I know reading a plug is not something you can just learn over night, but can anyone point me to a good source of information about plug reading for nitrous tuning?

Thanks,
Rick

 

yellowbullet.com

Alot more usable nitrous info there.

 

I went to yellowbullet.com and there are not very many threads on plug reading. I really don't want to have to register for that site just to ask what I am looking for on reading plugs. I know those guys most likely have a wealth of info. I'm just on here more and plan on on stepping up from the usual "150-175 plate shot type of guy" to a 300 total 2 stage setup in the near future here. I would like to know what I am looking for before I end up melting a piston or something.

Maybe Noyzee, ATVracer,or you could give us just some of the basics on what a good plug looks like after a nitrous run and what a plug looks like when there is something going wrong but you have caught it in time by pulling the plug. Everybody here that races most likely already knows a melt strap means something is DEFINITELY wrong!

Maybe this can be a sticky if its not already.

 

theres 2 good writeups ive seen here, i can get them for you later. but theyre in that "edelbrock intake + wet plate = boom" thread... 2nd page IIRC

 

Start off making a 300 foot pass and click the car off when you get started, and start looking at the ground strap. You should see a heat line at the tip and no more, as long as this is the case with every cyl, make a run to the 1/8th, then start cutting the threads off to see where the fuel ring is, you should see a heat line roudhly 1/2 way to the bend, that would be the timing mark.

Start with about 10 degrees of timing @ wot, that with good fuel will be a nice safe place to start, unless you're on an extreme compression ratio or something crazy. Fuel, don't mess around, C16 in both the main tank and standalone if you have 2 seperate fuel tanks, don't try mixing fuel, it's not worth it.

There should be a light pencil like line on the porcelan at about the point that it gets full diameter inside the threads, any more then that and it's still heavy on fuel. Depending on what kid of systems you are running, I can give you an idea where to start on the jeting/fuel psi. Get a flow ga. and flow the fuel systems thru a set jet size (most people use a decent size jet like a .079 or something around there, it's your ga so as long as you stay using the same one you are o.k, using the same as most other guys do will help compare tuneup's more)

Once you have the fuel ring and there's not too much heat in the plug amke a full 1/4 mile pass, unless you're only running 1/8th in that case it doesn't matter.

Start with NGK plugs, I'd start with a #10, that should be cold enough, you will probably be able to bump to a #9 when you're done, but the colder plug won't hurt you. Warm the car on a set of other plugs, then change them before running, this way you have a good clean set in the car to start reading off of.

Any specks on the plugs are bad news, any rounding of the edges on the ground strap are bad news, any signs of heat getting past the ground strap onto the base of the plug usually is too hot as well, at that point the tip will be burning off which is a no no, that means too much timing/too lean.

 

it may mean to much timing but not to lean. you will burn it up faster being rich than you will lean.

 

Yes, too much timing/too much fuel can also do this, but the usual that people do is put too much timing in first, then richen it up to try to get the plug right.

Start with the timing in the basement, and work on the fueling from there, do it that way, and you shouldn't hurt it, unless you're WAY out in left field with the fuel (I mean like 8 lbs of fuel on a square jet setup or something nutty like that that's way off)

 

Thanks guys, a lot of useful info here!!

Rick

 

thanks for the explanation!!! very short and sweet...

 

There are maybe 2 people on this site that have ever had a motor lean enough to hurt.
(Not counting failed parts)
So I would say rich is how most hurt parts. hurt my share rich thats for sure.

Oil in the chamber for those without a vaccum pump would be right up there also.

 

brings me to a good question what did you do for crankcase vacume? what options do you have for it without getting oil in the intake? i have a catch can but still gets oil in the intake...

 

i would like to know as well

 

Vaccum pump is the only answer.

 

Vaccum pump is one of the things that's definitely going on my car before it gets back together. Even at a lower power level, it's never going to hurt to have one on the car.

At this point:

Vaccum pump
moroso oil pan
melling oil pump

that should keep the oiling system happy (deeper sump in the pan and a good pump) and the vaccum pump should help keep the oil out of the cyl's

 

Thats what we ran all of 09'.

 

That worked pretty good yes?

Did you ever determine what/where something went wrong when it ate itself up some? Curious if the root cause was found.

 

Yes.

Not sure we will ever know.
We lost the belt to the vaccum pump on that run (weird it has never came off before)so we think it might have got some oil in the cyl's and tore some stuff up. We ran the whole season up to that point without pulling the heads off so it may have been hurt a little already.

 

could one of you guys post a little more info on a vacuum pump setup? ive heard of them but dont really know too much about them...

 

Vaccum pump will pull a vaccum on the crankcase, it drasticially cuts down on the oil in the air, and stops oil from getting sucked up past the rings.

ATV, I doubt that one run caused it to get hurt, chances are it was probably getting nipped a little for a while, then something finally pushed it over, maybe the vaccum, or lack thereof was it.

Shoot me a PM with the parts you used with your vaccum setup, I've looked at alot fo stuff but not sure what the best way to go about it is. I was thinking a moroso, but aerospace makes a nice setup, as well as several others.

 

Here are 2 pics from last year (2008) this was Q16 and 350 shot ...







See 1st pic the timing mark on the end of the strap and a light gray fuel ring at the bottom of the porcelin.