Bigport Ignition

[Raymond Reddington]

Question...

I have a Microtech MTX8 that isn't set up for a single coil, I'm planning on putting it on my Bigport, what's the go with using the std dizzy to run some GZE coilpacks (or even Excel/1ZZ etc).

What would be the best sort of way to set it up? I believe the Bigport dizzy isn't my best option, would I be better off using a small port one/GZE CAS?

So I understand the MTX8 will control the coils will the std Bigport dizzy be able to send the signal to the ECU and make everything work the way it should?

Cheers

[Hen may possibly be a nut]

You can't use the bigport Dizzy as is to run two or four coils. It gives a pulse 4 times per cam revolution, so there is no way for the ECU to know which cylinder should be firing when. Though I have seen some setups on the internet that claim to run with 4 coils each firing four times per cam revolution. Seems pretty dodgy to me.

Your best options are to:
- remove 3 of the 4 teeth off the pickup wheel in your bigport dizzy (there is also a 24 tooth wheel in there, don't touch that).
- Find a smallport dizzy or smallport GZE CAS. They have a one tooth wheel (in fact two of them) and a 24 tooth wheel which should be fine to run.

Good luck

[Futo_gt86]

Isn't the bigport dizzy able to be used as a CAS like the smallport and 20V dizzies?
If no, then get smallport dizzy or CAS.
What motor has the Microtech come off?

This a MTX8 (fuel and ignition) "Sequential Fire" version 2.1?
MTX8 have the the ignitor/drive built in, so the wires feed straight to the coils form the ECU.
I think the number of coils was set by Microtech and these are now obsolete and not supported.
If you strip back the loom you will find all 4 wires, not sure of the colours, should be obvious, they normally have a tag on them to say what they are and go from there.
- I think Orange, Orange/black, Yellow and Yellow/black but don't quote me on that.
I used a Imprezza Coil on ST20V with MTX8 ecu. They're compact, and only $40 from the wrecker.
36424
These links may help (or confuse you more as they did me)
http://microtechefi.com/download/ltmanual.pdf
http://microtechefi.com/wiring-diagrams/
- Note; MTX8/LTX8 wring diagram doesn't work from archives.
- LT8/MT8 is close but ignition wiring colours may change
Bearing in mind that these ECU's are ~20 years old now.....
They do the job to a satisfactory standard.

[Hen may possibly be a nut]

Bigport and smallport have different internal pickups.

Bigport is three wire for two pickups: 4 pulse and 24 pulse per cam rev. Can't be used for sequential/twin coils.
Smallport is four wire for three pickups: 1 pulse, 1 pulse (180 degrees offset from the first) and 24 pulse per cam rev. This can be used for sequential and twin coils.

If you open one up it's easy to see the difference and how to modify a bigport one if you want to.

[Raymond Reddington]

Cheers for the replys

The ECU is off a 4AGZE set up for Twin coils.

So I'm planning on swapping it over to run coilpacks etc

Hen I have read a few different things in regards to running the spark that way (4 times per rev) but I'm not overly keen on that.

Futo if that's the case (I'm still waiting on the ECU to arrive) then I'll have a look and see if it can be directly run from the ECU, that will then negate the need for anything to run to the dizzy at all? Or does it still need to the send the signal to say which cylinder to send spark too?

Might be just easier to source a smallport dizzy and use that. Haha

See how we go.. Gives me alittle more info. :)

[Sam-Q]

Question...

I have a Microtech MTX8 that isn't set up for a single coil, I'm planning on putting it on my Bigport, what's the go with using the std dizzy to run some GZE coilpacks (or even Excel/1ZZ etc).

What would be the best sort of way to set it up? I believe the Bigport dizzy isn't my best option, would I be better off using a small port one/GZE CAS?

So I understand the MTX8 will control the coils will the std Bigport dizzy be able to send the signal to the ECU and make everything work the way it should?

Cheers


Dylan in case you have not seen it, I have coils, a distirbutor blanking cover and ignition coils available on my site:
http://www.sq-engineering.com/upgrade-parts/engine/4age-16v.html




You can't use the bigport Dizzy as is to run two or four coils. It gives a pulse 4 times per cam revolution, so there is no way for the ECU to know which cylinder should be firing when. Though I have seen some setups on the internet that claim to run with 4 coils each firing four times per cam revolution. Seems pretty dodgy to me.

Your best options are to:
- remove 3 of the 4 teeth off the pickup wheel in your bigport dizzy (there is also a 24 tooth wheel in there, don't touch that).
- Find a smallport dizzy or smallport GZE CAS. They have a one tooth wheel (in fact two of them) and a 24 tooth wheel which should be fine to run.

Good luck

Why not just run waste spark and non sequential ignition? I have NZ coils on my own engine and they are paired up. On a side note Hen it's good to see someone whose been around as long as me still on here.

[Raymond Reddington]

Cheers Sam, I'll have a look mate.

To be honest this is my first dabble in aftermarket ECUs so I'm alittle lost atm.

I'm pretty sure the mtx8 is set up to use the GZE ignition set up. With the twin coils etc
I could be wrong in which case how do I go about setting it up for wasted spark?

Thanks :)