Ok so here is the story on the old 6AL, I had in the car.

When I installed the FULL MSD on the 4.9, MSD Coil, 8.5mm Superconductor Wires, 6AL Box and gapped the plugs at .060 there was a remarkable change in engine operation. The extra fuel at idle smell went away. Frankly the chip was programed too rich, but the MSD's act of firing each plug several times per crank revolution solved that issue. I also noticed quicker starters, and even with the huge amount of torque the 4.9 already had, it managed to add more off idle torque. It was such a big difference when my box died and I had to go back to just the MSD coil, I thought something was wrong with the car as it tried to stall when I lifted up the clutch pedal. With the Isuzu 5spd and a 4.9 with MSD I could take off without touching the gas pedal or touching it very lightly. It was great. On several road trips I got an easy 30mpg from the 4.9 5spd. It also helped with emission's testing which made me double happy.


So now with the new 4.9 motor being built at FOY I wanted to upgrade my MSD stuff, I picked up a Digital 6 Plus. It has a Launch Control feature that sets a low rpm rev limit for launching. Basically you put a switch on your brake or clutch pedal, and when pressed it won't let the engine rev over a preset limit, so you can Place your foot on the clutch mash the gas to the floor it will hold it at say 2500rpms and then you can pop the clutch and get that perfect launch every time. (you'll have to find your own correct launch rpm)
It also has a crank retard if enabled will back off your ignition timing during cranking to save on starters. I don't think I'll need that though.
It has a Nitrous Retard feature so that when I hit my nitrous it can back off the timing for me. This I really do need as I was running stock timing with a 100hp shot and I believe that is why I popped the head gasket in my 4.9 in the first place.

I really like the fact that it does multiple sparks at low rpms, as frankly with the 4.9 in town cruising around I am usually in 5th gear at 1500rpms so having a good complete burn gives me decent gas mileage and no stumble at all.

Who else is running a Digital 6-Plus or similar Ignition box, how do you have the triggers setup. I was planning on the clutch switch to be a proximity switch at the floor, I figure when I lift the clutch pedal off the floor there will be a 1/4 second delay before the clutch disk engages which should be enough for the motor to be ready to take off.

My Nitrous Retard will just be hooked to the 12v line going to the nitrous solenoid, so when the Solenoid goes hot, the box can pull the timing.

As for setup, I am planning on Plug gap of .050 during the summer with the Nitrous and .060 during the winter when I am not using the bottle. I already have brand new MSD 8.5mm Superconductor wires, with a good quality brass contact, cap and rotor and MSD Coil. I know all the special notes about checking plugs every 3000 miles and changing plugs every 6000-10000 miles, depending on Nitrous Use or not. When I was using the bottle all the time on my V6 I changed plugs every 3rd or 4th bottle. LOL, I would use Nitrous to go and get groceries from the store. I was a bottle junkie.

Even if you don't have the MSD setup, there must be other guys using similar setups with Throttle Triggers and clutch triggers.

I was even thinking it might be easier to instead of setting up the clutch switch on the pedal to rig it up off the clutch slave like a magnet on the slave rod and the proximity switch on the slave cylinder. Would let me keep more of the wiring in the engine bay and less going into the cabin.
Another side note, I have a remote mount battery up front, so obviously I can't wire the box to the Battery Directly. I am planning to wire it straight to the 3 ought ( 0/3 ) cable that runs to the block and to the starter or the 4 gauge that runs to the power distribution block.

Being in Canada where gas can hit over $6 a gallon we try to get every 5-10% fuel saving we can. If I can drive like a Maniac and still get average fuel economy I am happy.

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857GT Part 85GT Part 87GT Part Caddy, 93 Eldorado 4.9, 5spd Dual O2 Custom Chip, Custom Exhaust. MSD Everything Now with Nitrous. Capt Fiero --- My Over View Cadero Pics Yellow 88GT 5spd Full Poly Suspension, Lowered 1/2" in front, Corner Carver.

When I had my 4.9 with nitrous I was using the Mallory equivalant of what you just got. The Mallory 685 was cheaper and had better specs than the MSD so that's why I went with it. It had a built in rpm window switch as well so my nitrous was wired to that, a master switch, a full throttle switch, and the timing retard.

The Mallory has great specs on the box and is cheaper with more features than the MSD, but several of my friends bought the Hyfire 6 when it came out about 8 years ago, and one guy had 3 fail in 6 months, another had 2 fail and gave up, and a 3rd club member had at least 2 fail. They all switched over to the MSD units. MSD may not have all the bells and whistles of the Hyfire, and also cost almost 50% more, but for piece of mind, I'll stick with MSD. This is my first foray into MSD's Digital line up, and I know I'll have to purchase a window switch separately. However back to my main question.

How did you setup the WOT switches and did you use a staging rev limiter? If I was auto I might be tempted to just have a button on the shifter but being stick I think a clutch activated switch will work better for me.

Edit
This is all assuming my motor ends up being what I am expecting it to be. It blew up today at the shop that is building it.

quote Originally posted by Capt Fiero: The Mallory has great specs on the box and is cheaper with more features than the MSD, but several of my friends bought the Hyfire 6 when it came out about 8 years ago, and one guy had 3 fail in 6 months, another had 2 fail and gave up, and a 3rd club member had at least 2 fail. They all switched over to the MSD units. MSD may not have all the bells and whistles of the Hyfire, and also cost almost 50% more, but for piece of mind, I'll stick with MSD. This is my first foray into MSD's Digital line up, and I know I'll have to purchase a window switch separately. However back to my main question. How did you setup the WOT switches and did you use a staging rev limiter? If I was auto I might be tempted to just have a button on the shifter but being stick I think a clutch activated switch will work better for me. Edit This is all assuming my motor ends up being what I am expecting it to be. It blew up today at the shop that is building it.

