What coil would produce a stronger spark (I know there's a debate here):
Jacobs 321091 coils (same specs as Accel and Maxx Performance)
Primary Resistance: 0.5 Ohms
Secondary Resistance: 8.0 k Ohms
Turns Ratio: 75:1
Maximum Voltage: 45,000 Volts
Summit Racing High output coils 850017 (same specs as MSD)
Primary Resistance: 0.38 Ohms
Secondary Resistance: 8.85 k Ohms
Inductance: 4.5 mH-5.6 mH
Maximum Voltage: 40,000 Volts
The Jacobs coils have a higher maximum voltage, but the Summit ones have lower resistances.
12.6 @ 114.6 MPH
Secondary resistance on the Summit coils should have read 5.85K Ohms, not 8.85
12.6 @ 114.6 MPH
I would go with the summit coils. Less resistance is always better in my opinion.
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
why do you need stronger spark?
If I recall correctly he is getting blow out at 15psi.
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
If he is getting spark blow out at 15psi he needs to run the gap down. do not go more than +/- 0.08" from what the plug comes out of the box at though.
Something else is wrong if he is getting blowout. I was running 16psi, granted could be different from turbo to turbo, but some are running way more power with way more psi on stock ignition and not having problems. Sounds like he needs to re-gap.
Gap was at .025, then recently changed to .030. Had the issue at both gaps. But back on track with the actual post, do you all agree with Mike that a lower resistance is more important than a higher voltage to create a stronger spark?
12.6 @ 114.6 MPH
BuiltNBoosted wrote:granted could be different from turbo to turbo
bingo
it's about flow, not pressure
the bigger the gap you can run, the better. there's nothing wrong with upgrading your ignition... you upgrade your air.. fuel.. but stick with stock spark? I love my MSD coils.
2001 Olds Alero (LD9)
650 whp / 543 ft-lb
@turboalero
So do you agree that a little lower resistance is better than a higher voltage in coils?
12.6 @ 114.6 MPH
I would assume so, but I'm far from an electrical engineer.
2001 Olds Alero (LD9)
650 whp / 543 ft-lb
@turboalero
Voltage is more important because it is the rough equivalent of pressure. If you are increasing boost you will need more voltage.
[ion wrote: C2]you upgrade your air.. fuel.. but stick with stock spark? I love my MSD coils.
just saying its not necessary. 500+ has been achieved on stock components. Im going to make 400 I hope, on stock ignition. It will be the last thing to upgrade if I even decide to upgrade it.
Edited 1 time(s). Last edited Friday, February 24, 2012 5:33 PM
It's hard to say which will provide more energy to the wires. What's the turns ratio for the Summit? What's the inductance on the Jacobs? Inductance has a significant effect on transient events like when the primaries clamp, since...
V = L*di/dt + I*R
... and the magnetic flux to drive the secondary is dependent on the current through the primary winding. There is more to it than that, but if the inductance and resistance are lower and the turns ratio is the same or higher the Summit coils, then as a general rule of thumb, I would probably go with those.
I have no signiture
BuiltNBoosted wrote:[ion wrote: C2]you upgrade your air.. fuel.. but stick with stock spark? I love my MSD coils.
just saying its not necessary. 500+ has been achieved on stock components. Im going to make 400 I hope, on stock timing. It will be the last thing to upgrade if I even decide to upgrade it.
I hope you mean stock ignition.
But yes, I agree with Vince. You'll shatter your autotrans before the GM coils become a hinderance.
I have no signiture
Ah, yes, thanks for correcting me. I meant ignition. Ill break something else before i spend $500+ on msd to revamp the whole system.
Ahh conflicting information. Not sure about the inductance of the Jacobs or the turn ratio on the summits.
To those who say you don't need it until 500+whp, apparently I do. Maybe a stock coil is simply dying out, but either way I need to replace the coils, so mind as well do it with better ones.
Any other thoughts on voltage vs. resistance?
12.6 @ 114.6 MPH
if you have voltage and resistance and you want the most current looking up Ohm's law would be the ideal starting point.
BuiltNBoosted wrote:[ion wrote: C2]you upgrade your air.. fuel.. but stick with stock spark? I love my MSD coils.
just saying its not necessary. 500+ has been achieved on stock components. Im going to make 400 I hope, on stock ignition. It will be the last thing to upgrade if I even decide to upgrade it.
on stock LD9 coils? You sure?
FU Tuning
Addicted to meth wrote:BuiltNBoosted wrote:[ion wrote: C2]you upgrade your air.. fuel.. but stick with stock spark? I love my MSD coils.
just saying its not necessary. 500+ has been achieved on stock components. Im going to make 400 I hope, on stock ignition. It will be the last thing to upgrade if I even decide to upgrade it.
on stock LD9 coils? You sure?
ah didnt see he was ld9. that im not sure of.
Watts = Volts^2 / Ohms
Quote:
Primary Resistance: 0.5 Ohms
Secondary Resistance: 8.0 k Ohms
Turns Ratio: 75:1
Maximum Voltage: 45,000 Volts
14.4^2 / 0.5 = 414.72 Watts
45000^2/ 0.5= 4,050,000,000 watts
Quote:
Summit Racing High output coils 850017 (same specs as MSD)
Primary Resistance: 0.38 Ohms
Secondary Resistance: 5.85 k Ohms
Inductance: 4.5 mH-5.6 mH
Maximum Voltage: 40,000 Volts
14.4^2 / 0.38 = 545.68 Watts
40000^2 / 0.38 = 4,210,526,316 Watts
The Summit coils produce more watts of power...No mater how you look at it.
Below is a picture of Ohms law explained a little.
Edited 2 time(s). Last edited Monday, February 27, 2012 4:59 AM
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
There are 2 things wrong with that, Mike.
1) You are assuming that at DC you are generating 40kV, which isn't the case. As an ME guy, the mechanical analog would be a mass on spring problem. (inductance = mass, capacitance = spring, resistance = friction).
2) more importantly, if that is at DC, you are simply measuring the power dissipated in the secondary's winding and not the power delivered to the load (i.e. spark plug)...BIG difference.
So again, the problem is more complicated than you all seem to be making it.
I have no signiture
Yes, I'm probably WAY over simplifying this.
Walesac your more than capable of solving this. Help this dumb M.E. out, but I still believe that the low resistance one should perform better, but I have no way to figure out which has longer spark duration or anything since I can not find any more specifications on either...
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
Alright, new player in the game:
Jegs coils
promary resistance .35 ohms
secondary resistance 7.8 K ohms
maximum voltage 40,000 volts
induction 4.2mH
turns ration 80:1
12.6 @ 114.6 MPH
