1 step colder plugs for the BMW N54 – NGK 5992 Laser Iridium – ILZKBR7A-8G


If you’ve modified your N54 based BMW extensively pushing well past the stock power levels or you’re just looking to run a different plug than the OEM Bosch ZGR6STE2 for any reason the NGK 5992 (ILZKBR7A-8G) are a great alternative. They can be had for about the same price as the OEM Bosch with some searching, $10.79 from http://www.sparkplugauto.com for instance.

Now, I’ve been running them for the last 30,000km, racing, pushing high boost with race tunes with and without meth and these have performed strong as well as set some records without any issues.

Thing to note is that these plugs off the shelf come with a larger gap than we can use on the N54 so just direct swapping them in won’t work and the car will stumble/misfire that way. You MUST have them gapped either to the OEM 0.7mm (0.0275″) or, which I’d recommend, to 0.56mm (0.022″) for high boost. The original gap on the NGK 5992 plugs is 0.8mm (0.031″) so make sure to GAP them before installation!

Some of the reasons I personally like them vs. the OEM Bosch ZGR6STE2 plugs are as follows:

1) Single ground prong vs. 3-prong OEM (makes the NGKs easily gappable when/if required)
2) 1 heat range COLDER than Bosch – standard recommendation is to go 1 heat range colder for every 100hp past stock. I’m at ~300hp above stock at the motor currently so can’t hurt.
3) Iridium center tip
4) They haven’t let me down with literally TONS of very very hard driving on 20+psi boost on RBs, pump+meth. Literally hundreds of 3-4 gear pulls, many drag strip runs and 60-130mph runs.
5) They’ve helped set some records too

Here’s what the NGK 5992 plugs look like and some of its specs:

NGK 5992

Features & Benefits

OE style long life spark plug. Laser welded iridium center electrode and platinum ground electrode, tapered ground electrode to minimize quenching, consistent and stable spark and outstanding acceleration, high fuel efficiency and durability.

Part Number: 5992
Weight: 0.09 lbs
Ngk Part Number: ILZKBR7A-8G
Thread Size: 12 mm.
Resistor: Yes
NGK Heat Range: 7
Center Electrode Material: Iridium
Ground straps: 1
Insulator Type: Ceramic
Ground Electrode Material: Copper core
Thread Reach: 1.043 in. (26.5 mm.)
Seat Type: Gasket

Here’s the BMW N54’s OEM Bosch replacement spark plug and specs for comparison:


Part Number: ZGR6STE2
Weight: 0.12 lbs
Thread Size: 12 mm.
Resistor: Yes
Bosch Heat Range: 6
Center Electrode Material: Copper
Ground Straps 3
Insulator Type Ceramic
Ground Electrode Material Nickel Alloy
Thread Reach: 1.043 in. (26.5 mm.)
Seat Type: Gasket

One thing you may be left wondering about is the heat ranges. These are “manufacturer” heat ranges on the plugs and Bosch and NGK don’t have the same scaling. In fact they go in opposite directions to each other. Once you work it all out though, if you’re up for digging up the info on heat ranges (which is a bit painful by the way), you’ll realize the NGK 5992 are 1 step COLDER than the OEM Bosch.

In the end, nothing wrong with OEMs but there is a solid 1 step colder alternative out there that is easily gap-able.

For information on how to gap plugs and what tool to use see this instructional video from NGK:


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