Dominic Sorresso

I've communicated w the guy who designed and builds this. The module works and I was hoping it could be a sub for the LT-5 ICM which has no other replacement. The fact that this module can be configured to utilize
multiple reluctor types, i.e. 9 slot like the LT-5, is pretty great.
The LT-5 ICM manages dwell which required development of that capability for
the MPR unit. Due to the scarcity of LT-5s in Australia, Ryan decided not to support this any further. Really bummed me out since I believe adding
CNP to the LT-5 would provide a performance and mpg boost.

RBob

iTrader: (1)

Probably don't need the dwell control for a substitute LT5 ICM. The early ('92, $D0) ECMs still do the dwell calculations and control the EST regarding dwell and firing point. In fact, the internal ICM dwell is why you can't use the CnP coils with the stock ICM.

So if that is the plan then best to use the ECM dwell/EST signal.

The dwell control in the GM DIS ICMs, which not all do, is to make the dwell as short as possible. Not lengthen it.

Edited to add, checked the '94 $F0 LT5 firmware, it too does dwell control calculations within.

RBob.

anesthes

iTrader: (12)

One of the problems I had with the EDIS was I had no ability to cut the spark with the ECU. Additionally, if the signal from the ECU was lost the EDIS would keep on chugging with it's own advance curve.

I can drive 8 ls2 coils directly with my ECU, and use just about any trigger available, so I ditched the EDIS. Next time I try CNP I'll just use the LS2 coils.

What does the LT5 use for a trigger? Crank + cam sensor? I don't know much about LT5s.

-- Joe

RBob

iTrader: (1)

The LT5 ICM uses a single crank sensor. It is an 8 + 1 wheel with a waste spark DIS setup (4 coils). Trigger wheel is machined into the crank.

RBob.

anesthes

iTrader: (12)

Is this a cost prohibitive option:

http://www.megasquirtpnp.com/docs/mspnp_gP_zr9195.php

I dig C4's but never tinkered with a ZR1.

-- Joe

anesthes

iTrader: (12)

Interesting. The ICM then ties into the ECM ?

-- Joe

Dominic Sorresso

Joe,

There actually are a few MS units running LT-5s today. Its about $2500 but does not handshake w the CCM at this time. Graham Behan formerly of Lingenfelter Performance Engineering installed a GenIII LT-5(only one in existence) in a 93 ZR-1 recently and used the MS unit to run the fuel and spark. He estimated 520+hp at the crank from a 5.7L NA motor.
As Rbob points out the reluctor(9 slot) for the LT-5 is cast as part of the crank. Its actually in the middle of the crank for signal stability.
As Rbob has described it, the ICM acts as a CO-ECM.

Dominic Sorresso

As usual, u are amazing. If in fact the ECM can provide dwell control, does that open up possibilities for replacing the ICM?

anesthes

iTrader: (12)

That was the problem I had when I swaped to a '730 running $58 in my C4, I lost the dash functions (economy, range, etc).

I'm looking at C4's again, although this time LT1 cars. Probably just leave it stock though.

-- Joe

Dominic Sorresso

Joe,

Let me strongly recommend u look at a ZR-1. You can find some very good examples for 10-15k and you will have a car w stock hp higher than any other C4. Plus, there just isn't anything like getting to 5000rpm and realizing you have another 2000 to go. The car pulls top end. A little porting of the plenum and injector housings plus headers gets u to ~ 400rwhp.
If u are looking at C4s, u owe yourself a drive in a ZR-1. There's also a terrific community of owners who offer very strong support. The motor is an anvil. It doesn't break.
If I can help, let me know. There 's a registry member in Manchester.

syntax terror

"I'm using a Megasquirt ECM, but I imagine this is possible with a stock ECM as well. The Delco hackers might be able to chime in on that"
For someone that had a delco ecm this is a option for cop ignition. With a cheap 36-1 trigger wheel and you get full sequential control of 8 coils and a 2 step rev limiter.

anesthes

iTrader: (12)

Which stock ECM can do that?

I know Street Lethal was trying to do COP/CNP v8 with a '730 but the thread died and he never finished.

