NGK Iridium Spark Plug One Step Colder 2309 ( Part Number:NGK LFR7AIX)

NGK Iridium Spark Plug One Step Colder 2309

Manufacturer Part # LFR7AIX


MSRP: $18.31

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NGK Iridium IX Spark Plugs are designed specifically for the performance enthusiast. Iridium IX offers extreme ignitability, improved throttle response and superior anti fouling.

The fine Iridium tip ensures high durability and a consistently stable spark. Iridium alloy has extremely high melting point, perfect for today's high-tech, high-performance engines. Trivalent Metal Plating - superior anti-corrosion and anti-seizing properties. Outstanding acceleration, high fuel efficiency and durability. Ultimate design, technology and performance.

These are one step colder plugs and are recommended for higher horsepower applications. A higher heat range number does not improve engine performance, it increases the plugs ability to dissipate heat.

Stock Number 2309
Heat Range: 7
Plug Gap: .032

Please Note: This is a single plug. For a set of 4, use NGR LFR7AIX-GRP.
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Brand: NGK
Heat Range: 7
Plug Gap: .032
Stock Number: 2309

Mfgr. Warranty: 60 Days
Condition: New Product
Return Policy:

RallySport Guarantee - 30 Days

Items that are covered under the RallySport Guarantee offer a 30 day no questions asked return policy.

RallySport Guarantee items may be returned within 30 days of the original invoice date and must include all the original parts and contents for a refund.

The RallySport Guarantee does not apply to products that have been modified, damaged, misused or abused. All returns require an RMA (Return Merchandise Authorization) Number, and freight charges are strictly non-refundable. For more information regarding our freight refund policy, please refer to our return policy page found HERE.


Verified Purchase

Works as expected
larrysturgill8299286 3 years ago
Great product and as always RSD service.
Verified Purchase

pwatson13029 3 years ago
Car idles great and is smooth throughout the RPM range. The only downside was the install, but that is Subaru packaging for you.
Verified Purchase

One of those must do mods for stage 2+
LOLFUNCTION 3 years ago
I did so many other mods at once I can't say I noticed a difference. The rumors are true, the install sucks but it's definitely doable. Just takes patience, and a second set of hands definitely.
Verified Purchase

Great spark plug!
grobelny.ece50834 4 years ago
These plugs are the best. I love that they come pre-gapped. They helped to fix a rough idle/misfire issue on my '11 wrx.
Verified Purchase

Will buy again and again
jrkimmel87984 4 years ago
Gapped correctly and ready to install right out of the box. Recommended by tuner for rebuilt 2.5L 2007 WRX engine w/ forged internals.

  • Q: plugs   chrismoore6 2 years ago


    I have been looking to go to these but the upgrades I have are a full turbo back exhaust, new intake, new bov, and pro tuned. Would this be a good upgrade.

    • A: This is likely not a good option for your setup, sticking with the stock heat range plugs would be best.

      ryanw20299728 2 years ago
  • Q: 2008 WRX w/ VF52 swap  rstevensunleeshd25748 2 years ago


    I'm running a catless TBE, AEM CAI, Grimmspeed EBCS and VF52 turbo on a bit of an aggressive tune. I know I'm beyond 100hp over the stock 2008 WRX power levels and I've been having some issues with feedback knock, should I install these one step colder plugs?

    • A: Unfortunately we do not have a way to verify whether it would be best to run a step colder. I recommend speaking with your tuner and seeing what they recommend for your setup.

      Nick S. 2 years ago
  • Q: Gap high boost   Michell Lopez 3 years ago


    What is the best gap for 27 psi of boost with bloch Dom 2.5XT-R?

    • A: The answer to this is very relative. I recommend consulting your tuner regarding where he would like the gap set. Thank you.

      Sterling W. 3 years ago
  • Q: 09 WRX  distefano.vincent62253 3 years ago


    I have a 09 WRX(3 inch catted turbo back cnt, cobb lightweight pulley, synapse 100% recirc, and a very aggressive tune, estimated power of 280 and around 320 torque. would the one step cold be beneficial or harmful to my car? also would have to get a tune? Thanks!

    • A: We recommend doing colder plugs when you are at least 100whp over stock.

      Kyle A. 3 years ago
  • Q: One step colder plugs  Mh4life666 3 years ago


    Hi, I'm looking to replace the spark plugs on my 08 forester sports it's turbo but stock, so could I use these and would it be fine?

    • A: Stock heat range plugs are recommended for a stock car and up to Stage 2. You could install these plugs, but they would not last as long because colder plugs tend to foul out sooner than stock heat range.

      Zach G. 3 years ago
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