Shipping Estimate
USA
- USA
- CAN
- USA
- CAN
Ships within 48 hours · Estimated delivery Jul 12 - Jul 17
Promo Codes Available:
For Your Every Summer RSVP, with Code: SUMMER15
Description
HKS Super Fire Racing Spark Plug 50003-M525REM Series Super Fire Spark Plugs HKS M Series spark plugs are high performance Iridium plugs designed to provide improved ignition performance, durability and anti carbon build up. 0. 6mm Iridium Alloy Center Electrode Outer Electrode with Platinum Chip Short Type Outer Electrode (Anti Vibration) Thermal Edge Spark Support Gap M Series is recommended for reliable ignition, durability and anti carbon buildup under high load. The Iridium alloy is used
M-Series Super Fire Spark Plugs
HKS M-Series spark plugs are high performance Iridium plugs designed to provide improved ignition performance, durability and anti-carbon build-up.
- 0.6mm Iridium Alloy Center Electrode
- Outer Electrode with Platinum Chip
- Short Type Outer Electrode (Anti-Vibration)
- Thermal Edge
- Spark Support Gap
M Series is recommended for reliable ignition, durability and anti-carbon buildup under high load.
The Iridium alloy is used because of its durability and reliability. On an average plug, a narrow core typically shortens life span of plug but with the intense durability of iridium there is no sacrifice in any longevity. With a high melting point of 2454 degrees C, opposed to the 1769 degrees C of white gold, the electrode can tolerate the high levels of compression and minor knocking without any deterioration. A nickel coating on the housing also prevents the spark plug from premature deterioration. The Iridium plugs are available for multiple applications and offered in "colder" heat ranges of 7 and up and specifically for rotary, heat ranges of 9 and up are offered.
Heat Range: NGK # 10.5
Thread Size: 14mm × 12.7mm
Wrench Size: 20.8mm
Fits:
| 1983 - 1985 | MAZDA | RX-7 | ALL | ALL | From 10/1983 Thru 9/1985 Production Date | SA22C Chassis | Stock Plug/Heat Range: ROTARY:9 |
| 1985 - 1988 | MAZDA | RX-7 | R2 | 1.3 | From 10/1985 Thru 8/1988 Production Date | FC3S/FC3C Chassis | Stock Plug/Heat Range: ROTARY:10,11 |
| 1988 - 1991 | MAZDA | RX-7 | R2 | 1.3 | From 9/1988 Thru 12/1991 Production Date | FC3S/FC3C Chassis | Stock Plug/Heat Range: ROTARY:7,9 |
| 1993 - 1995 | MAZDA | RX-7 | R2 | 1.3 | From 12/1991 Thru 8/2002 Production Date | FD3S Chassis | Stock Plug/Heat Range: ROTARY:7,9 |
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.2 ★★★★★
Based on 584 reviews
Sort
Product Reviews
★★★★★ 5
An epic adventure with a rich cast of characters
Format: Paperback
Scout paints the Mojave as bursting with life, a poetic world full of chaparral and chinquapin, of creosote scrub and conifers. These wild vivid landscapes are a backdrop to the real heart of the story, which, like all great stories, is always about People.
The Human Drama, sometimes of People vs the Environment, but more often of People vs Themselves. Overcoming our own fears or injuries or burdens that life inevitably deals to us all. This book captures the pursuit of people stretching themselves, challenging themselves to change and grow.
He does an excellent job of capturing the "esprit de corps" of the trail, of near strangers and fast friends looking out for one another, and the crescendoing intensity as they race against Father Winter. We meet a wide ensemble of characters, which is one of the most magical aspects of any long hike. It is the great equalizer, where people from all walks of life come together and share fellowship.
There are numerous role models within this book. It is impossible to not be inspired by Jan, the quintessential Fixer, or the protagonists who demonstrate exemplary examples of forgiveness and reconciliation, and other humble benefactors and do-gooders who understand that their gifts are more than simply money. They are giving opportunity. The fixers, the reconciliers, the benefactors....we should all aspire to be these types of people.
