Why use a distributor?

[DonWG]

Thanks Jeff. It's not that I'm looking for something different than what I have, I'm just trying to understand what the short comings are of a waste spark system. I'm burning pure alcohol. Certainly not the easiest type of mixture to fire. I've run it at ratios approaching 4 to 1. Even harder to fire. So far I've been to 32 psi boost, and with a high overlap cam by most peoples standards for a turbo engine. I'm running a waste spark system that has been flawless on top of it all. I'm just looking for a reasonable explanation why everyone is so against waste spark.

[Jeff Rand]

Don, when I bought my MSD 7A from Dusty, he spoke of more HP and he also made a comment about reduced bearing wear without the waste spark. It was never really explained to me why the waste spark would effect the rod bearings.
Jeff

[DonWG]

Waste spark has been with us for over 20 years. It's used on the vast majority of domestic vehicles in the U.S. I find it very hard to swallow that waste spark has anything to do with bearing wear.

[DonWG]

On a scope, the typical waste spark system fire line and spark line of a cylinder on the compression stroke are not unlike any other ignition pattern except for maybe less coil oscillation. And since a spark is a spark is a spark, where's the extra hp coming from? If a waste spark system can be had that can put out the equivalent spark intensity and dwell time of another type of system, then I can't see any difference.

[speeder]

Don,

I too have wondered about this use of distributors among the Buick guys.

I know you use the TEC3... and there can be no argument that a 60-tooth crank trigger will give more accurate timing than a 3-magnet one.

The E-motive TEC3 has ignition circuits built - in that hits the coils on the DFU (Which contains 3 standard GM DIS Coils) with energy comparable to CD systems such as MSD. That's the difference. This is probably more than enough to make up for any energy lost by firing two coils at once.

On my Stage II (yes, I will shock the world when my project finally gets off the ground) I will be using the TEC3r to fire 6 coils in a non - waste spark configuration - but only because it's an odd - fire motor , using the GN cam sensor for a reference signal. I'm not very concerned about the accuracy of the cam sensor since the cam reference has a very wide tolerance. You could do 6 coils too with the TEC3 if there is a desire for even more energy to the plugs.

[Dusty Bradford]

Jeff. I don't remember saying anything about bearing wear. If something I said came across that way I apologize because I don't think it will affect bearings at all. I may have misunderstood something or worded something wrong in the process. I did say it will lower egt's....seen it on the racepak data.

We did it for the 2 step function as a #1 priority. The DIS 4's were junk and could crap out at any time.

Don, Domestics don't use spools or nitrous either. We're talking race cars No doubt a good waste spark system will work as will a coil on plug. We made the decision due to racing on a pro tree where launch consistency is a priority. The distributor is the easiest way to accomplish this.

If you race regularly the cap and rotor should be changed about twice a year because they do burn out. I have ran the same cap and rotor for over a full year, well over 120 passes with street driving as well with no issues but I replace them now as a safety factor to avoid issues.

Like has already been said. The distributor is nothing more than an element in the spark system. There is no vacuum advance or condenser. You run 1 tab on the reluctor for cam sync purposes.

If we race a car with a transbrake...it gets a distributor.

[DonWG]

So the problem was with the DIS 4 MSD box. Not the waste spark configuration. Problems with a MSD box. Why does that not surprise me. I'm having problems with a delay box I just installed. You guessed it. MSD. You know, there are W/S systems that have built-in rev limiting. The ECM I use has a fully configurable rev control, primary and auxiliary with an optional 3 step soft-rev control. I personally don't use it because I don't feel comfortable dropping cylinders with alcohol and nitrous, but I've heard from others it works very well.

Oh. And Dusty, some Domestics do use transbrakes and nitrous.

Yes speeder, doing 6 coils with the TEC3r is a well known and documented option, but up to this point I see no need. At one point in my tuning of the engine I purposely ran my engine excessively rich to try and find the rich limit with alcohol and this engine. Even when I did find the limit, it didn't miss a beat. Power dropped slightly and the engine was lazy, but absolutely no missing. If that's not a testimonial to the waste spark system, I don't know what is. Maybe nitro?

[laz]

Hey i have to disagree about the dis4 and the distributor set up . I know alot of ppl have had issues with there dis4 i have had one for over 5 years an its been trouble free with a max effort and with xfi . I can understand how ppl make claims of 75 and 80 hp with a distributor and msd 7al2 but i never seen it ,i remember when barry walkers twin turbo car picked up over 150 hp at Duttweillers but the only reason it picked up is it was breaking up with the coil pack and the dizzy let it rev higher and run more boost (not everyone is running a 1600 hp stage 2 twin turbo ). I ran TSM and watched alot of ppl switch to dizzy and i never saw them gain any power thats my opinion . Laz

[Trbobuick]

I was able to see it first hand..... car went 4 tenths quicker....

