1977 L82 Iridium plugs?
Race Director
Joined: May 2006
Posts: 18,726
Likes: 2,579
Looking at the AC-Delco web site there is no Iridium plug listed only platinum. What do you think you will be gaining? Exactly what brand and plug number were you looking at? The main point of these plugs is to last the 100,000 miles emission requirements.
Thread Starter
Intermediate
Joined: Aug 2014
Posts: 49
Likes: 10
From: Martinsville, Indiana
I was planning to install NKG brand #7401...was just wondering if the 'hotter' plug will create a more powerful fuel burn and thus improve fuel efficiency with the added benefit of never replacing the plugs again. The advertising make the plugs sound great!
Race Director
Joined: Apr 2000
Posts: 17,676
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
If you want to know whether the high output Iridium spark plugs will work then yes they will, but other than last longer there is no performance gain
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
Sounds like you think you will get some kind of performance improvement. The original plugs that came with engine are all you need . You don't need to go out and buy $10 spark plugs for your engine, there is no performance gain whatsoever.
If you want to know whether the high output Iridium spark plugs will work then yes they will, but other than last longer there is no performance gain
If you want to know whether the high output Iridium spark plugs will work then yes they will, but other than last longer there is no performance gain
If the spark is hotter, meaning the surface of the electrode and ground strap get hotter where the spark occurs, it may be more resistant to carbon fouling if oil burning or running rich is an issue.
Instructor
Joined: Jun 2015
Posts: 221
Likes: 13
From: Central Virginia
A hot spark plug vs a cold spark plug.
A hot spark plug is good for short city driving.
A cold spark plug is good for longer highway trips.
Most people don't know that when you get spark plugs from a parts store they are kind of the middle of the road for both city and highway driving.
A hot spark plug is good for short city driving.
A cold spark plug is good for longer highway trips.
Most people don't know that when you get spark plugs from a parts store they are kind of the middle of the road for both city and highway driving.
Burning Brakes
Joined: Dec 2005
Posts: 992
Likes: 56
From: Baldwinsville, NY
http://www.ngk.com/product.aspx?zpid=10179
NKG gap looks correct for HEI. the mileage is 40/50K.
Most just can not find a good reason to spend $10 for a $2 item.
A distributor recurve will give more performance and MPG.
NKG gap looks correct for HEI. the mileage is 40/50K.
Most just can not find a good reason to spend $10 for a $2 item.
A distributor recurve will give more performance and MPG.
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Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
The advantage for irridium plugs is that they last a lot longer. On many vehicles, they last 100K miles or more. I consider this to be an asset on a C3, as fiddling with the spark plug covers, etc. is a total PITA. So, having to do that with less frequency is a good thing.
Is that worth $5 [difference] per plug? That decision is yours.....
Is that worth $5 [difference] per plug? That decision is yours.....
Last edited by 7T1vette; Jan 22, 2016 at 01:14 PM.
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Average mileage is 5k a year, takes me 15min. tops to change them. I think what is more important is the heat range of the any particular plug, that has more impact on your engine than iridium or gold plated plugs.
Yet the question is rarely raised and the Heat number of that particular plug is 4 and I am betting if it said 8 they would still sell them to those looking for an Iridium plug
Yet the question is rarely raised and the Heat number of that particular plug is 4 and I am betting if it said 8 they would still sell them to those looking for an Iridium plug
Drifting
Joined: Aug 2009
Posts: 1,346
Likes: 160
From: new iberia la
You can pay $50 a plug if you want, it still won t make your car faster . The only advantage to a $10 Spark Plug over a $2 spark plug is change interval .. do not believe the advertised HP gains.. dyno tests disprove them
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
No performance gain from coated electrodes on plugs. And, if you can easily change plugs, go with 'standard issue'.
A 'full dress' early C3 might benefit, due to much longer replacement intervals.
Heat range is important, regardless of what plug you choose.
A 'full dress' early C3 might benefit, due to much longer replacement intervals.
Heat range is important, regardless of what plug you choose.
Cruising
Joined: Jul 2009
Posts: 10
Likes: 0
Hey folks. I just stumbled in here, but my take on iridium plugs is I have them in all 4 of my cars/truck.
I use Denso "Power" iridium plugs. They give better fuel mileage, better bottom end (run clean and smooth at least 200-300 rpm lower than others). No back to back dyno runs, but good power, too.
98 C5 LS1 (in an 83 Firebird)
97 JDM in a Prelude
97 T100 pickup
2004 Acura TL
The plug is amazing. Try them.
Good luck, guys.
I use Denso "Power" iridium plugs. They give better fuel mileage, better bottom end (run clean and smooth at least 200-300 rpm lower than others). No back to back dyno runs, but good power, too.
98 C5 LS1 (in an 83 Firebird)
97 JDM in a Prelude
97 T100 pickup
2004 Acura TL
The plug is amazing. Try them.
Good luck, guys.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Tried that trip complete waste of money
Went back to the stock plug runs great
All the plug has to do is light off the mixture thats it
If they are going out early you got other problems
Went back to the stock plug runs great
All the plug has to do is light off the mixture thats it
If they are going out early you got other problems
Drifting
Joined: Aug 2008
Posts: 1,381
Likes: 11
Affirmative, no improvement over the OEM plugs. Anyone who thinks otherwise is experiencing psychological horsepower, just like flipping the air cleaner lid over on your mom's 327 4 door Impala.