Triggering EDIS-6 using a 72-2 cam wheel in a four stroke?

[hoohaa]

If I'm overlooking something very obvious please forgive me and don't call me an idiot just yet. I've had ideas about the EDIS wheel mounting bouncing around in my head for a couple days now. I would rather not position the 36-1 Escort wheel on my VG30 crank pulley. The location is too low for my liking and I don't like the idea of a wheel out there in front of the crank pulley adding weight and length (I will be using the AC pulley). Also, mounting the wheel is a little tough to do.

 

Instead, I would like to mount the wheel on the passenger side camshaft pulley. Of course the VG30 is a four stroke SOHC motor, so could I simply replace the 36-1 wheel with a 72-2 wheel and still have the EDIS-6 module control spark? Or is there another way I could use the 36-1 wheel on my cam pulley but change the signal somehow through megasquirt? Thinking about all of this makes me wonder why/if we cannot just control the EDIS coil pack directly through MSII, bypassing the EDIS module. I need to read up on this stuff.

 

The only difference I can think of right now is that the wheel would turn at half speed, but there would be twice as many teeth to pick up, so I would think the EDIS would notice no difference. There is also the possibility of the timing belt slipping and throwing things off, but in this case the motor would be in trouble even if the wheel was crank-mounted.

 

Now the trouble is finding a 72-2 wheel that will easily mount to my cam pulley.

 

Escort wheel: 5.75"

ID: 4.04"

Cam pulley: 4.72"

crank outer pulley 5.15"

damper: 4.89"

[BRAAP]

MS-II should be able to control the coil packs by itself, but you’ll need igniters, to figure out the correct dwell, etc. By using the EDIS module, it has the built in igniters, all the dwell info has already been figured so as not to over or under saturate the coils, (could burn up the coils if they are over saturated), all you need to do is plot your timing map in the timing map, check off the appropriate EDIS option boxes in the MS configuration. Bypassing the EDIS module is totally doable, but does require a lot more work, research, set up, configuring etc on your part,. Oh, and if you do not use the EDIS module, don’t limit yourself to the EDIS coil packs. Think more coils, think exotic.. like say 6 individual coils, such as GM LS—x coils.

 

 

As for the 72-2 wheel on the cam or distributor drive, YES, that will work and EDIS would never know the difference. The only hurdle to jump with that is the finding a VR sensor that is capable of reading those small teeth AND still have a strong enough signal to the EDIS module for the module to interpret, especially at idle.

 

If you are wanting to play in uncharted territory regarding EDIS, (and I whole heartedly encourage you to as EDIS is quite robust and fun to play with), I strongly recommend you start out by reading mine and Ron Tyler’s write up on the EDIS Test bench. LOTS of very good useful information there from which to start your own projects regarding EDIS, i.e. the 72-2 wheel spun off the cam or distributor drive.

 

 

The EDIS Test bench. Lots of good info and pics..

http://www.msextra.com/viewtopic.php?t=14920

 

 

 

Some more good DIS ignition meat with info regarding EDIS…

http://forums.hybridz.org/showthread.php?p=666236

 

 

 

My own Mega Squirt w/EDIS-6 success story

http://www.msruns.com/viewtopic.php?t=15436

 

 

Here are a few teaser pics from the EDIS test bench…

 

 

 

 

 

EDIS-8 running full tilt…

 

 

[olie05]

Regarding the 6 coil setup, megasquirt will do a wasted spark setup with the VB921 coil drivers. You would have to install six of them into your case (not an easy packaging excersise). Megasquirt does dwell control, but you do have to put in an initial number, such as 3.0ms to start off with, and MS will do the rest for varying speeds/voltages etc.

 

The cleanest install would be individual coils controlled by MS. No EDIS modules on your fenders and no unsightly plug wires from the fender to the spark plugs.

 

Megasquirt will also do COP style firing (non-wasted spark) If you run the cam trigger wheel like you are saying. Your options are pretty unlimited with megasquirt.

[hoohaa]

I've always assumed COP would be hard to do on my budget. I would love to have the cleaner engine bay that COP would give me though. Are you running COP? What coils are you using? I have a pathfinder manifold on my VG30 and I could even hide the COPs under the manifold if I knew of some that were small (and affordable) enough.

[hoohaa]

 

 

I remember this picture from when I first started researching EDIS-6 ignition on this board. Very nice!

[Matt Cramer]

To make Megasquirt-II fire multiple coils directly, you'd need the MS2/Extra code. You'd need to run wasted spark as it has only four coil outputs.

 

I've heard of one guy who was running a 72-1-1 distributor mounted wheel to control an EDIS module. He said he was using some sort of Mazda VR sensor.

