speedtigger

iTrader: (16)

So, I am speculating that if a certain amount of timing is the fastest, but the strap shows too much heat, then it is time to go colder on the plug. Or, conversely, if the car runs it's fastest at a certain timing and there is no heat showing on the plug, you might go to a colder plug?

10secZ28

iTrader: (6)

this is where you can get in trouble, there is no set place the mark should be, if the heat is on the tip on a #9 plug, throwing a #8 in there might move it to the middle of the strap but if you chase that mark your going to hurt something. You can try running a colder plug and leave everything the same, if you pull a degree and she slows down put that degree back in and then try to go the other way until the car slows, at that point is when the motor is happy. Maybe I misunderstood your question.

speedtigger

iTrader: (16)

No, I think you get where I was coming from. I am merely trying to define some guidelines of when experienced nitrous racers would say: "It is time to go colder on the plug". Since timing can also affect the heat we see on the plug, I was speculating that one might just tweak the timing until it runs the fastest, and if the plug looks too "hot" at the fastest timing that would mean time to try a colder plug. That sound right to you?

ShiznityZ28

iTrader: (11)

Upping the jet is a good idea. funny i almost posted it looked like a 11.5-12.0 plug. get it closer to 12.5 and then work on timing etc.

10secZ28

iTrader: (6)

It depends...........on the combo. While it will work, most any combo only spraying a .028 jet, should not need a -11 plug.

People forget what a sparkplug does. It's ONLY function, is to light the fire, thats it. There is no performance gain or loss, in the basic function of a plug. While you can hurt the performance, with too cold a plug in a N/A combo, that is rarely the case in a nitrous motor. A "hot" or "cold" plug, only refers to the insulation around the electrode and how much heat the electrode retains between firing cycles. The "hotter" the plug, the earlier it lights the charge, because of the heat, retained in the electrode. Using this information, you could deduece, that about ANY heat range plug can be used, as long as you manipulate the timing correctly and you would be correct in that assumption.........but.........a "hot" plug can get you into trouble very quickly, because it retains so much heat between cycles. This gets you into a pre-ignition territory, that can play havoc on your tune up. You are much better off with a cold plug. This allows you to control the start of the burn, more or less with the timing only and not have to take the heat in the plug, into account.

I personally like to run as cold of a plug as the engine will tolerate and keep clean, while idling and doing a burnout.


But the cylinder temp DOES change with the colder plug and same timing, because of two reasons.............One, there is 140* tip temp change in the plug and two, the colder plug, ignites the charge later, hence the temp is less.

The plugs don't lie. Regardless of heat range, if the plug looks hot, it is.......if it looks cold, it is. One place where people get confused, is thinking the cold plug, makes their tune rich. While there is a small change, in the look of the fuel ring, from one heat range to the next, on a PROPER tune, the change is not drastic. Lets say, the entire porcelain was stone white on a -10 plug and you put a -11 in there. You MIGHT, I repeat MIGHT, see a little color on the plug, but it would not be much. The point here, is if you take a -11 out and it is black, and somebody tells you the plug is too cold and a -10 will clean that right up...........ain't gonna happen. Nine times out of ten, a plug with black porcelain is rich and a heat range change on the plug, is not going to fix that




Here are two great posts monte smith posted see if that clarifys it for you.

speedtigger

iTrader: (16)

That post was great. I love reading Monte's stuff. The above quote is the way I have always looked at N/A plugs. As cold as you can run and still keep the plugs clean.

speedtigger

iTrader: (16)

Great minds think alike. Looking at your signature, I can see you have the "big boy" experience to back it up.

M1SERY

new to nitrous the plug read post are great stuff, i need more information on reading plug dont really know what im looking at, i know if they are peppered to back it down, what i wanting to learn is fuel ring and ground strap heat ,like to see pic. so i dont have to learn this the hard way . seen one site a guy refered to the other night,was not alot there, if any one has any thing else i would appreciate it greatly

speedtigger

iTrader: (16)

I read a lot of great stuff on plug reading and viewed many pics on YellowBullet.com. WARNING: Those guys can be rough over there.

10secZ28

iTrader: (6)

follow Monte Smith on YB, that man is a wizard with Nitrous