I am installing a DIS ignition system on my '85 2.8L. Is anyone else interested in this upgrade? I ask because I plan to fabricate a trigger wheel, unless there were enough interest to get some laser cut ones made up. Laser cutting quantity one is a little cost prohibitive. Quanties of 10 or more would get the cost down some. I sent a DXF file out for quote.
This wheel would mount on the Harmonic damper and I intend to use a 90's Ford (*gasp*) VR sensor mounted to the "magnetic probe" bracket on the timing cover. Not a perfect set-up but a simple and functional one.

Edit 07/24/09: Sensor bracket pattern is available on page 2 post 3 of this thread.---

Edit 10/03/09: It works! check post on page 2 toward the bottom. No wheel needed, just mod the damper.

[This message has been edited by Gravitic Anomaly (edited 10-03-2009).]

http://wot-tech.com/shop/al...trigger/prod_42.html




WOT makes and sells it, and it is of very fine machine work, uses the 3100/3400 crank sensor (side of block sensor)

edit: it also allows you to advance/retard the timing.

[This message has been edited by hookdonspeed (edited 06-03-2009).]

I have seen those. They are a little spendy for me and I do not like how they stick out past the belts. I am sure they work great though. The plate I drew up also has some adjustment in the timing, and it will fit a stock or a Camaro balancer.

i like their setup because the wheel is fixed to the crank position as it should be, the sensor itself is whats adjustable, and its marked with the timing deg

and yea, it is a little more then some other setups, but damn does it look nice :P

I like your plan
I am using DIS, with the crank trigger - and there is ZERO adjustabality in the timing.

[This message has been edited by Pyrthian (edited 06-04-2009).]

quote Originally posted by Pyrthian: I like your plan I am using DIS, with the crank trigger - and there is ZERO adjustabality in the timing.

what crank trigger are you using?

quote Originally posted by hookdonspeed: what crank trigger are you using?

the stock GM one on the crank - reluctor wheel I think its called
it is a 3.1 block & crank

edit: I need a batter pic without all that sun glare....

[This message has been edited by Pyrthian (edited 06-04-2009).]

ah, the oncrank 7x wheel, gotcha, if you got the one from WOT you can put that on the front of your crank pulley and not have to change anything else except maybe the length of the wires.

its not the cheapest route, but it would allow you to adjust.

quote Originally posted by hookdonspeed: ah, the oncrank 7x wheel, gotcha, if you got the one from WOT you can put that on the front of your crank pulley and not have to change anything else except maybe the length of the wires. its not the cheapest route, but it would allow you to adjust.

yes. when I first did the 7730 swap, the original programming was for the alum head, and the timing was way retarded. Had a new chip made to advance the timing. having a simple adjustment would be great. I like what Gravitic is planning, but, I expect either his or WOT's would be kinda a b!tch to adjust tho. but, easier than trying random chips.

At the risk of sounding like a stupid question: What's the benefit for DIS?

What are the increased costs?

quote Originally posted by Austrian Import: At the risk of sounding like a stupid question: What's the benefit for DIS? What are the increased costs?

never wearing out a cap & rotor is the main gain
more precise ignition timing
stronger spark, due to not needing as much recharge
less RF noise
"one less thing to break"
you'll never have moisture in the dist cap

my 7730 swap cost me under $200 in parts from the u-pull-it junkyard.

quote Originally posted by Gravitic Anomaly: I am installing a DIS ignition system on my '85 2.8L. Is anyone else interested in this upgrade? I ask because I plan to fabricate a trigger wheel, unless there were enough interest to get some laser cut ones made up. Laser cutting quantity one is a little cost prohibitive. Quanties of 10 or more would get the cost down some. I sent a DXF file out for quote. This wheel would mount on the Harmonic damper and I intend to use a 90's Ford (*gasp*) VR sensor mounted to the "magnetic probe" bracket on the timing cover. Not a perfect set-up but a simple and functional one.

