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yeah, i'm going to say over my head man. from that video it sounds like you need dwell time, and from the threads about using them with an aem stand alone, they had to set up the dwell time to different setting. from the little i know, the icm does the dwell time and its built in. so its not adjustable.
He does not show the higher frequencies (aka higher RPMs) current and voltage output of the LS2 and yukon (truck and SUV engines) coil in this video. He speaks very highly of the yukon (truck) coil but my guess is the yukon (truck) coil is more powerfully at low RPMs but drops off at higher RPMS. This would explain why there are different coils for the higher revving GTO, corvette, engines and the lower reeving more torque truck and SUV engines. Either way it is a cool setup.
yeah, i'm going to say over my head man. from that video it sounds like you need dwell time, and from the threads about using them with an aem stand alone, they had to set up the dwell time to different setting. from the little i know, the icm does the dwell time and its built in. so its not adjustable.
either way good luck. hope you get them working.
So is your thought that in order for coils to work properly, dwell must be correct or or won't work. And since dwell is not adjusted via ECM,
they won't work with dwell coming from ICM?
So is your thought that in order for coils to work properly, dwell must be correct or or won't work. And since dwell is not adjusted via ECM,
they won't work with dwell coming from ICM?
They should work with the dwell coming from the ICM as long as it is within range for optimum power output \ spec for the coil. Do you have a scope, you could easily measure the dwell time on the ICM and compare it dwell times the LS1/LS2 PCMs output.
On the N* ICM it appears the ECM has some influence on the dwell time when the bypass signal is high (when the ECM takes over timing control). The falling edge of the ignition control signal used for timing turns off coil primary current. Tough from the documentation it is not clear when the ICM starts charging the coil if it is based of the ignition control signal or it's own internal control.
He does not show the higher frequencies (aka higher RPMs) current and voltage output of the LS2 and yukon (truck and SUV engines) coil in this video. He speaks very highly of the yukon (truck) coil but my guess is the yukon (truck) coil is more powerfully at low RPMs but drops off at higher RPMS. This would explain why there are different coils for the higher revving GTO, corvette, engines and the lower reeving more torque truck and SUV engines. Either way it is a cool setup.
It would have been nice if he cranked up the firing rate. I also noticed that the voltage trace was funny prior to the coil being triggered. Not sure what that is about.
Another aspect is that the coil dwell can be overlapped. At 6,000 RPM there is 20 msec between the firing of any one cylinder (2 engine revolutions). That provides plenty of time for 5 msec of dwell and a minimum of 600 usec firing time.
This makes me wonder why the different coils for the applications. Maybe the truck PCMs don't overlap the dwell. This would make the hardware (PCM) less expensive. Which is a major consideration.
So is your thought that in order for coils to work properly, dwell must be correct or or won't work. And since dwell is not adjusted via ECM,
they won't work with dwell coming from ICM?
There are two different types of ignition modules for GM waste spark systems. The C3I system and the DIS system.
The C3I system uses dwell control from the ECM. These systems are used on cars such as the '89 TTA and other Buick 3.8l engined FWD cars. This includes the Quick Start system.
The DIS systems, such as used on the typical 2.0l and 2.5l 4-bangers, and the 2.8l and 3.1l 6 bangers, along with the LT5 engine (maybe the N* too?), have the dwell control built into the ignition module.
The module looks at the time in current limit to adjust the dwell on the fly. With a coil being mostly inductive the current through the coil during dwell is a ramp. Once the current reaches a certain level, the ignition module limits the current to hold that level of charge.
If the length of time in current limit is too long, the next cycle reduces the dwell. And conversely will increase the dwell if the limit isn't reached for a long enough period of time.
A waste spark system has half the available dwell as a CnP system. Although on an 8-cylinder at 6,000 RPM it is still 10 msec. Plenty of time for full coil saturation.
