VEMS Community Forum

Technical => Ignition => Topic started by: PeepPaadam on February 10, 2015, 01:13:17 PM

Title: Best way to fire 16 passive coils?
Post by: PeepPaadam on February 10, 2015, 01:13:17 PM
What would be the best strategy to fire 16 passive coils? Engine in question is AMG 5.5liter V8 which has two plugs and three valves per cylinder. Engine is pretty much the same as on SLR McLaren.

I have put VEMS onto similar engine before once but then we did not have original coils and I used four Bosch 2x2 coilpacks.

This time it is not an option as I am doing a plug and play adapter for this engine, the owner wants to run original coils and engine harness.

Can I just wire two coils into one IBGT output? Or do I have to start building ignition expander where I install separate IGBT's to each coil?

Title: Re: Best way to fire 16 passive coils?
Post by: gunni on February 10, 2015, 09:52:14 PM
Ideal solution is one logic output operates two transistors

You can use TC4427A as the driver for two transistors.
http://ww1.microchip.com/downloads/en/DeviceDoc/20001423J.pdf

So logical output drives both inputs into the TC4427A and each output drives a transistor for each coil.

Title: Re: Best way to fire 16 passive coils?
Post by: Kamuto on February 10, 2015, 11:00:34 PM
Quote from: PeepPaadam on February 10, 2015, 01:13:17 PM
What would be the best strategy to fire 16 passive coils? Engine in question is AMG 5.5liter V8 which has two plugs and three valves per cylinder. Engine is pretty much the same as on SLR McLaren.

I have put VEMS onto similar engine before once but then we did not have original coils and I used four Bosch 2x2 coilpacks.

This time it is not an option as I am doing a plug and play adapter for this engine, the owner wants to run original coils and engine harness.

Can I just wire two coils into one IBGT output? Or do I have to start building ignition expander where I install separate IGBT's to each coil?
did one last year, no big deal. 2 coils per output., drift car, no failures or broken igbts, ecu case felt warm :)
Title: Re: Best way to fire 16 passive coils?
Post by: PeepPaadam on February 11, 2015, 05:18:17 AM
I have used TC4472A's to fire two VAG active COP's  from one output using 100 ohm resistors, worked fine.

ThoughI am a bit hesitant with passive coils, need to measure the resistance and calculate a bit how much the maximum current will be...

BTW, this engine also goes to a drift car in Germany, E86 Z4 Coupe.
Title: Re: Best way to fire 16 passive coils?
Post by: MWfire on February 11, 2015, 08:54:30 AM
You need 16x igbt transistors, two of them firing at the same time.
If you will fire only one coil, you will destroy a engine with knock(you will need many advance for power, then knock will start).
Title: Re: Best way to fire 16 passive coils?
Post by: PeepPaadam on February 11, 2015, 12:03:09 PM
I know that very well, I have been messing with twin-plug Porsche 911 engines for years.

My main point was that if it is safe to fire two coils from one IGBT. According to Kamuto it can be done.

Kamuto, can you tell me the resistance of the coils you used two per one IGBT output?
Title: Re: Best way to fire 16 passive coils?
Post by: Kamuto on February 11, 2015, 01:29:45 PM
Quote from: PeepPaadam on February 11, 2015, 12:03:09 PM
I know that very well, I have been messing with twin-plug Porsche 911 engines for years.

My main point was that if it is safe to fire two coils from one IGBT. According to Kamuto it can be done.

Kamuto, can you tell me the resistance of the coils you used two per one IGBT output?
I have never measured it, but it was same amg 5.5 engine with charger with stock double coils.
https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-xfp1/v/t1.0-9/s720x720/10013501_767534259932540_1652836942_n.jpg?oh=0638e67adbabb9a035c0a29e5a92e155&oe=554F2ABC&__gda__=1432586805_a503386bf872d9a36bfabf572658aeaf

that one, btw, it has one more dbw operated throttle inside charger unit, it has to be blocked somehow :D
Title: Re: Best way to fire 16 passive coils?
Post by: PeepPaadam on February 11, 2015, 02:33:07 PM
Yes, I know about this one. Did you use main DBW throttle with VEMS or did you converted it to cable?

Also, care to share your cfg file? I only have cfg file for 1.0.73 from 2007 lol :D

Thanks a lot for the info!
Title: Re: Best way to fire 16 passive coils?
Post by: Kamuto on February 11, 2015, 08:03:22 PM
Quote from: PeepPaadam on February 11, 2015, 02:33:07 PM
Yes, I know about this one. Did you use main DBW throttle with VEMS or did you converted it to cable?