-- Joe

syntax terror

7165 running 12p$ it should work on other delco ecm's

RBob

iTrader: (1)

Regarding LT5 DIS: yes, it uses the standard 4-wire interface plus an additional wire. This additional wire is a fault signal to the ECM. Don't need to use it, the ICM does similar to the ECM as it counts incoming and outgoing pulses. A mismatch triggers the fault signal.

RBob.

RBob

iTrader: (1)

Unless that 36-1 trigger wheel it connected to the cam you can't do full sequential control of the coils. With the trigger wheel connected to the crankshaft, the best that can be done is firing two coils at a time in a waste spark type of configuration.

RBob.

RBob

iTrader: (1)

Yes, it does open the possibilities. Part of the issue with a replacement LT5 ICM is what features are desired. If it is to be as factory as possible that is a tall order. Right down to mounting it and getting the proper electrical connectors and the ability to mount the stock coils.

Now, if what is desired is an ICM to read/sync with the stock trigger wheel, use the ECMs dwell control, and fire CnP coils, that gets a lot easier. Could design the case to mount in the stock location, but use connector pigtails for connections. Not sure how easy it would be to get the stock style connectors that are molded into the stock ICM. A lot of those type of connectors are not available as a separate piece.

So need to switch to inline metri-pack (or such) connectors which may require some splicing.

RBob.

syntax terror

Yes you do need a signal from the cam but that is much easier to do than the trigger wheel for a v8 running a delco ecm. The coils are not cheap but you can find them at a decent price. I don't have the cost on the module yet but it is an option for cnp/cop on gm v8's and less complicated than the northstar trigger wheel.

Dominic Sorresso

RBob,

The MPR unit would have installed somewhere away from the heat of the motor unlike the stock ICM. Also, while investigating use of the MPR, I realized it may not be necessary to use the current ICM connections. The input for the MPR was the same 4 wire interface, and the LT-5 has an ignition DIAG connector with a very stock and available 7 cavity connector like this one:

https://www.eficonnection.com/home/p...male-connector

In fact, I use it to pull the rpm signal for my shift light.
My interest would be to have something that utilizes the current crank sensor signal to run a CnP setup. The existing connectors would basically stay under the plenum and we might use the space to place the LS type coils there. As you know, I tried several years ago to use the LS-2 coils with the current ICM. Altho it only ran for 45 sec before blowing a fuse, the idle was noticeably smoother. My thought is that having individual coils firing for a high rpm motor like the LT-5 would be beneficial and potentially prodice more power. I recall a thread where Grumpy suggested that part of the magic for the LS motor power came from the CnP setup. And I remember that he used LS coils at one time w good success on his GN.

RBob

iTrader: (1)

Need to define what you want from the ICM. If there is no desire for it to fire a standard coil then don't need a heavy duty driver for it/them. Then if you do want to be able to fire a standard coil, do you also want the ICM to do dwell control?

So lets say, nope, going to use LS coils with built in drivers. OK, that makes them easy to drive. Now, do we want them to fire in waste spark configuration. Or in sequential mode. Need to define the spec as to what is wanted. Doing fully sequential can increase the cranking to start time as the cam signal needs to come around first.

But, we can also get tricky/smart and crank via waste spark mode. Then once the cam signal comes around switch to fully sequential coil firing.

Then for dwell, just use the ECM's dwell? OK, that means that as the RPM increases the dwell time decreases. Hmm, maybe spec the ICM to do some dwell calculation AND to overlap the coils being charged (dwell). Now the coils can be fully charged even at high(er) RPM.

As you can see we can get complicated or keep it relatively simple.

RBob.

Dominic Sorresso

RBob,

The absolute minimum requirement is to have an alternative to the existing ICM primarily because these units are approaching 30 years of service. They are robust BUT everything has an expiration date. And they were built so, unlike the ECM, they can't be rebuilt at least not easily.

Having said that, my objective would be to upgrade the capability of the ignition system on the LT-5 to take advantage of individually firing coils. And I say that because of the higher rpm range of the LT-5 motor. 8 individual coils would still have DOUBLE the time for charging than the stock waste spark coils. And at 7000rpm, a hotter spark would be beneficial. Even without overlapping dwell the individual coils still end up w more time to charge providing better spark at top end.
The LT-5 already has a longer crank to start cycle. It takes 2 revolutions for the ICM to determine where the #1 cylinder is. So I don't think that's a show stopper.
Also the Crank signal is what the ICM uses. Cam signal is only used for pulsing the injectors.
Does that help as a partial spec?

