As the title suggests, what sort of resistance should there be in ignition leads?
Ignition lead resitance
Started by
shanegtr
, Jul 31 2006 10:48 PM
26 replies to this topic
#1
shanegtr
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Posted 31 July 2006 - 10:48 PM
#2
rodomo
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Posted 01 August 2006 - 12:27 AM
4000 ohms per foot or length
#3
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Posted 01 August 2006 - 05:21 AM
just to add to the above.......consider that as a maximum at which you would replace the leads, in my limited experience here........trouble with a standard ignition can appear if the total resistance of the lead exceeds 10kOhm. If you run bigger spark gaps, this will exacerbate the prob.
#4
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Posted 01 August 2006 - 09:27 AM
Dependant on brand, a good quality aftermarket lead such as an Eagle 9mm or Tog Gun 10mm should have approx 1500 ohms per foot.
At work we use the MSD Super Conductor wire, which has 60 ohms per foot.
At work we use the MSD Super Conductor wire, which has 60 ohms per foot.
#5
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Posted 01 August 2006 - 09:39 AM
Is less resitance a benefit for ignition leads?
#6
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Posted 01 August 2006 - 11:36 AM
yes to ^, less is better than more.....providing radio suppression is maintained. Too much and spark jumps somewhere else or not at all.
How much benefit is obtained from lower resistance leads........dont know......never seen any b4 and after dyno figs even by the manufacturers of the leads.....so guessing not much. Certainly using a lower resistance lead will be less of a problem to the spark wanting to jump somewhere else.
How much benefit is obtained from lower resistance leads........dont know......never seen any b4 and after dyno figs even by the manufacturers of the leads.....so guessing not much. Certainly using a lower resistance lead will be less of a problem to the spark wanting to jump somewhere else.
#7
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Posted 01 August 2006 - 11:45 AM
HI Guys.
As [BOTTLEDUP] said their MSD cable has only 60 ohms per foot, this is common in modern spiral wound lead. We use Magnecor & it has a similar spec. Silicon type leads usually have 4 to 5 K ohms. The lower the resistance the better, as long as RF noise suppression is maintained. The old solid core copper leads had no resistance at all (less than 1 ohm), but caused all sorts of noise problems.
It's not just TV & radio noise either, cars with any ECU of any sort can be badly affected as well.
Dr Terry
As [BOTTLEDUP] said their MSD cable has only 60 ohms per foot, this is common in modern spiral wound lead. We use Magnecor & it has a similar spec. Silicon type leads usually have 4 to 5 K ohms. The lower the resistance the better, as long as RF noise suppression is maintained. The old solid core copper leads had no resistance at all (less than 1 ohm), but caused all sorts of noise problems.
It's not just TV & radio noise either, cars with any ECU of any sort can be badly affected as well.
Dr Terry
#8
shanegtr
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Posted 01 August 2006 - 12:01 PM
Once again the answer to the questions has been maintained and giving me something else to check on the weekend
#9
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Posted 01 August 2006 - 04:36 PM
I second Dr Terry's advice there. We also do the Magnecore leads as well, tho generally just their 7mm & 8mm wire for std type applications. We prefer the MSD, as it seems to have a better EMI suppression. This is really only in regards to EFI setups, where we've seen all sorts of crazy things happen as a result of EMI.
#10
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Posted 01 August 2006 - 05:58 PM
Thanks Gents..
I used Neon cable ( 9mm Pure silicone sheathed tinned copper conductor) as a temporary lead for my monaro.. Sure did the trick but i KNOW the EFI/RFI suppression would have been nil!
Cheers
I used Neon cable ( 9mm Pure silicone sheathed tinned copper conductor) as a temporary lead for my monaro.. Sure did the trick but i KNOW the EFI/RFI suppression would have been nil!
Cheers
#11
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Posted 02 August 2006 - 07:15 PM
Are the magnacore leads black?
On my torry(vs 5l) I have some kind of leads that are black,no branding.I would like to get a set for my vt 5l but don't know what brand they are,very low resistance compared to the new top gun leads on my brother's vs 5l.
