LPG and wasted spark?

1uz head

New Member
Hi all, just a question about spark.

I am planning an LPG conversion on my 1uz using a 500 cfm Gas Research carby and Megasquirt ecu using 4 holden commodore coils in wasted spark mode.
Can anyone see and problems with this? I am just concerned about backfires. The standard coils and leads may not be up to it if I decide to FI it in the future.

thanks.
 

Zuffen

Super Moderator
Staff member
You should be fine with wasted spark.

Running gas or fuel won't make any difference to the "backfire" risk.

Some of us run 20+psi on the standard ignition and it runs fine.
 

madmont

Member
Hi all, just a question about spark.

I am planning an LPG conversion on my 1uz using a 500 cfm Gas Research carby and Megasquirt ecu using 4 holden commodore coils in wasted spark mode.
Can anyone see and problems with this? I am just concerned about backfires. The standard coils and leads may not be up to it if I decide to FI it in the future.

thanks.
Just out of interest where would you you expect the backfire to come from?
 

1uz head

New Member
I had a problem with a lpg 351 motor in a f100 once. When I ran a dizzy it was fine but when I went to wasted spark we had backfires through the carby with the same timing. I figured it was because of the after market cam spec but was never sure. It had to go back to dizzy. I was thinking there may be a reason they used the twin dizzy setup over coil packs from factory and thought it best to check.
 

XR8tt

Moderator
Weak or incorrect ignition timing is usually the reason for backfire..
Backfire out of inlet.. The reason why most std LPG engines run springs on there aircleaners...Doesn't always stop damage though...
 

zen

New Member
sequential injection...no single point lpg crap...very cheap now..no backfires ever again..
 
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