TeamSwift

Home of the Suzuki mini-compacts ! Your Home for all things Suzuki Swift, Geo Metro, Holden Barina, Chevy Sprint, Pontiac Firefly, and Suzuki Cultus. TeamSwift is a technical performance oriented community!
It is currently Sat Nov 18, 2017 10:11 am

Underbody braces, turbos and more!

All times are UTC - 5 hours




Post new topic Reply to topic  [ 18 posts ] 
Author Message
 Post subject: plug reading
PostPosted: Thu Jun 14, 2007 2:05 am 
Offline
King of Pompous
User avatar

Joined: Sat Aug 25, 2001 4:22 pm
Posts: 5596
Location: Ottawa ONT.
So who wants to take a stab as to what is happening to this plug...of less than 100km driving and some "light" nitrous use :P. Plug is an NGK BP7 heat range.


Image

_________________
LNLC Founding Member

FAKE FRIENDS: Never ask for food.
REAL FRIENDS: Is the reason you have no food.


Top
 Profile  
 
 Post subject:
PostPosted: Thu Jun 14, 2007 7:53 am 
Offline
User avatar

Joined: Mon May 27, 2002 11:47 pm
Posts: 1974
Location: San Juan, Argentina
Well, If your cammera has a good white balance setting and all that stuff, and you were using pump gas, then...


1-central insulator is white. You're short of fuel during WOT condition. Surrounding areas show some detonation.

2-ground electrode shows color transition right in the middle of it. However, the transition is inverted from what should be considered normal. Timing condition is hard to tell, I would guess your timing was too advanced. First, solve the AFR issue

3-base colour is ok. Idle AFR seems ok

_________________
Megasquirt tutorial --- http://caaarlo.50megs.com


Last edited by Caaarlo on Thu Jun 14, 2007 8:46 am, edited 1 time in total.

Top
 Profile  
 
 Post subject:
PostPosted: Thu Jun 14, 2007 8:46 am 
Offline
User avatar

Joined: Thu Feb 14, 2002 3:00 pm
Posts: 914
Location: Atlanta, GA. USA
Fuel looks off. Plus heat range needs to go lower on the plug. Timing may a be a little high. Hard to tell with that many miles. You need to run short runs and pull the plugs and check them. Like 1/8 or 1/4 mile then check.


Top
 Profile  
 
 Post subject:
PostPosted: Thu Jun 14, 2007 2:03 pm 
Offline
King of Pompous
User avatar

Joined: Sat Aug 25, 2001 4:22 pm
Posts: 5596
Location: Ottawa ONT.
Fuel pressure and timing (ignition and cam) check out 100%. I have a 1 wire AF gauge (yes I realize they aren't a wideband) that shows well into the rich range on and off the bottle. There is an after market ignition which could be accounting for the ceramic being so white..or not. That plug was pulled after a 2nd to 4th gear pull.

Here's a pic of one of the plugs that came out of the car before the nitrous install. The timing was advanced a little too much (from what you can see on the ground strap) and the ceramic is still very white. You can't see any peppering but the electrode shows some rounding. That plug had maybe 400km on it and was a 6 heat range as opposed to the 7 heat range of the above plug. It was also gapped to factory spec. Mods to the engine are 50mmTB, headder, 2" exhaust, and high output ignition system. Compression checks out OK in all cylinders (as well as leakdown). How would you go about richening the mixture on the DOHC? Do I need to get an FPR or is somebody going to suggest crushing the return line :rock:...

Image

_________________
LNLC Founding Member

FAKE FRIENDS: Never ask for food.
REAL FRIENDS: Is the reason you have no food.


Top
 Profile  
 
 Post subject:
PostPosted: Thu Jun 14, 2007 4:23 pm 
Offline
User avatar

Joined: Thu Feb 14, 2002 3:00 pm
Posts: 914
Location: Atlanta, GA. USA
You need a piggy back ecu or super afc or stand alone. One wire AFM do not get good readings and are slow to change. It is hard to tell anything with a plug with that many miles also. Put fresh plugs with one heat range cooler with the gap opened about 10 thousands more. Run them for an 1/8 mile to a 1/4 mile. Shut down instantly. Pull the plugs and email or post the pic of the plugs.


