Someone help me read my plugs?

greasemonkee · Post by **greasemonkee** » Thu Jun 19, 2008 12:17 am

You gentlemen seem to take the position that running a hotter plug is a bad idea even if there is no sign of detonation. May I ask why? Do you feel the same way in NA applications?

sewell94 · Post by **sewell94** » Thu Jun 19, 2008 2:45 am

greasy

, if put in an enviroment where the ignition is advanced past mbt typically a hotter plug is more prone to preignition which can induce denotation. it can't expell the heat fast enough, and stays hot, hot enough to ignite the mixture in the combustion chamber. i always error on the colder side on plugs. Confused, The spark plug is always right, it may be \"read\" incorrectly though, normally the wb and the plug will \"agree\" on whats going on, but in doubt always trust the plug. I have a few q's for you. have you sync'd your ignition timing?? one or 2 of the plugs look like they have any oily substance on them, is that the pics or is it just me?? reading the plugs from some pics is hard, plus its kinda an art, different people can look at it and see different things. My gut feeling is that the timing is too conserative and on the lean side from those plugs, so what do you do??? add some fuel and pull some timing then look at them ,then if they don't look better, start slowly adding timing back in. It looks like your burning alittle bit of oil, which will really throw the plug reading off. Another trick you can do w/o a dyno is doing the same pull over and over, data log them and look at the amount of time it took to go from from say 40mph-100 mph and if the amount of time goes down(if your not spinning the tires) will tell you that you are making more power, which means your going in the correct direction.

greasemonkee · Post by **greasemonkee** » Thu Jun 19, 2008 8:27 am

Even though I have never dealt with this particular engine, I propose that achieving clean mbt under any significant boost is not likely to happen, assuming he is running pump fuel. Preignition in a honda = dead. While precautions should be taken to avoid it, the likelihood of him actually encountering real preignition is slim.

confUsed · Post by **confUsed** » Thu Jun 19, 2008 5:37 pm

So today I took out the plugs and cleaned them like Burgermass said. Here's the pictures, from #1 and #3:

I really cant see any color on the treads, so I dont know if you get anything out of these...? Only color I still can see after cleaning them is where the ground strap is welded to the plug. On picture 2 and 5 there's a black spot on the porcelain though. Is that how detonation looks like? Sewell94: Yes, I did the timing sync when I made the basemap, so I'm pretty sure its correct. The wet stuff on some of the pictures looks and smells more like fuel to me. In cyl#1 I'm not sure though. Something looks a bit fishy in there, with soot and some stuff on the ground strap. I havent noticed any oil consumption or smoke (except when I hit the rev limit with ignition cut) either, and I did a compression test last month with good results. SOmething might have happened last trackday, though, so I'll make sure to do a compression test. So I'm a bit confused, whats the next step now? Add fuel? Pull timing? Colder plugs (can I just buy one colder plug and see if I get the color I want, or do I have to buy all four)? Or all three at once? I also wonder what will happen if I use too cold plugs? I understand that running with too hot plugs can cause detonation or possibly pre-ignition, but what about too cold plugs? Blowout? And can it hurt the engine running with too cold plugs?

Post by **Bugermass** » Thu Jun 19, 2008 7:40 pm

Those plugs don't look like they are getting hot at all to me, but its hard to tell from pics. That spec on the insulator looks kinda fishy, I can't tell if its metallic from the images though. but even though theres no sign of heat in the plug they do look very lean to me.. I wish I could help more but its so hard to tell from the pics..

Post by **Bugermass** » Thu Jun 19, 2008 7:47 pm

what gear pull are you doing? try putting them back in and doing a bunch of hard pulls back to back to really get things hot and pull and clean 2 and leave 2 dirty and lets see if we can better tell..

confUsed · Post by **confUsed** » Thu Jun 19, 2008 11:54 pm

I understand its difficult to read those plugs from a picture, but I think its awesome to finally talk to some tuners thats willing to share some information, and not just tell me to go to a tuner and pay him doing it, not learning anything. Now at least I have a little clue what to aim for, so its helping me alot

I'm doing the pulls in 2nd, but I'm using the brakes a lot so it lasts about as long as a pull in 4th would have done. I have to drive almost half an hour to get to a road where 4th gear pulls is possible, and I'd still be in jail for doing 100 mph+ :p So I'll try add fuel and pull timing and doings some pulls on the same plugs, to see if I can get any color to it. Just have to find time to do it.