Really looks good. A this point in time I am in good shape, but I think it would be interesting to know what the total cost of a conversion and pieces involved. Also, if you did manage 10 orders and go laser cut what would one of these run?

count me in

With a gm 3.4 create engine what would be the better set-up. A crank sensor or this external one.

anyone?
and Thanks in advance
maybe interested too based on answer

[This message has been edited by DandRauto (edited 06-05-2009).]

quote Originally posted by DandRauto: With a gm 3.4 create engine what would be the better set-up. A crank sensor or this external one. anyone? and Thanks in advance maybe interested too based on answer

that is subjective. I mentioned my issue with the internal crank trigger: the lack of adjustability. you need to get a new chip to change the timing.

As far as I know the one that WOT sells won't fit on the fiero. I had looked into it before, there was a small discussion on here about it and I think also on the 60degrev6 form. I'm pretty sure I actually emailed them also and they need some measurements and working on making one that fit but I don't know what came of it.

The advantage I saw in DIS was you could mount the coil pack anywhere, to keep it away from heat. Also it gets rid of the ignition module that seems to fail often.

quote Originally posted by bnevets27: As far as I know the one that WOT sells won't fit on the fiero. I had looked into it before, there was a small discussion on here about it and I think also on the 60degrev6 form. I'm pretty sure I actually emailed them also and they need some measurements and working on making one that fit but I don't know what came of it. The advantage I saw in DIS was you could mount the coil pack anywhere, to keep it away from heat. Also it gets rid of the ignition module that seems to fail often.

really? i can go out and see if it will fit on this weekend, i dont see why it wouldnt?

Well it's Friday afternoon and still no reply from the laser shop. They most likely went fishing.
I hope to get the VR sensor mounting worked out this weekend.
I think adjusting the timing is best done in the chip for those with the capability. You will have to be running a 7730 ECM or similar.
The design for adjustment on the wheel allows for setting up the wheel to the exact sensor location and for timing adjustment on an engine with the stock ECM.
Also it let's the wheel be used with either a stock damper or a Camaro damper (Which is easier and cheaper to get). The alignment of the twelve holes in the rim to the keyway seems to be slighty different on these.

Any progress

I see that you have adjustment slots on the disk do they mount to the outer ring on the dampener ?Will that be a problem if the ring slips ?Have you received a price yet?

I have looked into the WOT trigger wheel setup and spoke with the manufacturer. Their setup will NOT work with our stock RWD-type crank pulley, it will only work with the FWD-type crank pulleys. I too have been searching for a way to add DIS to our 2.8 with no luck. Someone on 60*V6 e-mailed me that a guy by the handle forcefed firebird(?) was looking at making some, but I have not heard back since. I think this is the same guy who is making the Lebaron brake-swap brackets for GSJon.

If you want, you can send me the .dxf file and I can send it to the (fairly local) machinist I used to laser-cut the Lebaron brake-swap brackets I had sold. I can get you a price (he usually wants to do runs of 10 as you noted) and he was the cheapest guy around that anyone else could find. It's up to you.

[This message has been edited by rjblaze (edited 06-16-2009).]

quote Originally posted by DandRauto: With a gm 3.4 create engine what would be the better set-up. A crank sensor or this external one. anyone? and Thanks in advance maybe interested too based on answer

If your crate engine has the reluctor wheel on the crank already then all you have to add is the crank position sensor in place of the plug in the block. You then harvest the twisted pair of wires with each connector when you get the coil pack off your target junk yard car. You must make sure your crate engine has the reluctor wheel from the factory first. Of course you will also need an ECM to handle the DIS like the 7730.

[This message has been edited by Hudini (edited 06-17-2009).]

Sorry, I have not had a chance to work on the car lately. I fab'ed up a sensor bracket. I will post a drawing when the bugs are worked out. The sensor tucks in nicely between the water pump and the alternator bracket. I looks like it will not interfere with adding a belt tensioner either.

RJ, I sent you an e-mail. The laser shop local to me still hasn't responded to the RFQ.

JDV, yes, if the damper slips timing will be lost. At that point you need a new damper anyway. Slips are uncommon enough on a new damper for GM to place the timing mark on them.

