M84 Seq Injection with Hi6 and 8 Multi Coil (LS7)

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M84 Seq Injection with Hi6 and 8 Multi Coil (LS7)

Postby BJ 991 on Fri Jul 26, 2024 3:01 am

Hi all, relatively simple one but my knowledge in this arena escapes me.

Currently running an M84 on a Holden V8 engine with a VT sequential distributor (REF and SYNC) wired to the ECU.
Ignition is a Crane Hi-6 CD wired into the IGN-1, with a single PS92 coil.

I'm running into dizzy cap clearance issues at the back of the motor with an 8 trumpet intake manifold and figured I might as well convert it to multi coil (near plug). Not even an offset dizzy would work as it wouldn't clear the airbox / firewall.

Am I right in thinking that I can simply remove the dizzy cap and rotor button, cap off the top of the dizzy;

Maintain the REF and SYNC signals from the dizzy wiring as is, using it as the sensor device, not the spark device;

Get myself an IEX Ignition Expander, wire the x8 LS7 coils to the IEX and then wire that into the IGN-1 to let the M84 drive the coils. Would I then remove the Hi-6 CD altogether? Is that all I need and I'm good to go?

I DO know that my other option would be to wire the x8 coils directly in batch and use wasted spark, without the IEX, however this is a pretty serious 8 throttle engine so sequential trimming is absolutely desired.

I DO also know that using the dizzy to pickup the crank / cam is not as ideal as using the front balancer, but a hell of a lot cheaper and easier in this case! Room at the front of the engine is also a premium.

Cheers
BJ 991
 
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Re: M84 Seq Injection with Hi6 and 8 Multi Coil (LS7)

Postby Stephen Dean on Fri Jul 26, 2024 11:35 am

Hi, That is correct that the distributor is not the optimal place to get the Reference signal from, but sometimes compromises need to be made.

The IEX can be used in this situation, you will need to also purchase 8 coils to go with it, I would recommend smart coils such as the LS coils so that you don't need to use ignitors.
Stephen Dean
MoTeC Research Centre Melbourne, Australia
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Re: M84 Seq Injection with Hi6 and 8 Multi Coil (LS7)

Postby BJ 991 on Fri Jul 26, 2024 1:13 pm

Thanks Stephen, so with x8 LS coils and an IEX, I can simply remove the CD Ignition box altogether?

Out of curiosity, what type of ignitors would one use without smart coils? And how would they fit into the layout?

I'll be using LS coils, but for my own education I'm curious on that setup!

Cheers
BJ 991
 
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Joined: Sat Jan 27, 2018 7:17 pm

Re: M84 Seq Injection with Hi6 and 8 Multi Coil (LS7)

Postby Stephen Dean on Fri Jul 26, 2024 1:46 pm

These are what we recommend to use.

if you go to the inductive coils, you do not use the CDI box.
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Re: M84 Seq Injection with Hi6 and 8 Multi Coil (LS7)

Postby BJ 991 on Fri Jul 26, 2024 2:06 pm

Perfect! I understand the differences now.

Sheesh, that's almost too easy. I should've done this ages ago :)

Cheers much
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