ignition

[lt14mla]

I've been hearing a lot of things about ignitions. How much can it improve your car to change the ignition. I hear the opti-spark is pretty bad, but why? What can a new ignition do for my car? Any HP or TQ ratings? Any reccomened brands , Crane and MSD keep coming up from people I know. Lend some ideas. thanks guys

[Joe 1320]

Contrary to some beliefs, the optispark is actually a pretty good design. How many older cap and rotors would have lasted 100K miles on average? It is due to an optical sensor which rarely gives out and a traditional cap and rotor setup. The drawback is the location of the unit. Located directly behind and beneath the water pump, it is easily contaminated by fluid from either a leaking pump or washing the engine. There are still ways to protect it. Another problem is that LT-1 coils often don't reach full charge and could use some help. I run an MSD 6 to amplify the spark and the problem is eliminated. As far as a HP gain, well...... not much of one really. Maybe 1 or 2 HP at best. Fuel mileage and effeciency will pick up a bit and if you are running some sort of forced induction, you'll need the upgrade. Basically all you are doing is reducing the power lost by an ineffecient spark. There is also another setup that bypasses the cap and rotor portion and uses northstar coils to fire each cylinder based on the optispark's optical section. This removes the high voltage from the cap and rotor portion and makes the LT-1 coil charging issue and eliminates it. It also eliminates the ozone buildup within the cap and rotor portion that the vented style opti was supposed to eliminate.

[lt14mla]

thanks alot joe. Im thinking of installing a mds 6AL ignition system. The one with the adjustable rev-limiter. Does anybody know how high you can set the rev up to safely on a 97 lt1.

[95TransAm]

I myself am not too familiar with the opti, but a friend of mine said that the opti is a good design as well. He said this (but im not sure so im asking you guys), but according to him the opti is a double spark. In short, what it basically does is fire a spark during your power stroke as normal, but it also fires one during your exhaust stroke to eliminate all remaining fuel so your car runs more efficiently. Is this true

[Squat13]

Contrary to some beliefs, the optispark is actually a pretty good design. How many older cap and rotors would have lasted 100K miles on average? It is due to an optical sensor which rarely gives out and a traditional cap and rotor setup. The drawback is the location of the unit. Located directly behind and beneath the water pump, it is easily contaminated by fluid from either a leaking pump or washing the engine. There are still ways to protect it. Another problem is that LT-1 coils often don't reach full charge and could use some help. I run an MSD 6 to amplify the spark and the problem is eliminated. As far as a HP gain, well...... not much of one really. Maybe 1 or 2 HP at best. Fuel mileage and effeciency will pick up a bit and if you are running some sort of forced induction, you'll need the upgrade. Basically all you are doing is reducing the power lost by an ineffecient spark. There is also another setup that bypasses the cap and rotor portion and uses northstar coils to fire each cylinder based on the optispark's optical section. This removes the high voltage from the cap and rotor portion and makes the LT-1 coil charging issue and eliminates it. It also eliminates the ozone buildup within the cap and rotor portion that the vented style opti was supposed to eliminate.

Personal I think GM was Drunk when They came up with the OPTI. who ever heard of a distributor underneath the water-pump? I though Ford did stuff like that. O well, I only replaced or rebuilt mine twice.

[Jeff_in_Atl]

I have seriously thought about adding a MSD 6A for gas mileage purposes. Does anyone have any real life before and after results from adding one?

[Squat13]

I have heard of people puting Ignition Boxes on street applactions and they say the only gains from them are in the timing retard and REV control. They have told me that the power gains are very small on applaction under 500 HP because the stock spark is enough to burn complete.

[Injuneer]

I myself am not too familiar with the opti, but a friend of mine said that the opti is a good design as well. He said this (but im not sure so im asking you guys), but according to him the opti is a double spark. In short, what it basically does is fire a spark during your power stroke as normal, but it also fires one during your exhaust stroke to eliminate all remaining fuel so your car runs more efficiently. Is this true

Not true. It is a conventional cap/rotor ignition system, using a single coil, and one spark per cylinder's 4-stroke cycle. You may be confusing the operation of the Opti with the crank-sensor driven ignitions used on non-sequential fuel injectoin cars, which - because they con't know the position of the cam - use a "waste-spark" setup. One coil fires the plugs on two cylinders, one approaching TDC on the compression stroke, and one approaching TDC on the exhaust stroke. The majority of the energy is directed to the cylinder on the compression stroke, and remaining energy fires the plug in the cylinder on the exhuast stroke. To my knowledge, this is not done to eliminate any unburned fuel, but simply because that's the only way you can supply spark to an engine without a cam position sensor.

