View Full Version : Ignition system opinion

04-10-2005, 04:33 AM
I have heared a great deal about FBO's distributor blueprinting and phazing services and their ECU's, but I have a few questions regarding the systems.

1. I have a Jacob's Electronics Pro Street system new in the box with the coil that I plan on using. The Jacob's system uses the original electronic ign. and coil to send a signal to the box and out to the Jacob's coil for the 65,000 volts to the plug. Would there be any benefit over a stock replacement ECU since it only uses it as a signal?

2. There are 2 part numbers for the electronic ign. module. My truck has cruise control (which will also be used) and requires the uncommon unit because of this. Can I use the FBO ECU with the cruise control?

3. Does the FBO distributor have to be used with their ECU?

I would love to have my new dist. gone through with the FBO setup, but I don't know if my ignition system will even make use of it.

I currently have a Mopar Performance light spring kit and I blueprinted the curve using my degreeing wheel and adjusting the advance weight channel leingths. The distributor is a new reman unit from Carquest with 100 miles on it. I'm sure that the FBO phazing will help a little, but I didn't think it would be necessary on a street/strip engine.

04-10-2005, 07:48 AM
1, it's not good to use a system thant piggy bavks off the stock set up. You wont see the gains or have the accuracy that you would have using a stand alone msd box.
2,Cruise control is not effected by any ignition system.
3,No, it's just a stock dist that's been recurved. You can get those anywhere.
Since you have already curved yours, you wont see much gain by having someone else recurve it, unless yours has not been correctly curved. The fbo is an o.k. street set up, but you wont be able to beat an msd box. I talked to him about using one in a race car and he told me straight out if I already was using the msd box not to switch cause the fbo box is not as good as the msd. :king:

04-10-2005, 09:41 AM
The MOPAR ECU tends to have some issue with delay. That is seen in timing. If you piggy back the Jacobs on the MOPAR ecu, you will not correct that problem. Jacobs does have an ECU that can be triggered by the MOPAR electronic distributor. If you want to stay with the Jacobs, I would return your unit and exchange it for the correct one.

The FBO distributor can be used with any ignition system. You can also send your distributor in and have it modified by Don.

Even though you installed the MOPAR spring kit and went through the distributor, there is still alot of room for improvement. What you get from Don is a distributor that has been phased and tuned on a distributor dyno.

If you already have a Good multi spark system (eg. Jacobs, MSD) there is no really need for the FBO ECU. If you don't have a multi spark system and the car is mostly street with some strip, there is no reason to pay more than the cost of the FBO system.

04-11-2005, 12:34 AM
Ed's right.

You want an ECU that can be triggered directly by your distributor. Not by the stock ecu. The Ecu is the weak point of the stock sysytem.
Msd makes (or used to make) a ECU like that too. Not worth your time.

A quality ECU like a MSD 6al,(or whatever jacobs and Mallory's equivalent is) or an FBO are well worth the investment.

Yes Multi spark boxes are quality pieces. BUT they do have thier draw backs.

1)They are harder on ignition parts than oem style stuff.

2) When they break down(yes, I said when not if) your screwed. Not every corner parts store will have an MSD box. If you run something like an FBO, you can get a ecu anywhere you want if you break down.

The benefits of a multi spark system are gone between 3000 and 3500 rpm on most systems(that's when it drops back to single spark)

Most street cars will not see any benefit to a multi spark setup over something like FBO or a mopar chrome box.

As for your curve, the mopar spring kit will bring the timing in really early. Too early for some applications. Your carquest unit will probably have too much mechanical advance in it also. 30 degrees or so. With any amount of decent base timing, that's too much.

04-11-2005, 12:44 AM
Why are you using the Mopar ECU to trigger the Jacobs pak? Just hook up the mag trigger wires from the Mopar Distributor. Sounds like you have a good unit there already, FBO is very nice for the resto crowd that doesnt want to go to a spliced in Ignition system.

04-11-2005, 06:34 PM
I don't think I made myself clear.

The Jacob's unit is not like an MSD upon installation or function at all. Forget all you know about MSD boxes and their installation when you are working on a Jacob's Electronics system. They aren't the same.

The system is adapted onto your original complete and functioning ignition system and does not replace any component or cut any wires. It looks like this compared to an original system from the coil out:

Original system:
Coil - Distributor - Plugs

Jacobs system:

Coil - Trigger Pickup from coil output - Jacob's Box - Jacobs Coil - Distributor -Plugs

Upon a failure of the system, it is simply bypassed and uses your original system because it is all still functioning. So you're not screwed. It is triggered off of the original coil output wire. The system performs like a stand alone when it is working and only uses the original coil output for it's 1 wire trigger. It is proven stronger than an MSD 7AL and is actually computer controlled.

The Jacob's system does not work from 3000-3500RPM. It delivers from idle (even startup) through 10,000 rpm.

The MSD 6A, 6AL and 7AL are an analog inductor type multi spark system. The Jacob's Pro Street is a true computer controlled system. The MSD box fires 3-4 times per ignition while the Jacobs unit fires 8-10 times with 10,000 more volts than even a 7AL uses. I chose the Jacob's system over the MSD because of it's installation, performance and options over the MSD.

The jacobs system has excellent features including a fully adjustable rev limiter without chips, tune mode (manual shut off of system going back to stock system), start up mode, a silent alarm, and a maximum power output. All of which can be operated with the flip of a switch. It is a more expensive unit than the MSD6AL by about $160, but you get what you pay for. I got lucky because I found a Jacob's product distributor on ebay and got mine for $240.

