LSx Coilpack Conversion - Tuned SR ECU

[GroundPerformance]

Just looking for confirmation on the basic wiring schematic I put together since this will be my first time doing this conversion and have research enough information I need. Pinouts and dwell settings is not listed to make the diagram generic and I already have all that info as well. This will be used on my KA24DE-T Project running SR ECU/Harness. Thanks!

My Specs
- S13 SR20DET ECU
- Moates NEMU RT Board
- TunerCode Firmware
- LSx Coilpacks

[codyace]

Looks right to me. On my personal car I wired the ignitor across, and then used the existing coilpack harness plug to make a seperate subharness for my coilpacks...and used that 12v source to supply 12v to the coils.

[GroundPerformance]

Originally Posted by codyace

Looks right to me. On my personal car I wired the ignitor across, and then used the existing coilpack harness plug to make a seperate subharness for my coilpacks...and used that 12v source to supply 12v to the coils.

I'm planning on doing the same by re-using the coilpack harness as the subharness to the LSX coils. I just wanted to use a relay to get more power going to the coils and using the stock coil power as the relay trigger. Thanks for the input.

[codyace]

I'm curious as to why you'd need to add another relay to supply the 12v to the coil packs themselves, when the factory wiring already does that? I assumed that if it had enough amperage to fire 4 coilpacks as it was, that it should be plenty to supply power to 4 LSX based ones no? I'm obviously open for suggestions otherwise, and will change my setup accordingly if I discover the error in my current setup.

[codyace]

Off topic, but for what it's worth:

For those curious, you can have Magnecor (MAGNECOR Race Wires: WELCOME TO MAGNECOR!) create custom length wires for you that utilize a FWD SR20 plug boot on one end (with a solid long shank boot that goes into the spark plug well easily) and a LSX coil boot on the other.

Sure the LSX ones fit, and sure you can make your own with MSD straight boots and that sort (which I did), but let me assure you that they are a relative PITA to secure onto the actual plugs (as in clipping them on). Atop of that, upon removal they are an even bigger PITA, as you need to remove them very carefully/appropriately in order to not separate the boot and or rip the wire from your crimp itself.

To me the cost is really hard to justify making your own if you're going to mount them anywhere aside from the right atop the fuel rail area.

-$55 or so for 25' of bulk wire (6' is another option at like, 20 a section but if you mount these on the firewall, or shock tower etc etc it's not nearly enough...in fact if it's going to be the fuel rail area you may as well try to use the stock plug wires from the coilpcaks)
- $16 for the coil boots
- $11 for the plug boots
- $10 to 15 shipping/tax , adds up to 92-97 bucks...

Magnecor only cost me 115 shipped...to me the extra few bucks is worth it, as there is no goofing around making your own, there is a warranty, and you know it works. Obviously the best solution would be to find a DIY plug boot kit that had a long shank (like a FWD SR20, or a Honda) but I couldn't find any. You could also purchase a MSD wireset for a Honda and then cut/crimp your own ends on, but it's still right on par with the cost of the Magnecor set

(No I don't work for Magnecor, nor have any association other than a good experience in having my plug wires made)

[GroundPerformance]

Originally Posted by codyace

I'm curious as to why you'd need to add another relay to supply the 12v to the coil packs themselves, when the factory wiring already does that? I assumed that if it had enough amperage to fire 4 coilpacks as it was, that it should be plenty to supply power to 4 LSX based ones no? I'm obviously open for suggestions otherwise, and will change my setup accordingly if I discover the error in my current setup.

I've measured the voltage and amperage before that was going to the stock SR coilpacks and while it does provide enough power. There's still more room to be had by just adding a relay and direct power which increases power from 11~12v to 14~15v. From my experience most coils will take up to 16v maybe even higher.

Yashio sells this product to produce the same concept to the stock SR Coilpacks.

[codyace]

But aren't the LS packs designed to work the same in a specified voltage range as far as the 12v (as in, 10.5v to like 14v)? I can't see how power supply is going to affect how better/worse t works, as that's controled via the Signal wire from the ECU, and the dwell length specified in the ECU controlling how long it out puts the spark (which is self contained in the unit itself).

Again I'm not trying to be a smartass, just trying to sort the situation out. I had an iginition amp (XS Engineering Power Pack II, similar to the HKS DLI and the sort) in my car for a long time with the SR coilpacks, but that boosted the power going into the signal side of the coilpacks, not the constant power side of them.

