HT Leads Tested
Discussion
To satisfy my own inquisitive mind and for the benefit of others I decided to test three different brands of HT leads, the leads tested were:
1. Commercial Ignition - These should be considered as bog standard off the shelf every day leads at the lower end of the market
2. Magnecor kv85 competition 8.5mm - An expensive performance orientated lead
3. MSD 8.5mm Super Conductor - A well respected American made performance lead (cheaper than Magnecor kv85)
"ALL LEADS TESTED WERE AN ALMOST IDENTICAL 3' LENGTH"
First off lets look at the Commercial Ignition lead without the plug extender (measured using the 20k setting)
And now with the non resistor plug extender
So with the nothing special every day Commercial Ignition lead as our control lets see what the hugely more expensive Magnecor kv85 competition 8.5mm give you for all that extra money (again measured using the 20k setting)
For completeness I tested a second Magnecor lead of the same length proving they are indeed very consistent
Finally here's how the MSD 8.5mm Super Conductor leads perform, IMPORTANT This time it was necessary to drop the meter right down to its lowest 200 Ohm setting
So there we have it, if resistance genuinely is the measurement of HT lead performance we now have the figures to help choose HT leads.
The MSD 8.5mm Super Conductors were purchased from Summit Racing in the USA and arrived within a week of ordering, they are obviously a lot more expensive than the every day quality CI leads but do actually work out cheaper than Magnecor even when you factor in shipping & duty using Summit's excellent IParcel duty pre-pay option.
MSD claim 40-50 Ohms per foot, this was supported by my tests where I saw a very consistent & extremely low 44 Ohms per foot, & this was with the measurements taken with both coil & plug ends fitted.
The construction of the MSD 8.5mm Super Conductors also seems of extremely good quality, as soon as I've fitted them I'll report back here on how they perform on the car.
Dave.
1. Commercial Ignition - These should be considered as bog standard off the shelf every day leads at the lower end of the market
2. Magnecor kv85 competition 8.5mm - An expensive performance orientated lead
3. MSD 8.5mm Super Conductor - A well respected American made performance lead (cheaper than Magnecor kv85)
"ALL LEADS TESTED WERE AN ALMOST IDENTICAL 3' LENGTH"
First off lets look at the Commercial Ignition lead without the plug extender (measured using the 20k setting)
And now with the non resistor plug extender
So with the nothing special every day Commercial Ignition lead as our control lets see what the hugely more expensive Magnecor kv85 competition 8.5mm give you for all that extra money (again measured using the 20k setting)
For completeness I tested a second Magnecor lead of the same length proving they are indeed very consistent
Finally here's how the MSD 8.5mm Super Conductor leads perform, IMPORTANT This time it was necessary to drop the meter right down to its lowest 200 Ohm setting
So there we have it, if resistance genuinely is the measurement of HT lead performance we now have the figures to help choose HT leads.
The MSD 8.5mm Super Conductors were purchased from Summit Racing in the USA and arrived within a week of ordering, they are obviously a lot more expensive than the every day quality CI leads but do actually work out cheaper than Magnecor even when you factor in shipping & duty using Summit's excellent IParcel duty pre-pay option.
MSD claim 40-50 Ohms per foot, this was supported by my tests where I saw a very consistent & extremely low 44 Ohms per foot, & this was with the measurements taken with both coil & plug ends fitted.
The construction of the MSD 8.5mm Super Conductors also seems of extremely good quality, as soon as I've fitted them I'll report back here on how they perform on the car.
Dave.
spitfire4v8 said:
How is resistance a measure of HT lead performance? You need to consider the whole system not the lead in isolation. Have you measured the resistance of the air gap on the spark plug? and the drop as the air ionises? What does your aftermarket ECU think of running low resistance Ht systems? Most ecus throw a wobbler if you run low resistance, hence the need for resistor plugs for example. What resistance are you trying to target and why?
That's why you'll find my caveat statement above:Edited by spitfire4v8 on Wednesday 20th August 08:56
"So there we have it, if resistance genuinely is the measurement of HT lead performance we now have the figures to help choose HT leads
Don't confuse my results with me making any spurious claims, re-read and you'll see that's not what I'm doing here.