Dominic Sorresso

A couple of other thoughts this morning. If someone were to build a replacement for the LT-5 ICM and they were to market it to the LT-5 community, the largest potential group of buyers would be those that would want a plug n play ie connectors, placement, stock coils. That would be the ideal for the majority of users or collectors. However there is another significant segment that upgrade their LT-5s for performance, and don't have a problem either doing the mods themselves or having some of several LT-5 specialists do the work. We have at least 2 shops here in Chicago that are well known in the community. One of the characteristics of the LT-5 is that there's a lot of DIY work on it. In that regard it is like my Xfire which is what brought me to ThirdGen in the first place.
For the performance crowd, ICM placement would not be as critical. Some other features "would be nice to have" like managing water or meth injection, ignition cutoff, NOS?, change in firing order?, use CNP/LSx coils.

Street Lethal

iTrader: (16)

Dom are you still trying to get Bob to make an EBL for the LT5 lol... ?

RBob

iTrader: (1)

How many were built with the LT5 engine? Since the market is small (6922) you are looking at one very expensive ICM. Just the mold for the main ICM body is likely going to be $100K. Then the development time to replicate what GM did.

I wonder if the stock ICM does overlap coil dwell. I know that other smart ICMs don't, the max dwell is the time available minus the 600 usec minimum firing time. And unless the coil dwell is overlapping the CnP system will dwell the same time as the stock ICM.

Should be within one revolution, not two.

I know that, but if a dedicated CnP ICM is developed can easily use the cam signal. Which is required when fully sequencing the coil firings. My take on all this would be for someone to develop an ICM, harness, brackets and so on for a dedicated CnP setup. Which allows for more creative license in the physical layout.

RBob.

Dominic Sorresso

Well I am all for having an ICM that uses CnP. I'll be happy to beta test.

Six_Shooter

iTrader: (2)

IMO none of that should be handled by the ICM, but rather the ECM, so that it knows everything that is going on and can control, not only the injection of water, meth or nitrous, but command a change in timing and fueling to go along with it. Same goes for limiter/cutoff/2-step. It would be better for the ECM to know what's going on and be able to compensate as such.

That's a simple change in wiring, either in trigger wiring for the coils or swapping around the high tension wires to match the firing order.

Or any other coil that all might need a different dwell time or trigger type. This also depends on whether smart or dumb coils are used in the type of driver needed, which could be a simple jumper change or a software setting depending how the entire ICM would be setup.

TBH it sounds like a change in ECM is really what you desire.

regarding the 1 vs 2 revolutions during cranking, the GM DIS can sync up in one revolution and many times the SFI PCMs will fire in batch fire mode during cranking and then switch to sequential once above a certain RPM and the cam signal is seen by the PCM.

Dominic Sorresso

Ah let's see. Who has re-written ECM code? Hmmm?

Street Lethal

iTrader: (16)

Joe, had a few guys in the DSM world over at the track one night show me that it made no difference whatsoever, as they converted to coil-on-plug on their 4G63's and still needed to run a MSD box, so other than the look of a newer ignition system, it had no real benefit. Was going to try to finish it anyway, but life got in the way, of course...

Bob, is it possible to convert the 9x VR signal to a 4x logic signal, then run the EST fault signal to the coils in firing order? I remember reading this awhile back...

anesthes

iTrader: (12)

There are benefits, but not on a TPI motor. If you were turning high revs, the LS2 coils with built in dwell are fantastic. You also have more stable timing control (lack of mechanical parts that could fluxuate). And it looks cool haha

I'd run LS2 coils on my car, but I don't like bolting things to the valve covers. I like to be able to run the engine with the covers off to adjust the valves. Doesn't leave a lot of options open.

