[themightyquinn]

This is the story of one VW-loving man's quest to find the perfect NGK standard copper (nickel-alloy!) spark plug for our beloved 2.5L inline-5 cylinder engine...read on friends!


So the only recommended COPPER spark plug (aka standard aka NOT platinum or iridium tipped AKA nickel-alloy outer electrode...remember all spark plugs have copper cores so it's kind of a misnomer!) for our 2.5L inline-5's is a Denso plug, K16GPR-U11, which I have not been very impressed with after 2 sets of 30k and 20k miles. Don't get me wrong, they were decent especially for the money ($3.07 per plug), but meh...

The alternative? Just buy OEM 2.5L plugs and be done with it you say? :screwy: No way, what am I made of money?! $12/plug is absurd, and Platinum tipped never seems to run as good (and that is backed up by electrical science...go look up conductivity of metals).

And since I've never had a poorly performing NGK plug in any application ever....the obvious next step was to spec out the Denso K16GPR-U11 plug, crossreference to NGK and BOOM, sexy electrical magic! :heart:

I came down to 3 NGK plugs that matched the Denso's specs (and as a check, they are all in the base family of the OEM platinum plug, PZFR5Q-11, hooray! :thumbup:

ZFR5D-11, ZFR5E-11, and ZFR5J-11

So these are all the same-spec'd plug, with the variable letter denoting "special firing-end design" which of course NGK does not explain anywhere. Initially I was set on the "J" version, thinking that since the original OEM platinum plug was a "J" plug (PZFR5J-11), however I found some info indicating the "J" copper plug had a shorter insulator than the other coppers and the OEM platinum plug.

With that said, I chose the ZFR5E-11.

No real reason over the "D" version...I thought I saw that the "D" was a non-V groove electrode so that was my reason against it...wouldn't hesitate to try the "D" or the "J" though, but as always your miles may vary/do at your own risk yadda yadda...I can only comment on the ZFR5E-11 ...

... and let me say...THEY ARE AWESOME. Now of course these are not "official" OEM spark plugs for our engine, so just remember that...but the results speak for themselves. I'll say it again for effect...


THE NGK ZFR5E-11 STANDARD COPPER SPARK PLUGS RUN GREAT IN VW 2.5L INLINE-5 CYLINDER ENGINES !!!!!!!


Just had to gap down to .040"/1.0mm. The butt-dyno says YES, idle is smoother, MPG's are up (couldn't get more than 28 highway before, recorded multiple highway cruises on the NGKs at 72-75mph in the 30.X range!), and, oh yeah, did I mention they cost $2.50 per plug? The wallet also says YES.


So run along now to your local auto parts store, where they are literally ALWAYS in stock (part #4435) and rejoice at the thought of walking out with 5 quality NGK copper plugs for less than $13. Boom shakalaka. Y'all are welcome! eace:

 

[TheMysticWizard1]

I too went through this. I had ran the Denso K16GPR-U11, less than 20k miles and they were done. Well rounded electrode and ground and the gap had widened significantly.

I began reading and ended up buying a set of NGK BKR7E-11 (Stock# 4464).

From researching, it looks that the ones I got had the v-groove center and a little less projected tip. They are also 2 steps colder. I can't find the specific thread that made me decide to go with these, but I do recall reading that the 2.5 is somewhat prone to detonation in stock form and it might be a good idea to go colder with a tune or other mods.

It's been about 3k miles and the car is running great. Big difference over the Denso plugs as far as smoothness. I did not notice a difference in mileage.

I've ran copper plugs in it since I changed them the first time. Not going to pay 12 bux a plug, Seems unreasonable.

 

[themightyquinn]

Interesting about the BKR7E's, as people have been using that series plug in turbo engines since the 1.8t. The 7, a lot in the 2.0T...I wonder how on an n/a engine heat range 5 and 2 steps colder are both running good, but I do seem to remember hearing the same thing about pre-detonation. Maybe I'll try the BK's next or look for a colder ZF plug.

Anyone else?