Also, care to share your cfg file? I only have cfg file for 1.0.73 from 2007 lol :D

Thanks a lot for the info!
yes I have used it with vems, post your email, will send it someday
Title: Re: Best way to fire 16 passive coils?
Post by: PeepPaadam on February 12, 2015, 05:38:14 AM
Please send it to [email protected]

Tnx!
Title: Re: Best way to fire 16 passive coils?
Post by: MWfire on February 12, 2015, 02:09:36 PM
Quote from: PeepPaadam on February 11, 2015, 12:03:09 PM
I know that very well, I have been messing with twin-plug Porsche 911 engines for years.

My main point was that if it is safe to fire two coils from one IGBT. According to Kamuto it can be done.

Kamuto, can you tell me the resistance of the coils you used two per one IGBT output?
No, you can't fire 2 coils with one igbt. Problem isn't in current or heating igbt. Problem is different break down voltage for spark. So you will have one good spark and one weak spark.

dbw works very good, i done 10+cars with dbw.
Title: Re: Best way to fire 16 passive coils?
Post by: Kamuto on February 12, 2015, 09:33:34 PM
Quote from: MWfire on February 12, 2015, 02:09:36 PMNo, you can't fire 2 coils with one igbt. Problem isn't in current or heating igbt. Problem is different break down voltage for spark. So you will have one good spark and one weak spark.
this is something new :)
Title: Re: Best way to fire 16 passive coils?
Post by: gunni on February 13, 2015, 01:02:17 PM
Quote from: MWfire on February 12, 2015, 02:09:36 PM
Quote from: PeepPaadam on February 11, 2015, 12:03:09 PM
I know that very well, I have been messing with twin-plug Porsche 911 engines for years.

My main point was that if it is safe to fire two coils from one IGBT. According to Kamuto it can be done.

Kamuto, can you tell me the resistance of the coils you used two per one IGBT output?
No, you can't fire 2 coils with one igbt. Problem isn't in current or heating igbt. Problem is different break down voltage for spark. So you will have one good spark and one weak spark.

dbw works very good, i done 10+cars with dbw.

This is not correct. I have seen it in practice with easily over 40hours of full racing rpm's. 7000km at full load basically.
Title: Re: Best way to fire 16 passive coils?
Post by: PeepPaadam on February 14, 2015, 07:23:10 AM
Ok, evidently the reliability is not an issue as Kamuto also said but what about spark strength when firing both coils from single IGBT?
Title: Re: Best way to fire 16 passive coils?
Post by: gunni on February 14, 2015, 10:52:33 AM
Coil charge will double, so you need to know how much current you need and how much charge time that is.

Title: Re: Best way to fire 16 passive coils?
Post by: PeepPaadam on February 14, 2015, 11:51:57 AM
Coil primary resistance is 0.42 ohms. When connecting them in parralel, the resistance goes even less.

V3040P max current is 21A and continuous current is 17A.

Here's the datasheet for the coils: http://www.bosch-motorsport.de/media/catalog_resources/Twin_Single_Fire_Coil_2x1_Datasheet_51_en_2778159755pdf.pdf

Any ideas how I should/can fire these?


Title: Re: Best way to fire 16 passive coils?
Post by: gunni on February 14, 2015, 02:46:40 PM
You can make a box of transistors and use the TC chips I reccomended.
Title: Re: Best way to fire 16 passive coils?
Post by: PeepPaadam on February 14, 2015, 05:25:26 PM
And no issues from such a small primary resistance?
Title: Re: Best way to fire 16 passive coils?
Post by: Kamuto on February 14, 2015, 06:04:28 PM
I feel like lucky bastard driving these doubled on stock igbt's :D
Title: Re: Best way to fire 16 passive coils?
Post by: gunni on February 14, 2015, 09:22:54 PM
Quote from: PeepPaadam on February 14, 2015, 05:25:26 PM
And no issues from such a small primary resistance?

I meant to use 12 IGBTS, two IGBTS being run by a single ignition channel through a TC chip
Title: Re: Best way to fire 16 passive coils?
Post by: PeepPaadam on February 15, 2015, 02:36:18 AM
You mean 16 IGBT's I think :) Yes, that's what I meant.

Too bad these coils cannot be wired in series due to having common +12v supply, not separate..