spark plug
#1
01-27-2008, 05:14 AM
#2
04-18-2008, 12:18 PM
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#3
04-18-2008, 12:32 PM
#4
08-21-2014, 01:47 AM
IMHO, the best spark-plug for the Vrod would be a plug that had both an fine wire iridium center electrode and an iridium ground electrode in the common air-gapped configuration (the traditional looking spark plug). The iridium is better than platinum for longevity. The iridium is better than the platinum-iridium alloy as well.
The fine wire center electrode allows the plug to spark over the gap at a lower voltage and so will contribute to more stable idle and less stress on the coils.
You can also alter the temperature of the plug if you like once you have run some time and can pull the plugs to inspect their condition. If the plugs aren't getting hot enough to burn off deposits/oil, etc. then you can go to a hotter plug (experiment) but short of causing pre-ignition. A hot plug? You can go to a cooler one.
One other thing... these surface gapped plugs like the E3 may cause problems in a VRod (or any motorcycle using Delphi fuel-injectin system). This is because the Delphi system uses a "knock sensor" system that doesn't "listen for knocks" but rather measures ionization after combustion and from that deduces a whole slew of combustion characteristics which the ECU considered in dynamic tuning. After the combustion chamber is fired an 80 volt potential is created momentarily across the center electrode and ground electrode and ionization sensed and measured and from that the combustion conditions determined including "knocking" or "pinging". This would happen if you put 87 octane fuel in the motorcyle (too low Octane) however this sensor would sense that and slightly retard the ignition timing to accommodate the lower octane fuel (you would also lose power too -- not sure how much).
Porsche-HD put a lot of excellent design into this engine and it shows. The knock sensors sense free-ions that result from combustion by passing an 80 vdc potential across the 0.035 (0.9mm) spark plug gap between sparks and then measure the current that passed over the ions in the gap. This tells the ECM when the burn has begun and finished and allows decisions to be made regarding "pre-ignition" or "knock" (all without the use of auditory microphone style knock sensor which are problematic). I like what Porsche-HD did in selecting this "Ion Sense" system as it creates a very accurate method for the engine to sense knocking and then make timing adjustments too save the engine from damage. Theoretically you should be able to burn 87 Octane fuel in this engine without damage but with some retarded timing and less power output.
I think that it could be true that a traditional single electrode spark plug would need to be used to keep the Ion Sense system working properly and the gap would likely be somewhat critical. To much of a gap may cause the Ion Sense system to think that combustion has started later than it actually has and finished earlier than it actually has. The system also requires a resistor plug to helpreduce stray EMI that could play havoc with the ECM.
The fine wire center electrode allows the plug to spark over the gap at a lower voltage and so will contribute to more stable idle and less stress on the coils.
You can also alter the temperature of the plug if you like once you have run some time and can pull the plugs to inspect their condition. If the plugs aren't getting hot enough to burn off deposits/oil, etc. then you can go to a hotter plug (experiment) but short of causing pre-ignition. A hot plug? You can go to a cooler one.
One other thing... these surface gapped plugs like the E3 may cause problems in a VRod (or any motorcycle using Delphi fuel-injectin system). This is because the Delphi system uses a "knock sensor" system that doesn't "listen for knocks" but rather measures ionization after combustion and from that deduces a whole slew of combustion characteristics which the ECU considered in dynamic tuning. After the combustion chamber is fired an 80 volt potential is created momentarily across the center electrode and ground electrode and ionization sensed and measured and from that the combustion conditions determined including "knocking" or "pinging". This would happen if you put 87 octane fuel in the motorcyle (too low Octane) however this sensor would sense that and slightly retard the ignition timing to accommodate the lower octane fuel (you would also lose power too -- not sure how much).
Porsche-HD put a lot of excellent design into this engine and it shows. The knock sensors sense free-ions that result from combustion by passing an 80 vdc potential across the 0.035 (0.9mm) spark plug gap between sparks and then measure the current that passed over the ions in the gap. This tells the ECM when the burn has begun and finished and allows decisions to be made regarding "pre-ignition" or "knock" (all without the use of auditory microphone style knock sensor which are problematic). I like what Porsche-HD did in selecting this "Ion Sense" system as it creates a very accurate method for the engine to sense knocking and then make timing adjustments too save the engine from damage. Theoretically you should be able to burn 87 Octane fuel in this engine without damage but with some retarded timing and less power output.
I think that it could be true that a traditional single electrode spark plug would need to be used to keep the Ion Sense system working properly and the gap would likely be somewhat critical. To much of a gap may cause the Ion Sense system to think that combustion has started later than it actually has and finished earlier than it actually has. The system also requires a resistor plug to helpreduce stray EMI that could play havoc with the ECM.
Last edited by JayDRod; 09-30-2014 at 06:51 PM. Reason: Addition of information re: Ion Sense and mis-gapped plugs
#5
09-30-2014, 07:00 PM
I would be very curious to know what spark plugs folks are running in their VRods. I am running NGK DCPR8EIX iridium plugs with the traditional projected negative electrode (platinum) and single center electrode (fine wire iridium). These burn well and I am thinking of going 1 level cooler just to see what happens (DCPR9EIX). I am thinking that since the VRod may be operating right on the edge for 93 Octane fuel that maybe if the Ion Sense is turning out some minor knock that going to a slightly cooler plug may make just a bit more power. Anyone try the Bosch platinum-iridium plugs in the Vrod?
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