importwarrior Posted September 14, 2002 Report Share Posted September 14, 2002 all about NGK plugs, LONG 3 replies to complete too long > Below is a collection of information from Matt Blue, > an engineer at NGK Spark Plugs, about NGK's offerings > for the DSMs. He posted this information to the Talon > Digest in several different messages. The information > is posted here with Matt's permission. > -------------------------------------------------------------------------------- > Here's a typical NGK spark plug part number: > BPR6EVX-11. > > A quick run down of the part numbers. Each letter or > number has significance in the NGK part number, but > the same letter may hold a different meaning depending > on where it is placed. Here is a rundown of our part > number: > > B Thread diameter = 14 mm > P Construction = Projected Insulator Type > (K) Construction = Hex size 5/8 in, projected tip > R Construction = Resistor Type > 6 Heat Rating Number = 2 Hot -> Cold > E Thread Reach = 12.7 mm > S Firing End Construction = Standard 2.6 mm diameter > center electrode > (VX) Firing End Construction = High performance > platinum > (K) Firing End Construction = 2 ground electrodes > (N) Firing End Construction = Special side electrode > > (-11) Gap Width = 1.1 mm (0.044 in) > > As you can see, our heat rating number goes up as > speed, load and temperature go up. In other words, > higher numbers are colder plugs. A colder plug simply > has a better ability to cool itself. When combustion > chambers become more violent (higher temps) due to > aftermarket toys, the plug sees higher temperatures > approaching its critical temperature (~900 degrees C). > To avoid plug failure (burning away ground / center > electrodes, or just increasing the plug's gap) some > people must go to a colder plug. > > The reason we cannot use a colder plug from the outset > is fear of never getting the plug warm enough. A spark > plug must reach what is called its "self-cleaning > temperature" (or region) which generally occurs at > about 500 degrees C depending on the A/F ratio. This > is normally reached during high engine or vehicle > speeds. This "self-cleaning temperature" allows the > plug to burn off carbon deposits accumulated at lower > speed and idle conditions. If this temperature is not > consistently reached, you will have definite fouling > problems. Link to comment Share on other sites More sharing options...
importwarrior Posted September 14, 2002 Author Report Share Posted September 14, 2002 -------------------------------------------------------------------------------- > These are a couple questions I received personally, > but my answers may help a few of you out. > > I have a 95 turbo with 16g and a lot of mods, should I > use BPR7EKN instead of BPR7ES like the 1st gens? What > gap should I set the plugs at? > My friend got me the BP7ES instead of the BPR7ES plugs > by accident... What are the differences between these > two? Can I use the BP7ES? > My reply: > > Before I get started, I have to state that what > follows is MY opinion along with MY suggestions, not > NGK's. I have to say that crap for liability reasons, > although I still do not want to be held responsible > for an engine that blows up ( > something. But you asked for an opinion and I will > give you one. > > You are doing the right thing by stepping up one heat > range colder. After the mods you have, that is > probably a good idea. As you may know already, your > '95 vehicle came with NGK's BPR6EKN with a gap of > ~0.030" stock. Here is a quick run-down of that part > number: > > B Thread diameter = 14 mm > P Construction = Projected Insulator Type > R Construction = Resistor Type > 6 Heat Rating Number = 2 Hot -> Cold > E Thread Reach = 12.7 mm > K Firing End Construction = 2 ground electrodes > N Firing End Construction = Special side electrode > > The side electrodes, or 2 ground electrodes, are used > by the industry for a couple reasons. One is to > increase the life of the spark plug without having to > use the more expensive material (platinum or iridium) > and the second is an anti-fouling measure. > > You have probably changed your combustion chamber's > characteristics to a point that this will be more of a > guessing game than anything else. Let's think about > what we do know about your combustion… You have raised > your operating temps, therefore, you should probably > go to a colder plug (6 to a 7 ~ Done). You also have > made your A/F swirl more violent (i.e. faster flow). > This was done by raising the pressure (i.e. more > power). As a result, you should decrease your gap size > to literally avoid "blowing out" your spark. If you > keep your gap too large, your spark may never reach > the other side during high demand operating regions. > It is hard to say exactly what size the gap should be, > but I would begin at about 0.28 with either type of > plugs. > > Now for the difference between the BPR7ES and the > BP7ES. To begin with, the "S" represents a center > electrode diameter of 2.6 mm. The only difference > between these two plugs is the resistive element. The > BP7ES does not use one. Spark plugs use resistors to > suppress the emitted electrical "noise" from ignition > systems. We must do this to comply with government > (Canada, Europe, and South Africa) regulations on the > amount of electrical "noise" allowed by ignition > systems. Radio frequency interference (RFI) can also > be suppressed by using resistor (or inductor) wires or > plug caps. We use these things to avoid interference > with sensor signals and with your listening radio. > Sensor interference can occur if a sensor, or its wire > is un-insulated and is routed close to the plug or the > plug wires. > > I, personally, would not worry about the RFI > situation, but if you do see problems while using the > BP7ES, that may be why. You may even here your engine > through your radio. > > To understand how this carbon-based powder resistor > works, think of a resistor as a sponge while current > (or voltage) is flowing water traveling in surging > waves. The same amount of water will come out the > other end, but the current will not spike like the > leading wave of water. Thus, a resistor is used to > "tame" the current and voltage for RFI. As a result, > you lose that initial spike to your plug. Since we > rely on the trailing edge of this voltage spike for > ignition, a resistor has a small effect on your power. > > In conclusion, I think the BP7ES will work for you and > your operating system. Racers often use non-resistor > plugs, but they do not have the same worries we do > (with sensors, radios and regulations). Also, the > BPR7EKN would be a female dog to get a hold of. You > would have to special order them and they only come in > packs of 10. Not really worth it in my opinion. Link to comment Share on other sites More sharing options...