Top
 Profile  
 
 Post subject:
PostPosted: Thu Jun 14, 2007 5:01 pm 
Offline
User avatar

Joined: Mon May 27, 2002 11:47 pm
Posts: 1974
Location: San Juan, Argentina
I don't know how you're controlling fuel delivery on nitrous, is it a dry or wet system ? You can always control the extra fuel delivery, right ? If it's a wet system, then put larger fuel jets. If it's a dry system, it blocks the return line, so, you can either lower the nitrous, or increase fuel pressure.

Regarding the O2 sensor reading, keep it within 0,89 and 0,91 volts WOT, or get a wideband and adjust for 12:1 for security.

Once your plugs get some color, then you can tell whether the ignition is advanced or not.

Running a new plug for a couple of kilometers, won't give a good indication, because, during the first cycles of operation, the cadmium plating (silver/golden) on the ground strap burns white, so, you will see it white during the first minutes of engine operation, no matter what timing are you running. So, give it some time to burn and start getting combustion deposits.... I think the first pic clearly shows a white strap, and it could be the cadmium plating remais

_________________
Megasquirt tutorial --- http://caaarlo.50megs.com


Top
 Profile  
 
 Post subject:
PostPosted: Thu Jun 14, 2007 9:31 pm 
Offline
User avatar

Joined: Tue Oct 24, 2006 3:09 pm
Posts: 4998
Location: Palm Springs: Too hot from June to Oct.!
Looking at the flat ring surface where the 'ground electrode' is welded shows a rich mixture. It is black, and even chips off. So I agree with your one wire A/F gauge.

If you shut it down after a hard run, that would explain the rich looking ring.

What type of driving is this engine used for?

What is your estimation of the overall condition of the rings?


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 15, 2007 12:27 am 
Offline
King of Pompous
User avatar

Joined: Sat Aug 25, 2001 4:22 pm
Posts: 5596
Location: Ottawa ONT.
92GT wrote:
You need a piggy back ecu or super afc or stand alone.


No offense but where in the world did you get that info? You don't need any of that to run a nitrous system on a car.

92GT wrote:
One wire AFM do not get good readings and are slow to change.


I do realize that...but at the moment its better than nothing ;).

92GT wrote:
It is hard to tell anything with a plug with that many miles also. Put fresh plugs with one heat range cooler with the gap opened about 10 thousands more. Run them for an 1/8 mile to a 1/4 mile. Shut down instantly. Pull the plugs and email or post the pic of the plugs.


Your looking at the pics. The first plug was ran all the way through 3rd and 4th...shut down immediatly and coasted to a stop. Took the plugs out and put my old set in to drive the car home. As for the other plug pic...well...the car is lucky to see 400km a year so getting something with more miles ain't gonna happen any time soon.

Caaarlo wrote:
I don't know how you're controlling fuel delivery on nitrous, is it a dry or wet system ? You can always control the extra fuel delivery, right ? If it's a wet system, then put larger fuel jets. If it's a dry system, it blocks the return line, so, you can either lower the nitrous, or increase fuel pressure.


Sorry...thought I mentioned it. Its a wet system. I could jet for more fuel...but with nitrous adding more fuel to it sometimes compounds the problem...more fuel to burn with the n2o makes things even hotter if more n20 isn't added..I do plan on getting a jetting kit regardless and may have to fine tune more though. The car will see a dyno soon and have the wide band wired up to it to make sure all is OK.


Caaarlo wrote:
Running a new plug for a couple of kilometers, won't give a good indication, because, during the first cycles of operation, the cadmium plating (silver/golden) on the ground strap burns white, so, you will see it white during the first minutes of engine operation, no matter what timing are you running. So, give it some time to burn and start getting combustion deposits.... I think the first pic clearly shows a white strap, and it could be the cadmium plating remais


Yes I know about the plug going white from the Cadmium...I'm not terribly concerned with the way the engine runs during normal driving. Timing was perfect when checked today as well as cam timing. Fuel pressure was tested and also excellent. I just can't run the nitrous a dozen times trying to get some colour into them to get a reading.

Phil N Ed wrote:
What is your estimation of the overall condition of the rings?


