using FC3S TRAILING coil
01-20-06, 02:10 AM
#1
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using FC3S TRAILING coil
I'm planning on running a Megasquirt setup w/ a 12A dizzy on fuel (vacuum advance). I've researched the FC DLIDFIS Mod w/ transistor trick and plan to pick up a kit whenever the GB gets moving. However, I'm pretty sure that that setup only runs the Leading coils; and that most run a 1st gen coil to the dizzy-cap for the T-spark.
What I want to know is; can you run (spacifically) an FC trailing coil to the dizzy, and DLIDFIS to the trailing? if so, and it's not a bolt-up deal, what kind of resistors and whatnot or needed? Right now I'm sitting on a full FC ignition, a 12A dizzy and ignitors.
What I want to know is; can you run (spacifically) an FC trailing coil to the dizzy, and DLIDFIS to the trailing? if so, and it's not a bolt-up deal, what kind of resistors and whatnot or needed? Right now I'm sitting on a full FC ignition, a 12A dizzy and ignitors.
01-20-06, 02:25 AM
#2
You have a couple options. First, you are correct in that the TT only handles the leading ignition. It may be possible to do something similar for the trailing, but you need a way to determine engine position becuase you can't fire both trailing plugs together as you can with the leading.
- You can run the full FC ignition with the MS. They have recently got the trailing spark working. This is maybe the route to go eventually.
- Run dizzy for now and use either the TT, stock ignition, or some other form of DLIDFIS. I would maybe go this route first, so you can get the fuel tuned first. Once the fueling is setup well, you can then add the 2nd gen CAS and the rest of the FC igniton and fire it off the MS.
The TT kits are currently available. I am running the GB through www.rotaryx.com. I will do preorders for about 2 more weeks, then I will be ordering parts and then start shipping stuff out. The TT may or may not be a good choice for you. You will have an ECU capable of running the FC ignition, so you don't really need the TT to use the FC leading coil. Maybe the stock ignition and then switch to the FC stuff using the MS would be the cheapest route.
Kent
- You can run the full FC ignition with the MS. They have recently got the trailing spark working. This is maybe the route to go eventually.
- Run dizzy for now and use either the TT, stock ignition, or some other form of DLIDFIS. I would maybe go this route first, so you can get the fuel tuned first. Once the fueling is setup well, you can then add the 2nd gen CAS and the rest of the FC igniton and fire it off the MS.
The TT kits are currently available. I am running the GB through www.rotaryx.com. I will do preorders for about 2 more weeks, then I will be ordering parts and then start shipping stuff out. The TT may or may not be a good choice for you. You will have an ECU capable of running the FC ignition, so you don't really need the TT to use the FC leading coil. Maybe the stock ignition and then switch to the FC stuff using the MS would be the cheapest route.
Kent
01-20-06, 03:15 AM
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Actually I'm going to be running an O-G v1.01 MS that I've been camping on since 'squirt was in it's childhood. Running Dual-Table and a Distributor for ignition should be fine on a 4port N/A.
As for what I'm suggesting; I'm not too familiar w/ the 12A ignition setup. In stock form there are 2 coils, 1 for L and T respectively. W/ any direct-fire Leading setup, you run 3 plug wires to/from the cap (trailing plugs, and trailing coil) and 2 wires to the Leading coil(s).
My question is what would it take to use a single FC Trailing coil in place of the coil going to the distributor cap?
[ background; I'm really about clean engine bays, and it seems possible that I can just use the OEM dual-trailing bracket from an FC and have a 2-terminal leading coil, and single trailing coil on the same bracket, for a very compact and clean look in the upper right hand corner of the engie bay ]
As for what I'm suggesting; I'm not too familiar w/ the 12A ignition setup. In stock form there are 2 coils, 1 for L and T respectively. W/ any direct-fire Leading setup, you run 3 plug wires to/from the cap (trailing plugs, and trailing coil) and 2 wires to the Leading coil(s).
My question is what would it take to use a single FC Trailing coil in place of the coil going to the distributor cap?
[ background; I'm really about clean engine bays, and it seems possible that I can just use the OEM dual-trailing bracket from an FC and have a 2-terminal leading coil, and single trailing coil on the same bracket, for a very compact and clean look in the upper right hand corner of the engie bay ]
01-20-06, 03:29 AM
#4
The problem is theat the FC trailing pack is really two coils and has a select wire connected. The select wire tells it to say fire T1 or to fire T2. You can't fire them together as one of them would be firing into an incoming intake charge before the rotor was in the proper position. The leading can be fired together because of their location. When one is firing near TDC, the other rotor will be in its exhaust phase. The extra spark on the other rotor will just burnup any left over fuel vapor if there are the right conditions to ignite.
In order to use the FC trailing, you would need either an ECU or something like the TT in conjunction with an engine position sensor of some kind. You may be able to put a Hall effect sensor or similar on the front pulley with some additional electronics for the select signal and then something like the TT to get the correct voltage behavior to actually fire the coil. It can be done, just requires a bit of work. You are probably better off using the stock trailing or use no trailing at all. The trailing doesn't do much for power. It does help emissions and maybe MPG a bit. You probably wouldn't even notice if you didn't have it hooked up. If you really want to use the FC trailing, I can help you out and maybe we can come up with something that will work.