importwarrior Posted September 14, 2002 Author Report Share Posted September 14, 2002 > -------------------------------------------------------------------------------- > I am wondering about the effects of spark plug > gapping. I am running high boost with the 16g so my > plugs are gapped less than the stock gap of .035". Are > there any negative results associated with running too > small of a gap? How can you tell if the gap is too > small? > I recently discussed gap width on a Digest page last > week, but I spoke of the antithesis of small gaps by > talking about the big 'uns. I mentioned that when a > gap is too large, you can literally "blow out" your > spark under high end operation. Now we will discuss > the other direction, a gap that may be too small. > > To begin with, there are many determining factors to > find the correct gap for an engine. A perfect spark > should be an intensely concentrated spark between a > wide gap in the center of the combustion chamber. If > the world were perfect, all our gaps would be 0.50", > but it is not a perfect world and we have many > limiting factors. To begin with, we must have an > ignition system that can provide enough energy to > spark across that huge gap even under some wicked > operating conditions. That may be feasible, but now we > have to deal with the physical characteristics of the > spark plug which govern a spark plug's gap. To have a > big gap, we would be exposing a long ground electrode > to some violent temps and it may have trouble cooling. > With this large gap you also must somehow convince the > spark to travel to the end of the ground electrode > instead of the path of least resistance (which would > be to the side). That is literally impossible. The > ceramic insulator may also see problems by being > exposed to extreme heating and cooling rates which can > cause thermal shock and crack it in half. Some engine > developers have even had their plugs hit the top of > their piston looking for the optimal spark with > projected tips (not a pretty sight). > > Since I am sure you read my long post last week about > the large gap widths (yeah, right), we can now speak > of a gap that is too small. I have pretty much already > answered your question. Your engine wants a gap that > will be large enough to have good exposure to your A/F > swirl in the combustion chamber. The only real fear of > going too small is that you will not have healthy > combustion every time, especially at low-end (idle) > states. This will increase emissions and may even > misfire. > > We can see that gap sizes change with pressure after > comparing our own gap recommendations for the turbos > (0.032") vs. non-turbos (0.044"). If you have goosed > your car (like you have) you may see better results > with a smaller gap size under large load conditions. I > would personally hesitate substantially shrinking my > gap size until I saw my vehicle breakup (misfire) on > the high end. > > I hope this info helps you out. Link to comment Share on other sites More sharing options...
MeTaLLo Posted February 5, 2003 Report Share Posted February 5, 2003 hm.. good topic im a little confused i have a 94 starion es, stock - no mods and it's misfiring when i step hard on the gas i believe it has .044 because autozone and other places say it is .044 but under the hood it says something like ".035 to .043 i was thinking in buying new spark plugs to see if it solves my little problem, and i wanted to buy those splitfires ( http://www.splitfire.com/splitfire.htm ) - their online catalog gives me .044 too will i have lower performance with a smaller (stock) gap? Link to comment Share on other sites More sharing options...
importwarrior Posted February 13, 2003 Author Report Share Posted February 13, 2003 i believe you need to gap as big as possible before misfire. but boosted engines need to have a smaller gap sometimes depending oon boost. higher the boost need to gap a little smaller so the air fuel mixture wont blow out the spark. Link to comment Share on other sites More sharing options...
Metric-man Posted June 8, 2003 Report Share Posted June 8, 2003 MITSUBISHI Part number MS851881 for the NGK BPR6EKN are readily available at the dealerships no "female dog to get a hold of" problems. Radio Frequency Interference (RFI) is something to consider in regards to racing and after market electronics can actually help cause misfires or stumbles not to mention wreck havoc with pit radios. The smaller platinum or titanium centers have a tendency to break off under extreme conditions and have been focused toward north american markets because in Europe they 're regarded as crap. (Scaring cylinder walls) Splitfire have the inherent weakness of design in splitting of an extended electrode. They are fine for N/A applications but I would not use them in force induction engines. (are they still $5.00 a piece?) Might as well buy Silverstones. Link to comment Share on other sites More sharing options...
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