All I've done is posted the results after testing a range of leads so people can make their own minds up.
The facts are MSD Super Conductor leads have been used extensively in the States for years & years with a multitude of different engine management systems, and from my research with absolutely no issues whatsoever.
The American performance market is massive, making what goes on here on our little island look like a joke, so honestly if these low resistance MSD leads give trouble I'm sure we'd all know about it.
But hey lets see what happens on my car first, which is why I included this:
ChimpOnGas said:
As soon as I've fitted them I'll report back here on how they perform on the car.
I knew this post would provoke the age old debate on HT lead resistance which is why I specifically didn't make any claims that a lower resistance lead gives benefits, and no doubt that debate will rage on eternally with sound arguments either way.Lets not use Piston Heads as an opportunity to snipe, lets share information and politely debate after fully understanding whats been presented.
ChimpOnGas said:
So there we have it, if resistance genuinely is the measurement of HT lead performance we now have the figures to help choose HT leads. Dave.
The important word here is IFspitfire4v8 said:
I await this test and results and evidence with interest, but i suspect that whatever you come up with as a result will be clouded by the true picture of what happens in a full ignition system . Even the way the HT lead is wound (assuming said lead has both straight and wound wire within it) has an impact on its conductivity profile and electromagnetic radiation. I went through this when I had some bespoke HT lead wire made for my own ecu installs. Funnily enough though the actual conductor used in my HT lead when decided upon was imported from the USA ..
Interesting, so in the spirit of the PH forums being about the open sharing of information by non-traders, what brand of American leads did you find were best?I doubt my results will be seen as credible by the group because I freely admit I don't have access to the test equipment to make this possible.
What I will be able to report on after fitting the MSDs is subjective but simple:
1. How well my LPG powered TVR idles & runs
2. LPG & Petrol economy improvements if any
3. Durability & longevity of the leads
4. Any indication of EMI interference
Pretty basic stuff I admit, but dare I suggest.... important all the same
TBH I'm quite sure I'll see or feel zero power improvement so I haven't included this in my evaluation list, actually my little lead swap project had nothing at all to do with outright performance gains, it's just everyone here is obsessed with horse power so they immediately assume that's my goal too.
However with LPG proven scientifically to be way harder to strike than petrol it is possible there may be a small improvement in idle quality as there most definitely was when I ditched the ridiculous TVR OEM shrouded No7 plugs and fitted a No6 plug with an extended electrode.
Mostly though for me its about the durability & longevity of the leads as I'm burning propane which most definitely puts more load on the whole ignition system, leads very much included.
Perhaps these leads will prove more durable, perhaps they wont, perhaps they'll send my Canems dual fuel ECU into an EMI induced tiz?
Lets see
One thing is for sure, those cheapy Commercial Ignition HT leads have lasted longer than the expensive Magnecor KV85s operating in exactly the same high temp environment of number 7 & 8 cylinders & while burning LPG.
In fact I went back to the Commercial Ignition HT leads when the Magnecors failed and the bouncing tacho needle immediately disappeared, this has nothing to do with the catastrophic failure of the Magnecors either as the needle bounced from the day I fitted the brand new Magnecors.
Obviously replacing the completely feked Magnecors with anything would deliver a significant & immediate improvement, but what I can genuinely report is those cheap old Commercial Ignition leads do a better job than my Magnecors did even when they were brand new.
The CI leads instantly gave me a smoother idle & no tacho bounce, this makes me suspect some of leads Magnecore made me weren't the full ticket from day one.
I'm using those old CI leads right now and the car is running great, so I probably don't even need to make the switch to the MSD Super Conductors?
But for me this is a hobby not a business, so I'm just having fun trying stuff out, and I'll for sure share the honest subjective results whatever the outcome.
After all I haven't got any commercial reasons to hide my findings.
