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3.8l GM coils on z900 with dyna s?
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- loudhvx
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Anyone know if I could use 3.8l chevy car coils with a dyna s if I wired in resistors to total 3.0 ohms? And how about the output comparison with dyna coils?
They will probably work, but you have to put a 2.5 ohm resistor in line with each coil. Since the resistor will need to dissipate about 45 watts, you should get 100 watt resistors. They will get hot.
Edit: wattage
Just to make sure we are on the same page, are we talking about these coils (in the photo)?
If so, it's a shame to run them on the Dyna S since you will be burning away 100 watts in the resistors. They need about 5 to 6 amps to get a good spark. They measured about a nominal 0.5 ohms, but may be closer to 0.4 ohms depending on the manufacturer. They only need about 1 msec to charge to 5 amps, and the Dyna S will give them about 50 msec at idle and 6 msec at 10,000 RPM. That's a lot of time to sit burning away amps. If the coils can handle it (they probably can since they are huge, but they will be hot), they should work.
1981 KZ550 D1 gpz.
Kz550 valve train warning.
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Yes that's the coil but mine is a couple years older and is one piece with all three coils in one pack. They measure .8ohms. I just want to start the bike with them is all and thank you so much for the reply. I was hoping you would reply and the extra info is always welcome. That stuff RULES!nads.com wrote:
Anyone know if I could use 3.8l chevy car coils with a dyna s if I wired in resistors to total 3.0 ohms? And how about the output comparison with dyna coils?
They will probably work, but you have to put a 2.5 ohm resistor in line with each coil. Since the resistor will need to dissipate about 10 watts, you should get 25 or 50 watt resistors. They will get hot.
Just to make sure we are on the same page, are we talking about these coils (in the photo)?
If so, it's a shame to run them on the Dyna S since you will be burning away 20 watts in the resistors. They need about 5 to 6 amps to get a good spark. They measured about a nominal 0.5 ohms, but may be closer to 0.4 ohms depending on the manufacturer. They only need about 1 msec to charge to 5 amps, and the Dyna S will give them about 50 msec at idle and 6 msec at 10,000 RPM. That's a lot of time to sit burning away amps. If the coils can handle it (they probably can since they are huge, but they will be hot), they should work.
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- otakar
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74 Z1-A stock
76 KZ-900 Totaly stock vice MAC pipe
77 KZ-1000A stock
78 Z1-R 100%MINT 500 original Mi.
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82 KZ1000
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Also, those coils are to be used with a current limiting ignitor. The Dyna does no current limiting that I know of, (so the resistors are needed to do the current-limiting). The coils probably are designed for the 5 to 8 amp range, but once again, you'll be near 18 amps. You might have a melted plastic blob under the tank.
1981 KZ550 D1 gpz.
Kz550 valve train warning.
Other links.
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This will reduce the current below the maximum the Dyna can handle, but you don't need to run it at maximum to get spark. The coils will likely have no problem creating spark with 3 amps.
The other option is to get really big wattage, 2.5 ohm resistors, but you'll have to special order them through MCM (mcminone.com? I think) or Newark, maybe Fry's if you're lucky.
Also, you are using a booster to run this? There still needs to be a battery in the bike to smooth out the pulses from the booster or it can fry the Dyna or regulator. Also make sure you are not getting more than 14v average on the battery, with the booster or you could fry the regulator.
1981 KZ550 D1 gpz.
Kz550 valve train warning.
Other links.
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- Old Man Rock
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With that said, have to ask....
Why in KZ gods name why? :blink:
I can see for experimentations, seeing if it could just be done, boredom whatever but for actually running your KZ, I just don't get it... What's the benfit... For what you're going to pay in good high wattage resistors, then figure a proper heat sink for them, throw in all the possible FUBAR's that can occur....
Maybe I'm just not understanding... So be it...
OMR
1976 KZ900-A4
MTC 1075cc.
Camshafts: Kawi GPZ-1100 .375 lift
Head: P&P via Larry Cavanaugh
ZX636 suspension
MIKUNI, RS-34'S...
Kerker 4-1, 1.5" comp baffle.
Dyna-S E.I.
Earls 10 row Oil Cooler
Acewell 2802 Series Speedo/Tach
Innovate LC1 Wideband 02 AFR meter
Phoenix, Az
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- Old Man Rock
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1976 KZ900-A4
MTC 1075cc.
Camshafts: Kawi GPZ-1100 .375 lift
Head: P&P via Larry Cavanaugh
ZX636 suspension
MIKUNI, RS-34'S...
Kerker 4-1, 1.5" comp baffle.
Dyna-S E.I.
Earls 10 row Oil Cooler
Acewell 2802 Series Speedo/Tach
Innovate LC1 Wideband 02 AFR meter
Phoenix, Az
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