On my torry(vs 5l) I have some kind of leads that are black,no branding.I would like to get a set for my vt 5l but don't know what brand they are,very low resistance compared to the new top gun leads on my brother's vs 5l.
#12
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Posted 02 August 2006 - 07:39 PM
Standard Bosch leads are black(so they could be them), they are typically lower resistance than the top guns, I wouldnt get excited that they may be half the resistance of the top gun leads(they'll still be over 2kOhm........it wont make any measurable difference to performance.
#13
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Posted 02 August 2006 - 08:19 PM
gtrboyy,
The magnecor leads have MAGNECOR and some specs written on them in white.
Not hard to miss really.
John.
The magnecor leads have MAGNECOR and some specs written on them in white.
Not hard to miss really.
John.
#14
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Posted 05 August 2006 - 04:14 PM
The leads have BOUGICORD 403 CLASS F printed on them.Black 8mm with grey insulaters.
Anyone heard of them or know where to get another set?
Anyone heard of them or know where to get another set?
#15
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Posted 05 August 2006 - 05:20 PM
Hi gtrboyy.
What type of engine is this on.
The 'Bougicord' leads are the factory item for VT-on V6 & Holden V8 & fit the earlier V6s & V8s back to VN as a retrospective replacement of the Packard 8mm. But they are 7mm black with grey insulators, not 8mm.
Dr Terry.
What type of engine is this on.
The 'Bougicord' leads are the factory item for VT-on V6 & Holden V8 & fit the earlier V6s & V8s back to VN as a retrospective replacement of the Packard 8mm. But they are 7mm black with grey insulators, not 8mm.
Dr Terry.
#16
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Posted 05 August 2006 - 08:43 PM
You make the MSD's to length Dave ?,Aug 1 2006, 07:27 AM] Dependant on brand, a good quality aftermarket lead such as an Eagle 9mm or Tog Gun 10mm should have approx 1500 ohms per foot.
At work we use the MSD Super Conductor wire, which has 60 ohms per foot.
When the time comes I want to go under manifolds and hide them as best I can.... so will be longer than normal
#17
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Posted 05 August 2006 - 10:15 PM
The black leads are on the vs v8 s3 motor that was in my lc,they look fairly thin that's why I thought they were 8mm.Hi gtrboyy.
What type of engine is this on.
The 'Bougicord' leads are the factory item for VT-on V6 & Holden V8 & fit the earlier V6s & V8s back to VN as a retrospective replacement of the Packard 8mm. But they are 7mm black with grey insulators, not 8mm.
Dr Terry.
I managed to get a set of leads replaced under warranty for my vt 5l & they are grey.I'll see if they are the same brand.
The bougicord leads were far better than the champion,top gun leads we have tried IMO.
#18
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Posted 06 August 2006 - 05:49 PM
Hi gtrboy.
The Bougicord 7 mm leads were introduced on Holdens for '87 VT, so VS III would also have had them factory fitted. The grey Packard 8mm leads were factory fitted for all 6 & V8 '80 (Blue motor) to '87. In Holden spare patrs the 7 mm Bougicords have gradually appeared as a retrospective replacement back to the start of EFI V8 & V6. IMHO the 7mm Bougicords are a better lead than the Packard 8 mm (maybe is just the more reliable connectors), but for aftermarket leads you can't go past Magnecor.
Dr Terry.
The Bougicord 7 mm leads were introduced on Holdens for '87 VT, so VS III would also have had them factory fitted. The grey Packard 8mm leads were factory fitted for all 6 & V8 '80 (Blue motor) to '87. In Holden spare patrs the 7 mm Bougicords have gradually appeared as a retrospective replacement back to the start of EFI V8 & V6. IMHO the 7mm Bougicords are a better lead than the Packard 8 mm (maybe is just the more reliable connectors), but for aftermarket leads you can't go past Magnecor.
Dr Terry.
#19
shanegtr
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Posted 06 August 2006 - 06:22 PM
I measured the resistance in my leads. Largest amount was around 1400oms and that was on both no. 1 and 6 leads, the 2 longest.
