Rogue_Ant

I have not actually tested it, but from what I know, that coil should be a great option... I will test it over he next few weeks and let you know what I find.

Yep, as I mentioned earlier - the Blaster coil is a little harder on the ignition driver. The stock driver really needs a little help to properly latch on/off when using a non-stock coil. This is why I add a little capacitance to the driver front-end.

Yes, the HVC-II coil MUST have the hardware mod, and proper dwell map to be used.

User 52121

Re-reading this thread as I think about a misfire issue I'm having... wondering if my stock coil is tired. The Blaster coil Lindsey sells is reasonable $$$ (not ready to pony up for the Rogue DME and Blaster II coil) so I figure I'll toss one of those in.

To spare my 28 year old DME, and since I have the Tuner/Logger, I figure I might as well adjust the dwell map to accommodate the new coil. Based on the OP, the stock coil takes 6.5ms to charge, and the MSD 4.8ms. So is it as simple as adjusting the 12v column in the dwell map from 6.3 to 4.8 or so, until 5200 (then leaving stock values)?

Or... does someone (Josh, etc?) already have an appropriate dwell map for a Blaster coil?

refresh951

May want to carefully check your plug wires (both ends), I had an issue with misfire a while back and it was a plug wire. Also, check prices at Summit for Blaster Coil, may be a bit cheaper. If you use an HVC II coil, you will need to a capacitor to the DME to kill some harmonics. I will try to dig up the details if anyone needs them.

User 52121

Summit had it for $50 w/free shipping. Sweet.

Plug wires certainly *look* ok, they're only a year old (so maybe 8-10k on them). I had a spray bottle in the garage w/water in it but someone got ahold of it and filled it with some random cleaning product... so I'll have to go pick up another one - then I'll use that to fog the area and see if I have any sparks...

URG8RB8

Use plenty of dielectric grease.

Cauf61

Hello everybody.I am Patrick live in Antwerp Belgium.
For the moment I have 2 oldtimers .A porsche 968 and a sierra Cosworth turbo.
I have read this thread with great interest because I am building a mechanically driven wasted spark system for the ford Cosworth engine and found here much information I discovered myself also.
I tested some coils myself and will try to post my findings.

First I build a circuit that regulates a ,programmable, dwell time as the ecu only gives the firing point and the dwell is regulated , fixed , by the marelli ignition amplifier.


The dwell calculation is done by the PIC controller you see in the middle on the PCB.
The coil is switched by a Bosch BIP373 transistor.
It has great features ( temp protection , 11 amp current limit )

This way i can safely use a Crane LX91 coil.
This coil is very fast and very powerfull ! Rise time to max current of 8 amp in + - 3.2 msec. So usable whitout power loss till 6800 rpm on a 4 cyl engine. Spark time + - 1.2 msec.



For the moment i am driving with this module and the crane coil with very good results .

Sorry for my Englisch sometimes. :-)

blade7

I had a 87 Sierra RS Cosworth for 13 years, sold it 11 years ago. It was a great car and a lot easier to work on than a 944T. Not quite as good on twisty roads though.

Cauf61

This is the sierra. Big fun. Now at 280 bhp.

Cauf61

Here some results of the coil testing.

All test with Ubat at 14V and dwell 3.5 msec. On the scope vert 1div=1amp. Sparkplug gap at 1mm.



Situation as original. Red Bosch coil and marelli ignition amplifier with fixed dwell of + - 4 msec.
Picture not very good.



This is the crane coil. You can see more than 8 amp in 3.5 msec.So reduced dwell to 3.25 msec for this coil. Top line is sprakplug current.



This is the IGN-1 coil. Bit poor.Only 4.5 amps in 3.5msec. Rather slow coil but longer spark time.



This is the old Bosch coil. Not bad at all. 6 amp . Also used in the porsche 968 i think. Spark time of almost 2 msec !

67King

What great effin' cars. I had a few of the NA versions, the Merkur XR4Ti, before I got into 944's. Friend of mine has a very grey market one.

blade7

Nice Mine was in white, around 300 bhp. I fitted 8x16" Escort Cosworth wheels to fill out the arches, the original 205 tyres always struggled to put down the power . They make much higher prices than a 944T over here now.

Cauf61

Indeed , prices are mounting every year. Here in Belgium the sierra has a lot more value then my 968.

Here is my 968.

Cauf61

Did some testing on the wasted spark coil i am going to use. The Bosch 2x2 dual fire coil.



I used the advised dwell time of 3msec. Nice current of 7 amp and 1.4 msec spark time ( on two sparks )

The indutance is 3.7mH so at 7 amp L= 90.65 mJ.
At 8 amp it would be 118.4 mJ. Maybe i adapt the dwell to 3.25 msec to reach 8 amp.

Cauf61

Adapted the rotor.
Only use for the dizzy and rotor will determine the position of the crankshaft.
It’s using an optical reflection sensor who’s detecting the position of the rotor.



The stainless piece is polished to max reflection.
Make everything as symetrical as possible to not disturb the balance of the rotor.
Use the same 3 screws.
It's turning at 3000 rpm.
The dimensions are not super critical as it's just needed to indicate which set of cylinders to fire. 1 and 4 or 2 and 3.
I made it the same width as the largest part of the rotor.
Exact timing is done by ECU and stays as standard.

Cauf61

Glued in the reflection sensor.
It's a ir led diode and transistor.
As you can see it's in line with a HT connection.
I used an old dizzy cap and cut out the HT connections.