Dodge Challenger Forum banner
  • Hey everyone! Enter your ride HERE to be a part of September's Ride of the Month Challenge!
1 - 11 of 11 Posts

·
Premium Member
2014 Dodge Challenger R/T+ 100th Anniversary Edition 5.7L HEMI
Joined
·
70 Posts
Discussion Starter · #1 · (Edited)
Back in April my 2014 100th Anniversary Challenger R/T+ daily driver had 56k miles on the clock. I figured some new spark plugs wouldn't hurt, even if FCA says the stock NGK Iridium's are good for 100k. I splurged and went with the NGK Ruthenium's from Rock Auto and spent a gorgeous Sunday afternoon in my garage installing them.

Why did I choose the Ruthenium's over the Iridium's? I already knew how the factory iridium plugs performed, and I wanted to give the "latest and greatest" from NGK a chance. Supposedly they help improve gas mileage and are good for 120k miles.

Yes, yes I know - who cares about gas mileage in our epic muscle cars? I drive ~40 miles round trip highway miles for my daily commute, and if I'm... patient, kind, and forget I'm riding in a fire breathing dragon who can zip in and out of the mindless hordes clogging the highways and byways of my Midwest college town, I can get 10 days without refilling the gas tank and coast into the gas station on fumes on the 11th day. Averaging 14mpg city/23mpg highway on 89 octane gasoline - which I refuse to compromise on, but splurge and put 91 octane in her once a month or so.

Some of the OEM plugs were a real bear to break loose, and a handful of them reeked of gasoline even though my car had been sitting for almost 36 hours straight without a start. Cylinder#1's first plug (closest to the radiator) was oily and smelled bad, too. The worst gasoline scented plugs were from cylinders 2, 4, and 7. The only mods to my engine were installed at the dealership where I bought it and they are the Corsa stainless catback exhaust, the Mopar CAI, and an "advanced PCM tune" that I could never get a straight answer from the stealership on what exactly they did. I'm willing to bet they probably charged the 1st owner for saying they "tuned it" and did nothing of the sort. Otherwise the car is completely stock.

Brand new torque wrench, spark plug socket, flex extensions, a buttload of patience, and the job took around 4 hours for me to finish. Not bad for 16 spark plugs that haven't seen the light of day since factory assembly in October of 2013, and an middle-aged overweight I.T. nerd who remembers with cringe-y longing the days of flashlight ***** duty with his dad who also conveniently forgets that was decades ago and how CHONK style sausage fingers are rarely beneficial for any job wrenching on internal combustion engine... I bled, yes. Shredded skin and scars all over. But I'm got sh*t done on my daily driven dream car.

Another reason I decided to change the plugs was every once in awhile (~20th cold start or so) the car fired right up and died immediately 1-2 seconds later. It didn't matter what the ambient temperature was, it didn't matter if I was "wildly domesticated" commuter mode or Mach 2 hell on wheels the drive before I let it sit; the start-rumble-dead sequence was the weirdest and most random godd*mned thing! Zero warning lights, zero check engine light, no sign of any issue except for a momentary... hiccup/miss right before it died. I had to shut it back down, wait for a couple of moments, and then she'd fire right up like nothing happened. The new plugs have since completely eliminated this annoyance.

First impressions were startup was silky smooth without a hint of trouble. Idle was... MUCH smoother than the stock plugs were managing. I took her for a test drive and throttle response was improved, but maybe... +5% quicker at best.

TLDR? 56k mostly stock 5.7L HEMI got 16 new NGK Ruthenium spark plugs back in April. So far after 4k mostly highway miles = flawless starts, buttery smooth idle, marginally better throttle response and acceleration, +1 MPG city and highway on 89 octane.

Anyone else have iridium/ruthenium/other spark plug comparison horror/success stories to share?

1028083
 

·
Premium Member
The Bacon Hauler (‘12 Cop Charger)
Joined
·
9,429 Posts
Ive tried all different types of spark plug in my 2012 5.7L except for the ruthenium. I was running it the track on weekends and using a lot of OTC octane boost and wanted to see if any type handled the manganese deposits better than the others. Conclusion: they’re all susceptible, pull and clean often if using the OTC stuff.

Your mention of the gas-soaked plugs is disconcerting. If it were only one, I’d say maybe you have a leaking injector, but more than one would seem to point to something else. I’d definitely pull those after a few miles and see if the behavior continues.

If it does, there’s something going on that needs to be addressed. Extra gas in the cylinder means raw gas in the exhaust, and that will burn up a cat eventually.
 

·
Premium Member
Joined
·
3,964 Posts
I have had great results with NGK Iridium in everything from cars, boats to motorcycles.
 
  • Like
Reactions: Sith R/T

·
Registered
Joined
·
301 Posts
I'm getting that sudden shut off at cold starts too... Maybe I need to change my plugs.
 
  • Like
Reactions: Sith R/T

·
Premium Member
2014 Dodge Challenger R/T+ 100th Anniversary Edition 5.7L HEMI
Joined
·
70 Posts
Discussion Starter · #5 ·
Completely cured my ride of the problem, Gront.
 

·
Registered
Joined
·
1,526 Posts
I just replaced my spark plugs at 92k miles for the first time and all but two were in good shape. I replaced them with Mopar OEM I found on Amazon, $166 for the set of 16. Figure it the OEM lasted 90K+ miles without any issues why change...
 

·
Registered
2015 RT 5.7 M6
Joined
·
9,754 Posts
If you guys are swapping out plugs, it's also a good time to check the intake manifold bolts for proper torque as they tend to back out over time. Also don't forget to check/replace PCV.
 

·
Registered
Joined
·
1,526 Posts
If you guys are swapping out plugs, it's also a good time to check the intake manifold bolts for proper torque as they tend to back out over time. Also don't forget to check/replace PCV.
I noticed some oil in the spark plug channel (cylinder #4 & 5) so I'm also replacing the gasket.
 

·
Registered
Joined
·
301 Posts
1028672


Just ordered them from RockAuto, shipping is a little steep but I want them ASAP. Here's hoping FedEx doesn't damage them.
 
  • Like
Reactions: Sith R/T

·
Premium Member
2014 Dodge Challenger R/T+ 100th Anniversary Edition 5.7L HEMI
Joined
·
70 Posts
Discussion Starter · #10 ·
View attachment 1028672

Just ordered them from RockAuto, shipping is a little steep but I want them ASAP. Here's hoping FedEx doesn't damage them.
These are the exact set I put in mine back in April. Not a single complaint so far!
 
  • Like
Reactions: Gront

·
Registered
Joined
·
301 Posts
I just received them and have gapped them to 1.1mm/0.0433". (They had 1mm/0.040") Looking forward to getting them installed tomorrow.
 
  • Like
Reactions: Sith R/T
1 - 11 of 11 Posts
Top