Choosing the Right Spark Plugs for Your 1991-2005 Acura NSX
Keep your C30A or C32B engine running smoothly with the correct spark plugs.
- Stick with OEM brands: NGK and Denso are the highly recommended choices for reliability and performance.
- Use the correct part number: For most owners, NGK PFR6G-11 or Denso PK20PR-L11 are the correct plugs.
- Replacement is DIY-friendly but requires care: Access to the rear bank is tight, and using a torque wrench (13 lb-ft) is mandatory to avoid damage.
- No recalls exist: There are no factory recalls or TSBs for spark plug issues on the 1991-2005 NSX.
Signs of Failing Spark Plugs
Your NSX will give you clues when its spark plugs are wearing out. Ignoring them can lead to worse fuel economy and potential damage to other parts, like the ignition coils or catalytic converter. Look for these common symptoms:
- Rough Idle: The engine may shake or vibrate more than usual when stopped.
- Engine Misfires: You might feel a stutter or hesitation during acceleration. This can also trigger the Check Engine Light with codes from P0300 to P0306.
- Poor Acceleration: The car may feel sluggish or less responsive than normal.
- Reduced Fuel Economy: You may notice you're filling up the gas tank more often.
- Trouble Starting: Worn plugs can make it harder for the engine to start, especially in cold weather.
Choosing the Right Aftermarket Spark Plug
For the Acura NSX, sticking close to the original equipment (OE) design is the best path. The factory used specific plugs from NGK and Denso for a reason. While many brands are available, enthusiast and expert consensus points to using OEM-equivalent plugs for the best results.
Aftermarket Brand Tiers for Acura NSX
| Tier | Brands | Quality & Performance Assessment |
|---|---|---|
| Tier 1: OEM & Recommended | NGK, Denso | These are the original equipment suppliers for the NSX. Models like the NGK Laser Platinum (PFR6G-11) and Denso (PK20PR-L11) are the go-to choices for stock vehicles. They provide reliable performance and the correct heat range for the engine. For a daily driven or spiritedly driven NSX, you cannot go wrong with these. |
| Tier 2: Use with Caution | Bosch, Champion | While these are well-known brands, some Honda and Acura owners report inconsistent performance, such as rough idling or reduced power, when using them instead of NGK or Denso. While a specific plug might work, it's a gamble compared to the proven OEM brands. |
| Tier 3: Economy / Not Recommended | ACDelco, Autolite, Skyward | These brands often offer basic copper plugs that are much cheaper. However, they have a significantly shorter lifespan and may not perform optimally in the high-performance NSX engine. It is not recommended to use these to save a few dollars, as it could compromise the driving experience. |
Heat Range is Important
For a stock NSX used for normal driving, the standard heat range 6 plug (like NGK PFR6G-11) is correct. If you drive your NSX hard, live in a very hot climate, or have performance modifications, a slightly colder heat range 7 plug (like NGK PFR7G-11) may be a better choice to prevent detonation.
Installation Notes
Replacing the spark plugs on an NSX is a manageable DIY project, but it requires patience, especially for the rear cylinders which have tight access. You will need to remove the engine cover, coil covers, and the individual coil packs to reach the plugs. It is critical to use a torque wrench and set it to 13 lb-ft. Over-tightening can damage the aluminum cylinder heads, leading to very expensive repairs.
Frequently Asked Questions
What is the difference between Platinum and Iridium plugs?
Platinum plugs were the original equipment standard for the NSX and offer a great balance of performance and longevity, typically lasting around 60,000 miles. Iridium is a harder, more durable material that can offer a slightly better spark and a longer lifespan. Many modern NGK and Denso plugs are Iridium or a Platinum/Iridium hybrid. For the NSX, either a quality Platinum or Iridium plug from NGK or Denso is an excellent choice.
Do I need to gap the spark plugs?
Most NGK and Denso plugs for the NSX come pre-gapped to the correct specification, which is between 1.0mm and 1.1mm (.044 inches). However, it is always a good idea to verify the gap with a feeler gauge before installation. Never try to adjust the gap on an Iridium or Platinum plug by prying against the center electrode, as this can damage it.
How often should I replace the spark plugs on my NSX?
For OEM-style platinum plugs, the recommended replacement interval is typically every 60,000 miles. If you use basic copper plugs, you should replace them much more frequently, around 15,000-20,000 miles. If you track your car or have forced induction, you should inspect and replace plugs more often.
Are there any recalls for NSX spark plugs?
No. There are no recalls or technical service bulletins (TSBs) from Acura related to spark plugs for the 1991-2005 NSX.
Technical Specifications
OEM Part Numbers: 98079-5614H 98079-5615H 98079-5714H
Required Plugs: 6. Recommended Brands: NGK, Denso. Standard Heat Range: 6. Torque Spec: 13 lb-ft (18 Nm). Spark Gap: 1.1 mm (0.044 in).
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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