Any questions you have before you begin buying, building and installing.
#48246
Hi all

I'm in the process of converting my classic Alfa Romeo to EFI. I started off with the popular VW type 106b coilpack a lot of people are using here. This just to make sure everything works as it seems to be a proven setup. For the final solution I'm looking for something close to stock looking. My idea was to remove the guts of an old mechanical dizzie and transform it to a housing for four COPs. As size is critical I was looking around for different COPs options. All the BOSCH COPs are too wide and wouldn't fit. There are Denso COPs e.g. 129700-4400 which look quite compact but I wasn't able to find tech specs.

Does someone know where to find tech specs of Denso COPs or can recommend a compact (especially width - I could probably deal with length to a certain extend) COP that could fit?

Thank you for your help.
#48252
Unless you have an issue with excessive dwell reduction or weak spark, I would stick with coil packs or CNP, or the stock distributor and performance coil. COPs are cool to say you have them, but unless buying quite expensive versions, they use more amperage to make equivalent spark energy compared to the bigger coils.

In other words, and while there always exceptions to everything, there are few reasons to use COP over other methods with Speeduino. OEMs use them because distributors are more expensive than coil packs, which are more expensive than CNP, and those are costlier than COP (plus a few other features Speeduino can't use yet). If you want better answers, then we would have to know why you are considering them instead, and what your goals are. "Different" or "cool" are reasons or goals also. ;)
#48271
Hey PSIG

Thank your for your quick reply and the insight what can be a consequence of using COPs this way / in general. I came up with this naive idea because I saw others use COPs in the same way. But of course, you are using hardware in a way it was not designed to be used.

In my case everything gets a bit easier if the solution doesn't draw that much attention ;-) And besides that - although I'm not a purist - I think it would also fit the overall style of the car better. The main reason I want to switch to EFI is to make the car more efficient and improve driveability.

I had a look at the Bosch 0 221 503 407 coil but it's too big to fit it in the distributor housing and probably 4 LS type modules would be too. A friend told me that I might be able to fit a Ford (Edis I think) module, but I wasn't able to find dimensions of that either.
#48307
That's fine, but you haven't addressed why you need anything different than a single upgraded distributor coil. As Speeduino can dwell almost any type of coil(s), putting a high-performance coil in-place of your stock coil is an easy swap with big sparks. I hope you see my point, that if we don't know the reasons for not using a valid alternative, it's difficult to suggest others with confidence. Especially ones that may provide lesser performance if you're not careful.
#48333
VW 06A 905 097 looks like pretty compact; from some ebay images (helpfully shot against a usps box), looks to be about 4" x 5 1/2", and will give you 4 channels; From what you are saying, this may still be way too big. What model alfa, and what are the dimensions of the original distributor cap?
#48346
One of the hottest coils you can fit to your Alfa is the AEI 500 or AEI 600 from Magneti Marelli . They have less than 0.4 Ohm primary resistance and produce a spark that starts your engine in any situation. It makes the choke a thing of the past and you can keep your distributor. The driver is on the heat sink and does dwell all by it self. So you only need a 50% square signal to drive it. It is made to work directly from inductive pick up´s, but takes a 5V square as well.
You may get one used on eBay. They have been used on all kinds of engines, NA and turbo. The Ferrari 288GTO used two of them. Your ignition will not get better than this. The difference to the stock ignition is amazing. I combine them with Denso Iridium TT plugs.
If you want a more classic look take the AEI 200, it looks more than a stock coil, but is a little weaker than the 500/600.

Sticking COP´s in a distributor and fitting spark wires is a very bad idea. You will get less energy at the spark plug. They are not made to drive wires.
#48357
@PSIG @Chris Wolfson
I got your point regarding COPS. Thank you for the Magneti Marelli recommendation. If I just change the coil I won't be able to tune the ignition and will be stuck with my distributor's advance settings.

@fins
Thank you for your input. Inner diameter is approx 5.9cm. So there is not a lot of room :shock: The car is a 1974 Alfa Romeo GT 1600. VW 06A 905 097 looks nice but most likely too big as well.

If I cannot use COPs it's probably impossible to achieve such a conversion. I thought about it for a bit longer and probably the easiest solution would be to just solve it optically in the sense that it looks stock but use a coil pack in a more hidden way. That would also give me the possibility to use the dizzie instead of a cam signal as basis for a full sequential injector setup.
#48361
Jonas Berg wrote: Sun Feb 14, 2021 5:48 pm… If I just change the coil I won't be able to tune the ignition and will be stuck with my distributor's advance settings.
You certainly can tune it! Using a distributor for fully-controlled ignition timing and dwell is a basic function of Speeduino. It's also one of the easiest. The only requirements are:
  • Lock the mechanical and vacuum-advance mechanisms, through removal, or wire-wrap, screws, spot-welds, whatever.
  • Use an inexpensive coil driver ("igniter") from any single or multi-coil ECM-controlled car or truck. Many, many options or choices.
From there you have complete distributor ignition control. I get my single-channel coil drivers from the wrecking yard (they are very robust and reliable) for around $5-$10 with the connector. ;) You could have your engine on tuneable distributor ignition by this afternoon. It works like this, and is used like this.

There are also many options for distributor coils with higher-performance if you actually need that. For example, the 0.4-ohm MSD Blaster II coil performance (there are multiple perspectives of "performance") is roughly between the MM 200A and 500E, and is about $40 in the US.

The term "smart" coils is misleading. Most smart coils are simply passive ("dumb") coils with one of these on the inside, instead of outside. Examples of popular single-channel coil drivers to control distributor coils are the J131/PRW-1 or 2 (random example) on Japanese and US brands, or the little but powerful Bosch "034" used under many names worldwide that look like this:
Bosch 034 - DSM J142 Ignition Coil Driver.jpg
Bosch 034 - DSM J142 Ignition Coil Driver.jpg (18.96 KiB) Viewed 4336 times
#48366
Just to add: The module on the MM coils is a "smart" one, as it manages dwell. It is compareable to the GM HEI modules, the AEI200 actualy uses one, even if it has Magneti Marelli printed on it.

I had these coil/ module combinations on my bench, triggered by a function generator. I tried different signals like sine, rectangle, saw tooth with different voltages. It can do an incredible strong spark at ridiculous high rpm. A friend of mine uses it with a 2l turbo engine, still with distributor, up to 2.5 bar boost. At that boost level many stock turbo ignition systems fail.

All in a very compact, reliable unit. They only fail if you do not put heat conductive compound between module and heat sink.
The versions for electronic ignition/ injection/ Motornic systems have a 7 pin connector, while the ones for an inductive pickup have single ones. You can use both with the Speeduino.

A smart solution is not only to use the distributor for sparks, but fit an inductive pick up with just one tooth at the solid rotor. so you have an cam position signal for sequential injection.

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