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AFAIK Mark doesn't stock WR6DC+'s, and Roger's on vacation, so you should hurry while there's still no sales tax. Can you afford $12.74 so you can stop worrying about whether your 100+ race day spark plugs should be changed? (Hint: they should.)
AFAIK Mark doesn't stock WR6DC+'s, and Roger's on vacation, so you should hurry while there's still no sales tax. Can you afford $12.74 so you can stop worrying about whether your 100+ race day spark plugs should be changed? (Hint: they should.)
Thanks! yes, I've always leaned toward if the plugs are spark'n, they dont need chang'n. Illl order a set up.... the main reason i like to change them, is i remember Don hanson losing an ground strap on a race weekend that toasted the motor cylinder. so i figure with all that heat, the metal can get weak and break.... so change-em every season. Ill order a set up........thanks!
edit: just ordered 2 day delivery! actually thats a good idea, as it will be a new plug, only run at the track to see what is really happening with the engine when i pull one or two at the track.
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The pic you submitted originally looks anything but healthy to me and I associate light colouration with overheating probably caused by a lean burn condition. If the photo you submitted and the plug looks nothing like that in reality it is all pie in the sky.
How are you determining actual AFR on that or any other specific cylinder? I asked about the injectors because my experience with these things over here is that Bosch units seem to foul much quicker than other injector makes and not uniformly. Injector cleanliness is often assumed rather than verified by testing. One presumes something prompted you to post this thread whatever it was.
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The pic you submitted originally looks anything but healthy to me and I associate light colouration with overheating probably caused by a lean burn condition. If the photo you submitted and the plug looks nothing like that in reality it is all pie in the sky.
How are you determining actual AFR on that or any other specific cylinder? I asked about the injectors because my experience with these things over here is that Bosch units seem to foul much quicker than other injector makes and not uniformly. Injector cleanliness is often assumed rather than verified by testing. One presumes something prompted you to post this thread whatever it was.
yes, the picture in the sun close up doesn't look like the plug in normal light. they all look very dark grey . in the light, and close up, they look different. as i showed above. yes, i was curious as to the build up of residue on the plug as it is an old plug, probably the longest ive ever had a plug set in the car. yes, you are right, overall AFR doesnt represent any individual cylinder mixtures . this is the lightest of all the plugs and i can compare to other pics back a few years ago to see if it looks different. however, as an expert told me, the only real way, is to take a new plug, run it like you race it, and pull it immediately to see the effects of mixture. the fact that the pistons all have the same level of carbon, and the plug all look black.grey, tells me the injectors are probably alll pretty even. the injectors are 30lb'ers (i think they are too much for the power im making, so the pressure is pulled way back). i would have preferred to use the 24 lbers, over the 19 lbers i used with 335rwhp and 70psi. i think the high pressure is good for better fuel atomization. 375rwhp could have been easiliy achieved with 24lbers.
the original holbert injectors i think were very old and all plugs always looked very clean and light tan as we all saw the engine was clean as a whistle. all pistons looked near identical.(19lb Bosch) i think these are ford injectors., but cant remember.
MK
When I changed the stock 19lb injectors in my pristine 88S4 to the newer design 19lb 4 hole injectors the first thing I noticed was how much smoother the engine ran!!! The 4 hole atomize the fuel better
The peak power seemed the same, but Sharky always ran strong and typically had compression tests around 200psi warm...also dynoed at 286whp with cat's....
Call five-O...I'm sure they can get you the 24lb 4 hole design....you'll prolly gain some HP once you set the AFR....
I would be worried about the #2 plug...keep in mind your wideband samples ALL or at best 4 cylinders.....if you have a weak old injector you could be leaning out only one cylinder and there is no way to know....its a risk-reward thing.....leave the old injectors and take the risk.....spend a few bucks and get the 30lb cleaned and flow balanced or go all new with the 24lb..... The 24lb injectors in Casper were pretty far off when tested and balanced....
Kibort did the final assembly and the tune. So.....in a sense he's talking to himself?
Oh.....I get it.....you're trying to take another snide jab at Twin Turbo Todd, I get it. One thing is for sure, if and when this motor lets go, Todd won't blame the driver or the fuel he used.
Todd does have major concerns about the tuning of this motor and such concerns have been expressed to Kibort many, many, many times. But, this engine was built so well, it just keeps going like the Energizer Bunny.
How many hours does this engine have on it again?
You're our moderator? Constantly taking pot shots at me because the wrong fuel was put in the car?
For the life of me, I can't figure out WTF this discussion has to do with you....what is your goal?
I've never taken a "snide jab" at Todd. I don't know anything about him, nor have I ever seen any of his work...how could I say anything?
I do suspect, despite your overwhelming FanBoi ravings about him, that he doesn't walk on water....and isn't the only person on earth that can build an engine.
I do know this..... he must be really fantastic if he can build race engines that are made and tuned to run on a minimum of 100 octane race fuel that get run on any form of 91 octane street ****, without any damage.
Really, really, really good!!
As a point of order, mister unbiased moderator, I'm guessing that if you suggested to Todd that he run his 900hp tune on 87 octane fuel, he'd laugh at you as hard as I do.
