NZ951

As topic...

I am going to the running wasted spark ignition, what coils packs have people used? Any brackets out there? I am thinking right infront of the hood catch. There are a couple of studs handy that a bracket would mount nicely off.

Ski

Andrew, check Speedforce site and 944enhancement(Chris White) as I've seen photos of their TEC3 installation that's shown brackets and different mounting points.

B951S

Andrew, you will have to pull your distributor anyway to feed your link a cam signal right? You could build something off the back of the dizzy blanking plate.

m42racer

As long as you stay Wasted Spark, you will not need a Cam Sync. The factory triggering as decoded by Link is already with a sync for TDC, and with Wasted Spark it doesn't matter which one. I have seem dual post coils on 944 mounted on brackets on the Valve Cover. I will email you about who has the coils with the brackets already on them that mount the coils right there. I'm sure they have pics they can send you.

Chris White

Here is an option – I made up some of these for the tec3 kits, the bracket uses the rubber insulated mounting points of the stock air box. Looks good but it does make access to the belts a little more time consuming.

NZ951

Thanks M42Racer... PM received.

Chris, can you see the two studs next to the TB IC outlet to the right of the hood catch? I think I will make a bracket come off that and mount in the same position as you. Thats what I had planned. Your setup looks clean but a little bulky for me. I guess something off the dissy plate is the other alternative. So any dual post coil will work? Any known to have the same connectors as the stock ones? Or do you have to make some custom leads?

Chris White

Just remember – vibration is a bad thing. Go for as vibration free mounting as possible (rules out the dist. Plate). Any dual post coil will work – the GM based ones are cheap and work well.
The stock plug wires will work but you can get one specially made for the GM based coils.

Chris

NZ951

Hmmm I dont have the stock air box mounting points anymore... damn grinder happy. I will maybe use your adapter plate and change it a little of use those two studs and make another point to mount off further down. Would you recomment the rubber mounts like on the IC to stop vibration?

B951S

TDC is not what you should be worried about. How can it know which cylinder is on the bottom of the inlet stroke? To do this you need a cam sync signal. I bet you your car will run like crap if you can't tell it what pair of plugs to fire at any given time.

(I hope I am wrong otherwise I would be running wasted spark right now! Please show me how its done with just a crank TDC signal as I am itching to know.)

Thanks.

m42racer

B951S,

you have a Link with the factory triggering I expect. The Link factory triggering looks at the Flywheel teeth 132 of them and the other one or is it 2. It knows when the sync happens on ths Flywheel and then counts the number of Flywheel teeth to TDC. It does not know which cylinder is on Compression or overlap, but it does know TDC. As we have 2 cylinders always at TDC and the other 2 at BDC at all times, both Ignition channels within the software are 180 degrees apart. So in a 720 engine cylce, Ignition 1 channel fires cylinder 1 and 4 or whatever cylinders are paired together and so it fires one on compression and the othe on overlap. Then 180 crankshaft degrees later Ignition channel 2 fires cylinder 2 and 3 if they are paired together and one of them is on compression and the other on overlap.

If the Link only looked at the the Flywheel teeth, then indeed the system would require a distributor to set the ignition phasing. As the Link reads both sensors, Wasted spark can be used. The Lnk could not be used just with the 132 teeth on the Flywheel as the Injection still needs to know where TDC is. You could lose 1 tooth at whatever degrees before TDC to get this sync, but as these same teeth are used for the starter motor, it would not work.

To run the Link 2 sequentially, both with Fuel and Ignition ( multi coil) a Cam sync needs to be installed. As the Cam turns at 1/2 speed, 360 Cam degrees = 720 Crank degrees, the single Cam sync only happens once per 2 engine revolutions. Now this sync can be set up to sync just before #1 TDc compression, and with wiring and software the system will fire both the Injection and Ignition channels sequentially in the correct order.