Compression is excellent across the cylinders and leakdown is excellent as well so I'm guesstimating the rings to be in good shape. Engine, unfortunately, isn't driven enough. I get the car out once every couple of weeks and it maybe sees 20km on those trips. It is mostly highway driving though. The car/engine is being built to be fun. I may take it to the strip to see what it has..it will definetly see a track on occasion but its mostly a weekend car.

_________________
LNLC Founding Member

FAKE FRIENDS: Never ask for food.
REAL FRIENDS: Is the reason you have no food.


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 15, 2007 12:40 am 
Offline
User avatar

Joined: Mon May 27, 2002 11:47 pm
Posts: 1974
Location: San Juan, Argentina
m, I understand that you checked cam timing and spark timing, and it was fine. I don't know what you call fine. Remember that you should retard spark timing in order to avoid detonation with either nitrous or turbo. Higher HP = Higher Chamber pressure = faster burn rate = no need to advance spark as much as NA, actually you must have this in mind, to keep detonation away. Don't run stock timing.

Regarding fuel jetting... where did you read that ??? Enriching the mixture even more, will lead to lower temperatures (considering you're on the rich side), and will certainly help colouring your spark plugs. You need more fuel... or less nitrous.

_________________
Megasquirt tutorial --- http://caaarlo.50megs.com


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 15, 2007 1:11 am 
Online
Moderator
Moderator
User avatar

Joined: Sun Feb 23, 2003 4:16 am
Posts: 8042
Location: Ontario, Canada
From my experiences, I would suggest that if you're running pump gas, don't waste your time trying to read the plugs.
It doesn't work.
All the plug reading info you are using is based entirely on old school leaded fuels, with no alcohol.
These days, plug reading is no longer a valid means of checking for A/F ratio, as long as you are using pump gas.
You can use it to look for detonation, though.
What is your nitrous setup, and where did you get the current jetting info from?
Most of the factory recomended jetting is way rich.

_________________
Contact 3tech: g10pro@rocketmail.com


Last edited by suprf1y on Fri Jun 15, 2007 1:13 am, edited 1 time in total.

Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 15, 2007 1:12 am 
Offline
King of Pompous
User avatar

Joined: Sat Aug 25, 2001 4:22 pm
Posts: 5596
Location: Ottawa ONT.
Caaarlo wrote:
m, I understand that you checked cam timing and spark timing, and it was fine. I don't know what you call fine. Remember that you should retard spark timing in order to avoid detonation with either nitrous or turbo.

Regarding fuel jetting... where did you read that ??? Enriching the mixture even more, will lead to lower temperatures (considering you're on the rich side), and will certainly help colouring your spark plugs. You need more fuel... or less nitrous.


What I mean when I say that the timing is fine is that its retarded 2 degrees. With a small shot like that I shouldn't even need to retard it that much but I prefer to be on the safe side. The jetting with less fuel assumes that everything is running peachy to begin with. n2o makes power by how much fuel is in the engine...not the amount of n2o. Naturaly too little fuel leans out and detonates...but too much and you have a hotter burn with the n2o flowing. Much too much and yes..you run terribly rich and get a cooling effect. Its not always the case which is why I added the "sometimes" to the statement. I understand what your saying though. Hopefully I will get the wideband in the car in a few weeks and get much more precise numbers. I have a new set of plugs (its getting expensive changing them between runs :P) and will hopefully get the car out early next week to try and fine tune it a bit more.

_________________
LNLC Founding Member

FAKE FRIENDS: Never ask for food.
REAL FRIENDS: Is the reason you have no food.


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 15, 2007 1:15 am 
Offline
User avatar

Joined: Tue Oct 24, 2006 3:09 pm
Posts: 4998
Location: Palm Springs: Too hot from June to Oct.!
Not being an expert, would humbly submit plug looks pretty darn good for what you just put it through.

Since it is for fun, would suggest a little more air in the mixture, perhaps force it in a little more? Just a thought.


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 15, 2007 1:27 am 
Offline
King of Pompous
User avatar

Joined: Sat Aug 25, 2001 4:22 pm
Posts: 5596
Location: Ottawa ONT.
Only way I'm gonna be able to force more air in there is with a turbo ;).

