Brett928S2

Hi

Sorry but you are wrong....resistor plugs are for suppression ONLY... to save me typing why... this is a direct quote from NGK....

Quote" Q: When should I use a resistor spark plug?

A: NGK "R" or resistor spark plugs use a 5k ohm ceramic resistor in the spark plug to suppress ignition noise generated during sparking.

NGK strongly recommends using resistor spark plugs in any vehicle that uses on-board computer systems to monitor or control engine performance. This is because resistor spark plugs reduce electromagnetic interference with on-board electronics.

They are also recommended on any vehicle that has other on-board electronic systems such as engine-management computers, two-way radios, GPS systems, depth finders or whenever recommended by the manufacturer.
"Unquote

They have NO EFFECT whatsoever on spark plug strength....

All the best Brett

jbrob007

O.K... Ken... your turn

I dont know squat about hot/cold plugs, resister/non-resister, etc, etc, etc... Please enlighten us... or me anyway... as to why these particular NGK plugs are or arent the way to go. I love this crap!

Joel

PorKen

Try swapping in some Bosch plugs with the smaller gap.

I spent days testing both, with different gaps. I was surprised the difference the NGKs made. (I'm using NGKs only because you can't get non-resistor Bosch any longer.)

There are resistors in the plug wire ends and distributor rotors, so there isn't any observable radio or ECU interference. (I did find a problem with using cheaper aftermarket Hüco ignition amps, which are not well shielded versus Bosch.)

There is more voltage available at the anode without the resistor. In order to take advantage of this, you have to increase the gap. Increasing the gap size exposes more of the mixture to the spark kernel.


Side note: plugs with a tiny (platinum/iridium) tip also require a larger gap, as they require less voltage to fire.

Brett928S2

Hi All

Ok I am going to leave this thread now as nobody is listening....

Someone PLEASE ring NGK tech support who will tell you the same as I am...(they are very helpful)

For anyone reading this with starting problems/including flooding or uneven tickover, use either standard NGK BP6ES OR BPR6ES, or BP7ES OR BPR7ES (SET AT 25 THOU)

Do NOT use BP8ES !

All the best Brett

dcrasta

I use 8s on my turbo cars. I would think too cold for a NA car driven in the winter.
If you do use 8s and you get flooding problems from short trips or hard starts in cold weather, switch down to 7s.

jbrob007

Brett, No need to "go"... I"m listening to both of you VERY intently since it effects my car (specifically). Also, I still have one question that hasnt been answered... What is "tickover"??? I'm unfamiliar with this terminology

Thanks for the discussion guys - its very interesting... well, for me anyway!

Joel

Brett928S2

Hi Joel

I am still reading this thread as its one of the few things I know A LOT about , at my age lol

"TICKOVER" is an English term for what I "think" you call IDLE ?

In other words, when you start the engine and it slows to the lowest revs that it will sit at comfortably and smoothly ...thats "tickover"

Roughly 750 to 800 when warmed up....

If you have the wrong plugs in..as an example BP8ES ..your smooth running tickover will be erratic and your tickover will probably surge up and down from maybe 800 ish down to 500 ish, or even stall the engine...or it will sound ROUGH

You can always tell if its the wrong grade plugs...put back in BP6ES (standard for our cars) and it will all be smooth again at tickover...

Hope this helps...

All the best Brett

jbrob007

Brett,

Thanks for the explanation. I havent experienced any of these problems (yet) and the temps in Ohio are averaging 32 F + / - 10 degrees. She's starting up very well and tickover has been consistent & smooth. To Ken's point - the car is running very well Now having said that, I'll give you the benefit of the doubt since the NGK plugs have only been in the car for about 100 miles. I do appreciate your advice and I'll keep an eye on the cold starts and the idle (tickover). If any clue of these issues seems apparent, those plugs will come out lickity-split ( thats Southern speak for NOW! ). When we took out the Bosch plugs they had a perfect burn / color. If the weather clears I'm gonna take her for an extended ride and check the NGKs. I'll report back what I find

Thanks again,

Joel

PorKen

Problems using colder plugs and/or gap settings on a '86 ROW 16V S2 (Brett's) should not be applied to a S3 32V.


The S2 has only one (large) intake valve per cylinder. It has long duration, high lift cams which will not idle as well as two valve engines.

The S2 does not have a idle control valve. It uses a K/L-Jet type thermostatic valve for warmup bypass air (and a solenoid for A/C idle speedup).

The S2 does not have a oxygen sensor. Idle mixture is controlled by the MAF CO adjustment (and coolant temp). Idle CO is set richer than a closed loop S3 needs to be. S2s typically run lean at cruise, and are much more sensitive to MAF aging, overall.


The S3 has two (smaller) valves per cylinder. They require less lift for the same flow, so gas speed is higher, and there is much more swirl.

With the higher fuel pressure (3.8 bar) used with S300s chips, fuel atomization is better. TQrings help equalize airflow between cylinders.

Brett928S2

Hi Joel

At those temperatures you will probably be ok...BUT when you get to the summer it will probably get a lot worse.... at 70 F and over you may get problems... hopefully not, but at least you will know what to do if it occurs...

All the best Brett

Brett928S2

Hi

Sorry but you are wrong...

All I said applies to an S,S2,S3,S4,GT,GTS....

This is basic plug technology we are talking about ..it applies to ANY high performance vehicle... as I said before, ask NGK if you do not believe me...

You CANNOT put too cold a grade of plug in ANY vehicle without it affecting it...

All the best Brett

PorKen

IIRC, you have said a lot of 'things'.


Regardless of what a customer service agent in Bangladesh may have read to you, BP8ES gapped to 1.0mm have been shown to work on S3s without issue, and dyno at over 310 rwhp, SAE.

Brett928S2

Hi

I was dealing with the head of Tech support in the UK..not Bangladesh (was that a racist comment by the way?)

You obviously know NOTHING about spark plug technology.... let me give you ONE FACT about spark plugs you obviously dont know....

FACT ... If you open the gap to 1 mm you WEAKEN the spark....

If you dont believe me..google it....

All the best Brett

PorKen

No, racist would have been calling him/her/you a Pakki.


If you open the gap on a RESISTOR plug, then the spark will have a more difficult time jumping the gap, or it may not jump it at all, under certain situations.

If you remove the 5K resistor, the spark will have an easier time crossing the gap, with more energy available. This affects the duration and advance time of the spark, so to BALANCE the system, you MUST open the gap to make it again more difficult to jump the gap.

In the same vein, plugs with very small (platinum/iridium) tips have an easier time making a spark, so they also need to larger gap for the engine to run properly.


A larger gap exposes more of the mixture to the spark, which is always good. Emissions are lowered, and mileage improves...if you can keep your foot off the floor.


I spent many hours researching ohmless plugs, and many, many hours testing the gap size. To tell you the truth, it is not easy to change the plugs on an S3. The airbox lid, and intake plenums have to be removed. My back is feeling the pain of the memory of the days I spent doing this.


All this is academic, as my S3s, and the other folks that have installed them, have no problem running the big gap plugs. I have many, many dyno sessions with them installed. All are extremely consistent. BP7ES might be better for extreme cold weather operation, but the gap is unchanged.


Fun fact: since colder plugs have a shorter insulator depth, they raise (albeit by a tiny amount) the compression ratio of the engine.

jbrob007

"Fun fact: since colder plugs have a shorter insulator depth, they raise (albeit by a tiny amount) the compression ratio of the engine".

Well... that MUST be good!!! LOL!!! Thanks for the education guys! Seriously, this is a good conversation and I've learned quite a bit - which is what this place is for