 

[billyVR6]

ZFR5D-11, ZFR5E-11, and ZFR5J-11

THE NGK ZFR5E-11 STANDARD COPPER SPARK PLUGS RUN GREAT IN VW 2.5L INLINE-5 CYLINDER ENGINES !!!!!!!

I'll second this, been running both the ZFR5D-11, and ZFR5E-11, for quite some time now (two different cars). :thumbup:

 

[Bora Jon]

Thanks for the tip! I miss my NGK V powers. I always ran them in my 1.8T's and changed them every oil change because they were so cheap to buy. The Denso's suck. not even 5,000 miles and I had a slight misfire at idle. Put these in and she's as smooth as butter. Torque profile feels better at partial throttle too. Needless to say I am very happy. The best part was when I went into the parts place and the guy behind the counter looked at me like I was crazy when I said I needed five plugs.

 

[halbwissen]

There are some technical differences between the 2005.5 to early-2007.5 and late-2007.5+ OE 2.5l plugs that you don't want to overlook..

The 2005.5 to early-2007.5 2.5l uses OE part # 101-998-600-C / NGK part # PZFR5Q-11. These Laser Platinum plugs have a 3.0mm extended metal shell (unthreaded portion of the thread reach), 7.0mm projection of center electrode, 1k ohm and platinum center electrode.

The late-2007.5+ 2.5l uses OE part # 101-998-601-F / NGK part # PZFR5J-11:
These Laser Platinum plugs share the same specs as above except for the ground electrode is copper cored instead of the standard nickel core. For whatever reason this was updated by VW on late model 2.5ls.

Maybe this changed in correlation to the later 2.5ls making more power (150hp vs 170hp). That's not to say the plugs are what made the extra power, that would be foolish, but ECU programming and other minor hardware enhances did occur during this model year split.

Now let's compare the less expensive plug options the OP listed above..

ZFR5D-11: These plugs have a 3.5mm extended metal shell, 6.5mm projection of the center electrode, 5k ohm and standard nickel plug.
ZFR5E-11: Same as the 'D' plug listed above, but the center electrode has a V-groove for better ignitability.
ZFR5J-11: These plugs have a 0mm extended metal shell, 5.0mm projection of the center electrode, 5k ohm and V-groove plug.

The most important thing to take away from all this information is the extended metal shell value. This value should not deviate from the OE spec of 3.0mm. Therefore, none of these V-Groove plugs are technically compatible with what's recommend by VW (and NGK). The closest match is the 'E' plug chosen by the OP, but even so, it's still technically not qualified for use in any 2.5l. To date, NGK does not offer any alternatives for the Laser Platinum plugs PZFR5Q-11 & PZFR5J-11.

Your mileage may vary and by no means am I crapping on the OP, or other contributors. Instead, I just wanted to share what I've learned over the years of owning a few 2.5ls.

:beer:

 

[themightyquinn]

Thanks for the extra specs/info. I think the only design spec I would ABSOLUTELY want to pay attention to was the electrode extended projection...and that's only to say that I would NOT select a plug with MORE than the OE plug's projection. Not sticking that electrode any farther into the combustion chamber than stock, no Russian roulette for me thanks!

I honestly don't think that the shell shroud extension has much of an impact on plug selection in this instance. The longer shroud helps dissipate heat, but even in a hot-running N/A car like ours, I don't see this as a major specification.

Obviously the goal is to find a plug as close to the stock specs as possible but in copper/nickel electrode form.

I did have a question about spark plug resistor values that the above post reminded me of...does the 5k ohm vs 1k ohm resistor in the copper/nickel NGK plugs vs. the laser platinum ones make a difference? I know it's super high voltage anyway, so really it shouldn't make a huge difference, but just wondering if anyone knows forsure.

 

[Ronny Bensys]

@themightyquinn and @kölsch

Thank you for the valuable information. Replaced my OEMs this summer to Denso K16GPR-U11 and has been getting really good mileage and smooth idling since then. Now planning to try NGKs next time.

 

[Ronny Bensys]

Finally, NGK unveiled OEM specified spark plug. It specifies ZFR6T-11G for VW part # 101905601F.

