Spark plugs, do they make a difference?

[L99CAMA2011]

Ok I just took out the stock spark plugs that were installed like 8000 miles ago and installed some NGK TR6 plugs. Now I am wondering. Would these make my car run less powerful without a tune that optimizes the cooler temps these plugs allow or should I have kept my stock plugs in the engine with mods such as a tune, intake, headers and Vararam wedge.

[2012LS3VERT]

I wouldn't have switched to a tr6 unless I was getting knock, which would be a tune issue in the first place. Especially if you just put in copper ones. I'd go back stock or the iridium tr5's, which are the eqivalent. It is generally best to run the hottest plug you can without getting detonation. I run tr6ix usually in blower cars or head/cam cars with high dynamic compression. Colder plugs don't really mean you can tune for more advance necessarily, only if you had too hot of a plug to start with (like I do right now, lol, I really need to order the tr7ix).

[Josh @ Spartan LSX]

You're not going to gain a noticeable power increase with a simple plug change per say, but a smoother idle and better spark can be had with different plugs. The stock GM plug's main function is to last 100K as advertised by GM. Performance was second on the list.

As mentioned above, you went 1 step colder which isn't really necessary unless you're already having a knock issue and/or are using 87 octane gas. For those on a budget the plain ole NGK TR55 copper plug ($1.99/ea) works just fine. We use these in the majority of our performance builds unless it's very high compression or boost. If you want something that's going to last a little longer the TR5 iridium works great too.

[Anthony @ LG Motorsports]

Like they said above...you are not going to magically pickup 20 hp with a plug change, unless they were broken/fowled before you did it. Plug heat range should be matched to the HP/cylinder pressure that you are running in the car. In some cases going to a colder plug can allow for more timing given a certain fuel but that all comes with tuning..

This is a little experiment I did on my C6Z a few years ago.....FYI...




Something I have been playing around with on my own car...and some good info for you guys. Some of you have already went to a TR6, but may not have known why it is a good idea...so I did a little test.

...THE TEST...
No big build, high compression, stupid timing table setup here....STOCK GM parts and tune.

Test car....2008 C6 Z06 Corvette LS7
Stock plugs
Stock timing table
93 octane pump Dallas fuel
40k street driven miles.

This car developed a bit of audible knock, so HP Tuners was used to log the car to see exactly where the knock was going on and to what degree.
LOG FILE

Make note that we have knock across the board, not just at the top of the RPM range and it is happening not only under WOT but also at throttle tip in (noted by now far down the cylinder fill it goes)

To make a quick test we mixed 5 gallons of 104 octane fuel in the mix to see if it was mechanical or possibly fuel/timing related (remember this car still has the stock timing table and spark plugs in it)
LOG FILE WITH RACE GAS MIX

Here you can see that the knock is still there but greatly reduced from stock. Again still throughout the board but not as much in the lower ranges.


STOCK GM PLUG BEING REMOVED

Notice the detonation marks (bits of black)


Back ground checks...
Air/Fuel ratio checks out and is similar to any other stock car, reaching almost 11.4:1 when the car goes into cat over temp. So it is not running lean.

All plugs look the same, injectors check out and the car has plenty of fuel pressure.

02 sensors check out, and are functioning properly.

So now the question....what to do?

1. You can modify the tune and remove timing, which is also going to pull HP as well. Those of you wanting a stock tune...big no no
2. Run race gas full time...sorry $7/gallon for a daily driver isn't fun and it still has knock
3. Run a colder plug to reduce spark knock.


In this case I am going slightly colder on the spark plug to a NGK TR6iX plug to hopefully reduce the amount of knock.


At this point the car has no audible knock, and feels much stronger in the mid range, which is probably due to the lack of 4-6 degrees of timing being removed.


Tomorrow I will follow up with a plug removed for inspection, and also a data log of the same drive conditions to see if we have in fact removed all of the knock from the car with no fuel or tune changes.

Log results tomorrow with a plug pull for inspection

--------------------------------------------------------------------------


Results from a week of driving (did the plug change last week)

Log records were done last night and this morning, this is the worse of the two runs (approx 32mins of driving combined stop and go and highway, same as before log runs).

NGK TR6iX plug after 300 miles (approx)

Notice no more pepper marks.

Stock AC plug vs NGK

Notice the change in tip projection from the end of the plug vs stock

Almost to ZERO knock!


Need to dig a bit more into the table to see if this was on decell, if it was just a pop or possibly just general noise or the pump fuel itself. Either way we have killed 99% of the knock that was there before hand.


So the long and short of it.

Listen to your car, it will tell you what it is going to want. In this case we have a stock car that is running into some timing issues and the result is a better running car with a slightly colder plug. Those of you that are modifying the car, which most of us are. You can benefit in a number of ways because you are more than likely creating more cylinder pressure, more HP, and more heat. A colder plug will allow more timing and less chance of detonation.

For those not wanting to make a tuning change in the ECM this is a good way to help your car on track as well. Just like running better engine oils and better fuels on track under heavy load conditions.