I was using a Holley 2bbl carb on my 4.9 and the nitrous kit I bought was for that carb so it came with a full throttle switch. It was just a simple bracket that attached to the fogger plate mounting bolts and held a micro switch under part of the throttle linkage. I never bothered to use the launch control rev limiter because I only autocross and not drag race. I can get a more consistent launch and be easier on the clutch without the launch control (even in my turbo miata).

If you do want the rev limiter then most cars already have two clutch switches, one to prevent the starter from energizing unless the clutch is all the way to the floor, and one that disengages the cruise control if you push the clutch in. I'm not 100% sure if the fiero has either or both of these because I don't have one anymore, but take a look under your dash at the pedals and look for some switches on the clutch pedal. If you have them then just tap into the one the cruise control uses so the launch control will engage whenever the clutch is not fully engaged.

Using the clutch's starter disable or cruise was my first idea, but after checking, the cruise one is at the top of pedal travel so it won't work, and the clutch disable breaks a 12v circuit to disable the starter signal rather than creates a 12 signal. The launch control needs to see a 12v signal to turn on. So I can't use that.

By the way I took a ride in your old car a while back pretty fun car, Steve has however had a really steep learning curve on the mechanics of it. I heard he took it out to the local autocross and had a ball with it. He's also taken it on a couple club runs too. He loves the car and is taking really good care of it.

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857GT Part 85GT Part 87GT Part Caddy, 93 Eldorado 4.9, 5spd Dual O2 Custom Chip, Custom Exhaust. MSD Everything Now with Nitrous. Capt Fiero --- My Over View Cadero Pics Yellow 88GT 5spd Full Poly Suspension, Lowered 1/2" in front, Corner Carver.

quote Originally posted by Capt Fiero: My Nitrous Retard will just be hooked to the 12v line going to the nitrous solenoid, so when the Solenoid goes hot, the box can pull the timing.

How is your system wired?
Do you have separate "arm" and "fire" switches?

IE, the "arm" switch should supply +12V to the system, then the "fire" switch would complete the ground side of the solenoid circuit. The "fire" switch would be a throttle switch or a relay operated by a micro-switch on the throttle linkage. In this case, the "fire" switch should be what operates the ignition retard.

However, if you just have one switch that operates the entire system ("go baby go" button), then that switch should turn on the ignition retard as well.

In my first Nitrous install on my 2.9 I learned my lesson with a "Go Baby Go" button. It was totally cool to be all Fast and Furious MoHaHa. However missed shifts with the button pushed, Getting over anxious at a starting line and bogging the motor to under 1000rpms and using the nitrous to bottle launch out of it, kinda taught me a few things.

Currently its wired 12v battery to an arming switch in the cabin, then out to a WOT switch at the throttle body then from the WOT switch power went to the Fuel and Nitrous Solenoids and then they were connected to ground. The Nitrous and Fuel lines went into a NOS Jet which was threaded into the intake horn of the 4.9. (about 6 inches upstream of the throttle body)

I planned to hook the Retard signal line in between the WOT switch and the Nitrous Solenoids.

The next question is, if I back off on the nitrous shot to say a 75hp shot, how much timing do you think I should pull. Honestly I have not researched that yet. I know I had my jets set a little on the rich side and could have made more power if I leaned it out, but wanted to err on the side of caution because at the time, I was not using any retard at all, left it with stock Caddy timing. (hence why I squeezed out a head gasket on my last 4.9)

Will you commented on my 4.9 motor thread with FOY, I sent my car to him when I popped the last motor and he is trying to build me a new motor, with the expectation that the new motor makes almost as much power NA as the old motor did with the nitrous. In all reality sake, I was using the nitrous more for higher rpm range to overcome the small ports and puny cam that the 4.9 has. Basically just feeding it a denser air/fuel charge to make up for the lack of flow up top.
I didn't have a Window switch so I was doing my best to launch at 3/4 throttle then pin it to the floor once I was rolling and over 3500rpms,

I have no idea how much retard you're going to need... there are lots of performance forums on the internet that can help you figure that out. Live tuning will likely be necessary.

Do you have a knock detection system?

Also, for consistency, you'll want an RPM window switch in series with the arm and WOT switches.

You *WILL* want the RPM window switch to shut off the N2O *BEFORE* you get to the limiter. IE, if you're limiter is at 6000, the window switch should cut off the N2O at 5800 or so. When you hit the limiter, the ECM cuts fuel, but the N2O system would still be spraying fuel and N2O... bad news. There's no way to guarantee that the window switch and ECM limiter hit within the same revolution of the engine. The SAFE way is to cut the nitrous a couple hundred RPM below the limiter.

quote Originally posted by Capt Fiero: the cruise one is at the top of pedal travel so it won't work

That is what you want. You want the 2nd stage rev limiter to engage anytime the clutch isn't fully engaged. This will allow you to hold full throttle at a constant rpm while you feed the clutch in, and then only when your foot is fully off the clutch pedal will full power be restored. If it the rev limited turned off with the clutch slightly off the floor it would be totally useless because it wouldn't be doing it's job while the clutch was in the slipping range.