Check https://www.ngk.de/nc/en/product-finder/produktfinder/////ZFR6T-11G/

 

[halbwissen]

Finally, NGK unveiled OEM specified spark plug. It specifies ZFR6T-11G for VW part # 101905601F.

Check https://www.ngk.de/nc/en/product-finder/produktfinder/////ZFR6T-11G/

They're a step colder than OE. Interesting.

 

[halbwissen]

I noticed there's another new plug listed for 07K duty, but on the US website:

https://www.ngk.com/product.aspx?zpid=10208

This spark plug is not no longer listed as compatible with the 2.5l.

 

[halbwissen]

Here's some more info comparing the ZFR5E-11 and ZFT6T-11G plugs:

ZFR5E-11

• Standard nickel ground electrode
• 3.5mm extended metal shell (unthreaded)
• 6.5mm center projection
• 5 heat range
• Std. 0.8mm center electrode (v-notch cut in center to reduce quenching)

ZFR6T-11G

• Copper infused ground electrode (used to pull heat away from the ground electrode in certain applications)
• 3.0mm extended metal shell (unthreaded)
• 7.0mm center projection
• 6 heat range
• Std. 0.8mm nickel center electrode

Notice the ZFR6T-11G extended shell and projection values are the same as the PZFR5J/Q-11 Laser Platinum plugs.
Of all the options available, the ZFRT6T-11G plug seems like a good option for those with heavy modifications and/or hard driven vehicles.
That should keep temperatures high enough to prevent fouling of the 6 heat range plug is now the recommended plug for 2010+ CBTA/CBUA 2.5ls as well as Bosch's FR7HE02.

 

[facegame221]

cheap on ebay


https://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=NGK+ZFR5E-11&_sop=15

 

[billyVR6]

cheap on ebay

Ehh, Ebay can be pretty damn sketchy (knock-offs), I would suggest going to your local parts vendor/distributor.

NGK knock-offs are/were a problem and flooded Ebay for quite some time, they're basically garbage. If you search, there was website that noted the tell-tale characteristics related to knock-off. I've always played it safe and purchased in-store, the Pep Boys on the way home from work always has them in stock. The plugs are inexpensive as is, not worth the risk to save a few pennies...

 

[facegame221]

Ive bought from ebay/pepboys/autozone with no issues

 

[halbwissen]

Ive bought from ebay/pepboys/autozone with no issues

The nickel / copper V-Power NGK ZFR5E-11 plugs can be found at any big box parts store for ~$2.50/each and may be a good alternate for use in the 2.5l while not being officially recommended by NGK or VW if you don't want to spend big money on the PZFR5Q-11/PZFR5J-11 Laser Platinum plugs that are what VW calls for.

The ZFR6T-11G plugs Ronny mentioned back in Nov 2017 are Euro-only parts, so you'd have to stick to buying from a foreign vendor. are available at big box US retailers for use in 2010+ CBTA/CBUA 2.5ls applications.

 

[der skillz]

brining this back, because I forgot part number. and yes, these work fantastic. eace:

 

[SNS1938]

I was looking for new plugs, as I'm at 35,000 miles since I put in OEM plugs, and VW says 40k miles between changes. Anyways, OE are $8 something, but then the higher spec Irridium plugs are $6 something. According to RockAuto they both fit. Why wouldn't I just buy the Irridium? How do you confirm that they actually fit? A couple websites list them as fitting.

Any help much appreciated. Even the OE's, if the last 40,000 miles, will see me through my ownership of the car (as that'll be another 5 years), but if the Irriduim really are better, and cost less ... then why not?

Thanks,

 

[Ronny Bensys]

Better confirm with the manufacturers like NGK or Bosch. Afaik Bosch doesn't offer iridium or platinium for the 2.5L.

 

[Lenihan]

I see its recommended to run heat range 6 after 2010. Not sure why most people are still running heat range 5 plugs when its not recommended after the 2010 year 2.5 engines. I am having a go with some ruthenium plugs with same dimensions as the copper plugs

FR6AHX-S (94279)