Blue printing 44 mag

I am confused also because ProMagg 44's should all be putting out 44 amps plus or minus a little hence the name. Some may put out 43 amps and some may put out 46 amps or some may be 44 amps. Since the windings are sealed in rock hard epoxy they can't be touched. You do have some big magnets in there but you can't do anything with them. About the only thing that can be done is to move the plate the pickup is on to adjust the phasing to make sure it is in alignment with the rotor. Testing one is not magically going to give you anymore power if everything is working. If the coils, magnet or pickup go bad then the mag generator is dead. Guess you can have a bad bearing or seal but that is no biggy.

Again the real reason for high amps is to fire off a sparkplug submerged in nitro in a high pressure environment. An alcohol motor does not really need that kind of power but we have it so we use it. Our biggest problem is high pressure in the cylinder but a ProMag 20 functions just great in that environment with 20 amps. Once the spark jumps the plug gap and ignites the alcohol mixture then the job is done because that flame front is moving away from the plug and burning up that fuel real fast. If you can light off the fuel 100% of the time with 40 amps going through the coil then 45 or 65 amps is not going to do anything more for you. With nitro you make more power if you can put more fuel in the cylinder and light it off so again that is the real reason for the 44 amps

 

good

I hope more of my competition in TAFC and TAD buys into this...

 

In a blown alcohol motor more fuel being ignited is NOT more horsepower if you don't have the correct amount of air with it. It has to be at the correct air fuel ratio or it is rich and lazy and you can ignite that all day long and you are not going fast.

 

ignition

Net horsepower is horsepower made on the power stroke minus horsepower used on the compression stroke (and all the other things that take away power)...

One of the main reasons more timing was ran years ago was the mags did not have the power. So you had to fire it earlier. As mags got better, timing aka spark advance numbers went down because it would fire the mixture quicker. Sure smaller combustion chambers had something to do with that. You will have to run more timing to make power with a MSD 20 than you will with any MSD 44.

SO for the sake of argument let's just say that all mags make the same horsepower on the power stroke (assuming proper air to fuel ratio). If the 44 degree mag doesn't have to fire until 25 degrees BTDC and the 20 mag is at 28, the SM 3 is at 30, etc., isn't it safe to say the motor will make more NET power with stronger ignition because of less timing needed to make the combustion process?

We're talking about heads up racing here. When you lose by .001 it might as well be by 1.00. I'm going to have the best damn mag I can put on a car, period. I do encourage my competition to just make sure it 'fires'....

 

a/f

Mike, your assertion that a blown alcohol motor can't make more power by burning more fuel is based on a few flawed assumptions. Your statement is the only way a blown alcohol motor can make more power by burning more fuel is to increase the air in a proportional way, such to maintain the proper air to fuel ratio.

You are basing this on the assumption that you are at an ignition surplus; that any spark will fire this mixture completely, the same way.

What if we are not at an ignition surplus? What if the quality of the ignition is a limiting factor in how much fuel we can burn to a given amount of air? If so, improving the ignition quality could lead to more fuel being burned.

 

Will, that is what I said...the only way you can burn more fuel is to add more air and keep the air fuel ratio correct. Better go back and read what I said again.

What is this "ignition surplus". Once that spark jumps that plug and fires off that mixture it is over and done.

Sorry Will but the main and only reason the old mags ran more advance was because the mag retarded when it was put under load. The ProMag system has an automatic compensation circuit in the Points Box to take care of this. A mag without a compensation circuit can retard up to four degrees when put under load. You want all mags to end up firing at the same point. How you seem to have forgotten......let me refresh your memory.

This has been discussed several times before.

All magnetos have an inherent characteristic of retarding timing as the ignition load on the magneto increases. This retarding of the ignition is due to the inability to build and collapse the inductive field in the coil at a rate that will keep up with the load of the motor. The amount the magneto is behind or retarded equates to about four degrees total at high load conditions. If a standard magneto such as the Mallory points type is timed at 36* at idle the ignition will be retarded to around 32* during high load conditions. This means if you really wanted 32* under load one had to learn to set the points magneto at idle on 36*. Racers learned to live with that and they just knew where to set them to make the best power.

The points style magnetos under no load conditions such as idle can produce voltage at a fairly fast rate but when put under extreme loads the rise time of the voltage into the coil slows way down. The ProMag 44 has a much faster rise time for the voltage going to the coil so the collapse of the field in the coil also occurs at a faster rate. When under load this results in the spark being initiated at a much faster rate than the points magnetos. This faster build up of the spark results in the spark being able to jump the sparkplug gap faster when the cylinder pressure is higher due to extreme loading. This in turn initiates the flame front in the cylinder at a faster rate so the burn rate of the fuel in the cylinder occurs at a faster rate and less advance timing is required.

The MSD ProMag 44 magneto generator still has this characteristic retarding of the ignition as the load increases but MSD coupled it with the Electronic Points Box which contains a magneto timing compensation circuit to eliminate the retard. Automatic compensation is accomplished by the Points Box initially applying retard to the timing at idle and as ignition load is increased the timing is applied back as ignition advance at a rate equal to the amount being retarded. This automatic compensation offsets the ignition timing change by the magneto so the timing remains at one setting in all conditions. If you want 32* at high load conditions you could now set the ProMag 44 at 32* at idle and it would remain where set throughout the entire load range.

This ProMag 44 compensation feature and the improved characteristics of voltage rise time in the coil is why we now set the timing at idle at a lesser amount of approximately 4* on ProMag 44 equipped motors than we did before on the motors with the points magnetos. If you had the ability to observe the timing of the two type of magnetos under load you would find that the ignition timing on a points magneto is actually the same as a ProMag 44. It is only at low RPM during no load conditions that the timing is different between these two type magnetos.