Power FC LS2 coils with PFC
02-19-10, 08:04 PM
#1
I'm sorry wha?
Thread Starter
LS2 coils with PFC
Anyone try and run LS2 coils on an FD with the PFC? I assume it might not be possible because we can't adjust dwell with the PFC. That and each coil comes with its own igniter? I've seen some of the other people use them around here and get good results because they put out so much power. Figured these would go well for an e85 setup up to 400hp.
02-20-10, 08:23 AM
#3
I'm sorry wha?
Thread Starter
Let me guess the dwell can be adjusted but only if you have datalogit? So maybe a set of MSD coils instead?I'm not looking to replace all four because I don't think 400 rwhp with e85 merits 4 new coils? Im still not sure how I am going to attempt this feat either I'm curious to see if I can do it with the stock twins....if not I'm just going to change up to a holset with a long runner manifold. I'm sure an HX35 running 20-25 will easily get me there on e85.
02-20-10, 09:05 AM
#4
Yeah, you need the Datalogit to alter dwell. I just posted on the subject here.
https://www.rx7club.com/power-fc-forum-47/ignition-charge-time-calculator-888159/
There are some other posts on the subject too, though not a lot is said about it since the Twin-Power CDI box seems to be so popular with guys that want a decent amount of power and aren't inclined to swap to a different inductive coil. With a CDI dwell becomes moot. I'd go the Twin-Power route (with new stock coils) before doing the work to convert to LSx coil.
The problem with any of the LSx based coils, MSD or otherwise, is that they require a rather long charge time to achieve decent output. Full charge is in the neighborhood of 6mS. When used in a rotary application, in wastespark, if you try to charge them to 6mS, you hit 100% duty on the leading pair at 5000 rpm. At 8000 rpm there is only 3.75mS total cycle time to charge and discharge the coil, so you need something that saturates very quickly. The LSx coils seem to work decently well with ECUs that allow true four channel direct-fire on the leading plugs, which effectively halves the duty cycle over wastespark and allows twice the cycle time to charge the coils. The LS2 coil is pretty hot, it just needs to be charged a long time to make it happen.
I've had good luck with the Mercury Marine inductive coils with gasoline and with straight methanol injection to around 24 psi. Recently, with a car running 50/50 water/meth and 20+ psi I've had issues with these same coils and spark blowout. They're not liking the water... They reach saturation at less than 4mS, with about 90% saturation at around 3mS, so they're well suited to the application. They're pretty big though and packaging is a PITA. With the 50/50 injection car we're probably going to end up switching things over to a full M&W setup and answer all doubts.
https://www.rx7club.com/power-fc-forum-47/ignition-charge-time-calculator-888159/
There are some other posts on the subject too, though not a lot is said about it since the Twin-Power CDI box seems to be so popular with guys that want a decent amount of power and aren't inclined to swap to a different inductive coil. With a CDI dwell becomes moot. I'd go the Twin-Power route (with new stock coils) before doing the work to convert to LSx coil.
The problem with any of the LSx based coils, MSD or otherwise, is that they require a rather long charge time to achieve decent output. Full charge is in the neighborhood of 6mS. When used in a rotary application, in wastespark, if you try to charge them to 6mS, you hit 100% duty on the leading pair at 5000 rpm. At 8000 rpm there is only 3.75mS total cycle time to charge and discharge the coil, so you need something that saturates very quickly. The LSx coils seem to work decently well with ECUs that allow true four channel direct-fire on the leading plugs, which effectively halves the duty cycle over wastespark and allows twice the cycle time to charge the coils. The LS2 coil is pretty hot, it just needs to be charged a long time to make it happen.
I've had good luck with the Mercury Marine inductive coils with gasoline and with straight methanol injection to around 24 psi. Recently, with a car running 50/50 water/meth and 20+ psi I've had issues with these same coils and spark blowout. They're not liking the water... They reach saturation at less than 4mS, with about 90% saturation at around 3mS, so they're well suited to the application. They're pretty big though and packaging is a PITA. With the 50/50 injection car we're probably going to end up switching things over to a full M&W setup and answer all doubts.
Last edited by C. Ludwig; 02-20-10 at 09:09 AM.