It should be noted that the factory does want a very clean and hot burn for emissions. Those that rarely drive the cars, or do not drive them that hard, this might not be for you.

[GONIF]

IMHO ,a colder plug on a stock engine is a waste of time . NGK copper V power in the stock heat range TR5 is cheap and works as well as anything you can buy . May not last as long as iridium ,but just plain works in a stock LS 1, 2, or 3 . $1.50 each and that is one hell of a deal in these inflated times.

[Anthony @ LG Motorsports]

Originally Posted by GONIF

IMHO ,a colder plug on a stock engine is a waste of time . NGK copper V power in the stock heat range TR5 is cheap and works as well as anything you can buy . May not last as long as iridium ,but just plain works in a stock LS 1, 2, or 3 . $1.50 each and that is one hell of a deal in these inflated times.

Now I will say this....99% of the time, I would use a plain copper plug in the car. You are 100% right they will not last as long. If I would have had a set on the shelf when I did the above test it would have had a normal copper plug in it.

[GONIF]

Originally Posted by Anthony @ LG Motorsports

Now I will say this....99% of the time, I would use a plain copper plug in the car. You are 100% right they will not last as long. If I would have had a set on the shelf when I did the above test it would have had a normal copper plug in it.

Some day B4 I die I'm going to own a C7 with your headers on it . You guys make the best headers for a C7 I have ever seen . I hope to have a 2016 C7 and the first mod will be LG headers.

[JCunningham]

put your stock plugs back in. unless you added a supercharger, turbo,or change the compression there is no reason to put aftermarket plugs in. Your computer controlled ignition system was designed to use the stock plugs.

[VADER SS L99]

Originally Posted by Anthony @ LG Motorsports

Like they said above...you are not going to magically pickup 20 hp with a plug change, unless they were broken/fowled before you did it. Plug heat range should be matched to the HP/cylinder pressure that you are running in the car. In some cases going to a colder plug can allow for more timing given a certain fuel but that all comes with tuning..

This is a little experiment I did on my C6Z a few years ago.....FYI...




Something I have been playing around with on my own car...and some good info for you guys. Some of you have already went to a TR6, but may not have known why it is a good idea...so I did a little test.

...THE TEST...
No big build, high compression, stupid timing table setup here....STOCK GM parts and tune.

Test car....2008 C6 Z06 Corvette LS7
Stock plugs
Stock timing table
93 octane pump Dallas fuel
40k street driven miles.

This car developed a bit of audible knock, so HP Tuners was used to log the car to see exactly where the knock was going on and to what degree.
LOG FILE

Make note that we have knock across the board, not just at the top of the RPM range and it is happening not only under WOT but also at throttle tip in (noted by now far down the cylinder fill it goes)

To make a quick test we mixed 5 gallons of 104 octane fuel in the mix to see if it was mechanical or possibly fuel/timing related (remember this car still has the stock timing table and spark plugs in it)
LOG FILE WITH RACE GAS MIX

Here you can see that the knock is still there but greatly reduced from stock. Again still throughout the board but not as much in the lower ranges.


STOCK GM PLUG BEING REMOVED

Notice the detonation marks (bits of black)


Back ground checks...
Air/Fuel ratio checks out and is similar to any other stock car, reaching almost 11.4:1 when the car goes into cat over temp. So it is not running lean.

All plugs look the same, injectors check out and the car has plenty of fuel pressure.

02 sensors check out, and are functioning properly.

So now the question....what to do?

1. You can modify the tune and remove timing, which is also going to pull HP as well. Those of you wanting a stock tune...big no no
2. Run race gas full time...sorry $7/gallon for a daily driver isn't fun and it still has knock
3. Run a colder plug to reduce spark knock.


In this case I am going slightly colder on the spark plug to a NGK TR6iX plug to hopefully reduce the amount of knock.


At this point the car has no audible knock, and feels much stronger in the mid range, which is probably due to the lack of 4-6 degrees of timing being removed.


Tomorrow I will follow up with a plug removed for inspection, and also a data log of the same drive conditions to see if we have in fact removed all of the knock from the car with no fuel or tune changes.

Log results tomorrow with a plug pull for inspection

--------------------------------------------------------------------------


Results from a week of driving (did the plug change last week)

Log records were done last night and this morning, this is the worse of the two runs (approx 32mins of driving combined stop and go and highway, same as before log runs).

NGK TR6iX plug after 300 miles (approx)

Notice no more pepper marks.

Stock AC plug vs NGK

Notice the change in tip projection from the end of the plug vs stock

Almost to ZERO knock!


Need to dig a bit more into the table to see if this was on decell, if it was just a pop or possibly just general noise or the pump fuel itself. Either way we have killed 99% of the knock that was there before hand.


So the long and short of it.

Listen to your car, it will tell you what it is going to want. In this case we have a stock car that is running into some timing issues and the result is a better running car with a slightly colder plug. Those of you that are modifying the car, which most of us are. You can benefit in a number of ways because you are more than likely creating more cylinder pressure, more HP, and more heat. A colder plug will allow more timing and less chance of detonation.