The "waste-spark" ignition is used on the modern GM V6's, and in particular on the Buick GN/GNX turbo V6's. It is also used by Electromotive on their aftermarket ignition and engine management systems. And, it was used on the Northstar V8, the Aurora V8 and on the "marine" versions of the LT1. It is also the basis for the Delteq conversion.

You may also be thinking of the "multiple spark discharge" ( = MSD ) approach, where the plug is fired multiple times, with the claim that it results in more complete combustion.

A stock LT1 ignition system, in healthy condition, is an excellent setup. You will not gain any appreciable HP by upgrading it. You can "enhance" its performance under extreme conditions, like nitrous usage, with the MSD boxes, but you are not going to see any improvments on an NA engine, over a healthy Optispark driven setup. The MSD will cover up, and recover HP lost on "defective" ignitions, but that's not the question you've asked.

The Opti is an excellent concept... the only defect was the location. The Opti isn't even a "GM original".... it was used by Chrysler/Mitsubishi in the late 1980's, on their 3.0L "diamond star" V6's. If you pull you Opti apart, you will find the Mitsubishi tri-diamond logo on the optical module.

The Opti reduces spark scatter, providing extremely accurate and consistant spark timing. That alone is enough to help the engine make more power, while minimizing emissions. Some of us have used the Opti's optical module as the source of cam position info, to allow us to run very high HP, very high RPM engines, using aftermarket engine management systems like the MoTeC. The setup I've been running for 4 years is the same has been used in an 1,125HP, 8,000+RPM LT1 engine. Removing the high voltage function from the Opti seems to eliminate most of the problems.

[95TransAm]

Not true. It is a conventional cap/rotor ignition system, using a single coil, and one spark per cylinder's 4-stroke cycle. You may be confusing the operation of the Opti with the crank-sensor driven ignitions used on non-sequential fuel injectoin cars, which - because they con't know the position of the cam - use a "waste-spark" setup. One coil fires the plugs on two cylinders, one approaching TDC on the compression stroke, and one approaching TDC on the exhaust stroke. The majority of the energy is directed to the cylinder on the compression stroke, and remaining energy fires the plug in the cylinder on the exhuast stroke. To my knowledge, this is not done to eliminate any unburned fuel, but simply because that's the only way you can supply spark to an engine without a cam position sensor.

The "waste-spark" ignition is used on the modern GM V6's, and in particular on the Buick GN/GNX turbo V6's. It is also used by Electromotive on their aftermarket ignition and engine management systems. And, it was used on the Northstar V8, the Aurora V8 and on the "marine" versions of the LT1. It is also the basis for the Delteq conversion.

You may also be thinking of the "multiple spark discharge" ( = MSD ) approach, where the plug is fired multiple times, with the claim that it results in more complete combustion.

A stock LT1 ignition system, in healthy condition, is an excellent setup. You will not gain any appreciable HP by upgrading it. You can "enhance" its performance under extreme conditions, like nitrous usage, with the MSD boxes, but you are not going to see any improvments on an NA engine, over a healthy Optispark driven setup. The MSD will cover up, and recover HP lost on "defective" ignitions, but that's not the question you've asked.

The Opti is an excellent concept... the only defect was the location. The Opti isn't even a "GM original".... it was used by Chrysler/Mitsubishi in the late 1980's, on their 3.0L "diamond star" V6's. If you pull you Opti apart, you will find the Mitsubishi tri-diamond logo on the optical module.

The Opti reduces spark scatter, providing extremely accurate and consistant spark timing. That alone is enough to help the engine make more power, while minimizing emissions. Some of us have used the Opti's optical module as the source of cam position info, to allow us to run very high HP, very high RPM engines, using aftermarket engine management systems like the MoTeC. The setup I've been running for 4 years is the same has been used in an 1,125HP, 8,000+RPM LT1 engine. Removing the high voltage function from the Opti seems to eliminate most of the problems.

Thanx alot for clearifing. I always wondered exactly what the opti did. It's always good learning something new every day about an F-bod.
Appreciate the info again
Chris