I hope this is but the first of his trail books. I'm certain there are many of us who would enjoy reading about his adventures from New Mexico to Montana as well. How fortunate was he to meet such wonderful people, and how fortunate are we to share their experiences from the comfort of our homes.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on August 11, 2020
★★★★★ 4
OK book about hiking the Pacific Crest Trail.
Format: Paperback
I love books about people hiking the national trails. I thought this book was about the author's thru hike on the trail with his wife. Actually, this book had little to do with the Pacific Crest Trail and was mostly about the other hikers, their relationships, etc. It read like a fiction book, as the author often gave examples of conversations the other hikers had with other people, even when he wasn't around to hear them. He also gave examples of what they were thinking and even what the other hikers friends were thinking. There was no evidence of interviews, etc.
It is a very well written book, so I gave it four stars. If you like books about the relationships of thru hikers, especially their romances, I would recommend this book. But it reads more like a fiction book, in my opinion.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 2, 2026
★★★★★ 5
Walking from Mexico to Canada with a great cast of characters
Format: Paperback
I thoroughly enjoyed reading Journeys North. The story is about the Pacific Crest Trail and the people who hike it (thru-hikers) attempting to walk from Mexico to Canada. The author brings the trail to life across the story, but what really stands out is the story of the characters. You find yourself rooting for them as they encounter all kinds of challenges, and you get to know them through their backstory and past experiences that are shared. People attempt a thru-hike for many different reasons, and the story is enriched by their personal stories and histories that they carry with them each step of the way. Even their “trail names” had stories that often highlighted something about the characters themselves. One of the unique things about the book is the Pacific Crest Trail itself, as the author’s descriptions allow you to imagine what it looked like and felt like (including the aches, pains, and injuries along the way). The trail is ever present across this story of the people who walked it, bring them together, and then pulling them away from one other, sometimes for weeks or even months. The trail and mother nature create for an everchanging backdrop as the characters navigate their way north. I am not a thru-hiker and I doubt I would ever attempt to walk from Mexico to Canada, but I enjoyed tagging along on the adventure of Scout, Frodo, Blazer, Dalton, Tony, Nadine and many others whose lives intersected over the course of many miles. I found myself having a hard time putting the book down, particularly as the hikers neared the Canadian border. If you are looking for an armchair adventure along the PCT, or wondered what it would be like to tackle a thru-hike of a long trail, or are curious about the people who undertake such a challenge, you will enjoy Journeys North! I would imagine that if you are a PCT hiker you would find the book even more meaningful.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on August 4, 2020
★★★★★ 5
Incredible Life experience while hiking the PCT
Format: Paperback
As I began experiencing great stories about the "Camino" pilgrimage in Spain, books about "thru hikes" in the US seemed to find me too i.e. The Pacific Crest Trail, and did grab my attention for various reasons...
"Journeys North"-- To me, this story makes it more than apparent, that if you want to learn about yourself and open your "vault doors" so to speak, and free yourself of personal challenges-hiking the PCT could help. This book on it's own, is a wonderful treatise about the PCT, and taught me much about being open and honest with others to include oneself, and about being grateful."
This story "rings" of Freedom, is intense, and at times, raw. From the comfort of my living room... Frodo, Scout, Blazer, and company drug this old backpacker (me) a.k.a. "LightningLayne" along on a fantastic journey north clear from Mexico's northern border to Canada's southern one. Along the way, I noticed how the "goodness" in people replaces just about every negative the world throws in your face. Finally, I laughed, I cried, and even felt sorry at times for all the "participants." In the end, I was "grateful" for the individual and collective stories shared. This story is one that has burrowed in deep and is one I will never forget.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 2, 2021
★★★★★ 5
Now I want to hike the PCH!
Format: Paperback
Such an incredible story, actually several stories. Very inspirational. I can’t help but want to join the adventure and experience some trail magic of my own. Thank you for capturing these experiences, Scout. Well done
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on November 25, 2025