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LS 2 or 3 coils. Nah using the MSD universal crank trigger kit I had when I was going to use it to trigger the MSD6al 2. Just need a reluctor interface to convert the rising falling signal to Hall effect as the old SMC can only deal with Hall effect.

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Ah yeah. Forgot about the internal igniter. I hadn't formalised the coil side of the equation. Electricity has never been my strong point. Might just get some nice compact MSD or such single coils.

 

You got any suggestions?

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Bit of an update. Settled on the 90mm long Jenvey 48mm air horns. Best compromise on total inlet track length.

 

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Also got all the bits I needed to finish the throttle linkage. I've started design and manufacture of the custom fuel rail. No 'off the shelf' fuel rail is going to cut it in this application. Machined down a couple of -8 AN fittings to go into each end of the rail and another for reg/return. Bit more math to ensure enough internal volume in the rail.

 

Finalised injector sizing with Pat from Competition Systems. Very knowledgeable bloke. Just waiting on pricing of the genuine Bosch injectors. These come direct from BOSCH Motorsports. No eBay Bosch going on this engine.

 

The list is till very long, but I'm getting there in between paying work and other life stuff.

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Yeah got the price on the injectors and very happy, but that was for 1000cc injectors (which are actually 970cc) so I'm waiting now on price for 1350cc injectors and to see what they actually are.

 

I'm still researching coils. The M&W coil in the link provided by XPT crossy is a remake (Chinese) of a Mercury outboard coil. It has low primary and secondary resistance and a reasonable 70:1 turns ratio. MSD also do a nice coil with extremely low primary resistance, higher turns ratio and more zap.

 

Gotta admit I'm seriously outta my depth with this electricity stuff. Richard at autronic has tested the m&w coils but getting a straight answer from him is difficult. He is a genius and very hard for me as a lay person to understand.

 

I'll get the injectors sorted so I can finalise the rail and then I'll worry about the coils and mounting them.

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Yeah got the price on the injectors and very happy, but that was for 1000cc injectors (which are actually 970cc) so I'm waiting now on price for 1350cc injectors and to see what they actually are.

I'm still researching coils. The M&W coil in the link provided by XPT crossy is a remake (Chinese) of a Mercury outboard coil. It has low primary and secondary resistance and a reasonable 70:1 turns ratio. MSD also do a nice coil with extremely low primary resistance, higher turns ratio and more zap.

Gotta admit I'm seriously outta my depth with this electricity stuff. Richard at autronic has tested the m&w coils but getting a straight answer from him is difficult. He is a genius and very hard for me as a lay person to understand.

I'll get the injectors sorted so I can finalise the rail and then I'll worry about the coils and mounting them.

Ray Hall Turbocharging are apparently an M&W distributor according to the M&W website. Maybe have a chat to them

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Are you going Coil per plug? May I inquire why you're going with CDI and CPP? Any reason your not going straight inductive with some LS coils? (Forgive me, bit too late to be reading back through your thread =P )

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Yeah mate coil per plug. Couple of reasons.

 

a) I have had an autronic smc and loom to suit ford 6 for many years just sitting there and after talking to Mick at north side carbs I decided to go efi. So enter the old autronic. Then after reading the autronic manual what seemed like 100 times I decided if I'm going to do it, I'll just go straight to the top and go CPP. Then an autronic CDI came up super cheap so it was like an omen, I grabbed it.

 

The autronic is by no means modern, heck it has an analogue microphone Jack to serial port as a communications cable, but it is capable of doing everything I want to do. It's a bit funny in its set up and I don't think it would like the LS coils. So long story short I've now got an ecu and it matching CDI box for less than half the price of a modern Haltec or similar. Autronic was good enough for Larry Perkins so it's good enough for me.

 

B). I need BIG spark. Methanol and big compression demand BIG spark. The slow burning nature of the fuel added to the compression and amount of mixture all trying to blow the spark out means good zap is required. My thinking with the multi coil set up is that the 'dwell' time between the spark and then the next time it is required to spark is increased dramatically by going CPP. That has to be a good thing?