[GroundPerformance]

I was initially considering MS3 as my Management system and this is where I got the voltage info. Again I'm sure it would work regardless but since I'm wiring mine at the beginning best to deal with it now. Below is a link about MS3 and Ignition settings. It talks about Dwell time duration and assumed applied voltage of 14v to the coil packs.. Should be under Maximum Dwell Duration setting on the bottom of the page.

Megasquirt-3 MS3 Tach input and ignition outputs

[Yellow4g63]

Here are the Dwell tables for :

2001 C5 Corvette LS2 Milliseconds



2004 Silverado 5.3 LS2 Truck coil



Found on nico in one of the LSX coil pack conversion threads. hope it helps some what.

[GroundPerformance]

Thanks for the tables.. This actually confirms the Dwell Settings I was looking to put which is between 3.5ms ~ 3.6ms.

[GroundPerformance]

Just another good read on Ignition Coil Dwell Calibration. Shows some good spark results in upping Voltage/Amperage to the coils and adjusting dwell time accordingly.

Ignition Coil Dwell Calibration

[codyace]

I still don't see where there is a need to increase voltage to the 12v+ constant power terminal. If anything, there are examples of guys on 16v+ systems that have ruined the coil packs, which is another thing to consider (but then again, I'd say there are maybe only 1 or 2 16v systems on a 240 ever, but more on GM"s)

With electronics in general, simply applying more voltage to something does not always mean it's going to work as reliably (or better). I'm not trying to be a jerk with this, but I think there are bigger fish to fry on the car then getting more voltage TO the coilpack, especially when it's specifically designed to work at 12v. Gotta remember there are 1000hp+ guys on the factory coilpacks in GM's...all running 12v systems.

So while supplying the 'signal' to the coil with more voltage is a godo thing, and a non issue (again, exactly how those power packs, and ignition amps work), supplying more voltage to the 12v power source is, as it's overextending their design. The last thing I'd want is having 14v or whatever going to them, and potentially melting the windings.

[GroundPerformance]

Highly doubt upping to 14v will do that much harm if any. Thanks for the input. Again its something I've always done in terms of Ignition and Fuel systems. 12V is simply not maximizing its potential. Kenne Bell is still in business and actually does the same logic.

Kenne Bell Boost-A-Spark

Kenne Bell Boost-A-Pump

[GroundPerformance]

Originally Posted by codyace

So while supplying the 'signal' to the coil with more voltage is a godo thing, and a non issue (again, exactly how those power packs, and ignition amps work), supplying more voltage to the 12v power source is, as it's overextending their design. The last thing I'd want is having 14v or whatever going to them, and potentially melting the windings.

You lost me on this statement on how increasing voltage on the ignition output signal to the coil is a go do thing. Concept of the signal and 12v source to me is just like a standard relay. 12v is what provides charge/power and signal is just plain trigger since most ecu cant directly provide that much current. I'm not trying to be a Jerk also It's just something against how I understand things. Maybe somebody else can elaborate.

[codyace]

Originally Posted by GroundPerformance

Highly doubt upping to 14v will do that much harm if any. Thanks for the input. Again its something I've always done in terms of Ignition and Fuel systems. 12V is simply not maximizing its potential. Kenne Bell is still in business and actually does the same logic.

Kenne Bell Boost-A-Spark

Kenne Bell Boost-A-Pump

Kenne Bell makes a nice product, but we were running boost a pumps and Vortech FMU's before we could afford real EMS's, and Boost a sparks is an adjustable version of the HKS DLI, XS Engineering Power Pack, and whatever else is out there. I can assure you, boost a pump is one cleaverly repackaged bandaid.

Again it doesn't increase the voltage on the 12v side of the coils, all it does is increse the signal side/activation side.

[codyace]

Originally Posted by GroundPerformance

You lost me on this statement on how increasing voltage on the ignition output signal to the coil is a go do thing. Concept of the signal and 12v source to me is just like a standard relay. 12v is what provides charge/power and signal is just plain trigger since most ecu cant directly provide that much current. I'm not trying to be a Jerk also It's just something against how I understand things. Maybe somebody else can elaborate.

I may have typed that wrong, my brain to fingers link is sometimes off.


Most ECU's can't send a strong enough signal (SR for example is 5v, and the ignitor translates it into 12v), that is true. What I'm getting at is the fact that the LS pack has it's ignitor built in...that is, once that signal wire hits the coil (which is a relay in essence, you are correct) it fires off. The thing is, just because you are applying more voltage to the 12v constant power side, isn't going to make the final spark any more, or less. So putting 14v again isn't going to help, nor hurt...and is redundant to me.