For those not wanting to make a tuning change in the ECM this is a good way to help your car on track as well. Just like running better engine oils and better fuels on track under heavy load conditions.


It should be noted that the factory does want a very clean and hot burn for emissions. Those that rarely drive the cars, or do not drive them that hard, this might not be for you.

The TR6IX is the stock replacement spark plug for the LS9, LS7 and LSA engine. It's a different plug than the stock AC Delco which may or May not be what helped you out but it's suppose to be the exact same heat range. In other words according to NGK it is not colder. Are you sure your stock plugs weren't fouled or maybe something else was going on? I can't imagine that every stock LS7 using 93 octane is getting that much KR because of the spark plug design. If so it seems as though it's a design flaw in the spark plug itself and not the heat range that's causing the issue in which case all LS7 owners should switch to those plugs. Also, I'll never use the normal cooper TR5, TR6 ever again and I recommend that others who read this take my advise. They foul out to quickly and my idle, start up and driveability in LSx powered cars has always improved with the hotter platinum or iridium spark plug in the hottest range for the setup. Whether that be AC Delco, NGK, or Denso. My advise to the OP and others with a stock LS3/L99 long block and no power adder is stick to the stock spark plugs, NGK TR5IX, or Denso in the stock heat range.

[L99CAMA2011]

Originally Posted by GONIF

Some day B4 I die I'm going to own a C7 with your headers on it . You guys make the best headers for a C7 I have ever seen . I hope to have a 2016 C7 and the first mod will be LG headers.

Seems like a good plan bro. I like LG exhaust.

[DKT]

It all depends on the car. Like said above no reason to run cooler plugs in a stock or close to stock car.
I am still on stock heat range tr5s gapped at .040 on 730whp.

[L99CAMA2011]

Originally Posted by VADER SS L99

The TR6IX is the stock replacement spark plug for the LS9, LS7 and LSA engine. It's a different plug than the stock AC Delco which may or May not be what helped you out but it's suppose to be the exact same heat range. In other words according to NGK it is not colder. Are you sure your stock plugs weren't fouled or maybe something else was going on? I can't imagine that every stock LS7 using 93 octane is getting that much KR because of the spark plug design. If so it seems as though it's a design flaw in the spark plug itself and not the heat range that's causing the issue in which case all LS7 owners should switch to those plugs. Also, I'll never use the normal cooper TR5, TR6 ever again and I recommend that others who read this take my advise. They foul out to quickly and my idle, start up and driveability in LSx powered cars has always improved with the hotter platinum or iridium spark plug in the hottest range for the setup. Whether that be AC Delco, NGK, or Denso. My advise to the OP and others with a stock LS3/L99 long block and no power adder is stick to the stock spark plugs, NGK TR5IX, or Denso in the stock heat range.

Well the plugs are gapped to 41 or 42. The quarter sized guage I used for measuring showed that. The engine now starts up , idle and runs smoother than ever before. Feels like a new engine. Not sure that gap is correct but I measured the stock plugs I had and gapped the NGKs to same spec.

[Anthony @ LG Motorsports]

Originally Posted by VADER SS L99

The TR6IX is the stock replacement spark plug for the LS9, LS7 and LSA engine. It's a different plug than the stock AC Delco which may or May not be what helped you out but it's suppose to be the exact same heat range. In other words according to NGK it is not colder. Are you sure your stock plugs weren't fouled or maybe something else was going on? I can't imagine that every stock LS7 using 93 octane is getting that much KR because of the spark plug design. If so it seems as though it's a design flaw in the spark plug itself and not the heat range that's causing the issue in which case all LS7 owners should switch to those plugs. Also, I'll never use the normal cooper TR5, TR6 ever again and I recommend that others who read this take my advise. They foul out to quickly and my idle, start up and driveability in LSx powered cars has always improved with the hotter platinum or iridium spark plug in the hottest range for the setup. Whether that be AC Delco, NGK, or Denso. My advise to the OP and others with a stock LS3/L99 long block and no power adder is stick to the stock spark plugs, NGK TR5IX, or Denso in the stock heat range.

You are correct it is a different plug....but just like translating from English to Italian, somethings don't always cross 100%. If I remember correctly at the time, the NGK is built more like a colder plug given the electrode design.

My car was a daily driver that saw very little WOT time during the week, so I am sure carbon deposits were part of the knock to start with given the miles on the car.



I never said every OEM part was the thing to use either.....that's like saying every LS7 cylinder head was built perfectly.

[GONIF]

A little old school trick to get rid of carbon deposits on a car just B4 you change the plugs and oil . Remove all the plugs ,pour some GM top engine cleaner into each cylinder , let it sit over night . Spin the engine over with the starter to shoot out all the left over fluid .Install the new plugs start engine ,it will smoke for a while .When the engine is warmed up and the smoke has stopped ,change the oil . You now have no carbon on the pistons, rings, valves, and combustion chambers. With the proper heat range plugs and a carbon free engine knock due to carbon is gone . Then to keep it gone you pour in one can of Seafoam to a full tank of fuel every 2000 miles .your carbon build up problems are gone for good.