Reading Plugs

[maverick720]

I pulled my plugs tonight and was a little un-nerved by what I found. Each plug was def fouled and had a patch of oil left on the flange. Is this normal or are my rings washed? The bike doesn't smoke and this is the first time I have looked at my plugs since I started spraying. Need your input PB family.

[xclr82xtc]

the fouled plug, and oil could be two seperate problems....more than likely its a lil oil from the seals on the valve cover...they leak oil into and around the spart plug, then when you pull out the plug, its all covered in oil and looks like you broke something.... if its not smoking then your valve seals and rings should be ok. As far as the fouled plugs, if your on dope, it might be alil rich. those plugs look ollldd..to...anyways, they are expensive but try the new e3's (if you can get them for your bike, what plug is that)

[maverick720]

Ah I didnt think about the valve cover leaking. The bike doesnt smoke at all and believe it or not those plugs are only 2-3 months old. I'm runnin NGK IMR9C-9HES plugs. I believe thats the stock iridium electrode plugs. I replaced all four last night and I plan on pulling them after my next track session and see what's going on. I dont have a datalogger and i'm running a loaded map on the spray to get me by. I'm sure that this is why my plugs are fouled but I would rather replace plugs instead of a motor. Does spraying nitrous increase my crankcase pressure? I NEED the dynojet LCD-200 datalogger unit BAD. I'm flying blind. Thanks for the help man.

[xclr82xtc]

it doesnt increase crank case pressure (unless you have a ton of blowby) but it does increase cylinder pressure....thats the pressure that breaks parts. lol ...bttw..i would NEVER run nitrous on a "loaded" map...get it on a dyno or afr meter installed. some shops will do a couple test pulls for you for as low as $30. at least youll know where you are that way.

[maverick720]

Yea yeah i know... I have the wideband 2 sensor and sending unit but I havent purchased the logger yet. Def will be my next purchase. Don't judge me too hard. I dont't know everything about nitrous but i know enough to not run without knowing my A/F ratio. I've been leaning on the schnitzracing.com tables to spray. I can't quit the dope!

[pafundi]

Well you really dont know exactly what your afr is with a genaric map loaded and certainly not with adding fuel based off the chart. Unless you have had a dyno pull with it your not telling us about:) Until you datalog it or get it tuned and see the o2 info you wont know. The schnitz table gives suggested numbers to add to the fuel tables so you have a starting point to tune from. You very well may be fine as that shnitz table should have you at a safe starting point to tune from providing your original map wasnt lean to begin with. Anyhow since your reading plugs you will at least have some way to generalize how the tune is so thats good. You got that thing flying by the way congrats and hopefully you can get it tuned soon as it will only get even better.

[Franklin]

Well technically the best way to tune a nitrous motor is by reading the plugs. The O2 sensor is a great tool followed by EGT's. If you have a wideband commander you shouldnt need the logger. Just plug into it after the run and download the data unless you only have O2 reader. We used to use the O2 sensor on our 3 stage nitrous promod but that was used more to get us into the ballpark. Then we used the EGT to make sure that we werent melting pistons but the problem with that was is if you were on the wrong side of the fuel curve you were reading EGT at 1500 degree and it was because you were burning raw fuel out the exhaust valve and you were not making the horsepower because you were too fat. So the best way to tune nitrous is to read the plugs after each run until you get a good handle on you fuel map. What you are looking for is the ground strap to have the change of color (heat line) about 2/3 to 3/4 of the way up the strap. You also want to make sure that there is a grey ring down inside porceline where it meets the steel inside the plug. You may need a scope to look down inside. One more thing. If you have black speckles on the porceline you need to either pull some timing or add a little fuel...That is caused by detonation and thats what kills pistons.

Hope this helps.

[maverick720]

I really appreciate all the input guys. Hey Franklin, is the heat line visible in the pic i provided above? It looks like that line your talking about is right near the tip. Lean to move it up the strap (towards the porceline) and more fuel to move it down the strap(towards the tip of the strap)? One of the techs at Fuel Moto told me that the Wideband 2 system must have the LCD-200 to actually log or display anything. The original wideband doesnt need anything else if I understand correctly. I didnt have any black speckles so that's good. I dont want to go into the motor. Not yet anyways. O and one more thing. To get an accurate reading on my plugs I need to shut the bike down at the traps and push it back so I dont wash my results correct?

[xclr82xtc]

Well technically the best way to tune a nitrous motor is by reading the plugs. The O2 sensor is a great tool followed by EGT's. If you have a wideband commander you shouldnt need the logger. Just plug into it after the run and download the data unless you only have O2 reader. We used to use the O2 sensor on our 3 stage nitrous promod but that was used more to get us into the ballpark. Then we used the EGT to make sure that we werent melting pistons but the problem with that was is if you were on the wrong side of the fuel curve you were reading EGT at 1500 degree and it was because you were burning raw fuel out the exhaust valve and you were not making the horsepower because you were too fat. So the best way to tune nitrous is to read the plugs after each run until you get a good handle on you fuel map. What you are looking for is the ground strap to have the change of color (heat line) about 2/3 to 3/4 of the way up the strap. You also want to make sure that there is a grey ring down inside porceline where it meets the steel inside the plug. You may need a scope to look down inside. One more thing. If you have black speckles on the porceline you need to either pull some timing or add a little fuel...That is caused by detonation and thats what kills pistons.