Maddog20 · Post by **Maddog20** » Fri Jun 20, 2008 5:23 pm

do you have a dragstrip near by? Test n' Tune there

xenocron · Post by **xenocron** » Fri Jun 20, 2008 7:23 pm

sewell94 wrote:greasy , if put in an enviroment where the ignition is advanced past mbt typically a hotter plug is more prone to preignition which can induce denotation. it can't expell the heat fast enough, and stays hot, hot enough to ignite the mixture in the combustion chamber. i always error on the colder side on plugs.

You have it a little backwards, detonation will induce pre-ignition...not the other way as far as I know.

greasemonkee wrote:Preignition in a honda = dead. While precautions should be taken to avoid it, the likelihood of him actually encountering real preignition is slim.

I agree, pre-ignition is pretty hard to come by on the plug in a Honda and you know it when a complete hole forms in your pistons, and while I used err on the "colder" side as well, I have been running 6's in my car lately, running 87 octane and boosting 12-14 using the boost by gear and they read very nice

sewell94 · Post by **sewell94** » Sat Jun 21, 2008 4:58 am

Ok i looked a little deeper into detonation vs preignition. Most of stuff online says detonation induced preignition, BUT a friend who tunes the some of the fastest stuff in the world says it goes the other way, its the chicken and the egg theory in my book. We do agree both are bad though

sewell94 · Post by **sewell94** » Sat Jun 21, 2008 5:17 am

greasemonkee wrote:Even though I have never dealt with this particular engine, I propose that achieving clean mbt under any significant boost is not likely to happen, assuming he is running pump fuel. Preignition in a honda = dead. While precautions should be taken to avoid it, the likelihood of him actually encountering real preignition is slim.

You asked why i tend to err on the colder side of the plug, thats why, Do i think he is going to get pre ignition? no. Plus I always like to read the plugs when they are a little colder, they tend to be easier to read.

Post by **Bugermass** » Sat Jun 21, 2008 11:27 am

Detonation and pre ignition are 2 seperate things completely, although preignition is always followed by detonation.. Pre ignition can happen on a engine thats totally happy with timming, all it takes is a carbon ember on the top of the piston thats hot enough to ignite the fuel too learly.. Granted this rarely happens, but I have HAD it happen on high compression N/A setups before, I had a B20 VTEC with 12.5:1 pistosn that was on 93, and no matter how much timing I took out it was pinging like crazy down low.. We pulled the head, found some rough surfaces on the piston faces that the engine builder didn't smooth out, also cleaned all the carbon of the combustion chambers and the piston crowns.. we slapped the head back and and wallahh no more problems.. put all the timming back in it plus some , and it ran like a champ.. luckily it was a build motor with sleeves and I only did light part throtttle testing, other wise that small amount of driving with pre ignition would have toasted the motor, all it did was destroy a set of spark plugs. But anyways, detonation is a completely different beast. Detonation happens on ALL engines, in varying levels.. Your avg facory engine will experience very light detonation during most AVG driving.. Its the heavy detonation that kills the motors. I did some reaserch on the subject a while back.. They were using kistler spark plugs, which have pressure transducers built into them.. They were doing testing on some airplane engines and logging all the combustion data. Basically in a nut shell, under load there is almost always a small amount of detonation \"low level\" this kind of detonation is not detectable on the spark plugs and happends WAY before MBT.. As the timming is increase of backpressure is increased or fuel is leaned out or air temperature rises etc etc etc, this low level det increases and eventuyally become damaging to the engine. The expination is a bit more detailed but I'm short for time.. Anyways my point and actually testing have shown that using a colder spark plug will remove more heat from the combustion chamber reducing this low level detonation to an even lower state, the side affect of this is a more stable combution and that nets higher HP.. Not to mention the fact that you have just built in that much more cushion to your detonation equation.. Chris H. try this.. put your car on the dyno again when you get a chance.. put a fresh set of the 6 you use in there.. Do 3 pulls with as close to identical conditions as you can.. Then throw a set of 4554s in there, same plug gap.. Do 3 pulls again with identical ECTs and what not and see how mcuh more HP you can pickup.. I can almost garuntee you'll make a few more HP with the colder plugs. The affect my not be AS noticable since your usig water meth injection, since that does an amazing job at cooling the chamber as it is.. But try it when you get a chance. Or mabey on another car that doesn't have WM injection..