Since a DIS system needs to measure the time in current limit, it may error out if no current is ever seen. And, this current can not be supplied by a resistive load. That would cause the ignition module to eliminate dwell.
well that would pretty much explain it. now does that mean you can't wire a mds dis box to fire them? or maybe bypass the electronics of the coils and have the dis control them just as it would the normal stock coils(just + and - of the primary side) and just wires the 2 together to make wasted spark, or would that be a waste of time over just using the stock coil.
well that would pretty much explain it. now does that mean you can't wire a mds dis box to fire them? or maybe bypass the electronics of the coils and have the dis control them just as it would the normal stock coils(just + and - of the primary side) and just wires the 2 together to make wasted spark, or would that be a waste of time over just using the stock coil.
That would be a waste of time over using the stock coils. Besides, there is no way or nice way to bypass the built in ignitor. It would take some serious surgery to do it.
The problem is most likely as speculated a problem with too low of a dwell value. It takes time for the ignitors to turn "on", which takes away from overall dwell time. So if you have a stock setting of say 5 ms of dwell, and it takes 2 ms for the ignitor in the coil to change to an "on" state you now only have 3 ms of dwell time.
That would be a waste of time over using the stock coils. Besides, there is no way or nice way to bypass the built in ignitor. It would take some serious surgery to do it.
The problem is most likely as speculated a problem with too low of a dwell value. It takes time for the ignitors to turn "on", which takes away from overall dwell time. So if you have a stock setting of say 5 ms of dwell, and it takes 2 ms for the ignitor in the coil to change to an "on" state you now only have 3 ms of dwell time.
of course it couldn't be as easy as just hooking the trigger + & - together and using using the main coil wires to charge and dis charge/fire it.
oh well.
???,
Corner Worker posted in the Power Adder forum that you guys have the N* setup working now. What was the solution to the problem you guys were having? Was it the wheel, the position of the reluctor, wiring, or the code constants?
???,
Corner Worker posted in the Power Adder forum that you guys have the N* setup working now. What was the solution to the problem you guys were having? Was it the wheel, the position of the reluctor, wiring, or the code constants?
well a little bit of everything lol
but yes its running very good right now on the s_aujp with a wide band and 3 bar on order. to try boost soon.
what caught us up was a few things, first the code stuff was almost dead on, ref turned out to be 65* for us. not 70* but that wouldn't have been to big a deal. here's how it went... I still can't believe it worked lol. very happy
first when he made the wheel by hand, it was within a few .001ths of being dead on tooth spacing and stuff to the cad/lazer cut out one. but it was a little bigger, and thinner. like less than a 1/4 in bigger, and 3/16 thick, where the new one is 1/4in thick.
but we were going by the wheel being labled #1 & #2 tooth. so he lined sesnor A up to #1 at TDC and mounted everything up. well instead of getting 10* base we got 38ish with a dial back timing light. I then tried all kinds of numbers in the code and got nothing normal looking, but it did run fine on the base timing up to about 4500rpms. which seemed right to me at the time being a stock tpi tune on a lt1. figured it broke up because of the tune, not the wheel or sensors.
so next he moved the sensors down untill getting 10* base, which since it wasn't working, he didn't remake the bracket, just kinda temp as a test. so then I tried code stuff again and while it was different, it seemed better on the light but the car ran way worse. again, using a dial back timing light. flickers all over the place.
so then I'm like blah, maybe this doesn't work... and another buddy of mine said he could do up a wheel at work without getting in to much trouble and ship it down for us. so since the new wheel was a tad smaller, cornerworker remade the sensor bracket to aline to one tooth down from numbered 1(which is 27*) and made sure the sensors were 27* apart because of the smaller size. so we were sure about the spacing.
then the car ran much better, but timing on the light was off, so I tired more code changes to get it to show right. we hit upon 75* ref running best and even thou the light showed a little high at idle, any small rev where TP displayed say 44* we got 60+ on the light, and going up from there. but driving the car, it ran fine, pulled clean to over 6k no knock retard. we were stumpped. but then after posting about are failure, six_shooter asked if we were by chance using a dial back light, which we were, with just a pointer at TDC off the wheel. using the dial back for everything. he posted that normal dial backs dont work with a wasted spark setup, something I did not know, and I'm sure now we fought that thru this whole project. so with this info, I called corner worker, he then laid out the timing on the wheel itself and with the dial set to 0 the timing was now 10* low to what TP was calling out. but it was everywhere and not freaking out. I had him change the ref from 75* to 65* and bam... its the dead nuts to what is showing on the laptop.
