Monsterbox

iTrader: (6)

Recently purchased an LT12s from a member for use with the 20b that I'm currently installing.

ECU came with LS1 coils. Specifically the D581 truck coils. I have seen turbo V8 motors produce 800-1000hp on these coils with E85 and no issues.

Will these coils provide enough spark energy with the built-in igniters to push 20psi + 1000cc water/meth on a rotary? Should I ditch them for AEM Smart Coils?



Additionally, I cannot find a definitive answer on the compatability of igniter-coils with the LT12s. Does the ECU have to be PRE-Programmed for the LS coils? If it was pre-programmed for the X4 then it would not work with LS coils? Figured I would wire +12 to all the coils, run two grouds to the engine from each coil, and 1 signal wire to ECU output. Apparently the coils work on a +5v dropping signal. I'm hoping the ECU delivers this type signal as programmed. It did not come with the X4.

I'm just going to assume for now that this ECU will work w/ these coils. However, I'd hate to have to send it all the way back to Australia, Later then Sooner.

Thanks!

bumpstart

the ecu has user selectable dwell type and user selectable output trigger edge to the coils

essentially it sends only TTL level ( 5v command ) signals .. there is no igniter transister to take the current required to drive a coil

the x pack is essentially a pack of external igniters.. and the ecu's default settings are tailored for to signal them

in lieu of the x pack .. you can wire the ecu directly to coils with inbuilt igniters ( LS or AEM etc )
but you have to go back to the screen 31 setup and change the config to suit the new coils

if the ecu you have came with LS7 coils.. then i expect its last setup is to suit them.. and those coils are OK
.. as long as they are used with fixed dwell timing and that is kept below 5 ms to prevent auto discharge ( a coil protection feature particular to those coils and the d585 )

i doubt the AEM coils will deliver more, and i expect this is plenty

i would rate the mercury coil better



NB

the only issue that sometimes arises within marks of LT ecu is some are not sequential
( no S or no X code )
if you have one of these then it was intended to drive factory coilpacks ( with inbuilt igniters and or a toggle command )

these units are setup with only one leading output ( to drive a stock leading coil in wastespark mode )

doubling the wire up will run 4 coils ( with inbuilt igniters ) ,, but the leading spark will always be wastesparking and have effectively only half the dwelll window


these LT only ECUs may be setup from the factory to suit either FC or FD but not both
( FC using a trailing toggle command and FD using two individual trailing coil commands )
though an FD unit can be made to work on an FC by wiring the trailing coils as if FD
( the timing input commands and setup is also a little different , but it can be made to work )

Monsterbox

iTrader: (6)

Bumpstart, you are awesome! Thanks for the reply. Tons of good info. Answered all my questions. So I assume I'm headed in the right direction!