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]

1 hour ago, 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?

 

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.

13 minutes ago, 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.  

[GTSBoy]

15 psi on Splitfires with stock gap is trivial.

[Dose Pipe Sutututu]

28 minutes ago, 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

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