I haven't got to ride in it yet, but he says even with my quick cut and paste tune from the lt1 bin, it runs better and pulls smoother than it ever did with the opti and stock ecm. I still gotta work on the cold starting a bit thou.
the timing values we ended up using are from the A1 bin for max adv and max retard, also ended up with the same 65* ref but since the A1 has a place for the 10* base that seemed weird. anyway, here's the numbers. 65. -54.84 -6.33. I still don't 100% get the math to know what the true max and min timing is from those lol. I can follow along with someone else does it, but can't pulg the numbers in myself and be sure its right.
so I don't really know how the hand cut wheel would have worked, or how much easier all of this would have been without the timing light causing us to chase our tails from the start. but in the end, it works great.
I reread your idea about getting a obd1 ecm to run the lsx based motors and think that's a great idea, and this will make it work well.(firing the lsx coil packs seem to be a different story thou) I'm also thinking of swapping my super ram to girl's formula and putting an lt1 intake on mine once I get my n* setup running. it just plain makes sense once you don't need a dizzy hole cut.
and again incase anyone missed it in the older posts. thanks to everyone that offered ideas up on this project.
So everything made sense that you said, with a little fuzziness around the alignment of TDC to the sensors. Any chance you guys could rough up a crude drawing to show the relationship you used? would be worth a thousand words, as they say....and finish out this thread information neatly.
I will see what I can do next time in on my computer with paint shop. I'm on my phone now,
but for short, sensor A lines up 27* lower than the #1 on the wheel in the cad drawing. or better said 27* before as the crank spins, before the tooth numbered 1 in the drawing, which just happens to fall on the the next tooth down.
87 iroc z was asking too, so he could update the cad drawing with lines so anyone could get the sensor spacing just right too, since unless you deal with laying stuff out. figuring out what 27* apart is can be kinda hard.
OK, that is much clearer, the sensor A is 27 degrees before Notch 1 at TDC. A drawing will help, but that makes sense now.
great job guys, this is pretty cool, you can run an LT1 manifold on a SBC pretty easy now like you mentioned, without a distributor to worry about.(still need oil pump drive stub though......)
yeah, I'm kicking myself now, about a month ago I saw a caprice with an lt1 style intake still on it. I prob could have got the whole thing for cheap, oil punp drive, TB and all. blah. wonder if I could get the egr to work too without the dizzy.
I did up a quick paintshop hack job to a pic of the wheel and e mailed it to cornerworker to double check that its what he did with the sensors as far as middle of the tooth, leading or trailing edge. since I wasn't there when he lined everything else. when he says its right, I'll post it up.
yep, egr would work, same type of valve and solenoid. you would need the external plumbing though from the exhaust manifold or header. it's no big deal, i ran it for my vortec tpi conversion without much trouble.
hmmm well I just stuck sensor B on there to show both, but yeah the sensor's are 27* apart...
I'll see if I can get some true pics of the wheel to sensor's tonight. I thought it was one tooth down, maybe that's not 27*. I'll figure how how he mounted it forsure.
sensor "A" needs to be pointing at the notch that is the very next one below the one marked "1". just go one down. The sensors are 27* apart. So sensor "B" ends up almost to the 3rd notch down from the labeled "1".
ahhh ok that was my bad. its not 27* down from #1 tooth, its just the next tooth down. i must have got that from thinking the base timing was 27* high with A set to #1 tooth. but that was prob the timing light adding timing there too still confusing me. i need to edit my paintshop hacked up drawing and remove the 27* part and move sensor 2 down and show those 27* apart.
anyways, some quick pics and a video from last night. its dark and the light is to bight(hid Qbeam lol) but still. something.
since we don't have a wide band hooked up and the final plan calls for boost, i haven't spent any time with the start up tune. just e mailed a few changes over that didn't help much. so i don't know yet if it really can fire within a 1/2 turn or needs a full turn to crank up.
im just happy the car is running. I have to make some space in my garage before starting a new engine direction. I think the car needs to drive to the gap in NC before goin under for the turbo build.
???,
Good work, I have created a PDF people can print out to line up the sensors on the trigger wheel attached below. You are lining up the first sensor 15 degrees from notch 1. Were you getting a base timing of 10 degrees with the ECM timing control disconnected with this setup?
