Red or Black Extenders for a QV?

I dug around here for a while looking but didn't find a definitive answer. Some say black for carbed cars and red for injected. Another thread says Rutlands only sells black ones. Another thread mentioned no difference between them. One said it was just different lengths by 5mm.

Superperformance lists red for my QV and black for 80-82.

My 84 has black ones now.

What do I buy? I have a bad extender and I am going to buy eight, not one.

 

There was a recent discussion about extenders, initially for a 328, with photos of the different versions:
328 Spark plug lead extensions???

In post #3 in that thread, I posted my information from researching extenders when I was installing the XDI system last winter - I'm pretty certain that a 308QV used the red 100mm extenders, part number 116613.

328 extenders are red, 107mm long. https://www.ferrariparts.co.uk/part/ferrari/126699
308 QV extenders were red, 100 mm long. https://www.ferrariparts.co.uk/part/ferrari/116613 or https://www.awitalian.com/product/spark-plug-extension-red-100-mm-long-fits-4-valve-euro-cars-only-116613.html/
308i extenders were black, 100mm long. https://www.awitalian.com/product/spark-plug-extension-black-100-mm-long-115647.html/.

 

So the black ones in my 84 QV are definitely incorrect?

I need 100 mm red ones specifically for a US car?

What is the difference between the red for a Euro and the red for a US ?

 

I believe black or red supposedly designated the resistance of the extenders. I'm not sure that's always true now. For my 1985 QV I recently got red extenders from Superperformance to replace the black extenders which were in the car.. The resistance was consistent, but quite high (unfortunately I forget the specific number of ohms). The black extenders had very little resistance. Most of my other cars are from the 1960s with simple coil ignition so I was surprised at the high resistance and questioned David Feinberg at Sarasota Garage (they had rebuilt my Digipex units). He assured me that fairly high resistance was appropriate for the QV, since it had a positive effect on spark duration with the Digiplex. In any event, my QV seems to be running splendidly with the red Superperformance red high resistance extenders.

 

Black is 2 valve..red is 4 valve. Carries in to the flat 12s as well. Bb512.. black..tr red..

 

I'm planning on getting the wire set from Kingsborn
Their extenders come with the set

 

My 84 QV has the black ones and works great.

 

Is there a difference in resistance between the red and black ones available today?

Or are they just different lengths now with the same nearly zero resistance?

It sounds like the most correct for my 84 QV are the red ones.

 

My understanding is that the difference between the red and black is that one has a resistor built-in and the other does not. The resistor is simply to reduce radio interference.

Virtually all spark plugs now have built-in resistors so it doesn't matter whether you use red or black. The spark is a bajillion volts (approximately), so the spark is not bothered by the resistance or by doubling the resistance.

I was not aware that there was a length difference between the two colors of extenders but if the length difference is only 7 mm, both lengths would probably fit fine.

Again, this is my understanding. I am no expert.

(For the record, I have black Kingsborne extenders in my '83 QV.)

 

My suspected bad extender. All my plugs look like these two.
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Can't agree with that -- my original TR extenders, and every one I've bought (124792), has been black with zero resistance.
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As far as I can recall, we proved some time ago that color is no longer a 100% way to determine with resistance or zero resistance (as more suppliers have surfaced).

 

Do the QV's require resistance for the Digiplex?

 

Personally have never seen black extenders on a TR..ever..

 

You can buy one from Maranello Concessionaires: https://www.ferrariparts.co.uk/part/ferrari/124792?id=52715

 

I think the answer to that is that you need some reasonable amount of impedance in the complete chain of wire + extender + spark plug to not overstress the output transistor of the Digiplex ECU that fires the coil primary -- i.e., if running stock wires with a stock non-resistor plug = use an extender with some resistance; if running the stock wires with a resistor spark plug = you could probably use a zero Ohm extender safely.

 

I have had NGK iridium BPR6E1X in there with those black extenders. I hope that was not a problem. Do you think that was ok?

What would you recommend since I am renewing everything, caps, rotors, wires, the works.

 

Since the NGK BPR6EIX is a resistor plug, I think you'd be OK with stock wires (which also have a non-zero resistance and a non-zero inductance) and a zero Ohm extender. Have you measured the resistance of your existing "black" extenders?

 

I tried with one

The numbers wouldn't stabilize

 

I think I may stop the fancy stuff and go back to factory specs with the plugs.

If so, I need the red extenders, correct?

 

And the others?

(Usually the "burn thru" holes originate from the cut end of the wire that holds the spark plug end as that's where the charge density is highest -- yours, jumping of the smooth arc of the wire is a little unusual. Maybe just more related to that's where the old plastic material, where the spark jumped thru, had degraded the most -- and plastics have improved at lot in 40 years .)

 

Color is not important (nor determinant IMO). If you use a non-resistor spark plug = yes, use an extender with resistance.

 

Interesting that Maranello Classic Parts specifies Champion's N6GY plug with a Black extender. I am assuming the N6GY is a non resistance plug since there is an RN6GY option available.

https://www.ferrariparts.co.uk/Diagram/ferrari/308-quattrovalvole-usa/039-engine-ignition?part=119492

A non resistor plug with a non resistor extender on a US QV?

 

You are putting too much emphasis on color IMO. It could be a zero resistance extender, but I'd prefer to see a resistance measurement (vs color). Also possible, that they have just messed things up as suppliers change, etc..

 

I am only referencing color since it seems that black = non resistance and red = resistance.

Maranello Parts actually specifies "black" leading me to believe the extender is a NR .

I have looked thru a few different sites and I do not see any mention of resistance, only color and different sites list different colors with different year models. There is no consistency which troubles me since there is no resistance listing.

It appears I need some resistance in there somewhere in my QV to protect the Digiplex and/or improve the spark, not for radio interference. That is easy by simply getting a resistor plug, but now if I couple that with a resistance extender, will that be too much?


This has become a project now that I cannot find any consistency in my searches. For example, I stumbled on plug heat range concerns. The owner's manual recommends a 6 but SuperPerformance lists an 8 for my car and when I read a little on hot and cold plugs, it sounds like you really don't want to make a long term mistake there either. That is a big difference.

 

See post #8 in this prior thread:

https://www.ferrarichat.com/forum/threads/another-328-stumble-thread.212698

Color means nothing IMO.