[hoohaa]

Matt, thanks for the reply and also the great product. I ordered my MSII and stim from you and it was at my door in three days complete and nicely packaged.

 

I have already modded the MSII to run MSII Extra code, I just have to load the code. About the EDIS: I am still looking into this, but here are my initial thoughts and assumptions:

1. The EDIS-6 coil pack receives three signals through three wires from the module charging the three coils for the three pairs of cylinders.

2. MSII Extra has a nice trigger wheel decoder that I can set up to do just about anything, including running a plain 36-1 wheel right off of the cam.

3. MSII Extra has four (or perhaps six in the beta code?) ignition outputs if you do the mods and add the transistors, which is not that hard to do.

4. I could have MSII Extra read the cam trigger wheel and directly operate a single EDIS-6 coil pack through three of those four spark outputs. I would basically hook up the three spark outputs directly to the three wires on the coil pack.

 

I'd think this would be even better than the regular EDIS-6 setup since MSII will be able to cut spark for rev limiting and launch control, etc. One negative is the fact that the EDIS-6 will no longer default to 10 BTDC in this case since the EDIS control module will be removed.

 

What do you think? I don't really NEED COP, it would be nice, but I think triggering the EDIS-6 pack would be just as good for me, especially since I already have an EDIS setup.

[Matt Cramer]

Having the MS-II drive the EDIS coils through a 36-1 cam wheel ought to be pretty straightforward; you'll just need to add the input and output mods and specify a few trigger angles. You could also use a 12-1, 18-1, or other missing tooth cam wheel where the base teeth are a multiple of six and there are at least 12 teeth.

 

MS2/Extra has only four spark outputs at the moment.

[Brad-ManQ45]

hoohaa:

 

I purchased 2 sets of GSX-R coils on ebay for about $45 + shipping.

 

Six VB 921's and resistors will be about $36. Since AI will be utilizing the GPIO board for my 4L60E, I will put the VB's in that box...

 

You WILL have to do wasted spark for COP on a 6 banger or V8.

 

I am going to drill the back of my dampner and put in 12 magnets (one backwards) and use the MSII wheel decoder for my COP setup.

 

My '83ZXT has the engine and T5 out, tearing down engine compartment to fix inner fender/battery tray/pass firewall, will then paint entire engine compartment, then start on all bodywork and paint for exterior.

 

Hopefully by March will have it MSII'd with GPIO and intercooled, all back together for SEZ!

[hoohaa]

WOWZERS! I saw GSXR coils for even less than that on ebay. Very nice! It would be fun to go that route also because I could switch to non-wasted spark COP as soon as MS supports it.

 

Excuse my ignorance, but do those "coils" just push down on top of our spark plugs and sit there?

 

Here are a few pics of what I'm looking at for mounting the EDIS wheel to the crank pulley:

 

 

 

 

 

 

 

This is probably the easiest route to go, although the 72-1-1 cam trigger would be cool. Why fabricate a new wheel when I have a good escort wheel already? I have to hold myself back from acting on these crazy ideas sometimes.

 

A question for you machinists: If you were in my shoes and you needed to mount that escort 36-1 wheel to the front of the crank pulley as you see it pictured there, how would you do it? I can't machine down the AC pulley, as I believe BRAAP did, since I will be retaining AC. I don't have a lathe here, but I do have a welder, a drill press, and basic measuring tools like calipers, mics, and dial indicators.

[z-ya]

To use an EDIS-6 module, you must use a 36-1 wheel. The nice thing about EDIS is that it has a limp home mode. If something in the MS timing output signal path fails, the EDIS will fix the timing at 10deg. The EDIS system is self contained, and doesn't need the MS to operate.

 

If you want individual coils per cylinder, use the LS-1 coils (or any other with the ignitors built in). Figuring out where to put 6 VB921 drivers, and then mounting them for heat dissipation and reliability is a lot of work (and trial and error). GM already did all the work by integrating the driver in the coil. If one fails on a long trip, you can get one at any parts store.

[zbigtim]

A question for you machinists: If you were in my shoes and you needed to mount that escort 36-1 wheel to the front of the crank pulley as you see it pictured there, how would you do it? I can't machine down the AC pulley, as I believe BRAAP did, since I will be retaining AC. I don't have a lathe here, but I do have a welder, a drill press, and basic measuring tools like calipers, mics, and dial indicators.

 

Take a look at my thread. On post #14 I explained how I mounted my escort wheel. I too needed to retain the A/C pulley. Although it looks like the crank pulley you have from the VG30 is stamped steel and not cast like the L28 crank pulley. This may not work for you.

 

http://forums.hybridz.org/showthread.php?t=122334

[Brad-ManQ45]

Yeah, the coils go on the plugs - no spark plug wires.