Edited by ChimpOnGas on Wednesday 20th August 12:01
spitfire4v8 said:
I didn't import american leads dave just the central conductor core was imported. The actual lead was made in the uk. i say lead singular because it's on a large reel (just under a kilometer of wire was what i had to buy and i've probably used less than half of it but it was a god-send when making bespoke length leads up before you could buy such stuff on ebay etc). I went to the manufacturing plant which was something like 50m long and the machine doubled back on itself to fit all the manufacturing process in.
They had a clever system of being able to change reels midway through manufacturing so they didn't lose many meters of part made wire every reel change. My leads were a full silicone but I also bought a part reel of blue wire at the same time which was one layer silicone one layer epdm which i've never really used much of. Maybe I should ebay it. Must be a few hundred meters of the stuff on it gathering dust ..
Ok and thanks for all the info, your experience in these matters is respected & valued, I'll test the MSD leads on the car unless you genuinely feel I may damage my ECU in any way.They had a clever system of being able to change reels midway through manufacturing so they didn't lose many meters of part made wire every reel change. My leads were a full silicone but I also bought a part reel of blue wire at the same time which was one layer silicone one layer epdm which i've never really used much of. Maybe I should ebay it. Must be a few hundred meters of the stuff on it gathering dust ..
Edited by spitfire4v8 on Wednesday 20th August 13:42
What sort of symptoms would I experience as a result of leads that were too low in resistance, could they overload the spark drivers damaging them or is it just a case of experiencing a temporary misfire until I go back to higher resistance leads because the low resistance confuses the ECU?
Does the ECU need to see resistance in the ignition circuit before it'll fire the coil packs, or will it still fire the coils but put too much load back to the spark drivers or overheat the coils themselves?
I'm currently running NGK LPG Laser Line No2 which work very well and have a very long service life, TBH I'm not sure what resistance they run at as NGK list them as a direct replacement for both BP6ES (non-resistor) & BPR6ES (resistor), amongst many many others:
http://ngkntk.co.uk/wp-content/uploads/2011/04/LPG...
Thanks again, I freely admit I don't really have a grasp on how my Canems ECU relys on resistance in the leads & plugs to function correctly.
What I don't want to do is cause any ECU damage as I did when I experimented with the rather excellent but extremely low impedance Keihin LPG injectors that eventually over heated the peak & hold injector drivers in the dual fuel ECU if I drove it for longer than 2 hours in one sitting (works perfectly now with the 2 Ohm Magic Jets BTW).
Thanks in advance for your advice, Dave.
Ok & thanks again.
I'm guessing lower resistance could potentially equate to higher EMI and that could interfere with the operation of the sophisticated electronics within the ECU?
Everything I've read about MSD Super Conductors suggests their double silicone wall construction is extremely good at limiting EMI and as I've not had any ECU issues or radio interference arising from the NGK Laser Line LPG plugs (only benefits) in the last 10,000 miles I feel its safe to consider them proven.
But assumption being the mother of all f-ups, I will double check on these super low resistance leads with David Hampshire at Canems.
I'm guessing lower resistance could potentially equate to higher EMI and that could interfere with the operation of the sophisticated electronics within the ECU?
Everything I've read about MSD Super Conductors suggests their double silicone wall construction is extremely good at limiting EMI and as I've not had any ECU issues or radio interference arising from the NGK Laser Line LPG plugs (only benefits) in the last 10,000 miles I feel its safe to consider them proven.
But assumption being the mother of all f-ups, I will double check on these super low resistance leads with David Hampshire at Canems.
Sounds like a low resistance lead may well be beneficial on my LPG burning TVR then assuming it doesn't cause ECU issues.
Blitz's post supports all the results of many discussions I've had with recognised LPG specialists, LPG is harder to strike but once its lit it burns beautifully well.
My simple resistance tests above seem to prove the MSD Super Conductors are very low resistance indeed, so have the potential to deliver that short high powered spark needed to start the LPG burn.
watch this space
Blitz's post supports all the results of many discussions I've had with recognised LPG specialists, LPG is harder to strike but once its lit it burns beautifully well.