#20
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Posted 06 August 2006 - 10:50 PM
Thanks Dr Terry,
I quite like the bougicord leads,very good quality leads still worked even after I burnt one on the exhaust.
I"ll try holden for another set of the bougicord leads or try to find them elsewhere,if not I'll get the magnecor.
I quite like the bougicord leads,very good quality leads still worked even after I burnt one on the exhaust.
I"ll try holden for another set of the bougicord leads or try to find them elsewhere,if not I'll get the magnecor.
#21
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Posted 14 August 2006 - 09:31 PM
I have been told (and will again no doubt) that leads with higher resistance tend to concentrate the spark to a shorter time. Ie the current is concentrated until it overcomes the resistance and can then flow.
In old 6 volt systems the jump gap principle was sometimes used to do this. The gap in the HT cable created a point of high resistence.
So if there is anything to this, a lead with a reasonable resistance might well assist the spark than would a lead with virtually no resistance.
Fact or fiction. Bring on the Myth Busters.
In old 6 volt systems the jump gap principle was sometimes used to do this. The gap in the HT cable created a point of high resistence.
So if there is anything to this, a lead with a reasonable resistance might well assist the spark than would a lead with virtually no resistance.
Fact or fiction. Bring on the Myth Busters.
#22
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Posted 15 August 2006 - 10:44 AM
Sounds like myth to me, there's no electrically logical argument to support it afik, but if there is would like to know.
#23
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Posted 15 August 2006 - 10:52 AM
Dunno Finer, but they seem to recommend higher resistance leads. Mine are running Top Gun 11mm silicon leads (no wire in em whatsoever. Dunno how that works, but they do.
Hehehe, reminds me of the stolen burnt out UC donated to the Club. Didn't have a sceric of insulation on any of the leads or ignition lead. Hooked up a battery, shorted out the starter motor, started it, and run perfectly as though there wasn't anything wrong with it. Didn't think it would! Ya can't kill a red motor.
Hehehe, reminds me of the stolen burnt out UC donated to the Club. Didn't have a sceric of insulation on any of the leads or ignition lead. Hooked up a battery, shorted out the starter motor, started it, and run perfectly as though there wasn't anything wrong with it. Didn't think it would! Ya can't kill a red motor.
#24
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Posted 15 August 2006 - 11:51 AM
Hi Guys.
Yella SLuR said:- "Mine are running Top Gun 11mm silicon leads (no wire in em whatsoever. Dunno how that works, but they do."
This is the way many resistive leads are made. When wire leads were first replaced by so-called 'carbon' leads, the core was carbon impregnated into a fibre like cotton or similar. These early carbon leads were notoriously unreliable as the fibre disintegrated from engine heat & oil etc. They then used silicone impregnated with carbon which is far superior. As a matter of fact these days we have no problems with the silicone core of the lead at all, they usually fail because of a faulty end connection or the outer insulator burns or arcs thru. By the way, 11mm or 12mm leads only have a thicker insulating cover, they perform the same as a 7mm set.
Dr Terry.
Yella SLuR said:- "Mine are running Top Gun 11mm silicon leads (no wire in em whatsoever. Dunno how that works, but they do."
This is the way many resistive leads are made. When wire leads were first replaced by so-called 'carbon' leads, the core was carbon impregnated into a fibre like cotton or similar. These early carbon leads were notoriously unreliable as the fibre disintegrated from engine heat & oil etc. They then used silicone impregnated with carbon which is far superior. As a matter of fact these days we have no problems with the silicone core of the lead at all, they usually fail because of a faulty end connection or the outer insulator burns or arcs thru. By the way, 11mm or 12mm leads only have a thicker insulating cover, they perform the same as a 7mm set.
Dr Terry.
#25
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Posted 15 August 2006 - 12:44 PM
Your a bloody walking encyclopedia. Yup, it is Silicon impregnated carbon. So is carbon conductive? Thanks for the explanation.
Dunno what the go with em is, but the car loves em.
Dunno what the go with em is, but the car loves em.
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