-- Joe

peterc005

Has anyone tried something like the Holley Distributorless Ignition System (P/N 556-101) on a TPI engine?

https://www.holley.com/products/igni.../parts/556-101

Seems like a similar but easier conversion than a Ford EDIS conversion>

Street Lethal

iTrader: (16)

For $600.00, you still need to buy the trigger wheel and sensor mount which is sold separately, not to mention still figure out what your going to do to drive the oil pump. Are you planning on leaving the stock distributor in there with that expensive system, or make a dummy distributor to drive the oil pump, which will add to the overall price. Going the DIY Northstar DIS route is way way cheaper...

anesthes

iTrader: (12)

I have a milodon oil pump drive I used briefly with the EDIS.

I wouldn't touch the Northstar stuff with a ten foot pole.

There is a lot of off the shelf ICM options to run a standalone DIS. Aftermarket electronics are getting cheaper and cheaper.

Holley really is coming out with some impressive stuff, and the cost is very reasonable.

-- Joe

Street Lethal

iTrader: (16)

Holley is not needed though, the stock ECM handles everything, and GM parts are easier to get. We're talking coil pack, sensors, brackets, reluctor wheel and oil pump driver. There is no way I would pay that much for a similar system, not to mention the Northstar coil pack and crank sensors can be obtained at any parts store the same day if you're ever in a jam. Biggest obstacle would be the reluctor wheel, but plenty of sources out there to nab one...

peterc005

I'll create a separate thread for the Holley DIS.

anesthes

iTrader: (12)

When I first started this thread I had asked if the stock thirdgen ECM ('165 or '730) could run an EDIS. It cannot.

I realize we kinda went off the rails with the ZR1 stuff, and that's ok, but can a stock '165 or '730 run a northstar ? I've heard grumbles about it over the years but never seen one.

If you wanna tinker with that stuff that's cool, everyone's got a hobby. I'm getting the point in my life where I just want to buy stuff that works, and if it doesn't I can call or email the vendor. Be it MS, Holley, etc.

-- Joe

Street Lethal

iTrader: (16)

For now, I'm honestly very happy with the fat cap distributor and flamethrower coil though, but was thinking about adding an MSD box if I stick with it, that is for sure. But yes, the stock OBD1 ECM handles the Northstar DIS no problem. This is on a '7060 TBI ECM...;

RBob

iTrader: (1)

Yes, as long as there is a cam signal to sync up the firing order. I was actually going to do this using a modified distributor. I added a cam sync signal to it so that it would provide both the crank and cam signal. Even started to build the sequencing electronics. But life got in the way and it all sits. Have the modified distributor, eight LS1 coils, connectors, and so on.

But now I'd rather do the N* setup on that engine. Have all I need for that except the crank sensor bracket.

RBob.

anesthes

iTrader: (12)

N* is a 36-1 trigger, or two different triggers?

There is a thread on this from like 2003-2004, but it kinda went off into nowhere.

I have a 36-1 SBC wheel, trigger bracket, etc but it sandwiches between the balancer and the crank pulley which I don't like (especially on a blower car)

-- Joe

RBob

iTrader: (1)

It is a 24x wheel with a different pattern of missing slots in each quadrant. Syncs up within a 1/4 to 1/2 turn. Uses two crank sensors 27* apart. Can also use either crank sensor and a cam sensor. But takes a lot longer to sync up.

Is that the "doing away with the distributor thread?" I need to reread that one.

I don't like doing it that way either. Need to shim the accessories for belt alignment.

RBob.

Six_Shooter

iTrader: (2)

I've had spaced out pulleys on a couple of my engines now, one was a year round daily driver for a couple years (took it apart for upgrades that haven't got done... yet) and one is a spring to fall mostly daily driver. Never any issues with belts or alignment, etc. due to the spacing. As long as everything gets torqued down it should never come loose.

anesthes

iTrader: (12)

The problem is your crank pulley is hub centric (well it is on a SBC). The spacer is roughly the same thickness as the nipple on the pulley, so now you are trying to center the pulley using just the 3 bolts. You will get run out.

Blown motors snap crank snouts enough as it is. Adding more imbalance to an already spaced out crank pulley is not a great idea.

-- Joe

anesthes

iTrader: (12)

Yeah, I know Bruce got involved and everyone made it sound easy yet nobody in the thread actually completed it.