In order to use the FC trailing, you would need either an ECU or something like the TT in conjunction with an engine position sensor of some kind. You may be able to put a Hall effect sensor or similar on the front pulley with some additional electronics for the select signal and then something like the TT to get the correct voltage behavior to actually fire the coil. It can be done, just requires a bit of work. You are probably better off using the stock trailing or use no trailing at all. The trailing doesn't do much for power. It does help emissions and maybe MPG a bit. You probably wouldn't even notice if you didn't have it hooked up. If you really want to use the FC trailing, I can help you out and maybe we can come up with something that will work.
01-21-06, 12:29 AM
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full DFIS
I am working on full DFIS on a 12A. The L are fired by an Accel GM type HEI module (ignitor) wired to a dual outlet GM type Accel coil in a wasted spark configuration. The T will be fired by the existing pickups and ignitors through the two original coils. One for each rotor. This requires a two lobe reluctor and two pickups at 90 degrees from each other. The whole system should be finished in a few weeks.
It also looks like it may be possible to use two dual outlet coils and fire both plugs in each rotor simultaneously using the stock pickups and ignitors and a two lobe reluctor. I may try that next sice it would require less fabrication on the pickup mounts in the distributor. Either of these would result in plug wires less than a foot long and no secondary voltage in the distributor at all.
It also looks like it may be possible to use two dual outlet coils and fire both plugs in each rotor simultaneously using the stock pickups and ignitors and a two lobe reluctor. I may try that next sice it would require less fabrication on the pickup mounts in the distributor. Either of these would result in plug wires less than a foot long and no secondary voltage in the distributor at all.
Originally Posted by Liquid Anarchy
Actually I'm going to be running an O-G v1.01 MS that I've been camping on since 'squirt was in it's childhood. Running Dual-Table and a Distributor for ignition should be fine on a 4port N/A.
As for what I'm suggesting; I'm not too familiar w/ the 12A ignition setup. In stock form there are 2 coils, 1 for L and T respectively. W/ any direct-fire Leading setup, you run 3 plug wires to/from the cap (trailing plugs, and trailing coil) and 2 wires to the Leading coil(s).
My question is what would it take to use a single FC Trailing coil in place of the coil going to the distributor cap?
[ background; I'm really about clean engine bays, and it seems possible that I can just use the OEM dual-trailing bracket from an FC and have a 2-terminal leading coil, and single trailing coil on the same bracket, for a very compact and clean look in the upper right hand corner of the engie bay ]
As for what I'm suggesting; I'm not too familiar w/ the 12A ignition setup. In stock form there are 2 coils, 1 for L and T respectively. W/ any direct-fire Leading setup, you run 3 plug wires to/from the cap (trailing plugs, and trailing coil) and 2 wires to the Leading coil(s).
My question is what would it take to use a single FC Trailing coil in place of the coil going to the distributor cap?
[ background; I'm really about clean engine bays, and it seems possible that I can just use the OEM dual-trailing bracket from an FC and have a 2-terminal leading coil, and single trailing coil on the same bracket, for a very compact and clean look in the upper right hand corner of the engie bay ]
01-22-06, 11:12 PM
#6
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I'm running my MS in fuel-only mode; so I'm just wanting to get away w/ replacing the T dizzy coil w/ an FC T coil.
Last edited by Liquid Anarchy; 01-22-06 at 11:14 PM.
01-24-06, 02:34 PM
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Ok; so I thought I'd better illustrate what I wanna do... I also put a little bit more thought into it...
I'm wanting to setup my coils as-pictured (w/ the Leading-coil ignitor in the casing).
The wiring for the T coil would be J-109 ~> Ballast Resistor? ~> Coil ~> Dizzy ~> Leading Plugs
The wiring for the L coil would be J-109 ~> Transistor Trick ~> FC Ignitor ~> Coil ~> Trailing Plugs
I'm wanting to setup my coils as-pictured (w/ the Leading-coil ignitor in the casing).
The wiring for the T coil would be J-109 ~> Ballast Resistor? ~> Coil ~> Dizzy ~> Leading Plugs
The wiring for the L coil would be J-109 ~> Transistor Trick ~> FC Ignitor ~> Coil ~> Trailing Plugs
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01-24-06, 02:43 PM
#8
Yes, that should work. You will probably need a ballast resistor for the trailing, although some people have done the 2GCDFIS without the ballast and had no problems.
I was thinking you were wanting to bypass the dizzy and use a coil on plug setup like the FC on the trailing. One thing you could maybe do, but probably wouldn't make a difference, is to use a 2nd TT to fire the trailing FC ignitor. I wouldn't mess with it, though. I think this setup would work well. Trailing has very little impact anyway.
I was thinking you were wanting to bypass the dizzy and use a coil on plug setup like the FC on the trailing. One thing you could maybe do, but probably wouldn't make a difference, is to use a 2nd TT to fire the trailing FC ignitor. I wouldn't mess with it, though. I think this setup would work well. Trailing has very little impact anyway.
01-24-06, 02:54 PM
#9
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Someone brought it to my attention that you might not get I was going to run a coil through the cap; which was why the split-thing was an issue. I see you get my drift now. I think it will make for a pretty good alternative to my stock FC ignition, nowhere near as much of a downgrade... but it's towards a greater good :-D
The unimportance of the T coil is what would keep me from dropping another $30-45 on a second TT-box. This is Po'Mo'Fo Racing at it's finest.
The unimportance of the T coil is what would keep me from dropping another $30-45 on a second TT-box. This is Po'Mo'Fo Racing at it's finest.
