Hey guys, just wondering, I had mine wear out and went down to the local auto store and got some caps, but they have 5k resistors in them, sled seems to run OK perhaps? But just wondering if the stock ones had any resistors or not, never got to check.
Stock spark plug caps, so they have resistors in them?
- Thread starter Octanee
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I had issues with my sled cutting out under heavy load. Was making me crazy ! Somebody recommended SLP's plug wire set. Turns out its MSD ignition wires and a cool retainer to keep the plug caps tight.Awesome set up I HIGHLY recommend it !
Yeah I've learned all about that cutting out lol, spark plug caps wearing out, seemed to be when I switched to ngk plastic ones, you need a full body rubber/silicone. Now I'm just curious if I shouldn't have a resistor in my cap as well or not though.
I can't say for certain that all newer sleds have resisters, but I'd bet they all do. My '02 does, and even the older models all seem to even though they don't have ECUs and such. The resister is there for EMI suppression, which is critical on EFI motors – electrical noise tends to interfere with sensors. I replaced the wires and terminals on my sled with universal NGK CR4 wires. Nothing wrong with the originals that I could see; it was a cosmetic upgrade if nothing else. I wish now that I'd got the CR2 wires: they interface directly with the screw tip instead of the capped tip, and I've noticed that the capped terminals seem to build up a fair amount of fine dust from arcing between the contacts.
Anyway, I'd be surprised if any recent sled calls for a non-resistor terminals, and I doubt you'll have any issues with replacement pieces from NGK or SLP/MSD.
Anyway, I'd be surprised if any recent sled calls for a non-resistor terminals, and I doubt you'll have any issues with replacement pieces from NGK or SLP/MSD.
I wonder about that too, but I know my sled specs both a resistor plug and terminal (Champion RN57YCC or NGK BPR9ES). NGK makes a non-resistor plug (BP9ES) that should be the same thing without a resistor, but I'm not sure if running it would be a good idea. Theoretically you could get a little more spark and maybe run a bigger gap, but I have no idea whether the single resistor would be enough EMI suppression.
Non resistor plugs and caps DO cause problems. I use to drag race sleds back in the early 2000's. I raced yamaha triples and we figured out if we ran racing plugs (no resistor) and caps with no resistors that it effected some other sleds.
The ones ski-doos that had the tether as the key.... if we got with in about 7-8 ft of their sled while making a pass it would cause their sled to cut out. :face-icon-small-ton
Good info guys, for me I was curious, I wasn't sure if the stock sled was a resistor cap and resistor plug together or if they assume your spark plug has the resistor in it that you don't need to double up and have the cap have a resistor too? I have yet to see or purchase a non resistor plug. But yes we sure don't need it messing with our computers and such, I don't seem to have any issues my self with spark but was sure curious on the matter 
And that's interesting how the other guys sled would cut out. I bet that took a while to figure out!
And that's interesting how the other guys sled would cut out. I bet that took a while to figure out!
I dont know if any of the guys I raced against ever knew what happened. It didnt work out all that often but a couple times it sure came in handy! lol
The only way we knew what was going on was from a day of testing with a buddy. He had an MXZ 700 and I had one of my SRX's out. I just happened to be testing Spark plugs and we made a pass together and his sled ran like crap. Then he made a solo pass and it was fine.... About an hour later we figured it out!
That's a pretty good one: "hey, every time you line up next to me your sled dies, must be afraid of me!" Anyway, what I was thinking of was a non-resistor plug with a resistor cap. I can't imagine no resistor at all would work with EFI, but I wonder what would happen with either a resistor plug and a straight cap, or non-resistor plug with a resistor cap.
I've got an older (but still computerized) Mercedes that is designed specifically for non-resistor plugs, with a 1kOhm resistor at the end of the plug wire. On that engine, running resistor plugs causes more wear on the rest of the ignition system. Unfortunately – even for that engine – it's getting harder to find non-resistor plugs. It's a little counter-intuitive that more resistance could cause more wear. That may be a special case, but I mention it as an example where deviating from the way the system was designed causes problems. There is always some EMI any time you generate a spark, but increasing the resistance between the coil and tip of the spark plug reduces the noise. It's a trade-off between stronger spark and keeping the EMI at an acceptable level.
Getting back to sleds, I can't find anything to confirm that the newer motors run a resistor cap (in addition to a resistor spark plug), but I'm fairly confident they do. The talk about running non-resistor plugs and such is only something you'd do if you're trying to gain performance. There could be significant benefits for someone running a turbo, for one. You might be able to run a single resistor (in either the cap or the plug) without causing trouble, but it's hard to be sure without extensive testing. It could also be hard on the coil. Like I said, my sled, and I think most others run a resistor cap and plug. That may be more for safety margin and redundancy than out of necessity. If a sled is designed for two resistors, removing one isn't going to be nearly as drastic as going to no resistor or even going from one to none – that said, they wouldn't put two in there if they didn't think they needed it.
I've got an older (but still computerized) Mercedes that is designed specifically for non-resistor plugs, with a 1kOhm resistor at the end of the plug wire. On that engine, running resistor plugs causes more wear on the rest of the ignition system. Unfortunately – even for that engine – it's getting harder to find non-resistor plugs. It's a little counter-intuitive that more resistance could cause more wear. That may be a special case, but I mention it as an example where deviating from the way the system was designed causes problems. There is always some EMI any time you generate a spark, but increasing the resistance between the coil and tip of the spark plug reduces the noise. It's a trade-off between stronger spark and keeping the EMI at an acceptable level.
Getting back to sleds, I can't find anything to confirm that the newer motors run a resistor cap (in addition to a resistor spark plug), but I'm fairly confident they do. The talk about running non-resistor plugs and such is only something you'd do if you're trying to gain performance. There could be significant benefits for someone running a turbo, for one. You might be able to run a single resistor (in either the cap or the plug) without causing trouble, but it's hard to be sure without extensive testing. It could also be hard on the coil. Like I said, my sled, and I think most others run a resistor cap and plug. That may be more for safety margin and redundancy than out of necessity. If a sled is designed for two resistors, removing one isn't going to be nearly as drastic as going to no resistor or even going from one to none – that said, they wouldn't put two in there if they didn't think they needed it.
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