Hopefully one day I will get this whole thing up on a bench with a scope to nail out the exact spot the sensors should be in relation to notch 1.
???,
Good work, I have created a PDF people can print out to line up the sensors on the trigger wheel attached below. You are lining up the first sensor 15 degrees from notch 1. Were you getting a base timing of 10 degrees with the ECM timing control disconnected with this setup?
Hopefully one day I will get this whole thing up on a bench with a scope to nail out the exact spot the sensors should be in relation to notch 1.
yeap, this was 10* with the bypass wire unpluged. I'll be printing this out soon for making my sensor bracket. thanks and the pdf was a good idea.
I think I'll be trying this on both V8s that I will be tuning in the spring.
One will be using a '7427, running a (Corvette) Crossfire system, using $OD, and hopefully a 4L60E. System is about half installed now. I will fire it and do initial tuning using the dizzy.
The other will be using a '7730, and at least starting with S_AUJP, and then switch it over to a 1 BAR $59, that I need to test. Again I will be doing initial tuning on a dizzy, since this one has more going on than meets the eye. It's a Crower injection being converted to electronic.
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Love this thread.. another sticky from this site..
Quote:
Originally Posted by 89 Iroc Z
He does not show the higher frequencies (aka higher RPMs) current and voltage output of the LS2 and yukon (truck and SUV engines) coil in this video. He speaks very highly of the yukon (truck) coil but my guess is the yukon (truck) coil is more powerfully at low RPMs but drops off at higher RPMS. This would explain why there are different coils for the higher revving GTO, corvette, engines and the lower reeving more torque truck and SUV engines. Either way it is a cool setup.
however..
There is a giant thread on a certain ls1tech site disproving your theory and providing big results for what it is. A simple coil swap. Having actual heat sinks are the key. I suggest reading it, I can pm the link if you like. I don't know if the mods get mad if you post links to other tech sites or not.
Yes the LSx coils are 4 wire with power, trigger, ECM and power grounds.
The LT5 DIS operates like the others where the ICM provides the power ground to the coils acting as the trigger. I decided to use that power grounding as the "sequencer" for the LS coils since obviously the ECM has no such routine. So rather than actually grounding the LS coil, the ICM triggers the circuit we built to provide the proper trigger signal the LS coils are expecting 5v. It also needs to be inverted. The ICM grounds the appropriate coil pair. The power used to power the DIS coils now just powers the trigger circuit and the LS coils get 20a fused BAT power. This is switched on through relays that are also powered from the circuit that was originally providing power to the coils since that is switched power. I know Grumpy had LS coils running in waste spark on his GN. What we don't know us if the LT5 ICM
has some additional intelligence to it that the previous DIS modules didn't have. For example, it appears that dwell is controlled by the ICM in the LT5.
Thanks guys for being interested in this. With the high revving power of the LT5, I believe LS coils could really benefit performance.
The fourth wire is Ref Low, which is a misfire diagnositc for the PCM. All four coils for each bank are tied together leaving a per bank diagnostic signal. This combined with the crank sensor is used for misfire diagnostics, required by OBD2.
Grumpy DID have LSx coils running on the GN, but I'm pretty sure he used an eDist unit for them.
Very interesting stuff going on here, I just wish I was keeping up with it better, as in using it on my car! Maybe the expense will get worked into the budget somehow?
Very interesting stuff going on here, I just wish I was keeping up with it better, as in using it on my car! Maybe the expense will get worked into the budget somehow?
if your talking about the coil packs. it really isn't that much these days. the junk yards are full of the coils/icm and the sensor's. only real hard part is finding a local place to lazer cut a wheel for you, and mounting the sensors.
only real hard part is finding a local place to lazer cut a wheel for you, and mounting the sensors.
or we could have a CT wheel and sensor mount combo package available for purchase. you find the coil packs and sensors, and do your own repin, bobs your uncle...... and you have no need for a dizzy aside from a nice place to put your beer when working on your car. (and spinning your oil pump)
Besides, there is no way or nice way to bypass the built in ignitor. It would take some serious surgery to do it.
