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Discussion Starter · #1 ·
Time for an indepth technical discussion comparing the use of a Dizzy (Distributer) and the use of DIS (Distributerless Ignition System). I'm posting it here, because I am looking at this from a trubocharged aspect moreso, than just running an engine.

Now, for myself I'm looking at this from an all out performance standpoint, this will be for the Franken60 (3.2L Turbo hybrid) or the FrankenBeast (The next build that I am collecting parts for).

Now my understanding of the DIS system that is used on teh GM 660 is mostly for emmisions, mainly due to the wastespark system that is used.
My understanding also is that waste spark will actually slow the exhaust gases when it fires, which is not something that is desirable with a turbocharged engine, high rate of flow + lots of heat = quickly spooling turbo.
Another benefit of DIS is the dwell and charge times can be LONG, so the spark can be very strong, and last for a long duration of crank degrees.

Benefits for Dizzy, would be no wastespark, which if the theory is correct, then the exhaust gasses would not be slowed any, upon exit from the cylinder, cheaper aftermarket ignition systems, I.E 6AL/6BTM/Digital6, one coil, so cheaper there too.
Drawbacks include custom intake manifold (GenIII heads), which is going to happen anyway, in my quest for mo' powa, so the manifold isn't THAT much of a concern, shorter dwell time, though there can be things dne to change that, and less coil charge time, which may or may not be a factor.

The other thing I have noticed is that most of the faster turbo cars are running a dizzy, some have even been converted from DIS, such as a few late model F-bodies, so there has to be some ultimate reason for that.

What are your thoughts?
 

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Discussion Starter · #3 ·
That system looks really good, but I already have the GM version of it. ;)

I really want to get away from the wastespark.

Don't get me wrong I love most of the benifits from DIS, like the longer dwell time and longer charge times, and a stronger spark because of this, but, I see most of the really quick cars using a Dizzy or switching to a dizzy from wastespark DIS.

Just one example, the GM sponsored turbo ECOTech Cavalier. Normally these engines use wastespark DIS, but GM adapted an MSD dizzy to it. Unless the rules stated dizzy only, there has to be a good reason for this. I don't think a rule was the case.
 

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Discussion Starter · #8 ·
Thanks Novachris for the info, I had heard from someone else about Duttweiler picking up the same 100 horses, but there was no further information.

I'm drawing a blank, what is "TSM"?

I don't nessisarly think it's about "accurate spark" so much as good spark, or strong spark.

I have a feeling that that when the DIS coils are measured, especially with the dual output, they are measuring both terminals, so when some spark goes to one cylinder and some spark goes to another, then there is a drop in spark energy is the cylinder under compression. This is my theory, not really based on anything I've read to confirm it just yet.

My initial plan is to have both ignition systems in my truck, and will be able to switch between them in a matter of minutes for testing, both on the dyno and at the track.

Going by feeling, I've driven very similar engines that were equipped with either ignition system and the dizzy equipped engines always sounded and felt a little stronger, a little more crisp. But I haven't driven the SAME engine with both ignition systems yet.
 

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Discussion Starter · #14 ·
redvictor, interesting article, and I agree, strong sparks still need good direction, but with some careful tuning, I'm sure the dizzy would be fine, as has been for many years. ;)
 
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