Ignition drivers

Hardware inside and outside of the ECU
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Simon@FutureProof
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Ignition drivers

Post by Simon@FutureProof »

What is everyone using for ignition drivers with these boards?

The common goto Bosch BIP373 IGBT seems to be no longer available at least in the UK so I am thinking there are better alternatives out there.

I have come across the stgb10nb37 which is an ST version specific for ignition systems and the irgs14c40l which seems to be very similar again.

http://codecard.eu/files/STGB10NB37.pdf
http://www.irf.com/product-info/datasheets/data/irgs14c40l.pdf

I am also hearing about a BU913 which I have not looked into much.

Personally I don't have too much preference as long as it clicks a coil on an off. :)

What have people used and what has had the best results?
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Re: Ignition drivers

Post by AndreyB »

What vehicle are you playing with again?

70% of the cars here (miatas) are blessed with logic-level coils. Some swap GM LS coils just to get logic-level coils. Do you consider to switch to LS or similar coils?

Do you consider used parts to get external igniter?

Sounds like I really want to move the ignition drivers further away from the board :) On my Dodge Neon I believe I've used BTS2140 from either eBay or aliexpress.
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Re: Ignition drivers

Post by kb1gtt »

Generally you are better off using an OEM igniters, instead of trying to roll your own. The mix has been of a high diversity. I have helped people use the J701. Also some talk about ignition modules in this thread.
https://rusefi.com//forum/viewtopic.php?f=4&t=286
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Re: Ignition drivers

Post by Simon@FutureProof »

Far as I am aware all BMW stuff is internal igniters right through to current cars so all would need some kind of igniters adding. The coils are designed to fit inside the cam cover so the switch to other coils would be pretty tricky on most cars and the wiring needed would negate any possible plug and play system. It also seems to be tough to find 6 cylinder OEM modules over here.
Image

The Bosch ECUs all use an unmarked variant of the BIP373 inside the casing.

On my own personal car the switch to LS coils is an option (well the euro equivalent of those coils) but the other few I have to look at are setup with stock style coils and will need drivers.

In this case my plan was to build a module pack into the adapter loom needed to go from the Frankenso to the 88 pin loom.
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Re: Ignition drivers

Post by kb1gtt »

Most modern cars, if they still have spark, use a coil on plug design. Often that's cdi or similar small coil design. They include an internal ignitor. Could you use a pencil coil or something like that?
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Re: Ignition drivers

Post by Simon@FutureProof »

Ford have been 3 wire "smart" coils (IGBT in coil) for a while that's for certain, I know for a fact the newest stuff is smart coils. Cant be sure about the french stuff but the 2005 ish pencil coils I have from Renault are simple dumb coils. They may have gone to smart coils now as well though.
Pretty sure Jag is smart coils as are VW/audi and FIAT.

Oddly BMW are sticking firm with the IGBT in ECU, it might be something to do with their use of a misfire detection by changes in ground plane voltage that result from the coils firing. They watch for the small spike and if it does not hit a certain voltage threshold then they log it as a possible misfire.
All of their coils are 3 wire but it is a red herring, the 3rd pin is actually the cable shroud/overbraid, same as their VR sensors, they are all 3 wire as one pin is the shielding, that one catches a lot of tuners out.

In my application the exhaust is just way too close to use pencil coils so I am using M50 coils in a "coil near plug" setup, for the more stock stuff it would only really be a step backwards as it would mean taking perfectly good reliable coils off and making mountings for the other coils and probably not then being able to get the engine covers back on as the stock design is actually sort of flat and boxy.

I guess one other issue is a lot of the easily available smart coils here are from front wheel drive family cars that are basically white goods, the coils are designed to be as small and light as possible while still doing the minimum job, the stock BMW coils however are actually pretty stout units that can throw a fairly decent spark, despite internet "fact" coil failures are actually pretty rare in the real world and normally due to bad maintenance (i.e. bad plugs or damage connectors). I have seen a car running fine with the plugs so worn that the gaps were ~1.2mm, a whole half mm over spec, wasn't even reporting misfire just had a slight audible lope to the idle when hot.

On a starting from scratch build I would go to smart coils directly if the ECU did not have ignition drivers in it already like the Frankenso or if the engine did not already have a half decent coil setup but for these it just feels like reinventing the wheel.
Personally the real goal is charging the coils off a 48v system and throwing sparks across some massive gaps which also comes along with other goodies a 48v supply allows but that's a whole different bag of modifications/crazy stuff. :lol:

I think the best bet for mating up with a stock BMW loom without loom mods is an IGBT box that I can build the IGBTs into and mount external to the ECU, really something like that Bosch Igniter box would be ideal but yet to find anything in 6 cylinder and buying 2 seems wasteful.
Really an OEM 6 cylinder unit would be perfect, we just don't have that much in the UK that is not a 4 cylinder shopping cart to rob it from.

Edit - Just did a bit more checking into the Bosch 4 cylinder ones, seems the audis with them in are fairly uncommon and a pair of new ones would be $170 here, :lol: for some IGBTs in a box... just no.
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Re: Ignition drivers

Post by kb1gtt »

The coil voltage doesn't seem to be very important to me. I guess it would decrease dwell, which could be handy for high rev applications. However if you have one coil per cyl on a 4 stroke, you likely have plenty of time for dwell, even at high revs. For larger gaps with higher compression pressures, what you really need to care about is the IGBT's ability to drive a higher kick back voltage. Keeping a good kick back voltage without creepage or leakage issues under a variety of temperatures and over a lengths of years, is why OEM igniters are often preferable. Most OEM's clamp around 300V to 350V kick back voltage tolerance. The higher performance igniters can hold up to 600V. When looking for your IGBT, look for at least 450V, if not higher. As well when you connect wires, use stuff that's rated for at least 600V. I'd also suggest potting it to keep good insulation under a variety of humidity and other environmental conditions.
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Re: Ignition drivers

Post by Simon@FutureProof »

Very valuable info, thanks.

On the voltage side that's just about the total coil energy available, there's some benefits to this shift to 48v being available under bonnet on the new mild hybrid cars as you can run solenoids and coils off the 48v which mean smaller more efficient VVT solenoids, injectors with faster opening times and coils that can produce larger sparks thanks to the relationship of the primary and secondary voltages scaling with primary volts.
No one is staking much advantage of it so far as the 12v system works ok for what we need at the moment and is kind of the standard but as we see more cars with mild hybrid at 48v it means there is already a 48v supply in the bay to take advantage of.
Means you can start to do fun things with stuff like E-boosters and mild hybrid to band aid torque holes on peaky race engines that were never meant to go in road cars. :twisted:

I have found the VW Passat B5 1.8t ignition igniters are much more affordable and easily available, I should be able to get a pair for about $50 but there is little info on them, I think they are the same as the Bosch 4M motorsport igniter but I will have to see.
Going to do a bit more digging and see if there is more info out there, will report back as LS coils and other stuff is a bit more tricky to get from a junkyard here.

Edit - https://www.audiworld.com/tech/elec181.shtml
Bit more info there, looks like they will be fairly ideal but I am seeing some reliability issues with them, could just be a result of the 1.8t being turbo and thus harder to spark and loose plug gaps.
They do need a heat sink on the back as they normally live with the back side exposed to the inlet air. As I need to run 2 I might back to back them with a big alu heat sink between them.
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Re: Ignition drivers

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