemian, if you are questioning the operation of this modification, it has been proven many times in the past,, I am just adding my experience of the modification and clearing up some errors that are in the original text.

http://www.valkyrieriders.com/shoptalk/ect-mod.htm

[Farther]

He's questioning the redundant statement.

The pot was selected and customized (adding the 3.9kohm Resistor) to give you approximately half of that advance when the pot is turned half way up. 

The pot was selected and customized (adding the 3.9kohm Resistor) to give you approximately half of that advance when the pot is turned half way up.

[MarcusS]

I was looking in the service manual and it gives the resistance numbers for the ECT transducer. When the engine is cold it is between 2 and 3K ohms. When warm it drops to about 200 ohms. Any combination that keeps the resistance above 2K keeps the ECU thinking it is cold. I used the radio shack parts list and built mine. Only change I made was using the on off function of the pot to allow the neutral feed back to be completely disconnected from the ECT circuit when it is off. The switch is there so I use it. I get the 150-200 RPM increase at idle going from neutral to gear and can tell a little more rattle loading below 1500 RPM. I have set the throttle lock and played with it at 65 MPH and can not really tell any difference. I have a stock 99 IS. I do use the ECT function at about 1/2 turn on hwy to get better MPG. I know acceleration between 2 and 3000 RPM feels better. I would like to know if the ECT system is progressive or it switches in and out? IO wish I could see the logic software.

[pancho]

He's questioning the redundant statement.

The pot was selected and customized (adding the 3.9kohm Resistor) to give you approximately half of that advance when the pot is turned half way up. 

The pot was selected and customized (adding the 3.9kohm Resistor) to give you approximately half of that advance when the pot is turned half way up.

I got you....  No, there is only supposed to be one copy of that statement Tx Bohemian,,, so much for me correcting grammer.

"I would like to know if the ECT system is progressive or it switches in and out? IO wish I could see the logic software."

Yeah,it would be interesting to know exactly the curve if there is one or where it cuts out.

[dig66]

hi I'm new here , with the ect mod with the pot are 2 resistors used òr just the 1 on the pot

[pancho]

I just tried to go to the "old tech archives" to take a look (I don't remember), but can't access it right now for some reason dig66. The information is there.

I did see one thing, when this was written, I said I was getting 38-39 MPG,, went to car tires, 205/55, and did some other work since then, and can't remember seeing anything near 38MPG for quite awhile now,, more like 33-34.....

[98valk]

Since the I/S ICM already has an advance of 2 degrees built into it,

that is not the case, see the ignition curves here.
http://www.timskelton.com/valkyrie/tech/trigger_wheel_plus_dyna3000.htm