Another spark plug thread ?

[trel]

Guys, a friend of mine is telling me Motorcraft part number agsp22ye11 for XR6t is a compatible fit for an RB25DET. I've searched and funnily enough in a different thread someone mentions the very same plug but never really went into detail. Subsequent Google searches led me to endless loops of equivalent plugs ? but not much else..

At $40 for a set of 6 iridiums is a steal. Otherwise, the trusty BCP6RE stays. Would be nice to do plugs less frequently though. Thoughts?

Edited July 30, 2020 by trel

[Unzipped Composites]

  On 30/07/2020 at 10:13 AM, trel said:

Guys, a friend of mine is telling me Motorcraft part number agsp22ye11 for XR6t is a compatible fit for an RB25DET. I've searched and funnily enough in a different thread someone mentions the very same plug but never really went into detail. Subsequent Google searches led me to endless loops of equivalent plugs ? but not much else..

At $40 for a set of 6 iridiums is a steal. Otherwise, the trusty BCP6RE stays. Would be nice to do plugs less frequently though. Thoughts?

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The reason everyone uses copper plugs in RB25's is because the Iridiums and Platinums don't last as long as they are quoted in a modified engine. So you would still have to do frequent plug changes - you will just pay more for them.

[KiwiRS4T]

The Motorcraft plug is recommended for Fords running on gas. 

The RB plug is NGK BKR7Eix so if the Motorcraft is equivalent then yes they are cheap.

[Dose Pipe Sutututu]

Mixed review about those plugs, I've had first hand experience, I would say do not go there.

I know of a workshop that raves about them, so I gave it a go...

They work fine for moderate boost, then I started to wind in the boost on when I decided to tune my car on the dyno and it started to misfire. Initially thought it was the R35 coils, so rammed in about 4ms of dwell and I kept adding till about 4.2ms with 1.3bar of boost (18psi for those who think Fahrenheit is a useful UOM).

I felt a bit defeated with tuning then, Alex (owner of Birrong Automotive) came over with a box of NGK BCPR7ES and said throw those junk plugs out. I gapped the BCPR7ES at 0.6mm and popped them in and surprise surprise no misfire, I ended up dropping the dwell down to 3.0ms and kept adding boost and peaked at 2.1bar of boost, bleeding down to 1.8bar.

Moral of the story, don't bother with them.

[hardsteppa]

Yep, unlikely to be a unicorn, that cheap. I use Iriway 7's, straight out of the box with r35 coils, last for years and never had an issue.

[trel]

Thanks for that input fellas. My setup is very mIld. 15psi, Nistune, Splitfires, yada yada... My gap is on 1.1 with BCPR6ES-11 plugs always come out looking OK. I guess this is a case of "if it ain't broke, don't fix".

Edited July 31, 2020 by trel

[GTSBoy]

Copper plugs should last you for years in that application.

[TXSquirrel]

Wow you ran 6 with 1.1?  I think that's a bit much even at 15psi...  I'm surprised you're not getting knocks...  I would have suggested at least 7 if you are running 1.1, but preferably 0.9.  

[Ben C34]

plug gap and heat range are completely different and unrelated.

  On 31/07/2020 at 4:12 AM, TXSquirrel said:

Wow you ran 6 with 1.1?  I think that's a bit much even at 15psi...  I'm surprised you're not getting knocks...  I would have suggested at least 7 if you are running 1.1, but preferably 0.9.  

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[GTSBoy]

15 psi on Splitfires with stock gap is trivial.

[Dose Pipe Sutututu]

  On 31/07/2020 at 4:12 AM, TXSquirrel said:

Wow you ran 6 with 1.1?  I think that's a bit much even at 15psi...  I'm surprised you're not getting knocks...  I would have suggested at least 7 if you are running 1.1

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Spark plug gap has no correlation to knock, you can't just reduce the spark plug gap and miraculously increased your knock threshold.

 

[trel]

Nothing wrong with my setup. Ran like this for years almost daily driven. It's all in the tune and being sensible. It's also being anal like I am when it comes to maintenance on the car and not fiddling with things that shouldn't be touched.

Edited July 31, 2020 by trel