I'm no expert on this, but did this help?

m42racer

Also, if you are running the Distributor, you will be sequential with the Ignition. The software asks if you want Distributor or multicoil does it not. If you have selected multicoil, then it asks single or dual coils if I remeber orrectly. Then it a matter of wiring and the coil type and the cam sync. I cannot imagine running 4 coils without a Cam sync unless they are wired correctly. I think you have to have 1 channel of ignition per Coil, so 4 Coils run as as wasted spark set up would require the CDI or Igniter to be paired on the input side from the ECU and the output then to all 4 coils. If you use 2 dual post coils, this would never be a problem as each coils firs 2 plus at the same time.

So I'm not sure what you have. Can you tell us how and what you have in the way of Ignition.

B951S

Thanks for that M42, my set up is just a Link ignitor and stock dizzy. Link 2 is looking at both stock crank sensors, . It does not really see anything more than the stock sensor saw in stock form (132 teeth plus one separate TDC peg, some angle before TDC), Its analogous to a 60-2 or similar where the -2 is the TDC. No matter how many reference teeth or pegs are on the crank, they are still on the crank which does 720 deg per cycle (i.e. two signals per engine cycle)

I still think to do any type of sequencing, weather full sequential or wasted spark, the Link or any system for that matter should have a sync signal from the cam (one rotation per engine cycle). Although the computer knows when there is a pair of cylinders at TDC and BTC with crank sensors, it has no way of knowing which pair to provide the ignition signal to. Counting crank teeth alone will not work becuase to know which pair need firing, it needs to reference it to engine firing order which can only be done using a cam signal is it provides ONE discrete signal per cycle, not 2 like the crank does. Stock and Link Plug and play only need the TDC crank signal becuase it pulses all injectors together (batch) every TDC and an ignition signal every TDC, using the dizzy to time them. All it needs is crank sensors.

I guess another way to approach this would be to ask if anyone knows of ANY set up with just crank based sensors that uses wasted spark. All the cars I have ever dealt with that use fuel injection run of a crank triggers only use batch injection and one ignition signal per TDC event timed by a dizzy (per most Porsche Motronic 944/968/911 set ups to mid / late 90's).

I might ask Neil at PD to get his input and find out if he has ever done a Link on crank sensors only that did wasted spark. I think I know what the answer might be though.

Thanks for your feedback.

NZ951

Davinder, do you have the Link manual? Check out page 27 if you do.

m42racer

He did my Oild Black car with 2 dual Coils in wasted spark with Link 1 ECU, and that only has 3 ignition outputs. The Link 2 has 8, but with Wasted spark you only need 2. You forget that the ECU knows that the engine has 4 cylinders, therefore it knows the firings are 180 degrees apart. The TDC crank sync comes up every 360 degrees or every 2 Cylinders worth of firings. It knows where TDC is because it counts the number of Flywheel teeth after it see the Crank sync. So now that the ECu fires the Ignitions every 180 degrees, all you have to do is wire up the Ignition legs as per which one happens first after the sync. In our case its before TDC so Ignition leg # 1 gets wired to Coil # 1 which fires Cylinder # 1 and 4 and Ignition leg # 2 gets wired to Coil # 2 which firs cylinder 2 and 3. Very simple. No Cam sync is required. A Cam synnc is required only when you want the individual cylinders to fire in firing order on their own. The ECU need to know TDC # 1, and that only happens once evry 720 crank degrees or once every 360 Cam degrees. Then its just a matter of wiring the coils as per the ignition sequence after the sync. In most case the sync happens before TDC, but in some Japanese engines the sync happens after TDC # 1 so the wiring is done to suit this.

You will need a dual channel Igniter to go with 2 dual post coils. This is a very typical setup with the Link system on 944 engines now. You know PD has a Cam wheel that will give the ECU all the triggering it needs to be sequential. The Crank triggers are not required. This wheel is a 24-1 wheel, so the sync is there along with the other teeth. Bolts directly up to the stock Cam pulley.

As you state, give Neil a call. He will explain it far better than I can ever.

NZ951

Thats basically what page 27 says The wiring is dependent on the firig order. I have ordered my Dissy delete plate of Chris White and will have this running in a month on wasted spark.