Mr. Anderson made a bigger change in octane than this in Joseph's race engine. When I built this engine for Joseph, he completely understood that this engine had more compression and had to be run race fuel....only!
No matter how good I am, I don't have the materials or pieces to survive what someone else does after I build the engine.
And BTW, your "God Todd" (as most people refer to him, after all your FanBoi rantings) can't do this, either.
why do you think there is an issue?..... if you look at the dark pictures above, all the plugs look like that. pretty normal in my experience. actually a little on the rich side if you notice all the carbon on the edges. Ill take a picture of the plug in question after a day at the track, or bedding the brakes this weekend. im sure it will look fine. keep in mind , these are two season old plugs, but the "stuff" on the ground strap and electrode insulation, is very soft and comes off like a powder almost. mixtures show 12:1. the motor is healthy and running in a safe tune i would say. the lighting of the close ups are making it look like its "white" but its not. the two pictures above showing the rich looking plug, that are grey and black, are the same plugs in the close ups.
If you already knew the answer, why did you ask the question in your first post?
The carbon on the edges isn't from fuel.....it's from oil making it down into the cylinder. The entire combustion chamber and top of the piston will look the same. Oil reduces the effective octane of the fuel, BTW.
Your "salvation" is the stock chips you run. Porsche made the WOT mixture very, very, very rich for one reason and only one reason....to control detonation. You "Sharktune" your engine and lean down the stupid rich mixture (for a race engine) in order to make more horsepower.....and it too will only run for one weekend.
Study up and understand WTF you are talking about!
Here's a place to start, without all the big words you won't understand. Get someone to read it to you.
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
Greg, i was talking about the ground area near the threads and usually , with a rich engine, that will always be dark and black. the usually oil, will cause a film on the electrod and ground strap and they are realtively clean, but with the appearance of additive diposits. yes, i was able to see the top of the pistons and they are carboned covered. im not burning much oil at all .. much less than most 928 engines i know of. so i dont think there is much oil in the combusion chamber, especially for the ratio of oil i use to fuell i use. (the acid test) 1 quart per 30 gallons of fuel is hardly something to consider
im asking because the plugs are very old and i havent looked at them for a long time. actualy, just checked my records.. its been over 3 seasons of racing, so there is layers of diposits and carbon. one thing an expert did tell me, is that you cant really see anything on the external portion of the plug, you need the light and magifying glass to look down the insulator to really know what is going on, OR, run the car very hard, turn off the engine and coast to a stop and pull the plugs.. lll do this when i do my WOT tests and brake bedding today.
here are all the plugs in normal sunlight. (even the #2 plug which was the first picture) New plug are in!!!!
Originally Posted by GregBBRD
If you already knew the answer, why did you ask the question in your first post?
The carbon on the edges isn't from fuel.....it's from oil making it down into the cylinder. The entire combustion chamber and top of the piston will look the same. Oil reduces the effective octane of the fuel, BTW.
Your "salvation" is the stock chips you run. Porsche made the WOT mixture very, very, very rich for one reason and only one reason....to control detonation. You "Sharktune" your engine and lean down the stupid rich mixture (for a race engine) in order to make more horsepower.....and it too will only run for one weekend.
Study up and understand WTF you are talking about!
Here's a place to start, without all the big words you won't understand. Get someone to read it to you.
If you are watching the nascar event at sonoma Sears point, a guy did a money shift and you can clearly hear the problem , frequency wise. post shift out of 1st is 7500rpm and peak rpm is 9000. the money shift happens and the RPM that he hit was 9600 rpm and it hurt the motor. clearly you can hear the frequency going from F0 to G#Ab and then the money shift is A0. almendinger did it. ugggg!
the point is, you can clearly hear RPM frequencies and if you know a value, you can easily figure out audibly, what the increase of RPM is. Anderson in no way was shifting over 6800rpm.
Your compression readings show that each bank of your cams are timed perfectly.
Thanks... i was really worried about the timing, especially, since the timing belt installation during the water pump i thought the cams moved during the alignment process. I marked them up pretty well, but you never know. glad to know that the even readings show something good! by the way, i pulled a plug out tonight after beating up the engine during brake bed in..... did a compression test, and the 195psi # 2 went up to 210psi when hot.
Here is what a brand new plug looks like for running about 45mins, and WOT for 30 mins. I was looking at my note... these original plugs in the pictures of this thread were over 5 years old. so, no wonder there was all sorts of layers of soot, and carbon.
Originally Posted by ptuomov
How much has the spark plug gap increased over the use?
I don't understand all the references to fuel octane and engine damage. Must be some inside baseball stuff that I'm not privy to.
the gap is almost exactly the same as the new plugs. 0.030"
Now, you want to see the same newer plugs after a fulll weekned of WOT racing? you tell me what you see.. the 5 year old plugs that are the first pictures dont show much..... here is the acid test. a few days of racing. all the plugs look the same. this is the same # plug that the first picture showed. #2 and #1.
with all the black around the edges of the plug, do you run any oil control system , like the ones the major vendors sell....????? if not pm me....I might be able to hook you up....
06-22-2018, 02:35 PM
