Microtech Area is for discussing Microtech systems

LT12s with LS1 Coils, switch for AEM coils? Keep?

Old 06-30-14, 10:33 AM
  #1  
Rotary Freak
Thread Starter
iTrader: (6)
 
Monsterbox's Avatar
 
Join Date: Jun 2006
Location: Birmingham, Al
Posts: 2,921
Received 58 Likes on 36 Posts
LT12s with LS1 Coils, switch for AEM coils? Keep?

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!
Monsterbox is offline  
Old 06-30-14, 09:49 PM
  #2  
talking head
5 Year Member
 
bumpstart's Avatar
 
Join Date: Apr 2008
Location: Perth, WA, OZ
Posts: 2,775
Likes: 0
Received 2 Likes on 2 Posts
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 )
bumpstart is offline  
Old 06-30-14, 09:54 PM
  #3  
Rotary Freak
Thread Starter
iTrader: (6)
 
Monsterbox's Avatar
 
Join Date: Jun 2006
Location: Birmingham, Al
Posts: 2,921
Received 58 Likes on 36 Posts
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!

Originally Posted by bumpstart View Post
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 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
dillrx7
Single Turbo RX-7's
3
09-07-15 09:38 AM
SakeBomb Garage
SakeBomb Garage
0
09-04-15 05:20 PM
SakeBomb Garage
Vendor Classifieds
0
09-04-15 05:19 PM


Thread Tools
Search this Thread
Quick Reply: LT12s with LS1 Coils, switch for AEM coils? Keep?


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: