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-   -   Power FC running Ls coils on power fc? (https://www.rx7club.com/power-fc-forum-47/running-ls-coils-power-fc-878753/)

rotorkid 12-19-09 02:50 PM

running Ls coils on power fc?
 
would the power fc be able to run the Ls coils like some of the haltech people are doing?

C. Ludwig 12-19-09 08:57 PM

Yes. The PFC will drive any of the coils that have internal ignitors. You will need to gang two coils on the single leading output.

thewird 12-20-09 01:37 AM

I've always wondered about this. Has anyone tried this in the past? On the PowerFC, you can't adjust dwell and such. Would you have to find coils with similiar characterists or? Is there any real benefit to doing this?

I'm currently running stock coils and the twin power and had no problem taking it up to 20 PSi with 800cc's of water.

thewird

rotorkid 12-20-09 02:20 AM

no i was more curious due to the fact me and a friend are looking in to swap a rew in to his rx8 and he has ls coils so i was just wondering if it would be worth trying to keep them or going with a fc leading coil and fd trailing...

C. Ludwig 12-20-09 09:13 AM

I've done it with Mercury coils with excellent results. Replaced a stock coil / Twin Power setup that was giving poor results. In my experience the Mercury coils give the best results of any of the inductive coils I've used (stock, LS1, LS2).

The PFC does allow dwell control if you're using the Datalogit.

Speaking of dwell, one of the reasons I like the Mercury coils v. the LSx stuff is that, since they were designed for use with 2-stroke engines, they'll achieve saturation very quickly. The LSx coils take close to 6ms to fully charge, the Mercury coils only half that. When firing in wastespark on a rotary you only have 5ms to charge and discharge the coil at 6000 rpm, so there is no way you're getting saturation at 6000+ rpm with the LSx coils.

fd_neal 12-20-09 10:29 AM


Originally Posted by C. Ludwig (Post 9690100)

Speaking of dwell, one of the reasons I like the Mercury coils v. the LSx stuff is that, since they were designed for use with 2-stroke engines, they'll achieve saturation very quickly. The LSx coils take close to 6ms to fully charge, the Mercury coils only half that. When firing in wastespark on a rotary you only have 5ms to charge and discharge the coil at 6000 rpm, so there is no way you're getting saturation at 6000+ rpm with the LSx coils.


If someone was to fire each plug directly (1 LSx coil per plug) charge time would no longer be an issue correct? (assuming 8000rpm redline)

C. Ludwig 12-20-09 04:43 PM


Originally Posted by fd_neal (Post 9690139)
If someone was to fire each plug directly (1 LSx coil per plug) charge time would no longer be an issue correct? (assuming 8000rpm redline)

Yes and no. You will need one coil per plug regardless of how you fire them. The PFC though is only capable of wastespark (3 channel) output. In this scheme you will fire both leading coils at the same time every 180* of crank rotation and as such your available charge time will be limited. With an ECU that is capable of direct-fire ignition (4 channel) you would fire the leading sequentially, or each coil would fire once every 360* of crank rotation which gives twice the available charge time.

fd_neal 12-20-09 08:47 PM

Cool, that makes sense.



Originally Posted by C. Ludwig (Post 9690584)
Yes and no. You will need one coil per plug regardless of how you fire them. The PFC though is only capable of wastespark (3 channel) output. In this scheme you will fire both leading coils at the same time every 180* of crank rotation and as such your available charge time will be limited. With an ECU that is capable of direct-fire ignition (4 channel) you would fire the leading sequentially, or each coil would fire once every 360* of crank rotation which gives twice the available charge time.



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