STUARTQ

interesting thread.

I remembered seeing the set up Gus has! is the only real advantage modern electronics versus and Rob has but it Clockwork?

kos11-12

agree with Rob.

I think we all realize there is absolutely no performance advantage to this upgrade. (maybe some weight)
the idea is to simplify the wiring, and make it free maintenance,
it probably make sens to do this upgrade when one is doing other things like, RS carpets, aftermarket ECU, or if it's time to change the distributor belt or renew your caps,

robt964

Yep, I'd do this when I change the ECU. Tot up all the individual parts involved in the twin dizzy setup. Its a lot longer than you think!

trophy

Not quite clockwork vs mechanical, All the distributor does in our cars is send the spark to the right cylinders in the correct firing order, in roughly the right time. The timing itself is completely controlled by the ecu. The length of the electrode on the rotor determine the absolute max and min advance/retard and the ecu works within this range to deliver spark at the right time.

Unlike distributors of old where they did everything.

On stock engines the benefits of going to Wasted spark or even COP are not fully experienced, as soon as you start modding the engine the benefits can start to be seen, the actual gains I would have to leave with those that have done back to back dyno pulls.

I am interested in knowing why cosworth went down the COP route on their engines, and also interested in understanding what they did to deal with the heat issue as colin has eluded to.

kos11-12

https://rennlist.com/forums/964-foru...slueths-2.html

Lorenfb

"The length of the electrode on the rotor determine the absolute max and min advance/retard and the ecu works within this range to deliver spark at the right time."

That's not correct. The rotor itself does not affect the spark timing (advance/retard),
and it's the width of the rotor's electrode that's key. The rotor only provides
a 'window' for each cylinder's spark to occur within. It's the DME ECM that
totally controls the advance/retard. The rotor width must be wide enough
and aligned properly so that the spark is always directed to the correct
cylinder as the spark timing changes with RPM. The DME/ECM does not
'know' where the rotor is as implied in the quote. If the rotor is not aligned
properly, the spark could jump to the wrong cylinder as the timing changes.
With a conventional non-ECM controlled ignition timing, the rotor always points
to the correct cylinder when the spark occurs.

trophy

Loren, We are saying the same thing...

evanscott964

Wow this thread is getting interesting!!
On previous cars I have gone to wasted spark from electronic dizzy set up and always seen gains albeit small!
Unfortunately when I went this route with the 964 I also fitted bodies so could not do a direct comparison. However I've got to say I would think if you got 1-2 BHP you'd be lucky for me it was to reduce the components and potential for breakdown. I no longer worry about the belt or having to change it again!!

Captain Ahab Jr.

Interesting thread, with some valid view points for and against COP

I'd like to fit a COP for a variety or reasons but would do it when upgrading the engine as I don't see what extra performance it would add over the distributor system without any internal engine mods.

Having designed a coil cover panel for a COP system on a race car I agree with Colin, the heat around the lower cam cover would probably kill any electronics. A little bit of ducted blown air from the fan shroud would solve the heat problem and keep out the road salt, dirt, water etc.

I'd guess it might save at best 1kg max. of weight, What do people think the weight saving would add up to?

Also how would it improve the spark on a tuned engine and what sort of improvements to power and torque would it add?

evanscott964

Weight savings are dependant on what you strip out? The loom to the original ECU on its own was 1Kg and as I removed the rear fuse box etc it was about 2Kg then all the hardware. But the 2 coil packs are quite heavy!!

trophy

I would think the weight saving would be minimal, and if this is the only potential gain that is some serious cost for weight reduction ... For $300 I could save you 30lb , with a Lithium battery...

I would think think there would be ways to protect the electronics in the COP's, the gold foil type reflective shields are extremely effective. I have a friend with a turbo R32 Golf with the turbo just inches below the hood of the car, with some gold reflective foil on the underside of the hood the reflection is incredible..

Maybe a ducted cover with foil to reflect may be a great way to go, the additional benefits may be cooler valve covers, who knows what additional benefits there could be....

Lorenfb

"We are saying the same thing.."

Not really.

"The length of the electrode on the rotor"

It's the width of the electrode on the rotor, not the length.

"I would think think there would be ways to protect the electronics in the COP's"

Not all COPs have electronics, i.e. coil driver transistors, but are just simple ignition coils.
Those can obviously operate in much higher temps.

"Also how would it improve the spark on a tuned engine and what sort of improvements to power and torque would it add?'

Once the minimum spark energy (about 30-50 millijoules) is provided to ignite the charge
in the cylinder, no additional benefit is realized. There's also a minimum dwell time for the
spark.

kos11-12

proper race spark plugs, with the right grade may help delivering consistent power & reduce heat, specially on a long event

robt964

evanscott964 - do you happen to know the dwell timing for the Vauxhall coil pack?

Also does it have the ignitor built-in? or does the ECU require additional drivers to switch it?

robt964

Oh and whilst I think of it...
Have you fitted a cam phase sensor or are you running batched injection?