Hudini, here is a dumb question. If your running a stock ECM would the DIS work if the base timing is set to 10°? I thought the sync and timing pulses were handled in the DIS module and the ECM just adjusted the referance pulse. I have heard of people running DIS on old cars that do not have an ECM.

The problem is the way advance is handled. On dist engines advance is handled on the current event and on DIS advance is handled on the next event. I'm not sure exactly what you would have to change to make a dist only ECM work. I know the 7730 can handle both a dist and DIS but don't know if the stock Fiero ECM can do the same. Darth Fiero could answer this, others too. I'm still in the noob phase with all the variables. It might be it's the code and not the ECM.

Lately I've been trying to make code59 (hacked version of $58 for the turbo 4.3L syclone/typhoon) work with the 7730 and DIS. This code is for a dist engine and allows up to 30psi boost and has a wide-band O2 input. You have to trick the code into advancing the timing so far it's actually firing on the current event. Others have managed to make this work but I'm still having issues.

no, the stock Fiero ECU will NOT do DIS
the main reason is there are 7 pulses (6 + #1 pulse) - per revolution. you'll note the DIS wheels have 7 notches - not 6
I at first thought the same thing, and on the 7730 swap thread, you'll see my posts on the topic, near the end. because all the signals to the DIS block are the same as the signals to the ignition module. I expect there maybe a way to make it happen - but I sure am not gonna try and work it out, since the 7730 is such a easy swap compared to trying to manipulate the crank pulses. The Fiero ECM has NO CLUE which pulse is TDC #1, which is the reason for the 7th pulse. and, in order to run DIS - you need know where TDC #1 to know which coil to fire.

I think the sync (7th) pulse is used internal to the DIS module. Just like in the HEI system the ECM recieves a tach pulse and outputs a timing advance pulse and a cranking bypass signal. The sych pulse could be read by the ECM on the tach line, however, it is my understanding the the timing advance can only delay the spark event and not initiate it. If the ECM totally ran the show a bypass signal would not be required. Once the module is placed in bypass mode the EST referance (timing advance) signal is ignored. Any DIS equiped engine should run at base timing, no advance, with the white EST line disconnected and the tan & black at ground potential. If I had a running vehicle with DIS ignition I would do the experiment.
I actually placed a Fiero ignition (HEI) module and a DIS coil into my old skidsteer. NOW the Damn thing starts at -30°F!

Hudini, I agree with the 7730 ECM upgrade. I have it my car. I was wondering about DIS for dems that are running stock. The HEI module also makes timing changes on the following pulse like a DIS module. I think the actual coil driver IC is identical in both types, the DIS just adds the syncronizing and switching logic to fire the appropriate coil.

I noticed in your other thread the dis coil pack do you have this set up on your car ? Anything new on this ?

Actually, the stock ECM will do DIS but you have to swap some values for the reference and retard/advance limits. For the effort, just change to a newer ECM like the 7730.

As for the speed of the ECM, the same timing loops exist in both the C3 and P4. The overall concept and design is the same. If you really think about it, the events in an engine happen pretty dang slow relative to the speed of the processor. In addition to that LSI chips handle the fuel and spark so the processor isn't involved at a spark/fuel event basis. The processors is just reading sensors and sending new values to the FMU and spark control and the outputs for EGR, FP, etc. If you removed the processor the engine will still run but nothing will be updated. The spark control and FMU just keep on running at their last values. The same equations are used to calculate fuel and lookup spark.

The big change was going from embedded control/ROM in the processor to all of the operating system being in the mem-cal so they could change *everything* without having to replace the hardware. That also gave them more ROM to work with for trans and cruise integration too plus more RAM as needed.

In the really tight loops (3 and 6mS) the faster processor did allow them to move some sensor reads and control sends to the shorter loops but all and all, the FMU and spark controller don't need to be updated all that fast.

Certainly, the faster ALDL speed is nice for sure but at the heart of things, they aren't all that different.