Suprf1y:

Nitrous jet size info is from manufacturer and various jetting calculators. The calculators also take bottle pressure and fuel pressure into account...so I try to use them more...interestingly they jet me a touch richer than Zex does :blackeye:

Setup is a simple wet system..haven't put the electronics on it yet. Single nozzle 6" from TB. Pretty much it.

_________________
LNLC Founding Member

FAKE FRIENDS: Never ask for food.
REAL FRIENDS: Is the reason you have no food.


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 15, 2007 8:17 am 
Online
Moderator
Moderator
User avatar

Joined: Sun Feb 23, 2003 4:16 am
Posts: 8042
Location: Ontario, Canada
You are probably way rich on the jetting, then.
How big a nitrous shot are you using, anyway?
Like I said, don't even try reading plugs.
If you get them looking like you think they are supposed to, you will be so rich its not funny.
Your nitrous jetting could also be so grossly rich that its actually washing the plugs, making them look like you're super lean(not like you can tell rich/lean anymore, anyway).
Are you using Sunoco 94?

_________________
Contact 3tech: g10pro@rocketmail.com


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 15, 2007 8:21 am 
Offline
User avatar

Joined: Mon May 27, 2002 11:47 pm
Posts: 1974
Location: San Juan, Argentina
m wrote:
Naturaly too little fuel leans out and detonates...but too much and you have a hotter burn with the n2o flowing. Much too much and yes..you run terribly rich and get a cooling effect.


Well, I think this is where most people gets confused. Peak combustion temperatures happens at the stoichiometric AFR or 14.7..... Add fuel, and you get:

1-more power
2-less temperature

Temperature decreases as you move to either side of the AFR scale, the peak point is stoich.

So, adding more fuel, won't increase temperature, but exactly the opposite.

An ideal, powerful AFR of, ~12.5 has a cooler combustion than stoich, so... if you are running ~14... adding fuel won't increase temps, it will cool things down, produce more power, and save your engine from damage.

_________________
Megasquirt tutorial --- http://caaarlo.50megs.com


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 15, 2007 8:57 am 
Offline
User avatar

Joined: Thu Feb 14, 2002 3:00 pm
Posts: 914
Location: Atlanta, GA. USA
I was refering to a piggy back etc. For a proper tune on normal operation. If that is off. The rest of the readings will be off.
Yes, you can adjust fuel buy jetting on NO2 or leaning out more. This is usually done for applications were the amount of no2 input is very great. Or for those adjusting for temp, weather and altitude changes. Yes, you back timing down 2 to 4 degrees for every 100hp shot of Nos as a general rule. Talk to a nitrous system company. If you doubt me.
The closer to the max timing over all for the octane. The more you need to retard the timing.
Even the unleaded fuels you can still see changes in the plugs. Even new ones. The closer to the the edge you run the motor the more you need to watch any readings you can get. You will even see changes in a 1/4 mile run. You see more generally on setups that are running at peak for conditions.


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 15, 2007 11:07 am 
Online
Moderator
Moderator
User avatar

Joined: Sun Feb 23, 2003 4:16 am
Posts: 8042
Location: Ontario, Canada
Quote:
Even the unleaded fuels you can still see changes in the plugs. Even new ones. The closer to the the edge you run the motor the more you need to watch any readings you can get.

Yes, but they are meaningless.
If you are running 'close to the edge', and trying to use plug readings, you're wasting your time.

_________________
Contact 3tech: g10pro@rocketmail.com


Top
 Profile  
 
 Post subject:
PostPosted: Sun Jun 17, 2007 2:31 am 
Offline
User avatar

Joined: Tue Oct 24, 2006 3:09 pm
Posts: 4998
Location: Palm Springs: Too hot from June to Oct.!
Will have to agree with above. Plug reading is of more interest in a long hauler, rather than a quick race-type situation. If you are pouring the fuel to it, and 'having fun', then shut it right down, you should end up with a rich looking plug.

If you drive it at highway speeds, steady, for at least 30 minutes, and fairly light on the accelerator, let it idle a few seconds before you shut it down, and all other things being in good working order, you would probably have a more valid 'plug reading'. It can validate your compression tests.

You can change the heat range of your plugs, and that may change your performance; perhaps trial and error would be your best friend in that regard as no one knows your engine as well as you.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 18 posts ] 

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 6 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group