Hope this helps.

egt, air fuel, and a knock sensor is 100 times more accurate than reading plugs...plug reading is old school. Its ok, but its not the most accurate. for a quick check at the track, yeah sure..but not for making the most power safely...to each his own i guess. there is lots of people that do it that way and go fast. but in 2010, there is alot of people that do it with technology to.

[xclr82xtc]

I really appreciate all the input guys. Hey Franklin, is the heat line visible in the pic i provided above? It looks like that line your talking about is right near the tip. Lean to move it up the strap (towards the porceline) and more fuel to move it down the strap(towards the tip of the strap)? One of the techs at Fuel Moto told me that the Wideband 2 system must have the LCD-200 to actually log or display anything. The original wideband doesnt need anything else if I understand correctly. I didnt have any black speckles so that's good. I dont want to go into the motor. Not yet anyways. O and one more thing. To get an accurate reading on my plugs I need to shut the bike down at the traps and push it back so I dont wash my results correct?

i dont know what your using for a nitrous controller, but get you a daytona NC2. you can log that wideband voltage with it. also some other things as well as use it as an autoshifter. 300 for a controller, or 300 for a screen that is functional, but not as much as the nos controll....just my 2 cents. and yes about shutting down at the end of the run. where are you located?

[JSpin]

egt, air fuel, and a knock sensor is 100 times more accurate than reading plugs...plug reading is old school. Its ok, but its not the most accurate. for a quick check at the track, yeah sure..but not for making the most power safely...to each his own i guess. there is lots of people that do it that way and go fast. but in 2010, there is alot of people that do it with technology to.

i have to disagree with most of that. those can all be useful tools, but the spark plug is the only thing that is actually sitting in the combustion chamber. take a walk through the pro mod pits and see if they think plug reading is a waste of time.

knock sensors are just about useless, especially in motors like ours. they'll pick up valvetrain noise at high rpm, transmission noise, and you wont be able to tell the difference between BS knock count and a real problem.

high egt's can be the result of just about anything. a lean condition will cause temps. an overly rich condition allowing raw fuel to burn in the exhaust will cause high egt's. a late spark event will cause will cause egt, blah blah blah. once you have your tune up right, you can monitor egts for drastic changes, but its limited as far a tuning device.

now i use an o2 sensor, but i understand its limitations. like EGT, it can be affected by a ton of different things. even a change in timing can show up on a wideband, yet you didn't alter the amount of air or fuel going into the motor.

you need to read your plugs.

[xclr82xtc]

im not saying DONT look at your plugs...i mean obviously if your missing half an electrode strap something is wrong...but another thing here is that we arent building old school tecnhology promods. we are building 13-16000 rpm small cc engines. the more information you have the better. a egt alone, or a knock sensor alone, or a o2 alone will not give you much info...all three together will get you spot on. If you wanna take a bet. bring me a bike, ill tune it my way, then pull your plugs out and i bet you they will look like ole boy described. You also have to remember there is alot of different materials in plugs now adays and a tune that has a line at 1/2 the strap on one plug might put the line at 3/4 on another...how are you gonna know which is right without an egt and o2?? Im not in anyway saying he is wrong, im just sayin different strokes for different folks. the more info, the faster you go...use ALL your options.

[JSpin]

i agree more information is better than less. that being said, your engine doesnt know whether there is a set of carbs and a nitrous bottle hooked up to it or throttle bodies and a computer. a spark plug is physical evidence of what happened in your motor, there's no reason to not pay attention to it.

let me ask you this: do you have individual o2 and egt probs for each cylinder? maybe you do, but most guys dont. maybe your o2 and egt sensors told you that you had a lean condition, so you had some some fuel. next pass everything looks ok. next pass you melt a piston. you had an injector that was clogged up and was already operating at 100%. you added fuel across the board so everything averaged out and made the sensors happy, but it melted anyway. had you taken 2 minutes to look at your plugs, you could have saved your motor.

again, those are all great tools, but i wont put my high dollar motor in thier hands.

[JSpin]

let me simplify the scenario......your sensors say you're running good, your plugs say you need more fuel. what do you do? what do you have more faith in? whats a more accurate source of information?

[xclr82xtc]

let me simplify the scenario......your sensors say you're running good, your plugs say you need more fuel. what do you do? what do you have more faith in? whats a more accurate source of information?

the dyno, and the ET slip is the most accurate source of information.

the scenario you described DOES make the sensors happy...but simply hooking up the temp probes to each headers on a dyno pull can tell you if your average is right...if you have 3 cylinders that are at 650-700 degrees, and one that is at 1100 degrees...well. you got a problem.. and again, thats why i say use ALLL your info. not just the a/f by itself.

if my dyno tells me i make the most power at 12.8 afr and x degrees timing, then im gonna do whatever it takes to keep it at 12.8... not 13.1 or 11.5 "because the plug said so"...ill put in a hotter/colder plug and then re-dyno several fueling maps to see if it still like the same afr until i find the plug/afr combo that makes the most power everywhere...there is ALWAYS more power to be found.


man we can argue for hours bout different ways to tune a bike! in the end, there is no "right" way, (several wrong ones though lol) what really matters is that you dont burn up parts and break stuff and that you win races...like i said, dont NOT look at your plugs...its a real quick and easy way to keep from breaking stuff, but dont rely on ONLY that.