NGK BCP7ES VS NGK BKR7E V-Power

[Classic 911]

I am currently using NGK BCP7ES spark plugs on my twin spark setup and they work great. But I have a set of 12 NGK BKR7E V-Power on the shelf I was thinking of testing. I have read that the resistor type BKR7E can result in power loss due to weaker spark.

Have anyone on the forum tried these or any thoughts on which of the two that is the best.

Cheers

[Black_Hat]

Cut and paste from NGK on the WWW:

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.

In fact, using a non-resistor plug in certain applications can actually cause the engine to suffer undesirable side effects such as an erratic idle, high-rpm misfire, engine run-on, power drop off at certain rpm levels and abnormal combustion.

[Classic 911]

Originally Posted by Black_Hat

Cut and paste from NGK on the WWW:

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.

In fact, using a non-resistor plug in certain applications can actually cause the engine to suffer undesirable side effects such as an erratic idle, high-rpm misfire, engine run-on, power drop off at certain rpm levels and abnormal combustion.

Thanks a lot

I have now tried out the V-Power ones and they gave a great improvement in power. The old plugs looked just fine but I guess they were worn and ready to be changed.
But I see on my PLX gauge that the AFR must be adjusted some.


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[G450X]

Which engine are you referring to? I need to change my plugs soon and I may try these on my 3.0 (or my 3.2 build) SC.

Thanks

[Classic 911]

Originally Posted by G450X

Which engine are you referring to? I need to change my plugs soon and I may try these on my 3.0 (or my 3.2 build) SC.

Thanks

This is a 3.2 short stroke RSR twin plug engine.


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[Geneman]

This is great to know. I have virtually same motor ( built by William Knightrace). its out for valve adj. gearbox swap and i was thinking of doing plugs. (while you are in there..).

What gap did you use?

So the difference is definitly detectable?

What was the change in AFR?

Thanks. Frank

[Classic 911]

Originally Posted by Geneman

This is great to know. I have virtually same motor ( built by William Knightrace). its out for valve adj. gearbox swap and i was thinking of doing plugs. (while you are in there..).

What gap did you use?

So the difference is definitly detectable?

What was the change in AFR?

Thanks. Frank

Hi.
I used the factory 0.9mm gap. In my engine it was definitly detectable yes, but maybe the old plugs were tired / worn from +/- 20.000 miles of driving so when the new ones was mounted they might just restored the spark back to new spec.

BUT the car got a little bit more lean all over and this combined with the new found power leads me to believe that the new plugs does a better job igniting the air/fuel micture.

The car is going back on the dyno in the end of august, then I will know more.

Cheers


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['78 SC]

Originally Posted by Classic 911

BUT the car got a little bit more lean all over and this combined with the new found power leads me to believe that the new plugs does a better job igniting the air/fuel micture.
...

If you are using a wide-band O2 sensor to measure AFR, incomplete combustion (say, from ignition issues) will appear as a lean condition. This is because the sensor detects only oxygen, not unburned fuel or combustion products. Incomplete combustion will increase the O2 content of the exhaust gas thus increasing the indicated AFR.