The Definitive S2 Spark Plug Thread

[20Vcqdriver]

NGK BKR7EIX or 8's dependent on the car's tuning.

I've been using the BKR8EIX in my 3B set to 0.6mm for the past 4 years without issue, whether blatting around or in traffic

[gmac78]

Just checked a spare S4 B5 engine that I've got and forgot that it had brand new OEM plugs. They are NGK PFR6Q. Will these be suitable for the S2 engine? Never really experimented with different plug heat ranges etc so not sure what to expect. Cheers

[gmac78]

Hey. Thanks for that. Currently running the Volvo 7400 at around 1.5-1.6 bar. Which NGK would you suggest for this state of tune. Are these plugs suitable for use with the coil conversion? Cheers.

[SteveH]

NGK BKR7EIX or 8's dependent on the car's tuning.

[gmac78]

Alright gents. I'm looking to order new plugs for my 3B with a TFSI coil conversion. What would you recommend I order, was thinking of the FR5DP due to recommendations here but perhaps there is a better plug. I'm currently running F5DPOR but have a stumble in idling and and small throttle conditions so trying to cure that. These were fitted prior to carrying out the coil conversion so possibly not suited to my current setup, also why is one plug better than an other for using in coil conversions, I'm not sure on the reasoning behind it?
Cheers
Gordon

[Greg_S]

Thanks AndyP will get some ordered

[AndyP]

Still working well for me, I usually get them from here

http://www.gsparkplug.com/1x-ngk-iridium-ix-spark-plug-bkr7eix-2667.html?___SID=U

But I think I'l be looking at Opie next time

[Greg_S]

Thanks Tim, will take a look

[oilman]

I can't say how well they work for people, but we have them and you get 10% off the website prices with the club discount code.

http://www.opieoils.co.uk/p-63603-ngk-bkr7eix-2667-iridium-ix-spark-plug-sparkplug-taper-cut-ground-electrode.aspx

Regards

Tim

[Greg_S]

Just looking around at plugs, I have F5DPOR fitted now, but been looking at BKR7EIX which work out at about £6.56 a plug. Are these working well for people?
Any retailers recommended her in UK?

[Tridac]

The dwell time is set in software by the ecu, so I guess it's enough to store enough enargy in the coil, but what's interesting is what happens after the circuit is broken. I tried to find out typical voltage rise times on break, but there's very little info online. Looks like it could be in the 10's of microseconds range for a standard coil and less for a low inductance type. Anyway, plug gap for the NGK plugs is specified as 0.6mm, or 0.024". Will leave it at that, as the ecu has no way to compensate for a non standard gap in terms of timing...

[RichLV]

Never thought of it that way...
OEM Bosch plugs are 0.6mm.


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[Tridac]

Haven't measured it here, but it's not the dwell time so much as the fact that when the coil is energised, it takes time for the voltage to rise to plug breakdown level. Think of it as a graph of a rising voltage against time. At 6000 rpm, 1 degree of crank rotation takes 27 microseconds, (6000 / 60 = 10mS per revolution) / 360), not very much, so depending on the coil rise time, a larger than spec plug gap could retard the ignition.

Whatever, may not be significant, but the plug gap and delay would have been factored in to the design of the original ecu map, irrespective of what plugs you are using. What does the manual say is the correct plug gap ?...

Chris

[RichLV]

I put in a set of NGK BCPR7ET recently and all ok so far, no misfiring, but the engine is completely stock and not exactly driven at the limit.

One thing to consider about using a larger than spec gap is that the timing will be retarded a little. It requires a higher voltage to fire the plug and the coil output takes a finite time to reach that point anyway. Don't know if this is significant, but perhaps at red line. May be worh sticking a scope to sense (not directly connected !) the rise time of the coil voltage...

Chris

Mine is stock too, for now.

That's a fair point, but at this stage, with stock coil dwell times, FSI coils are getting overcharged. Might that balance it out?

[Tridac]

I put in a set of NGK PFR7B, recently and all ok so far, no misfiring, but the engine is completely stock and not exactly driven at the limit.

One thing to consider about using a larger than spec gap is that the timing will be retarded a little. It requires a higher voltage to fire the plug and the coil output takes a finite time to reach that point anyway. Don't know if this is significant, but perhaps at red line. May be worh sticking a scope to sense (not directly connected !) the rise time of the coil voltage...

Chris

Edited: Part number incorrect