My simple resistance tests above seem to prove the MSD Super Conductors are very low resistance indeed, so have the potential to deliver that short high powered spark needed to start the LPG burn.
watch this space
TV8 said:
How about the plug extenders? Do they change anything given that they are in- line to it all? Also, do they go wrong and if so, can they be tested? Dave's showed a small change in resistance in the pics above. Is that right?
The extender shows 0.3 on the 20k setting so 300 Ohms which is nothing when you look at the resistance of the CI leads and even the Magnecors. But if we're looking at the super low 130 Ohm MSD leads the extenders more than double the resistance from coil to plug. Extenders can definitely be a source of failure but many may argue they are essential. Personally I think at best they are a necessary evil and removing the extenders has to be a good thing if it can be done without compromising the reliability & longevity of the HT lead.Sardonicus said:
ave I dont need to tell you that as lower resistance as possible is the way to go without causing interference/noise etc you want as much energy reaching the plug as possible hence the take up of pencil/direct fire coils and engine mounted coils and shorter & shorter HT leads in recent years 
I am happy my American Accel leads 
Precisely Simon and some excellent examples there, just one look at a Chevy LS says it all, they didn't make it that way for fun. I am happy my American Accel leads The 3' Commercial Ignition lead showed a huge 12,700 Ohms and the Magnecor a far better 4,200 Ohms.
But with the MSD Super Conductor lead showing just 130 Ohms on a 3' lead I'd need to shorten the Magnecor lead to just an inch long to see similar levels of resistance.
Or put it another way I could run a 30' MSD Super Conductor lead and its resistance would still be lower than a 3' Magnecor lead.
Whether this will all translate to something that can be felt is yet to be proved but the MSD super low 43 Ohms per foot can't be a bad thing assuming the EMI is still well supressed.
Watch this space
Bobby Shaftoe said:
Would summat like this be any good: http://www.ebay.co.uk/itm/331296262956?ssPageName=...
Seems to be the same spiral would stuff as Magnecor use and low resistance but a fair bit cheaper. The normal carbon string ignition cable doesn't seem to last two minutes in the red hot engine bay on my wedge.
Looks the same & performs the same are two different things, the spiral wound MSD Super Conductor leads look a lot like Magnecors too but have a resistance that's a massively lower!Seems to be the same spiral would stuff as Magnecor use and low resistance but a fair bit cheaper. The normal carbon string ignition cable doesn't seem to last two minutes in the red hot engine bay on my wedge.
The best thing to do would be to order a foot of it and test its resistance, they say 350 Ohms per foot in the EBay ad but you've really got to test the lead yourself to be sure.
350 Ohms is still a long long way off the MSD Super Conductor 43 Ohms per foot but I doubt you'd feel it.
There's a host of HT lead test results on the net originating from the US if you go looking, every time what the Yanks call plug wires get tested the MSD leads come out as having the lowest resistance.
But I also found comment on how a respected magazine did a back to back dyno test on a host of HT leads and the results showed zero power gains.
That doesn't surprise me at all, this whole HT lead thing has nothing to do with power gains for me.
But there is a chance the MSD leads could give me an even smoother idle on LPG and this better idle combustion will likely show up on my mate's gas analyser as lower emissions, I dont give two ships about emissions by the way but it's nice to know the gas I put into the engine at idle is getting burnt as effectively & completely as possible.
At the end of the day I needed to change two burnt Magnecor leads anyway so I'm just experimenting, there's also a very good chance the MSD leads will make fek all difference I can feel.
But at least I'll have the new leads I need and they'll be good quality ones that last (I hope).
Taken from some tests done in the States:
Granatelli wires (2 OHMs)
Here we have the Granatelli wires. These wires were the lowest wire OHM resistance wire we have ever tested, at 2 ohms of resistance. Granatelli uses a stainless steel core, wrapped in silver plated copper wiring. This is the highest quality wire we have ever carried, and the wire that we strongly recommend.
MSD wires (33 OHMs)
In second place, we have the MSD wire set. Compared to the Granatelli wires in first place, these wires are red in color, and come in at 33 ohms of resistance to the Granatelli wires's 2 OHMs of resistance. The MSD wires are still good quality though. Msd states on their boxes that they use a copper alloy conductor for their wires.