We may be arguing the same thing here. All I'm saying is no need to fix what isn't broken. Feed it 12v like every other GM car that rolls off the assembly line, and you'll be fine.

[GroundPerformance]

Originally Posted by codyace

I may have typed that wrong, my brain to fingers link is sometimes off.


Most ECU's can't send a strong enough signal (SR for example is 5v, and the ignitor translates it into 12v), that is true. What I'm getting at is the fact that the LS pack has it's ignitor built in...that is, once that signal wire hits the coil (which is a relay in essence, you are correct) it fires off. The thing is, just because you are applying more voltage to the 12v constant power side, isn't going to make the final spark any more, or less. So putting 14v again isn't going to help, nor hurt...and is redundant to me.

We may be arguing the same thing here. All I'm saying is no need to fix what isn't broken. Feed it 12v like every other GM car that rolls off the assembly line, and you'll be fine.

Looks like I will be retaining the stock SR Igniter in place. I'm still leaving the relay redundant or not. Thanks for the info.

[blundar]

codyace is mostly right, but not necessarily for the right reasons.

1. You need to drive the LSx coils straight off the ECU, no ignitor. The LSx coils are smart coils with a built in ignitor module designed to be driven off logic levels. If you put an ignitor in the middle, you typically invert the signal. Doing so will cause the coils to fire at the wrong time because they fire on the falling edge ALWAYS.

2. 3.6ms dwell is pussysauce for these coils. There is a video out there if you look around of Bruce Bowling (i.e. Megasquirt creator) doing a test with an oscilloscope to determine optimal dwell settings for the coils. If I remember right, he came up with ~5.5ms dwell for the LS1 coils and ~5.25ms for the LS2 truck coils. I believe he was testing at 12V. At this level of dwell, these coils get hot a little quickly, but they are beefcake. I've run them on roadracing vettes above 4.5ms dwell and had the cars do 45 min lapping session running awesome. I haven't seen a significant drop in coil life on any of the LSx things I've tuned that have had the dwell jacked up. The default configuration for the BigStuff3 typically runs the coils at 5ms dwell, battery compensated. I typically run them at about 3.6ms at idle / low RPM and step the dwell up when you're going to have boost / actually need it. I've done a bunch of RB25/26 cars with great luck with these coils but no SR20s.

3. On the whole voltage issue... You typically have a dwell vs. voltage table in the ECU. The point of this table is to adjust the dwell to charge the coil to a uniform current level across varying voltage conditions. LSx coils might be 'smart' but they're still just a big inductor. The strength of the spark produced is determined by the strength of the magnetic field in the inductor, which is influenced by two factors - voltage and how long you charge things. The dwell battery table varies the charge time to normalize the charge current versus voltage. Charge longer at low voltage, etc. Bottom line: if you have a proper dwell/battery table, it shouldn't matter what voltage your coils are at AS LONG AS YOU HAVE ENOUGH DWELL TIME. This is rarely an issue at idle, but you can run into issues at high RPM when there is less time to charge, especially if you're only running one coil. With 4 coils on a 4cylinder, this isn't an issue unless you're talking 10K+ RPM.

[blundar]

Originally Posted by codyace

Kenne Bell makes a nice product, but we were running boost a pumps and Vortech FMU's before we could afford real EMS's, and Boost a sparks is an adjustable version of the HKS DLI, XS Engineering Power Pack, and whatever else is out there. I can assure you, boost a pump is one cleaverly repackaged bandaid.

Again it doesn't increase the voltage on the 12v side of the coils, all it does is increse the signal side/activation side.

KB Boost-a-Pump are awesome for situations where you'd have to go to 2 pumps otherwise. I've seen ~25-30 increase with the 40A "competition" 20V BAP pretty consistently. The new Vortech units are bad ass too. Same designer, updated product.

KB Boost-a-Spark are great for a lot of domestic (*cough* Ford) applications where you do not have access to dwell control through tuning. In these situations, the only way you can increase spark intensity is by increasing voltage because the ECM is going to run fixed dwell independently of what you're doing. I haven't seen much benefit from these things. Per earlier post, there is virtually NO benefit if you have adjustable dwell via tuning and you're not out of time due to RPM.