Honestly, the whole crank trigger thing sounds insane unless you've got bolt on stuff that requires no engineering. I know Rob thinks the Holley setup is big money, but if someone sold an SFI approved balancer with integrated wheel and a bracket that doesn't interfere with standard accessory brackets I'd pay good money, and so would others.

This is the wheel/trigger/bracket I was using briefly with EDIS:




-- Joe

Six_Shooter

iTrader: (2)

That's why the crank triggers are hub centric...

The MSD crank trigger that was on my T-Bucket is hub centric, and teh custom one that my Grandfather made for my V6 was also made to be hub centric...

It's not a difficult thing to do.

Six_Shooter

iTrader: (2)

IIRC there was at least one person who completed the N* DIS swap in that thread, or a thread that was a spin off from it.

Many people have used the MSD crank trigger with blown engines for many years without issues caused by the crank trigger.

If you REALLY don't want to put the crank trigger between the harmonic damper and the crank pulley, it can be mounted in front of the crank pulley.

I really think you're making a bigger deal out of this than it is.

anesthes

iTrader: (12)

The wheel I have is NOT hub centric:



The MSD wheel IS using different inserts, however it is VERY thick which either requires cutting down the back of the balancer (which I did on mine to avoid shimming all the accessories), or shimming everything out at least .250":





Putting it in front of the crank pulley would be interesting in a supercharged application:




I'm not saying you can't make it work, I'm saying it's not optimal. Probably a good reason most people go with the 24x conversion using a vortec cover and wheel. (Although you still need to turn down the balancer)

I've yet to meet someone on the forum that has done an N* DIS swap on their thirdgen, however I did a DIS swap on mine (I started this thread). I bailed on it for the following reasons:

1) The ignition module used prevented me from cutting spark with the ECU, and at the time I didn't realize I could drive coils directly with my ECU.

2) The coil packs mounted on the firewall were quite ugly, and just looked out of place. I couldn't mount them in the front because my turbo was in the way.

3) When I considered going back to supercharger, I realized that the spacer would have caused way too much runout since the blower pulley hangs about 5.5" away from the motor. Breaking crank snouts off is not cool.

I put all the stuff in a box and listed it for sale over a year ago. I've had zero interest in any of it. (wheel, trigger, mount, fancy oil pump drive, coil packs, icm). Yet I've seen a number of people convert to 24x with '411 PCM's in the same time.


-- Joe

Dominic Sorresso

Sorry about going into the LT-5 stuff. I had some knowledge about the DIS module being discussed someone found on pcmhacking.
It's just a bit frustrating to be close but no cigar.

anesthes

iTrader: (12)

No worries, I enjoy technical discussion, and I know very little about the ZR1 so the education was appreciated.

My C4 is an LT1 car by the way. The cheapest ZR1 locally is just under $18k, and it's a '90 and very rough.

The only other ZR1s for sale locally this past year have been 26k and 30k. (a '90 and a '95). They go for big money around here, where the L98 cars are almost given away and LT1 cars are reasonably priced.

If I was gonna spend more than 15k I'd just get a C5. I realize the LT5 is a cool engine, but so is the LS1 and the comfort of a C5 can't really be debated.

I still like my cheap, old '94 LT1 car.

-- Joe

Dominic Sorresso

Regarding reluctor wheels, I believe ATI makes balancers that incorporates a trigger wheel. Also have read about people shaving the balancer or using a thin reluctor wheel without much alignment issue.

Street Lethal

iTrader: (16)

Hmm, what if I told you it's possible to have CnP and SFI w/out a crank sensor...

anesthes

iTrader: (12)

I'd tell you that using a cam sensor only is silly because you (potentially) need to perform TWO revolutions on start up for it to sync up.

I suppose you could modify a distributor and lose two poles 180* out instead of one, which would essentially be a crank sensor at that point.

There used to be a product called an edist that did that if I recall.

-- Joe

Street Lethal

iTrader: (16)

I already made a V8 cam sensor using a SBC distributor, I just didn't get a chance to post anything yet on that thread I started, but that is the reason why I stopped with the Northstar crank trigger because it is no longer needed. Two revolutions is a piece of cake, I kinda hinted to what I was doing above...