[DonWG]

Well now, I can understand that! If the w/s system being used is low on reserve power (stock system?) and causes the engine to miss at high rpms and high boost, it's a no brainer that if you switch to a more powerful system, NO MATTER WHAT TYPE, the engine is going to make more power up high.

[DR BOOST]

i agree with the 3-4 tenths quicker.

but...

is it true that on the passenger bank of cylinders, the spark plugs fire from ground strap to the center electrode?

[DonWG]

Originally Posted by DR BOOST

i agree with the 3-4 tenths quicker.

but...

is it true that on the passenger bank of cylinders, the spark plugs fire from ground strap to the center electrode?

If the w/s system being used has enough reserve capacity, that is a non-issue. It is harder to initiate the spark reverse polarity, but if the system is designed for high performance, the extra capacity should be there. If it isn't, you have the wrong system.

[DR BOOST]

if the w/s system had enough capacity, why would the quicker cars need to keep closing the plug gap in order to prevent misfires.

[DonWG]

Originally Posted by DR BOOST

if the w/s system had enough capacity, why would the quicker cars need to keep closing the plug gap in order to prevent misfires.

There are two different reasons why you close the spark plug gap in a high boost situation.

As cylinder pressures increase and fuel mixtures get richer, it takes more voltage to initiate the spark across the plug gap.

Number one reason why you close the gap: The ignition system is not capable of providing the voltage necessary to initiate the spark under those harsh conditions, so you close the gap to make it easier for the spark to jump the gap using a lower voltage level.

Number two reason: The system has plenty of reserve capacity and is more than capable of initiating a spark across a wide gap in those harsh circumstances, but you close the gap to control the level of the secondary voltage.
Explanation: When you force an ignition system to use higher secondary voltage (assuming the particular system is capable of providing this high level of voltage) to jump a spark plug gap by increasing the gap and/or creating a harsher environment in the cylinder, you run into other problems. Strong coronas build around the spark plug ends, increased chance of cross firing, secondary insulation breakdown, shorter ignition wire life, increased spark plug wear and cap and rotor wear, shorter coil life. Basically, it's unnecessarily hard on the whole secondary ignition system. The trick is to close the gap to control the secondary kv level, and not so much as to start causing miss-firing.

I run a .032" gap on alcohol and 32 psi boost. I've run larger gaps with this system with no problem. Electromotive recommends an even smaller gap than .032 for my application. The only reason they recommend that is to save against undue wear of the secondary system. There is more than enough capacity. And no MSD boxes to worry about failing.

I know some are into the 'whose got the most electronics on their car thing', but I believe in obtaining the desired result with the least amount of electronics. Less to go wrong.

[dr_frankenstein]

while we were on the subject,

What about a Magneto? I Havent seen anybody else running a Mag, is there a reason to this? I was planning on using a Mag with my Blower - but this thread has made me have second thoughts.

A.j.

[DonWG]

Originally Posted by dr_frankenstein

while we were on the subject,

What about a Magneto? I Havent seen anybody else running a Mag, is there a reason to this? I was planning on using a Mag with my Blower - but this thread has made me have second thoughts.

A.j.

Check the rules of the class you plan on running in. The use of a magneto may be specified. If you're not planning on running in a class, then your options are wide open.

[dr_frankenstein]

Originally Posted by DonWG

Check the rules of the class you plan on running in. The use of a magneto may be specified. If you're not planning on running in a class, then your options are wide open.

Right - im limited strictly by cubes and weight,
But in terms of the Stage motor are there advantages to running a Mag vs the Waste spark or MSD? Or is a mag considered outdated tech already?

A.j.

[DonWG]

Originally Posted by dr_frankenstein

Right - im limited strictly by cubes and weight,
But in terms of the Stage motor are there advantages to running a Mag vs the Waste spark or MSD? Or is a mag considered outdated tech already?

A.j.

Mags were necessary when high energy ignition was not around (points and condensers). These days I think it's a nostalgia thing.

[dr_frankenstein]

Thank you,

My logic was that the high amperage would help overcome the effects of high boost/exotic fuels. But I can see now where the electronic ignitions are almost required for the EFI on the turbo cars.

A.j.