BTW, those plug wires you recommended are pretty damn slick. Thanks for sharing.

[Yellow4g63]

Originally Posted by blundar

codyace is mostly right, but not necessarily for the right reasons.

1. You need to drive the LSx coils straight off the ECU, no ignitor. The LSx coils are smart coils with a built in ignitor module designed to be driven off logic levels. If you put an ignitor in the middle, you typically invert the signal. Doing so will cause the coils to fire at the wrong time because they fire on the falling edge ALWAYS.

2. 3.6ms dwell is pussysauce for these coils. There is a video out there if you look around of Bruce Bowling (i.e. Megasquirt creator) doing a test with an oscilloscope to determine optimal dwell settings for the coils. If I remember right, he came up with ~5.5ms dwell for the LS1 coils and ~5.25ms for the LS2 truck coils. I believe he was testing at 12V. At this level of dwell, these coils get hot a little quickly, but they are beefcake. I've run them on roadracing vettes above 4.5ms dwell and had the cars do 45 min lapping session running awesome. I haven't seen a significant drop in coil life on any of the LSx things I've tuned that have had the dwell jacked up. The default configuration for the BigStuff3 typically runs the coils at 5ms dwell, battery compensated. I typically run them at about 3.6ms at idle / low RPM and step the dwell up when you're going to have boost / actually need it. I've done a bunch of RB25/26 cars with great luck with these coils but no SR20s.

3. On the whole voltage issue... You typically have a dwell vs. voltage table in the ECU. The point of this table is to adjust the dwell to charge the coil to a uniform current level across varying voltage conditions. LSx coils might be 'smart' but they're still just a big inductor. The strength of the spark produced is determined by the strength of the magnetic field in the inductor, which is influenced by two factors - voltage and how long you charge things. The dwell battery table varies the charge time to normalize the charge current versus voltage. Charge longer at low voltage, etc. Bottom line: if you have a proper dwell/battery table, it shouldn't matter what voltage your coils are at AS LONG AS YOU HAVE ENOUGH DWELL TIME. This is rarely an issue at idle, but you can run into issues at high RPM when there is less time to charge, especially if you're only running one coil. With 4 coils on a 4cylinder, this isn't an issue unless you're talking 10K+ RPM.

Do happen to know the spark out put of the LS2 coils? I remember looking but couldn't find out. I was comparing them to the spitfire coil packs to show a friend a while back.

[blundar]

~135 mJ if I remember right. It's about the same as a baby M+W Pro-10 box but it's inductive vs CDI so not quite a fair comparison. Do you have data on the splitfires? I'm keeping my eyes peeled for the necessary high-value resistor and current transformers to build a test setup for coils.

In case you haven't seen it:
LS2_Yukon_ign_coil_test.wmv - YouTube

[Yellow4g63]

I thought I had the link bookmarked but I guess I didn't. I kinda remember seeing the info on a skyline forum. I'll search again and post the link.

[Yellow4g63]

OK found it.

Originally Posted by lokiR33

So according to graph 2 i think they are saying that the normal/stock sr20det coils output a stable 20 millijoules up to 8000 rpm, whereas the splitfires output around 30 millijoules

[codyace]

Originally Posted by blundar

codyace is mostly right, but not necessarily for the right reasons.

Hehe, I am a redneck afterall

Originally Posted by blundar

- voltage and how long you charge things. The dwell battery table varies the charge time to normalize the charge current versus voltage. Charge longer at low voltage, etc. Bottom line: if you have a proper dwell/battery table, it shouldn't matter what voltage your coils are at AS LONG AS YOU HAVE ENOUGH DWELL TIME. This is rarely an issue at idle, but you can run into issues at high RPM when there is less time to charge, especially if you're only running one coil. With 4 coils on a 4cylinder, this isn't an issue unless you're talking 10K+ RPM.

But to reaffirm what I was mumbling/trying to explain earlier, the point is that these things aren't going to gain any significant 'advantage' by applying some wacky about of voltage to them, or increasing amperage to them via a relay...as the coilpack itself just uses the 'signal' to work, and the rest takes place (obviously) in the coilpack itself in regard to output/spark. To me the 5v output from the ECU is plenty, and a regular solid 12v source is all it needs... (or am I wrong again here)

Originally Posted by blundar

KB Boost-a-Pump are awesome for situations where you'd have to go to 2 pumps otherwise. I've seen ~25-30 increase with the 40A "competition" 20V BAP pretty consistently. The new Vortech units are bad ass too. Same designer, updated product.

