NGK spark plugs
Thread Starter
Burning Brakes
Joined: Dec 2009
Posts: 820
Likes: 0
From: Houston TX
NGK spark plugs
Im confused as to which spark plugs are needed.
Ive been told that either TR5 or TR6, but when I go to my parts store, neither show up as listed for an LS2 vette
When they search NGK this comes up:
NGK TR6 V power, # 4177
NGK TR5, # 2238
Are these the correct ones? neither are listed for the corvette but this is what they have from NGK.
Also, my car is getting full exhaust and tune, nothing else. thanks
Ive been told that either TR5 or TR6, but when I go to my parts store, neither show up as listed for an LS2 vette
When they search NGK this comes up:
NGK TR6 V power, # 4177
NGK TR5, # 2238
Are these the correct ones? neither are listed for the corvette but this is what they have from NGK.
Also, my car is getting full exhaust and tune, nothing else. thanks
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
The difference is the gap. The TR5 are designed for a .040" gap while the TR55 is .059" gap. The factory spec is .040" gap.
If you want to gap your plugs at .040" use the TR5 and TR55 if you want a gap ~.060".
Thread Starter
Burning Brakes
Joined: Dec 2009
Posts: 820
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From: Houston TX
Pro
Joined: Jan 2011
Posts: 554
Likes: 1
From: Evington VA
I pulled up this part number, but the autozone and advancedauto websites both say this part does not fit a 2008 c6. Does it fit just the ls2 or are these also the plugs that I need? I have headers and C/A intake on the LS3 if that info is needed. Thank you
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Team Owner
Joined: Feb 2001
Posts: 27,254
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From: Short Hills, NJ
If you're not all that concerned about extracting every last bit of horsepower from your car and would also rather not change the plugs quite as often than the Iridiums might not be a bad move.
Le Mans Master
Joined: Oct 2006
Posts: 5,078
Likes: 19
From: Cumming, GA
Why the TR55? According to an email NGK sent me, their website incorrectly listed the TR55 for the Corvette. They told me the TR5 is the correct plug for the Corvette.
The difference is the gap. The TR5 are designed for a .040" gap while the TR55 is .059" gap. The factory spec is .040" gap.
If you want to gap your plugs at .040" use the TR5 and TR55 if you want a gap ~.060".
The difference is the gap. The TR5 are designed for a .040" gap while the TR55 is .059" gap. The factory spec is .040" gap.
If you want to gap your plugs at .040" use the TR5 and TR55 if you want a gap ~.060".
Most feel that the V powers (copper I believe) are actually a better performing plug than the more costly and longer lasting Iridiums but I'm sure the difference is minute.
If you're not all that concerned about extracting every last bit of horsepower from your car and would also rather not change the plugs quite as often than the Iridiums might not be a bad move.
If you're not all that concerned about extracting every last bit of horsepower from your car and would also rather not change the plugs quite as often than the Iridiums might not be a bad move.
Safety Car
Joined: May 2000
Posts: 4,827
Likes: 352
From: Albuquerque NM
The iridiums are for long life, the copper for power. A well respected tuner for the LSA and LS9 engines has stated he can add two degrees of timing to a tune for a car with NGK TR6's compared to stock iridiums. The stock iridiums have a very small diameter center electrode which is prone to stay hotter than the copper electrodes and can cause knock under WOT.
Le Mans Master
Joined: Oct 2006
Posts: 5,078
Likes: 19
From: Cumming, GA
When I spoke to NGK they advertised them(iridium) as their "peak performance plug" which differs from what you note above. ^^
Knock was more prone with the iridium's though from what I recall.
Knock was more prone with the iridium's though from what I recall.
Le Mans Master
Joined: Oct 2006
Posts: 5,078
Likes: 19
From: Cumming, GA
^^^What mods do you have?
I'm thinking of giving the 6's a try since I'm pushing 150rwhp more than stock.
I hear 75-100hp gain should call for a 1-step colder plug.
I did some research and found that my TR5's are burning very well though so I'm torn. May test it out one of these days and see which the car prefers.
I'm thinking of giving the 6's a try since I'm pushing 150rwhp more than stock.
I hear 75-100hp gain should call for a 1-step colder plug. I did some research and found that my TR5's are burning very well though so I'm torn. May test it out one of these days and see which the car prefers.
Burning Brakes
Joined: May 2006
Posts: 1,171
Likes: 2
From: foley al
The iridiums are for long life, the copper for power. A well respected tuner for the LSA and LS9 engines has stated he can add two degrees of timing to a tune for a car with NGK TR6's compared to stock iridiums. The stock iridiums have a very small diameter center electrode which is prone to stay hotter than the copper electrodes and can cause knock under WOT.
Last edited by da vette guy; Apr 2, 2011 at 10:33 PM.
Safety Car
Joined: May 2000
Posts: 4,827
Likes: 352
From: Albuquerque NM
If you're happy with how your car runs stock, great, leave them in. But, just know, our engines are designed to run on the edge of knocking all the time, that's where they are the most efficient. If you monitor your engine when driving you will see times when the best amount of timing for power/efficiency/mpg will cause knock and the ECM will pull timing (knock retard). If you install copper plugs you will probably see less periods of KR. Some people have reported dynoing their car, changing to TR6's while still on the dyno, and then doing another pull gaining 20 rwhp because of less/no KR. The for sure downside: They don't last as long. I change my NGK TR6's every 12,000 miles. They cost less than $2 each and the job is easy. The maybe downside: Some cars (not all) get an occasional code and "service charging system" report because the different plugs put out electrical noise which can confuse our very sensitive PCM controlled alternator/voltage regulators.
Burning Brakes
Joined: May 2006
Posts: 1,171
Likes: 2
From: foley al
GM installs iridiums because they last a long time. Aftermarket companies love to sell them because they're rare metal, and can get a big premium price for them.
If you're happy with how your car runs stock, great, leave them in. But, just know, our engines are designed to run on the edge of knocking all the time, that's where they are the most efficient. If you monitor your engine when driving you will see times when the best amount of timing for power/efficiency/mpg will cause knock and the ECM will pull timing (knock retard). If you install copper plugs you will probably see less periods of KR. Some people have reported dynoing their car, changing to TR6's while still on the dyno, and then doing another pull gaining 20 rwhp because of less/no KR. The for sure downside: They don't last as long. I change my NGK TR6's every 12,000 miles. They cost less than $2 each and the job is easy. The maybe downside: Some cars (not all) get an occasional code and "service charging system" report because the different plugs put out electrical noise which can confuse our very sensitive PCM controlled alternator/voltage regulators.
If you're happy with how your car runs stock, great, leave them in. But, just know, our engines are designed to run on the edge of knocking all the time, that's where they are the most efficient. If you monitor your engine when driving you will see times when the best amount of timing for power/efficiency/mpg will cause knock and the ECM will pull timing (knock retard). If you install copper plugs you will probably see less periods of KR. Some people have reported dynoing their car, changing to TR6's while still on the dyno, and then doing another pull gaining 20 rwhp because of less/no KR. The for sure downside: They don't last as long. I change my NGK TR6's every 12,000 miles. They cost less than $2 each and the job is easy. The maybe downside: Some cars (not all) get an occasional code and "service charging system" report because the different plugs put out electrical noise which can confuse our very sensitive PCM controlled alternator/voltage regulators.
