vlad01 wrote:ordered few bits and pieces from summit racing, just some ARP bolts for the lower bellhousing support bracket, spicer yoke to suit Astro A5 main shaft and a set of genuine D576 ACdelco coils which are a higher output version to the D555 used on N/A engines. D576 is what the L67 and L32 are factory fitted with, well at least in the states. Not sure about here though.
Have you already bought a Astro A5 main shaft ? I am gathering that is what you want the spicer yoke for.
No I don't have astro anything yet. Yes its for that, for when I do get one.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
vlad01 wrote:ordered few bits and pieces from summit racing, just some ARP bolts for the lower bellhousing support bracket, spicer yoke to suit Astro A5 main shaft and a set of genuine D576 ACdelco coils which are a higher output version to the D555 used on N/A engines. D576 is what the L67 and L32 are factory fitted with, well at least in the states. Not sure about here though.
Since building the Coil Tester i got a set of L67 coils and N/A coils and couldn't get either to beat each other, same dwell potential and current draw. Though id be interested to test any other type of coils, i haven't been able to try those or MSD yet.
was the bottom connector a different colour from each other? According to "experts" on the matter the D576 coils have a blue connector base where as regular coils are often grey.
Yep the L67 ones were Blue and the N/A ones i have so far are Yellow or Gray. I could not find any difference from my testing between any of them. Perhaps im missing something i dont know, ive watched the current draw on the power supply at different dwell times and visual on the spark plug and seen how far i can take them on the dwell, i can't tell any difference, perhaps monitoring charge time on a scope might show something but i wouldn't think it'd matter considering dwell is tested.
maybe you'd need to test breakdown under a pressurized environment. My understanding is the D576 will allow a larger gap under higher pressure, ie boost or high comp.
I recall reading they are similar to the MSD in the output which are marginally better than the stock vanilla ones, but that can make a difference under boost. I think the difference is only 5kV which should give sparks about 4.5mm longer in normal atmosphere.
worth measuring both primary and secondary impedance and inductance just to see if there is a turn ratio or winding difference.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
Yeh there's plenty of people touting they have more energy but no one's ever done testing, maybe some diodes can be used to test voltage, atleasst to compair coils
Create a variable spark gap to measure voltage. Rule of thumb is around 3kV per mm in free air, compression makes a big difference though. Can easily calc the spark gap under various pressures.
You can also calculate coil energy by monitoring dwell charge current and coil discharge current on a scope. Power supply average current is not really a good indication, need to look at the current on a scope and integrate it.
VL400 wrote:Create a variable spark gap to measure voltage. Rule of thumb is around 3kV per mm in free air, compression makes a big difference though. Can easily calc the spark gap under various pressures.
You can also calculate coil energy by monitoring dwell charge current and coil discharge current on a scope. Power supply average current is not really a good indication, need to look at the current on a scope and integrate it.
Yeh i was thinking of measuring current on a scope. Im thinking it would get a point where it is fully discharging it will only draw so much vs dwell time? The dont know if the free air thing is correct, ive had them arc up in mid air when i dropped the plug a good 10cm or more lol
The1 wrote:Yeh there's plenty of people touting they have more energy but no one's ever done testing, maybe some diodes can be used to test voltage, atleasst to compair coils
2 different coils from the same manufacture, there has to be a good reason for it. But yeah testing is the only way to get figures.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