Admittantly I've not used any of the new stuff due to such concern/issues/experience with the older junk.

Originally Posted by blundar

BTW, those plug wires you recommended are pretty damn slick. Thanks for sharing.

I kick myself for even goofing around with buying new stuff to make my own. I've made plenty of plug sets for v8's, and I've never had a single car give me more issues than the straight MSD boots in the SR20 head. I got so frustrated with them, that I was almost willing to go back to stock. The other nice thing is that the wires may cost even less if someone wanted them mounted closer to the engine itself...being that my packs are mounted over where the cruise control stuff is, I needed the longer/custom setup.

[Black240Ct]

i just did this with LS1 coils and a haltech..

set my dwell time to 3 ms and it runs fine.. care going on the dyno tomorrow morning to dial the coils in.


I had moroso make wires for me with fwd SR caps or what ever.. but they are too long and stand up about 1/4 inch or so about my s14 sr, and the rubber caps on the wires dont have a large enough grommet to fit around the hole on the SR valve cover (if they were they right height)

i tried searching for a code or something to match up with s14 SR20DE plugs but the inter-web had nothing for me... plugs still work just dont seal on the VC

[blundar]

Originally Posted by codyace

But to reaffirm what I was mumbling/trying to explain earlier, the point is that these things aren't going to gain any significant 'advantage' by applying some wacky about of voltage to them, or increasing amperage to them via a relay...as the coilpack itself just uses the 'signal' to work, and the rest takes place (obviously) in the coilpack itself in regard to output/spark. To me the 5v output from the ECU is plenty, and a regular solid 12v source is all it needs... (or am I wrong again here)

You're wrong here again. Forget for a minute we're dealing with electricity here. Let's pretend we're dealing with water, to make an analogy. If electricity were water:

-The ignition coil could be modeled as a bucket that you fill with a garden hose. It needs to be filled (charged) with water (current). It can only hold so much water before it is full. When you dump it, the water comes out very quickly.(spark)
-The amount of water in the bucket when you dump it determines how wet you can get things. (energy for spark) You want to get the bucket as full as you can without making a mess from the bucket overspilling.
-You can get more water in the bucket by increasing the water pressure (voltage). As long as you have no restrictions, you'll fill the bucket faster with higher pressure.
-When you have low water pressure (voltage) you can still fill the bucket up all the way by running the hose for a longer period of time. (i.e. more dwell. This is why the dwell vs. voltage table exists)
-If the piece of garden hose (wire) you are using can't handle the pressure because it is too small, you will benefit from switching to a fire hose (larger gauge wire)
-If the faucet you are using is a restriction, you can benefit from using the fire department's bad ass hose hookup. (relay)

Bottom line: charge time (dwell) varies to get the coils saturated with current. If you put heavy gauge wire to the coils and/or add a relay, you'll have less voltage drop to the coils because you've decreased the resistance of the wires feeding them and that will mean you end up with a higher voltage at the coils themselves. A rule of thumb is to measure the voltage difference between the Coil+ and the battery+ with key on. If it is more than 0.25v, you can improve the system's performance with relay+wire. Putting a Boost-a-Spark on the system will only improve things IFF you have run out of dwell time. If you have control over dwell and you can increase it without hitting limitations imposed by RPM, you don't need to do any fancypants shit with coil wiring - you just need to properly tune the dwell-battery table.

Hopefully that makes more sense.

Originally Posted by codyace

Admittantly I've not used any of the new stuff due to such concern/issues/experience with the older junk.

I've literally tuned at least 150 cars with KB BAPs. I've installed at least fifty of the units. I've seen one bad unit. I severely dislike Kenne Bell as a company for other reasons, but I have NOTHING negative to say about the BAP product. One of the most awesome reliable pieces of kit there is IMHO when installed properly. The biggest issue I have seen is people melting stock wiring with the BAP, but it's not the BAP's fault the wiring used for the install is too small.

[GroundPerformance]

By far the best read I had in Zilvia in awhile now. Part of the reason I wanted to keep the relay setup and tuning dwell accordingly.

[AsleepAltima]

question - with a jwt tuned ecu, dwell isnt going to be a problem to worry about - going from the sr packs to the lsx packs, is it?

[Options13]

damn good thread!! resurrection needed.

[TheRealSy90]

Still waiting for someone to just make a plug and play gm coil harness for sr20's >.<