A friend of mine, who is not a car guy, saw this article, and passed it on to me. Id like to pass it on to you. There are a lot of links within it...



http://www.ag.auburn.edu/users/gparmer/efi/myfaq.htm

 

What's old is new again...

Greg Parmer goes back to the days of Programming 101. One of the original good guys, BTW.

 

Reading that leads me to believe, one should be able to take a DIS module, and coils off any GM car and run them with a '730 (with the research you have done on reversing the tables to make it work).

Am I wrong?

-- Joe

 

Yep.

The module's 4 interface to ecm leads, are universal in the voltages, and how they work from what I've found.

Just a matter of lining the cal entries.

 

So why arn't we taking coils and dis modules from the junkyard, and tweaking $60 rather than spending money on things like eDist ?

I've been reading a lot on this, and can't see why (I) couldn't use 4 coils from a grand prix (dual cyl waste type) with a dis module, and some tweaking - but I don't know as much as some of you guys about the signal stuff so I dunno what works with what.


-- Joe

 

You can if you're running a V-6, sort of. The DIS module needs to see a specific crank trigger pattern. I'm working on (er.... was before I ran into a couple road-blocks, such as cash....) a way to use the Northstar DIS system with about any Small Block V8, and it wouldn't take much to make it work with other's too....

 

I see.

So what about the ZR1 corvette? If uses 4 coils, a dis module, and crank wheel. The ECM outputs look identical to a '730. Seems like a neat setup. Plus, you'd only need the 4 coils since they're dual output, wasted spark vs 8.

Comments?

-- Joe

 

the problem with the ZR1 stuff is that its PRICEY. and not readily available. The Northstar stuff is the ticket, you just need to spin up a trigger wheel, and use the existing coil pack, module, and crank trigger(I'd use both of the factory ones). the cam sensor is not needed, its only used for sequential injection. Problem for me right now is getting my machinist to spin me up something(my father), then I'd be able to set it up in the lab and play.

this set up should work on any eight-cylinder BTW. I'm thinking a wheel behind the balancer, or something between the balancer and pulleys.

as for code, I believe its just as grumpy says, some spark ref angle tweaks, min and max settings set-up, but there was also some talk awhile back that the signal is inverted, and I had hoped to look at that on a scope, but I still need hardware. its low priority right now.....

 

How much is a northstar DIS module?

eDist is around $300 for the module. Which seems a little pricey but. Ok.. But i'd like to run 4 coils, rather than 8. (I.e, grand prix coils) - which are READILY available.

Then as far as the crank sensor, Grumpy says a '90 caddy dizzy can be used. Have you looked into that?

-- Joe

 

I'm not sure of the caddy that keeps getting mentioned. I know that the 4.5-4.9L caddys run a sequential ecm, and have a hall effect cam position sensor. I don't think it fits in a chevy though, and I have never seen a chevy motor in a caddy that was sequential, other than an LT1. I could be wrong, just never seen the distributor out of the engine to see if its the same. even then, you don't need that with the northstar stuff.

I see the coils and module routinely go for about 120 bucks on ebay all the time. the caddy crankshaft sensors I would think are around 15-20 bucks a pop. SO, if you can make the trigger wheel, you would only need about 160 bucks for hardware, plus some connectors, IF the software can be tweaked to work.

 

What is the crank wheel need to look like? I have been looking for some specs but all I have come up with is lt5 info.

ftp://ftp.diy-efi.org/uploads/dis_lt5_dis2.jpg
ftp://ftp.diy-efi.org/uploads/dis_lt5_dis.jpg

and electomotive designs

http://www.electromotive-inc.com/tri...220-72707.html
http://www.electromotive-inc.com/pro...g_sensors.html

Any one have Northstar crank trigger info?

 

it is on this website messge board somewhere, I haven't looked in awhile. I have it, as a ZIP, but i don't think it will attach, I got from here anyway.

its basically a wheel with 24 evenly spaced notches, with 8 more for syncronizing in between them. Its hard to draw, but they have diagrams.

there are no dimensions, so you have to do some math and eyeballing, but should be doable.

looks like I'll have to dust this off again, get my dad to machine the wheel, and play around.

if you can't find it, i can email it to you. i guess just pm me, i think i can get em.

 

Put it on Craig's site.
Misc Uploads

 

http://www.jpteck.com

Click on the EFI Stuff button. I have some of it there. A couple nice pictures, a .zip file, etc... Not much text description at this point, but seeing threcent interest in this, I'm becoming more inclined to get back in gear on this!

If someone could get me some dimensional info off the trigger wheel on a N* crank, I could finish the drwings of the trigger wheel. From there, it's simply a matter of finishing the bracketry to hold the crank sensors (I'm going to run both, although it will work with just one.) then installing the system. I'm going to try making some calls to see if I can find one locally to get some measurements. As soon as I get the measurements, I can finish the CAD drawing, and share them with people that have SERIOUS interest in this.

 

Did a little research tonight and made a Northstar DIS.pdf just put it up on Craigs site.

ED89

 

i don't think you need much for the dimensions, the reluctor pick-up has a round point, about 1/8" diameter. SO, if the notches are wider than that by at least double, it SHOULD work. the sensor works by the changing magnetic field of the iron/steel being .050" from the sensor head, to much greater than .050".

my plan is to use something like a 3/16" or 1/4" wide notch, at least like 1/4" to 5/16" deep. all on a 8 1/2" wheel. this way, it will stick out above any (chevy)harmonic balancer.

i'm thinking 1/4" thick, so that i might be able to squeeze it behind the balancer.

the two sensors need to be 27 degrees apart, i think i calculated that to be about 1 3/8" center to center for the two sensors based on a 4.025" radius. then you need to just figure out the phasing of the notches to TDC and the sensor location.

hopefully, once i get the wheel machined, i can spin it up on a drill or some other motor, and check it out on a test bench.

 

Do the notches need to increase in size proportionally to the diameter of the reluctor wheel? What about a wheel that is an 1/8th inch thick or machined with an offset, so it can be put between the pulley and the balancer? Will a thinner wheel generate the same signal?

ED89

 

yeah, i think the notches should get larger as you go out radially, but i don't think it matters to a point, since the reluctor measures the zero-crossing, meaning, the ignition module gets a logic signal when the notch is pretty much centered over the pickup. As for an 1/8" thick wheel, it probably will work, but you might get some fringe effects on the magnetics which may make the triggering not stable. If you were to look at the northstar documents, you can see the type of waveform the reluctor makes., kind of a Z shaped thing. the voltage will first go low, immediately swing high, then drop back down to zero again(or the other way 'round) most of the reluctor ignition detectors look for that second 'zero cross' which is why its important to hook up the pickup coil wires in a regular distrubutor correctly.

i wanna find out all this stuff shortly, just need to get the wheel made then maybe i can play with the notch sizes.

 

Yes. As the diameter increases so does the surface speed. So while a .030" notch might work on a 3" diam, at 6" the sensor might not see it.

Depends.

I wouldn't count on it.

GM spends a ton of money on this sort of stuff, second guessing them might not work. On some items while you might get it to work on the bench, it might not *in car*.