ACCEL wires 124 OHMs
In third place, we have Accel wires. These use a copper/alloy wire core, and are has a 8mm silicone jacket. These wires had a cheaper feel, and look compared to the other wires, but still had a great, low resistance.
Mopar wires 390 OHMs
Fourth place belongs to the Mopar Performance spark plug wires. We measured these wires to have 390 OHMS of resistance which is quite high, but still acceptable.
Magnecor wires 1548 OHMs
Fifth place place belongs to the Magnecor wires. Magnecor wires had the highest resistance out of all of the wires we tested, coming in at 1548 OHMS of resistance. (In Magnecor's defense, they claim that low OHM resistance wires are not a measure of quality).
The results on the Magnecor & MSD leads come very close to my own, the Granatelli leads perform the best but I prefer to trust MSD as they have a very long history in the US performance ignition market with an excellent reputation for quality & customer service.
I've been running MSD Mustang performance coil packs on my TVR for some time, these are very popular in the States with guys fitting turbos to their fox body Mustangs who suffer spark blow out on standard coil packs.
I dont want to provoke a debate on MSD vs standard coil packs, all I can say is after thousands of miles they've proved to be 100% reliable on my LPG TVR that will definitely be putting more load on the coils than the same car burning petrol.
Granatelli wires (2 OHMs)
Here we have the Granatelli wires. These wires were the lowest wire OHM resistance wire we have ever tested, at 2 ohms of resistance. Granatelli uses a stainless steel core, wrapped in silver plated copper wiring. This is the highest quality wire we have ever carried, and the wire that we strongly recommend.
MSD wires (33 OHMs)
In second place, we have the MSD wire set. Compared to the Granatelli wires in first place, these wires are red in color, and come in at 33 ohms of resistance to the Granatelli wires's 2 OHMs of resistance. The MSD wires are still good quality though. Msd states on their boxes that they use a copper alloy conductor for their wires.
ACCEL wires 124 OHMs
In third place, we have Accel wires. These use a copper/alloy wire core, and are has a 8mm silicone jacket. These wires had a cheaper feel, and look compared to the other wires, but still had a great, low resistance.
Mopar wires 390 OHMs
Fourth place belongs to the Mopar Performance spark plug wires. We measured these wires to have 390 OHMS of resistance which is quite high, but still acceptable.
Magnecor wires 1548 OHMs
Fifth place place belongs to the Magnecor wires. Magnecor wires had the highest resistance out of all of the wires we tested, coming in at 1548 OHMS of resistance. (In Magnecor's defense, they claim that low OHM resistance wires are not a measure of quality).
The results on the Magnecor & MSD leads come very close to my own, the Granatelli leads perform the best but I prefer to trust MSD as they have a very long history in the US performance ignition market with an excellent reputation for quality & customer service.
I've been running MSD Mustang performance coil packs on my TVR for some time, these are very popular in the States with guys fitting turbos to their fox body Mustangs who suffer spark blow out on standard coil packs.
I dont want to provoke a debate on MSD vs standard coil packs, all I can say is after thousands of miles they've proved to be 100% reliable on my LPG TVR that will definitely be putting more load on the coils than the same car burning petrol.
Sardonicus said:
ChimpOnGas said:
Simon mate, can you foresee any Canems ECU issues for me on the MSD leads?
Probably not Dave so long as you keep the resisted spark plugs , EDIS ignition is proper fussy with this stuff and I have had no issues with my Accel leads (metal cored) but with resisted plugs.
Thanks for your contribution Mark and very informative it is too.
So in summary, the opinions on the benefits of low resistance leads still seems divided and is very much depending on what side of the pond you live on.
In your words "the American aftermarket seem favour the short spark, and hence their leads etc", TBH that's good enough for me. As we all know the Yanks certainly have never had a problem making big power from pushrod V8s.
