So best N/A coil 41.5mm 124,500v
Best MSD 50.0mm 150,000v
Question is does the extra voltage make much difference. I know VL400 with his LS driver and coils made a difference i dont know what voltage they delivered.
Im not sure where they got that figure from as I have seen vastly smaller ones listed on wiki on similar pages. General figure is 11Kv per cm and that stands correct according to the spark gap I measure verses specified transformer output. I have a number of HV transformers including an NST which is spec'd at 12Kv and it sparks start to break the air down at just over 1cm.
That said, on my own v6 coil test setup I am getting sparks around 6-8cm long on initial spark gap break down but I am using a chopper from a light dimmer, some motor starting caps and mains to drive my coils lol
As for does it make a difference? in a standard engine, nope. In extra high comp NA and boosted engines yes as more gas pressure = smaller breakdown gap vs voltage. So higher output allows the gap to be maintained on such application instead of closing it up where shrouding starts to effect ignition reliability and % of good firings/miss firings.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
My wording is probably poor, i know there will be a difference, but will the extra little bit of these msd's make much of a difference, going by immortality's post it maybe so, every little bits helps. I guess are you willing to pay more than double the cost for the little bit extra spark. Dyno testing would be interesting to see if you can widen the gap and change the coils does it make more power with everything else unchanged.
Going by 11kv per cm you would end up with 41.65kv vs msd 55,65kv so an extra 14kv. That is going by max values, the least performing msd made 49.5kv which is 7.85kv extra. Also of note going by the 2 faulty coils i tested it only takes 11kv to make a N/A engine run with a slight miss, boost would be highly different. All very interesting.
That amount of increase of stock isn't anything to sneeze at, would def make a difference in maintaining a good gap in boost or high comp.
My only concern with the MSD is overall quality and longevity? As its evident the resin failed, something I have never seen on a stock coil before. Also I have seen number of these coils fail in short time but more of the ones in recent years and not so much really old MSD coils. So it seems like quality isn't as good as it used to be, but at least performance is finally proven.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
Please keep in mind that the coils I sent for testing have done ten years worth of fault free hard use, have had hundreds of heat cycles, blasted with mud and washed clean with high pressure water...
On a side note, the new MSD coils appear to be much squarer in shape...
I've had a few OEM coils with cracks in the casing going up the terminal posts but not quiet as bad as those MSD cracked ones above. The cracked OEM coils were replaced to get rid of a miss. Clearly even the failed casing on the MSD coils hasn't degraded the performance enough to match the lower output standard OEM coils...... Be interesting to see what new MSD coils put out.
Fortunately the previous owner fitted the MSD coils on our Calais
Unfortunately even MSD manufacture shit in China these days
Biggvl wrote:Please keep in mind that the coils I sent for testing have done ten years worth of fault free hard use, have had hundreds of heat cycles, blasted with mud and washed clean with high pressure water...
Yeah I don't think they like the high pressure cleaning. I think each time I've had issues with coils is after cleaning the engine bay. These days I keep water away from the coils.
Biggvl wrote:Please keep in mind that the coils I sent for testing have done ten years worth of fault free hard use, have had hundreds of heat cycles, blasted with mud and washed clean with high pressure water...
Yeah I don't think they like the high pressure cleaning. I think each time I've had issues with coils is after cleaning the engine bay. These days I keep water away from the coils.
yep, I killed a coil like this and rusted the posts of several. I found the post is actually a separate injection moulding and then that with the core gets moulded in the final body. More than often there isn't a good seal at the base of the posts and water will enter it and can travel up inside the post, shorting the high voltage and often transporting water the terminal up top causing the rusting. Its a good idea to get some runny super glue and put a bead of it at the base and let it soak in to the gap filling it. Even doing that I am careful washing the engine and put a bag over the coils just to be sure.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
Biggvl wrote:Please keep in mind that the coils I sent for testing have done ten years worth of fault free hard use, have had hundreds of heat cycles, blasted with mud and washed clean with high pressure water...
Yeah I don't think they like the high pressure cleaning. I think each time I've had issues with coils is after cleaning the engine bay. These days I keep water away from the coils.
yep, I killed a coil like this and rusted the posts of several. I found the post is actually a separate injection moulding and then that with the core gets moulded in the final body. More than often there isn't a good seal at the base of the posts and water will enter it and can travel up inside the post, shorting the high voltage and often transporting water the terminal up top causing the rusting. Its a good idea to get some runny super glue and put a bead of it at the base and let it soak in to the gap filling it. Even doing that I am careful washing the engine and put a bag over the coils just to be sure.
Interesting, I had rust on the same post of 2 coils, I thought it was due to the lead not making good contact and it arking but it's probably what you said.
ive have one or two here OEM that have cracks in them, but you can only just see it, it's not actually split like the MSD coils, i wonder if it's because of the extra windings they had to make the case thinner to keep the size the same, hence easier to split.
