NEW PLUGS K8 vs ZE/DE

[Josh]

so since im the V6 noob, looking around Rock Auto wanting to buy new plugs I love the NGK laser Iridiums. Looks like they only list them for the K8, any DE/ZE motors from 626, mx6, milly do not list the Laser Iridiums.

I am sure the plugs will work but do they use the same plugs?

[Josh]

Just want to make sure before I blow 60 bucks on plugs

[Nd4SpdSe]

Get them for the FS Probe 2.0L. That's what I ran when I used just the regular Iridiums (The Rx8 gets the Lasers)

[Josh]

I have found regular iridiums, I just want the Lasers. The RX8 loved them and i have used them on the wifes C230 Kompressor and it loves them. I just want to use them on the ZE.

[SuperK]

the part numbers are different.

ZFR5FIX-11 are the iridium's for the KL
BKR5EIX-11 are the iridium's for the K8. And the FS. And the B6.

[SuperK]

Here is the breakdown on the plugs. with this information you should feel confident enough to purchase IFR5E-11's

IFR5E-11

I: Iridium Platinum Plug type
F: Metal Shell Size: ø 14, 19mm (3/4”) Reach, 16mm (5/8”) Hex.
R: Construction: Resistor
5: Heat Rating Numbers (2=Hot, 11=Cold)
E: Firing End Construction
11: Wide Gap: 2.2mm or .044"

ZFR5FIX-11

Z: Extended Gap Plug Type
F: Metal Shell Size: ø 14, 19mm (3/4”) Reach, 16mm (5/8”) Hex.
R: Construction: Resistor
5: Heat Rating Numbers (2=Hot, 11=Cold)
IX: Firing End Contruction
11: Wide Gap: 2.2mm or .044"

BKR5EIX-11
B: 14mm Thread Diameter
K: Hex Size 5/8” Projected Tip (ISO)
R: Construction: Resistor
5: Heat Rating Numbers (2=Hot, 11=Cold)
E: Thread Reach: 19 mm (3/4”)
IX: Firing End Contruction
11: Wide Gap: 2.2mm or .044"

[SuperK]

Depending on your application you may want to consider a colder plug.

Advancing ignition timing by 10° will cause the spark plug tip temperature to increase by approximately 70° to 100°C.

Significantly increasing the static/dynamic compression ratio will increase cylinder pressures and the octane requirement of the engine. Knock may occur more easily. If the engine is operated near the knock level, a colder heat range spark plug may be necessary due to the resulting increased cylinder temperatures.

A colder heat range spark plug may be necessary due to the increased cylinder temperature as boost pressure (manifold pressure) and subsequent cylinder pressure and temperature increase.

When using an ethanol blend fuel with high ethanol content in high performance applications, a colder heat range may be necessary. The spark timing can be advanced further because ethanol blend fuel has a higher resistance to knock (higher octane). Due to the decreased knock, there will be less audible “warning” from knock before the spark plug overheats and pre-ignites.

If the engine is to be operated at high RPM, under a heavy load, or at high temperatures for long periods a colder heat range may be needed.

Conversely, if the engine is to be operated at low speeds or at low temperatures for long periods, a hotter heat range might be needed to prevent fouling.

[SuperK]

when compression is raised, along with the added power comes added heat. Since spark plugs must remove heat and a modified engine makes more heat, the spark plug must remove more heat. A colder heat range spark plug must be selected and plug gaps should be adjusted smaller to ensure proper ignitability in this denser air/fuel mixture.

Typically, for every 75-100 hp you add, you should go one step colder on the spark plug's heat range. A hotter heat range is not usually recommended except when severe oil or fuel fouling is occurring.



END INFORMATION DUMPING. I love NGK's. this was all from them <3

[SuperK]

And now for my PERSONAL opinion:

We use the stock "5" heat range plugs originally designed for the KL-DE. Going with the model suggested by NGK, we have increased compression ratio and HP about 30-40 extra. I believe a stock KL-ZE is perfectly happy with the stock setup.

If you have turbo'ed, increased compression, advanced timing, or designed your ZE for high revving, get a "6" plug.

[Nd4SpdSe]

Back in the day (lol) it was said that you couldn't use DE plugs in a ZE because of the high compressoin pistons, where they would end up slapping the plugs. This I believe is actually false.

So, it was recommended to use NGK Iridium plugs for a Ford Probe FS 2.0L 4cyl, stock heat, stock gap (plugs come pregapped properly), worked great.

[Josh]

Thanks for all the info, my main concern was with plug swap ability between the US motors and the ZE because of the higher comp. I would like to go with the Laser iridiums IFR5E-11 and was thinking for going with a colder plug and advancing the timing just a smidge.

I am also going to complete the HEI and swap to my blaster 2 and my MSD digital SCI

In the RS I have swapped to the colder range due to the boost. On the dyno I have seen a boosted NA BP gain 50 WHP from swapping to a colder plug it makes a difference.

[SuperK]

The difference is that the I plug has a 3.5mm firing position and the Z has a 5.0mm firing position.

So there you have it.

[wagZE]

Back in the day (lol) it was said that you couldn't use DE plugs in a ZE because of the high compressoin pistons, where they would end up slapping the plugs. This I believe is actually false.

So, it was recommended to use NGK Iridium plugs for a Ford Probe FS 2.0L 4cyl, stock heat, stock gap (plugs come pregapped properly), worked great.

No, 100% true, it happened on my friend's curveneck ze. He is not mechanically inclined at all, he thought the sound was a broken piston. It was just the piston hitting the bottom of the plug. (Was cylinder 1) it messed plug but pisto was a ok.
zfr-5f11 = klde ngk copper plugs
Bkr-6e11 = klze ngk copper plugs
copper plugs are recommended in kl's

[Josh]

The difference is that the I plug has a 3.5mm firing position and the Z has a 5.0mm firing position.

So there you have it.

What is this in relation to? the angle in the head, the distance to the top of the piston..

[SuperK]

I'm pretty sure they take their measurements from the bottom of the plug, so it's in relation to itself.