Have you herd anything back from the laser cutter about the dis wheel?

Gravitic - any idea what thickness and what material you were planning for the wheel? My machinist wants to know before he gives me a price.

Rjblaze, I was thinking of 10 Ga. CRS sheet. It has to be the low carbon steel for the magnetic properties. Stainless wouldn't work very well.
On a machined part the corners of the notches can be full radius instead of square. Tell the machinist to quote on the file I sent to you, but the final file will have a few changes.

- Tim

I can't see any advantage to going DIS on the 2.8 engines. It will add work, tuning time, higher cost and probably won't give you any more horsepower than the distributor system. Same with the 7730 ECM. It may make for a unique and interesting setup but there is zero gain to be had. If I am missing something, please expain what it is.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Dennis the dis set up will allow you to use 3400 heads that flow quite well. A hybrid motor and a 4 speed is my plan.

quote Originally posted by Dennis LaGrua: I can't see any advantage to going DIS on the 2.8 engines. It will add work, tuning time, higher cost and probably won't give you any more horsepower than the distributor system. Same with the 7730 ECM. It may make for a unique and interesting setup but there is zero gain to be had. If I am missing something, please expain what it is.

from the original swap thread:
The biggest advantage to using the 7730 ECM in a Fiero application is not only more tunable options in the programming, but the drivability and response time of the engine improved significantly. Gone was the unstable idle characteristics of the stock 2.8 which some have said existed from the factory. Gone was the high idle flare upon startup. We quickly found out that using the 7730 ECM system on the stock 2.8 greatly improved it's drivability as well as throttle response and performance characteristics. Believe it or not, using the newer computer, even this stock 2.8 ran and acted like a new engine found in today's new cars! And because the 7th injector, fan switches, and vacuum-controlled EGR valve were no longer required, it also allowed us to clean up the wiring and vacuum lines on the stock 2.8 engine as well...

yes, there are no direct "gains"
but, being able to use the newer digital EGRs is a good thing
and, they are easier to setup for a turbo - which was why I did mine
the idle is better
but - yes - with DIS - no options for kicking up the timing, unless you use something like what is being discussed here - an external timing wheel

Well, I am still working on this and came up with another way to do the job.



I am looking to machine slots into the damper outer ring and making the mag pickup adjustable. On the bracket I have a slot for mounting the sensor position from 0° to 12°. The two small slots are for setting the gap between the sensor and the damper ring.
Holes drilled radially into the outer ring could be used in place of the slots.

NICE
even better knowing that 3 of the 7 slots are already in place
of course - it will need to be re-balanced

My machinist wants to know if A36 HRP&O (10 ga.) will be OK for what you want. BTW, what if the outer ring slips on the rubber? Won't that affect your timing? They way I understand it is that there is always some "movement" between the inertia ring(outer) and the crank hub(inner). Notice that anything that is bolted on the lower point is always bolted onto the center "hub" and not the inertia ring. It seems that a triggger wheel will have to be bolter between the lower pulley and the crank hub and the center of the crank hub would have to be machined flat to allow this to happen. Just some extra thoughts for you.

while it is true that the outter ring can slip - and has done so to some folk - that is NOT a common failure.

and, any Fiero this happens to has trouble with the timing - so - basicly the same thing happens - only quicker

Yes, A36 will work. It's a low carbon steel. NP.
I did look at mounting the wheel to the damper hub. If the front of the hub is not machined down you have to space out the water pump, alternator, and compressor pulleys. If you do machine the hub flush (or nearly so) a little thinner wheel will fit. Once you have to pull the damper and machine it I think you might as well just cut the slots into the damper and not have to buy/add the wheel. It would be an easy job to mount the damper onto a indexing wheel, indicate off of the keyway, and cut the slots with an end mill.
In operation there is some movement between the hub and outter ring. It is not much, or the rubber would soon burn up. I believe it will give less error than the variation you get from a mag pickup. I plan on placing a match mark on the hub and ring for a quick check of slippage.

[This message has been edited by Gravitic Anomaly (edited 07-17-2009).]