I'd like to start a dedicated thread on ignition systems for high output motors. This subject is not my strong suit.
My personal interest (currently) is regarding a 1000cc motor, 315 or 327 cam, RC race ported head(reworked by MRieck
), JE 10:1 compression 71mm pistons, Golden Rods, etc. It's going in a lightweight 4130 chassis, fat rear street tire, 375lbs all up ...or less
. Will only be interested in ET Street(street legal, DOT tires, no wheelie bars) at the track, and the track is NOT my main focus. It's more of an excuse to occasionally visit other card carrying members of the RC Engineering fan club
.
I will be retaining my alternator, using a later 70s alternator as it's about 2 lbs lighter than the early ones. I will have onboard starting, and I'm leaning heavily toward having Paul Cashio build me one of his DOHC 800W 900 based super starters and run it off a single generous CCA 12v battery to keep everything simple and all on the same system. The package needs to be "fully streetable". Let's say 90% street, 10% race.
There is both old school and modern ignition options. Lets start with modern:
First there is the transistorized ignition mod from Hondaman:
"I make these Transistorized Ignitions specifically for the SOHC4 bikes, but they also will run any points-driven, battery-and-coil ignition system from 6 volts to 24 volts (including a car!). These leave your points in place as triggers, operating transistors to switch the coils. This makes the points last a VERY long time, without adjustment. It also gives you 100% "backup" in the event you ever destroy this unit: you can unplug the wires from the points and coils and plug them back together again in about 2 minutes' time, putting you back on the road. If you'd like to see the whole development thread, search for "Transistorized Ignition" and it will take you to 2006 when we developed it here."
Then there is the popular Dyna S.
Product Overview : Sportbikes - Dyna S Ignition System
Dyna S Ignition System is a complete self-contained electronic ignition system built with the latest state-of-the-art engineering. This is the same ignition used by top racers over the past 2 decades. The Dyna S is completely housed behind the ignition cover and uses a magnetic rotor with the original spark advancer, so the factory advance curve is maintained.
The venerable Dyna S ignition System is a time proven solution to the basic ignition needs of the vintage muscle bike. As a stand alone ignition the Dyna S is the standard of performance and reliability
Had some teething problems with some people, but most seem to report them to be very dependable. They replace the points, and can either be a stand alone or run in conjunction with the Dyna 2000 box.
The Dyna 2000 box
Product Overview
The Dyna 2000 for four cylinder engines represents a breakthrough in motorcycle ignition flexibility. The Dyna 2000 system consists of a state-of-the-art microprocessor controlled ignition module along with an adjustable Dyna dual sensor crank trigger. For the first time you can actually set the ignition timing to what you want to maximize engine performance. A number of different advance curve modes and a broad range rev limiter let you tailor the ignition to your needs. Dynatek has added the ability to custom program the Dyna 2000 Sportbike ignition via a personal computer. Like our programmable Harley-Davidson and Dyna FS ignitions the Dyna 2000 can be programmed with a custom advance curve, retard mode curve and RPM limit using the optional accessory curve maker kit. There are also 2 user programmable RPM outputs that can be used to activate a shift lightor other RPM activated device.
I believe that the Dyna 4000 box requires a different digital sensor than the Dyna S. The 4000 has more features
Product Overview : Dyna 4000 Super Pro Ignition System
Dyna 4000 Super Pro Drag Race Ignition is a high energy inductive ignition designed to meet the needs of the professional drag racer. The DYNA 4000 includes a built-in two stage rev limiter that is used for launch control and over rev protection.
Dyna 4000 Super Pro Features:
◾Uses the DYNA Pro Series Crank Trigger as a pickup. The DYNA 4000 Super Pro is simply connected between the trigger and the ignition coils.
◾Automatically shuts off when the engine is not running, even if the ignition power is left on. This prevents battery drain and coil overheating.
◾Built in diagnostic circuitry and an indicator LED that can be used to static time the motor.
◾Must be used with DYNA DC9-1, DC9-2, or DC9-4 coils for proper operation.
◾Available as both a dual output unit for single plug per cylinder engines and as a quad output unit for dual plug per cylinder engines.
◾Available for both in line four cylinder and Harley Davidson engines.
◾The DYNA 4000 Super Pro is housed in an easily mounted case, approximately 6" x 3 3/4" x 1 1/4".
I know some are using the MSD MC-3 or MC-4 ignition boxes along with the Dyna S. One large benefit seems to be if you have a Dyna 2000 or 4000 failure, you are out of commission. If a MSD MC3/4 dies, it can be turned off and the bike will run off the Dyna S as a stand alone with the coils. MSD ignition boxes seem to have a very good reputation for reliability.
Old School:
First there is factory points ignition. These can be run with more powerful coils like the 3ohm Accels, Dyna, Williams, etc. 3ohm coils can be taxing on the charging system, but have been known to work if that is taken into consideration and dealt with. Dyna 3ohm coils are said to produce in excess of 30,000 volts and can run off points as well as Dyna S or other ignitions. Other than points wear, this seems to be a decent basic option for a powerful street motor. No rev limiter or launch control that would be so handy at the track, but a solid SIMPLE option.
Current wisdom suggests not using my ARD magneto
. The biggest drawback seems to be the fact that the timing is set at full advance, all the time. This makes starting them more difficult, kickbacks are common, and full advanced timing isn't exactly ideal for idling or low end on the street. Doable, but not ideal. As a side note it DOES fire only one cylinder at a time and the spark increases as the rpm increases. This is not a "wasted spark" ignition. Another feature it has going for it is that it is self exiting, as in no battery is needed. Convenient for a non self starter drag bike trying to save pounds. As I'll be running an alternator, full sized battery, and an onboard starter anyway, this takes up much of the ARD magneto's "bare bones" advantages...
Then there is the RC distributor. Based on a 4 cylinder VW distributor, it also fires one cylinder at a time, and runs off a single coil. Has points, can throw a big single spark, and has adjustable advance. Rare, old school, but not adaptable(or easily adaptable) to any modern desirable drag bike features like launch control or rev limiter.
There are probably others that I am missing(Hunt magneto, etc), but this is a start.
Some random questions:
Is there any significant advantage to a non wasted spark ignition on these motors?
Does a "Multiple Spark Discharge" type of ignition make a big difference on these motors?
How much disadvantage is there performance wise and "streetability" wise with a full time full advance ignition like the ARD magneto?
How big of a deal is it to have a rev limiter on a high performance bike? Safety factor?
Is an rpm limiting launch control a huge deal at the track?
I am open to comments and experience, as I always want to learn, and perhaps others can learn as well.
Thanks,
George