I think my question is answered about the FBO unit. The Jacob's system will not see any benefit from it knowing that it only uses the original coil output for the trigger, I think I'll just leave my stock system alone (I have all new components).

I may see a little benefit in phazing the cap, but not much in the RPM range that I will be running the system at.

The cruise control original ECU is a part of the cruise control system and is a different component than the non cruise control vehicle units. I think I'll just leave mine in place knowing the nature of the Jacobs system.

04-11-2005, 08:13 PM
Again, that is the failing of the Jacobs unit that you bought. It is a secondary ignition computer that is being triggered by the poor quality MOPAR ECU. Even the Chrome box wanders as the RPM goes up. The EZ install unit (that you have) is just that. It still relies on the crappy MOPAR ECUt for it's signal feed. Simply put, garbage in - garbage out.

The Jacobs with the magnetic pickup is the better choice. If you put the correct connectors on everything, you can still fallback to the MOPAR ECU. It just isn't in the circuit, when the Jacob's is running.

Yes, the Jacob's is good for 10,000+ RPM. Like all other multi-spark systems, it stops multi-spark at about 3,500 RPM. Beyond that, it is a single spark. That is what dave571 was getting at. He wasn't trying to tell you that it falls down at that RPM, it's just that it no longer produces multi-spark.

Phasing of the distributor is more important on a multi-spark system than on a single spark system. It helps to insure that the rotor and cap are aligned, to give you the best use of multi-spark. If the rotor isn't pointing at the contact, when all of the sparks are flying, it won't get many of the sparks to the plug. Then you really have no point in using a multi-spark system.

04-12-2005, 01:04 PM
Distributor phasing is all about getting the reluctor trigger timing in synch with the rotor-to-cap contact timing, taking into consideration the amount of time it takes the ignition controller to actually trigger the secondary coil. If the relationship between these events is way off then a distributor phasing effort can be one of the most important performance-gaining adjustments that can be made in the ignition system.

The Jacobs computer controlled system is different than just a multi-spark box. It is quasi-self phasing because it "waits" and does not adjust the spark until the spark initially jumps the gap. It hits the spark plug with a known-to-it voltage, and as the gap is bridged the Jacobs computer uses the voltage drop in a complex formula with rpm mixed in to decide whether to tailor the spark to be multiple strong hits, or a solid hit, or a big hit tapering off to a smaller hit or a smaller hit building to a big hit. In essence it uses the spark plug as a sensor to tell it what may be going on in the combustion chamber.

After all that it sends a quick hit of the same amount in reverse phase, this supposedly returns electrons back where they came from and aids in component longevity.

The Jacobs type unit is self-phasing in that it knows when the spark is actually happening in the compustion chamber and waits to do it's thing, but it cannot make up for bad mechanical phasing if the pickup signal is way off from where the rotor tip is in range of the contact inside the cap. If the rotor is already part of the way onto the cap contact before the reluctor triggers the distributor pick-up coil then a Jacobs type unit or MSD type unit has a very small amount of time to deliver the spark.

If the reluctor triggers the pick-up coil before the rotor is in range of the cap contact then the Jacobs type unit in essence phases it electronically (by waiting to adjust the spark unitl the gap is bridged) and can get the maximum amount of time for spark delivery.

04-15-2005, 02:04 PM
Thrashed, I have what I think is the same Jacobs set up you have. On mine there was two different ways to set it up. The simple way using exsiting ignition componets or the perfered way of just replacing them with the Jacobs stuff. I don't have the manual hand right now but you might want to double check!

04-15-2005, 03:29 PM
I had my Jacobs hooked up to the Orange box at first, but changed it to trigger off of the dist. You can leave the factory box in and bypass the Jacobs should something go awry. Using the trigger off the distributor works much better and is a simple change in the wiring. If you didn't get the universal install, you will need to splice in a connector for the distributor. I think I still have my schematics if you wand a picture. I also had my distributor done by FBO for proper curve and it made a huge difference in response and idle.

04-16-2005, 02:46 AM
Thrashed, I have what I think is the same Jacobs set up you have. On mine there was two different ways to set it up. The simple way using exsiting ignition componets or the perfered way of just replacing them with the Jacobs stuff. I don't have the manual hand right now but you might want to double check!

I have the same set up - Here are just some of the ways you can hook it up. (see attached files). You may also like to look at http://www.moparchat.com/forums/showthread.php?t=84546

04-17-2005, 06:46 AM
The Jacob's system uses a voltage drop sensor inside it's ECU to correct, regulate and distribute a consistant spark to all of the plugs in any manor that it sees necessary. I could see poor mechanical phazing dropping the window of time to distribute energy to the plug, and maybe I will have it done in the future, but I have re-curved the distributor and I think I'll be using what I have for now.

I don't see the wiring schematcs for my system coming from the blueprints that you have posted, choper. My system does not have two wires leading off of the box iteself for the trigger. It only uses one. How do you trigger the Jacob's ECU off of anything but the provided coil wire trigger attached to the single green wire?

My system looks like this:

[Jacobs Electronics ]<-<-(red+wire & black-wire)-<-[batt.]
[Pro Street Ignition ]>->-(white wire & black wire)->-[Jacobs Ign. Coil]
[Pak lllllllllllllllllllllllllllllll ]<-<-(green wire)-<-[Jacobs Adapter]-<-[Stock Ign. Coil]

Any other system uses two trigger wires, like the diagram you show. I would like to run directly off of the distributor, but I don't know how to do that with a single wire pickup.

04-17-2005, 03:51 PM
As I already stated, Jacobs makes a couple of different ECU's. You did NOT get the one that allows you to connect to the MOPAR electronic distributor.