confUsed · Post by **confUsed** » Sat Jun 21, 2008 11:30 am

So today I got a little time to play with my car again

I added a bunch of fuel, and thought I pulled some degrees timing, but my computer decided to crash, and I probably didnt save the changes, cause now that I am home I see that my ignitin map is still the same :p I actually noticed that a crispy sound I had earlier in my detcans now was gone. Dont know if it was slight detonation before, but its gone now, so I guess its good. I changed plug #3 so I could get some decent readings, and did a few pulls, then stopped @7000rpm. My wideband now reads between 9 and 10 AFR (difficult to get it stable, cause I couldnt get ectune to read that low atm, so I just kept an eye on logworks). Here's todays pics of cyl #3:

I finally got some color to the porcelain, but mostly on one side, though. Dont know if that just means it'll take some more pulls to get it even all around? And the blue line on the ground strap was really easy to see now (if I'm looking at the right thing), how does that look to you? One thing that I noticed was that around 4500-5000 rpm I got a real powerboost, the turbo spools @ 3000 rpm, but once I reached 4500-5000 it felt much stronger. That was weird. And I'll have to go to a real road to get a feel on how it really pulls, anf maybe play a little with vtec point. It seems like my WB is totally off, though, so I guess its time to buy a new sensor (I have tried calibrated it several times). Havent heard of any turbo honda that needs to run 9'ish afr before...?

confUsed · Post by **confUsed** » Sun Jun 22, 2008 12:07 pm

I tried to take a few pictures thats easier to read for you guys today. Found a thread in a forum where they hacked up their plugs after a run to see the color on the porcelain, so I did it on one of my old plugs that looked really lean for me and got pretty surprised when I found a nice coat of black soot. So I tuned my AFR to 10.5 in boost, and pulled out another 3 degrees. My car was actually bogging at low rpm at that point, and pulling like crap, so I just put the timing back in there. Im pulling 1.2 degrees per psi now, leaving me at 14.5 degrees at 11psi and redline. Heres the plug before cleaning:

And after cleaning (and hacking):

It looks to me like the blue line at the ground strap is right in the middle of the curve. Thats pretty conservative and should be safe, right? Here's the rest of the plug:

There's apparently more color to the porcelain than what I thought before, so I guess I just suck at taking pictures. I guess it has probably been more or less like this all the time. These pictures was taken after 3 3rd gear pulls in a row, wot and some braking, to get maximum load on the engine. Now it leaves me with a few questions for you: Why is the fuel ring not connected all around? Why is it sitting there, and not on the bottom of the porcelain, like in the pictures in every \"how to read spark plugs\" on the web? There's no sign of black \"pepper\" on the porcelain, so it doesnt look too bad, does it?

Post by **Synoptic** » Sun Jun 22, 2008 2:48 pm

On the very first pics, I could see aluminiums specs on the procelaine and some white spots ont the rim. At that point, I think you were a little bit too lean . This lean condition (hotter burn), mixed with the current timing map you had, could have lead to some preignition (alu specs). Adding more fuel could have lowered the temperature enough to keep the same timing map maybe, no one can tell. I think your are running too rich right now looking at the last picture. No pre-ignition though, which is good. The black coloring is not all around the procelaine because it's the way the flame contours the procelaine and leaves it's black trace only on the side it directly touch. This tells you how the plug is placed relatively to the exhaust valves. Black rim and white tip is normal for turbo car running a bit on the rich side. The carbon will stick to the rim because the rim is colder than the tip. The tips will be a little whitish because of the carbon that deposit on it (because it's runnign rich enough to cool the plug and sick a little bit on it's tip) and get's burned at very high temperature. When pple say white plug = too lean, they are not always right. A lean condition shown by a white plug is valid only when the plug is USED and was COLORED BEFORE. The carbon on it will turn white be cause of the heat generated by a lean combution. NEW plugs will never turn white as the carbon will not deposit before getting burned because there's not enough fuel. The spark plug however will show signs of over-heating and maybe sign of preignition/detonation. running lean, in itself is not a bad thing, it's the heat created by the lean burn that is bad. If you can remove the heat, you can run leaner and make more power. Running rich serves only to cooldown the combustion. If your wideband is right, ake some pulls around 11.5 - 11.8:1 wthout touching the timing and check the plugs back. Post pics and then we'll see.