 

c) I have done the big single coil and MSD box before, so I wanted to do something a little bit different with this engine. I had to come up with a home signal for the ecu so it was going to be a one tooth dizzy (like Jason did) but then I thought about not having long leads everywhere and that sort of led me to the last reason

 

d) I think it's going to look 'hectic' as with 6 coils on the rocker cover and 6 short, same length leads.

 

Yep it probably won't make any more power than a single coil set up, but it might do it cleaner and will look wicked under the bonnet of a sunbeaten old corty drag car.

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Great thread, and beautiful looking crossflow. That's a serious amount of fuel @ 6 X 1350cc.

Yes, yes it is. I've done the math on what the engine would require on pump fuel, then added in the methanol factor plus headroom. I've learnt about injector duty cycle and not having them maxed out so if the 1350cc units come in at 1200cc I reckon I'll be fine. They won't be running 1350cc full time but if I've done my job properly this engine should be wanting a serious amount of methanol.

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Yeah mate coil per plug. Couple of reasons.

 

a) I have had an autronic smc and loom to suit ford 6 for many years just sitting there and after talking to Mick at north side carbs I decided to go efi. So enter the old autronic. Then after reading the autronic manual what seemed like 100 times I decided if I'm going to do it, I'll just go straight to the top and go CPP. Then an autronic CDI came up super cheap so it was like an omen, I grabbed it.

 

The autronic is by no means modern, heck it has an analogue microphone Jack to serial port as a communications cable, but it is capable of doing everything I want to do. It's a bit funny in its set up and I don't think it would like the LS coils. So long story short I've now got an ecu and it matching CDI box for less than half the price of a modern Haltec or similar.

The reason i ask:

You say dwell, but CDI ign systems don't dwell the coil. They fire a burst of current through it from a bank of charged capacitors. The instantaneous charge of power over a very short time induces the voltage into the secondary.

Normal inductive coils dwell for a time period, determined by the ecu (or other discreet circuitry) until the primary winding in the coil is at it's maximum potential (This is set by the user), then cut it abruptly cuts that current away. The collapsing magnetic field induces the voltage into the secondary winding.

To CPP with a CDI box your box will need either 3 (for waste spark) or 6 (for sequential) outputs?

 

I have NO experience with methanol ign systems.

But is saying that, all the research i did concluded that the "best" ign system for any application would be an inductive CPP. and this is what i think i know:

The advantages are granted by the difference in operation between CDI and inductive.

Inductive systems build power until there is enough potential to overcome the plug gap, when the arc is struck, the potential is maintained until all the energy from the coil is used. This gives you the spark duration. If you close the gap, you reduce the sparks voltage and increase it's duration. and the opposite if you increase the gap. The duration from a good inductive setup can be well over 3 times that of a CDI.

The difference is, if a CDI delivers 50kv and 3us duration. It will deliver that regardless of plug gap. This is what give them such massive spark intensity. but it also wears your plugs quicker, and the spark event is over sooner. I would argue that a 6us duration spark will be exposed to far more mixture than a high intensity 3us spark. (I'm just making these numbers up for the purpose of explanation)

 

The LS coils should work fine off the ECU? as long as it has 3 or 6 logic (5v) outputs (I'm pretty sure LS coils use logic levels with inbuilt igniter) then the ECU just needs to be setup to give 5v to wire 'x' when crankshaft is at position "y" Minus the dwell period.

So if at 5000rpm, a 7ms dwell period takes 1 degree of crankshaft rotation and you want to spark at 30 degrees, The Ecu sends the charge pulse at 31 degrees BTDC and cuts it at 30 Degrees, the cutting of the charge pulse causes the spark. and the 7ms determines the energy in the spark.

ECU's will even adjust the dwell based of instantaneous voltage, so it increases dwell when your elec systems drops in voltage, to keep the coil delivering maximum spark energy.