[WizardBlack]

If I understand correctly with EDIS and MS2, you can use the coil on plugs or coil NEAR plugs setups but it will still be pairs of wasted spark? I've seen coil near plug and I like that setup, but I know there are only three drivers on the EDIS module. Can the module fire TWO of those coils (per output) without being damaged or sacrificing coil output?

[z-ya]

If I understand correctly with EDIS and MS2, you can use the coil on plugs or coil NEAR plugs setups but it will still be pairs of wasted spark? I've seen coil near plug and I like that setup, but I know there are only three drivers on the EDIS module. Can the module fire TWO of those coils (per output) without being damaged or sacrificing coil output?

 

Use COP coils that have the igniter built in. It is a much better solution that using VB921 drivers in the MS-II. Yes, there are three ignition outputs, so in a sense you are firing two coils when only one is required. With COP you have one coil per cylinder, unlike real wasted spark setups that share a coil between cylinders. In this case one cylinder always get slightly less spark than the other.

 

The LS-1 and GM truck coils work great, and are easy to find used.

[Nismo280zEd]

Why is it better to use built in ignitors than use the VB921 off MS?

We plan to run wasted spark with COP on the 911, from the diagramns i have off of the MS site, you only need 3 VB921 not 6 like mentioned here. I don't see the advantage of having the built in ignitors honestly it seems like more of a hassle when trouble shooting time comes along.

[z-ya]

The ignitor is electrically designed to fire that coil. As long as the maximum dwell is not exceeded for an extended period, it will be very reliable. The whole assembly is designed to be in the engine compartment, and is potted (sealed). The driver is extremely close to the coil, minimizing resistive and inductive losses (more energy to the coil). OEM components are usually super reliable. You can get a new one at any auto parts store if you have a failure.

 

Using VB921s, you need to mount them on a heat sink, and seal them. If you mount them in the MS, you will have long wires from the VB921 to the coil. Plus, having all that inductive noise inside the MS is not such a great idea.

[olie05]

Use COP coils that have the igniter built in. It is a much better solution that using VB921 drivers in the MS-II. Yes, there are three ignition outputs, so in a sense you are firing two coils when only one is required. With COP you have one coil per cylinder, unlike real wasted spark setups that share a coil between cylinders. In this case one cylinder always get slightly less spark than the other.

 

The LS-1 and GM truck coils work great, and are easy to find used.

 

In the case of having three ignition outputs, wouldn't it be better to actually waste the spark? i.e. not send full spark energy to the exhaust stroke piston? After all, this is the point of wasted spark, and you are only asking the charging system for power for one coil, rather than two.

 

so rather than LS-1 or GM truck coils, something like this (assuming it has abuilt in igniter:

[WizardBlack]

In the case of having three ignition outputs, wouldn't it be better to actually waste the spark? i.e. not send full spark energy to the exhaust stroke piston? After all, this is the point of wasted spark, and you are only asking the charging system for power for one coil, rather than two.

 

so rather than LS-1 or GM truck coils, something like this (assuming it has abuilt in igniter:

 

Wasted spark is for design convenience, fewer parts and emissions. That's about all I can see being a benefit for it. You can't control how much 'power' is sent to one cylinder versus another. The coils are completely blind.

I think coil near plug (CNP) or coil on plug (COP) is by far the best. Almost all new sports cars seem to be going to it. Sportbikes which have high specific output and high rpm capability always use them.

[Six_Shooter]

I know this is an old thread, but just wanted to say for sure that the above pictured coil, twin post GM does NOT have a built in igniter. It is a simple coil with twin high tension outputs. There is a positive and trigger connection on the bottom side (below the plug wire towers), that connect directly to the ICM (Ignition Control Module). Only way around the need for the GM ICM (which would be an easy way to get a DIS ignition BTW), would be to use the MSD coil adaptors and only use the coil side of the adaptors to connect to an ignitor or trigger source.

I can get pics of these coils if need be.

 

Now the use of the GM ICM with these coils would be very easy to set-up. All it requires is a 7x trigger wheel (6 equally spaced and one "home" signal which IIRC is 10 degrees before #4 TDC on the original 6 cyilnder application). The timing is adjusted via the ECM through 4 other connections, which are the same as a GM elecronic remote coil dizzy. The engine will run without any ECM connection as the base timing is set in the ICM, and deciphers what coil to fire on it's own.

The 4cyl variant also uses the same trigger wheel. I don't understand quite how that works, but I found it rather interesting when I had my GM 2.0L DIS crank and my GM 60 degree V6 crank side by side and the trigger wheels were identical. I don't recal where the home signal had to be refernced to for the 4 cyl though.