Ignition testing

**bradrs** · 10-20-2015, 10:26 PM

Originally Posted by Jimvr4

I should be able to get some more time in the garage soon. I've been hesitant to cut my harness but interrupting the supply voltage without cutting requires a couple of connectors and wiring and costs too much. Right now my plan is to cut it and install a pair of mating spade connectors.

Can't you just unbolt a ring terminal at the coils? Would save the cutting up of the harness.

**Jimvr4** · 10-21-2015, 01:10 AM

Originally Posted by Greg E

I'm sorry. I was talking about an ignition amp that works similar to the Keen-Bell boost a pump that would have a high/low switch triggered by the ECU which the user could set in chrome.

Got it. You're talking boost a spark.

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**bradrs** · 10-21-2015, 10:38 PM

Is it possible to put in a value of >100% for that max dwell value? And is that value part of a table?

That current measurement appears to be showing the coil 12V for all 3 coils, correct? Looking at the current measurements, it looks as if 100% might correlate to only 33% of the actual time available, so you probably could overlap the dwell a bit.

That assumes the ECU firmware wouldn't get confused by overlapping them.

**Jesters Deadd** · 10-29-2015, 12:48 AM

DC/DC 12V to 18V 8A 144W [Step UP] Waterproof Power Voltage Converter
boost a spark 12v to 18v.
Use the second fuel pump relay to activate, viola!

**Jimvr4** · 10-29-2015, 12:55 AM

Nice but the coils will demand more current than 8A at 18 volts. I can test if my circuit will push that high.

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**Jesters Deadd** · 10-29-2015, 01:25 AM

Im still thinking there is a 8A PTU limit... Sorry.
I did find a platue during my testing but I don't remember the measurements.

boom!
Waterproof 12V to 15V 15A 225W DC DC Step Up Power Converter Regulator | eBay
or
Waterproof 12V to 19V 15A 285W DC DC Step Up Power Converter Regulator | eBay
btw my initial test was very similar to your setup.
I still have a 20v converter with full stock plug conversation in my testing box.
never finished the full testing because I had some issues with my old oscilloscope.

**BaadVR4** · 10-29-2015, 09:51 AM

I have no clue about most of the technical details of this discussion. My way of putting 15V on the hot wired coil set up is to adjust the voltage on the Mechman 240amp alternator to 15.1V at the battery terminals. At dead idle the voltage at the battery is only 14.3V or so, but by 14-1500rpm and all the way to red line, the battery has 15.1V. This doesn't provide voltage boost in response to different rpm set points, but it does provide a method to deliver higher voltage from just off idle on up. I haven't tested to see how much higher I can adjust voltage, but I know it will go as far as 16.5V. The down side is the voltage is applied to the entire electrical system and there may be components that won't like higher voltage very much. While most components should be designed for at least 18.5V continuous duty, I would hate to burn up my car because some two dollar widget started a fire. And if you are just running a race car, there are a host of batteries/alternators available in voltages greater than 12V. My complete system is hot wired stock coils/Taylor 300M wires/DLI/Mechman alternator. I don't have real high ignition demands, but I can boost to 25psi with standard NGK plugs gapped at .035" and have no blow out. And no idle/low speed intermittent miss.

Are the stock coils really better than MSD or Acell?

**AdamVR4** · 10-29-2015, 02:42 PM

Like Jeff L, I'm a mechanical engineer so I'm out of my element here. I've acquired both a KB boost a spark and HKS DLI. I will test my coil voltage and if I need to, won't hesitate to hotwire.

Now, immediate requirement is to light e85 or e95 at 30+ psi in the 600-700 awhp range. In the past, my stock ignition was good on gasoline (c16) with tiny plug gaps (.020")...

Long term goal is more like 850 awhp. I may end up with chrome in the future, but not for now. Given the choice, would you use the DLI or BAS?

Thanks,
Adam

**Jimvr4** · 10-29-2015, 06:06 PM

Originally Posted by BaadVR4

Are the stock coils really better than MSD or Acell?

I honestly can't answer that one without testing. What I can say is that the stock coils look to be more than adequate for a strong Inductive Discharge system

Originally Posted by AdamVR4

Like Jeff L, I'm a mechanical engineer so I'm out of my element here. I've acquired both a KB boost a spark and HKS DLI. I will test my coil voltage and if I need to, won't hesitate to hotwire.

Now, immediate requirement is to light e85 or e95 at 30+ psi in the 600-700 awhp range. In the past, my stock ignition was good on gasoline (c16) with tiny plug gaps (.020")...

Long term goal is more like 850 awhp. I may end up with chrome in the future, but not for now. Given the choice, would you use the DLI or BAS?

Thanks,
Adam

Hi Adam. I think the benefit of BAS over hot wiring the coils will be that the voltage should stay constant at the coils with a BAS whereas it is likely to droop with the hot wire setup due to demands on the charging system. IF I was to make my own BAS I would build something that regulated the output to ~15-16 volts for the coils and was independent of charging system loads. The stuff that Jester found could do the job far cheaper than a KB BAS.

On the other hand it is a proven fact that Capacitive Discharge ignition (CDI) provides a much hotter spark than Inductive can. In theory the DLI would let you run the largest possible spark plug gaps and light off the mixture with more control. The reason is the CDI is able to hold the high voltage for a set pulse duration whereas the BAS just cranks up the primary side so that the high voltage side hits a higher level but without a controlled duration. That said CDI might not be better than BAS in practice.

**bradrs** · 10-29-2015, 07:19 PM

Does the DLI have a max voltage limit that it works on? You might be able to run the DLI in conjunction with a Boost a spark, giving you more charging for the inductive side. The CDI side of that spark will still be the same energy, but the stronger inductive would result in even longer duration.

You wouldn't want to use the BAS with an ignition that is just a CDI though.

At some point though, you will heat the heck out of the coils. You only need enough to get the flame front started, beyond that the energy is really wasted.