 

The only downside to inductive ign is the Dwell. If dwell gets too long, then the coil cannot rest before it has to charge again, and overheats, and if it dose not, it will eventually have to reduce the dwell (and spark energy) in order to meet the next ign even. This is a problem with single coil dizzy inductive systems, and crossys get this at about 6000rpm. As soon as you go coil per plug, you open up to well above 10,000rpm before you even need to think about it.

 

Well i hope that's all accurate, it's been a while. I don't want to tell you to go a different way, If methanol guys as saying (properly set up) inductive systems cant keep up, and it's from experience. then I'd listen to them because I have NFI.

To be told inductive systems are not been used on meth because they are inferior, would surprise me.

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Cheers mate and thanks heaps for the explanation. I guess I threw you out a bit when I mentioned 'dwell'. I was referring to the time between the coil firing events being extended when you go to full sequential operation. The autronic is capable of firing 6 coils in full sequential mode when using the CDI.

 

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That's straight from the manual. I'm sure these days with the LS style coils it could have been done simpler but not the way I wanted to go. The following blurb is from the autronic forum and explains the way the 500cdi works compared to other capacity discharge ignitions.

 

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Now they may well have just sucked me in with my lack of zap zap knowledge but it sounded good to me.

 

The timing and spark stability above 6000rpm is what I'm really trying to achieve. Hence the crank trigger, CPP and CDI. I got the CDI cheap but now I have to get the coils. In the end Its not a cheap excercise but it's sorta the way I want to do it.

 

I found with the MSD 6al2 and hvc coil and .030" gap I was killing plugs in the burnout beast. Now that's something I lived with cause I was flogging that thing at 5500-6200 for 3 minutes at a time. 2 heats and then a feature. It was just part of the maintenance schedule on a methanol car.

 

Thanks heaps everyone for your input and filling in my knowledge gaps. I really appreciate it.

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I've used both factory style ignitions and CDI on meth cars and I can tell you without a doubt they go much better with the CDI. It seems to demand a very strong spark in my experience. I've been playing with methanol for about 10 years now but I wouldn't class myself as an expert on it. Again I truly appreciate the inputs. It's expanding my knowledge

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fair enough. Then your just up for finding CDI compatible coils to suit the task.

 

I'd like to call old mate out on his blurb about electronics however. Not outright deny it, but i need more info. It seems like he's seen a wiki page or had someone explain it to him, without actually understanding it himself.

For example, The architecture of PNP and NPN transistors is simply a result of the switching method(circuit requirements). I wont explain why, but:

A BJT transistor which he appears to be talking about has 3 legs. Collector, base and emitter. PNP transistors allow current flow from the collector to the emitter when the base is NEGITAVE, compared to the emitter. NPN transistors allow current flow when the base is POSITIVE, compared to the emitter.

NPN = Positive base. PNP = Negative base

The ability for a BJT transistor to pass current is a result of it's packaging. NOT if it's NPN or PNP. depending on the design of the circuitry, the utilization of NPN vs PNP may result in a circuit that can deliver more current. But the BJT itself does not.

 

And his argument is more current = better? Nope. Not gonna cut it. Why? How does it deliver that current? You know what else has a lower voltage and a lot of current? A welder. We are not trying to weld the spark plug shut. But at the same time hes got people saying "If it's the same voltage then they must be the same" ? Also no. When it comes to this kind of electronics things are not so simple. CDI's could be doing any number of strange things to the power they deliver to the coil. The questions is Why.

 

 

Anyway sorry.

So this is a waste spark setup going off the diagram. There's no reason it wont work, Just gotta track down some suitable coils.

https://www.diyautotune.com/product/ign-1cd-capacitive-discharge-coil/

Never used it, Cant attest to it's performance, But I use it's Inductive brother on Betty and it packs a punch.

Assuming your CDI is not some outrageous current throwing weapon, (Which would just destroy plugs anyway so we can assume its not as that would be counter productive?), Most quality coils rated for CDI work should be fine.

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