The bit about spark plug electrode size is of particular interest to me as I'm running LPG, like you say a thinner pointy electrode creates higher electrostatic field so requires less voltage, which I guess is why the NGK Laser Line LPG range of plugs look like this:
This one is straight out of my engine, I can confirm after 10,000 miles these plugs work brilliantly even though people told me the tips would fall off and destroy my engine
NGK make the best spark plugs in the world bar none, and they didn't get to where they are now by producing products that destroy engines
Back in the day I had an old Champion spark plug tester, you would hook it up to an air line and put the connected plug into a sealed chamber with a little window. The machine had a 12v coil so you could get the plug firing as you wound up the pressure, eventually when the air pressure got high enough you could put the spark out and watch it happen before your very eyes.
The idea was to test for a bad plug, but it also showed the effects of increased compression or forced induction can have on the spark. And that's why when our American cousins go forced induction they often need to upgrade their ignition systems with capacitive discharge coils, close their plug gaps and fit better HT leads.
With our antiquated Sun Tuner machine and this prehistoric spark plug tester we could pretty much diagnose any ignition fault, its just a shame I dont have accesses to them now
Your point about LPG being more difficult to ionise than petrol is very true, those NGK plugs certainly made an improvement for me so now lets see if (following American thinking) the MSD leads will work well too.
With all this technology out there I still believe in listening, smelling & driving to tell if an engine is healthy. A bit like when that Austin Healey came into Mech Repairs when you had my TVR on the rolling road, you may recall I went straight to the SU throttle spindles
Oh and the hunting on my car we couldn't solve during that £600 morning disapeared the moment I removed the main cat that you told me was such good quality, I put my money on a blocked exhaust and won that bet too.
I have to say ditching that big cat made almost as much improvement as ditching the 14CUX
And for completeness, my reconditioned Vectra injectors you insistent on removing and then found to be perfect like I said they would be, are indeed still perfect now I'm on the fully mappable by anyone Canems system.
Best regards, Dave
So in summary, the opinions on the benefits of low resistance leads still seems divided and is very much depending on what side of the pond you live on.
In your words "the American aftermarket seem favour the short spark, and hence their leads etc", TBH that's good enough for me. As we all know the Yanks certainly have never had a problem making big power from pushrod V8s.
The bit about spark plug electrode size is of particular interest to me as I'm running LPG, like you say a thinner pointy electrode creates higher electrostatic field so requires less voltage, which I guess is why the NGK Laser Line LPG range of plugs look like this:
This one is straight out of my engine, I can confirm after 10,000 miles these plugs work brilliantly even though people told me the tips would fall off and destroy my engine
NGK make the best spark plugs in the world bar none, and they didn't get to where they are now by producing products that destroy engines
Back in the day I had an old Champion spark plug tester, you would hook it up to an air line and put the connected plug into a sealed chamber with a little window. The machine had a 12v coil so you could get the plug firing as you wound up the pressure, eventually when the air pressure got high enough you could put the spark out and watch it happen before your very eyes.
The idea was to test for a bad plug, but it also showed the effects of increased compression or forced induction can have on the spark. And that's why when our American cousins go forced induction they often need to upgrade their ignition systems with capacitive discharge coils, close their plug gaps and fit better HT leads.
With our antiquated Sun Tuner machine and this prehistoric spark plug tester we could pretty much diagnose any ignition fault, its just a shame I dont have accesses to them now
Your point about LPG being more difficult to ionise than petrol is very true, those NGK plugs certainly made an improvement for me so now lets see if (following American thinking) the MSD leads will work well too.
With all this technology out there I still believe in listening, smelling & driving to tell if an engine is healthy. A bit like when that Austin Healey came into Mech Repairs when you had my TVR on the rolling road, you may recall I went straight to the SU throttle spindles
Oh and the hunting on my car we couldn't solve during that £600 morning disapeared the moment I removed the main cat that you told me was such good quality, I put my money on a blocked exhaust and won that bet too.
I have to say ditching that big cat made almost as much improvement as ditching the 14CUX
And for completeness, my reconditioned Vectra injectors you insistent on removing and then found to be perfect like I said they would be, are indeed still perfect now I'm on the fully mappable by anyone Canems system.
Best regards, Dave
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