[Markrt7]

I've got a 2010 challenger r/t and it's coming up around 30,000 miles already and I wanted to change the spark plugs on it does anyone know what are the best ones for it ?

 

[dodge boy]

Most of us here go with the factory NGK plugs.

 

[bad8nti]

Most of us here go with the factory NGK plugs.

X2..........,

 

[oilslick]

Most of us here go with the factory NGK plugs.

X3!! Unless it's engine is highly modded.

 

[jklotz10]

What they said^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
For a car that's mainly stock I'd stick with OEM recommended plug NGK #LZFR5C-11.

 

[TheOldGuy]

Those of you that have replaced your spark plugs... Have any of you bothered to index them?

For the new Hemi engine, there is an actual recommended aiming point for the electrodes that is supposed to be of great benefit.

-John

 

[jklotz10]

How can you index the plugs? The threads are fixed on the plugs and in the heads. You have to install within a specified torque. How would you index the electrode unless you can get lucky and have it rotate into position without exceeding the torque spec (or be under the specified torque)?

 

[TheOldGuy]

How can you index the plugs? The threads are fixed on the plugs and in the heads. You have to install within a specified torque. How would you index the electrode unless you can get lucky and have it rotate into position without exceeding the torque spec (or be under the specified torque)?

Indexing washer kits are sold with 3 different thickness washers available.
You torque in your new plugs with the original washer being the sacrificial component. You then read a supplied chart of where the electrode will end up with a new washer and the selected index washer. then it will aim within a few degrees of where it is recommended to be for a particular head design.

If you have tapered seat plugs without a washer, washers are supplied with a cone shape and again the same procedure is followed.
About 40 years ago, I had a degree wheel supplied by a German (Bosch maybe) company that had a 3/8" square cutout in the center so it could fit between a ratchet extension and the socket so you could line up the electrode.

Using the washers of either type really don't affect the installed height of the plug due to the miniscule thickness of the washer.

-John

 

[jklotz10]

I never heard of that (but then again I'm not a performance engine builder either) - Great info!:smileup:

What kind of gains will you typically see?

 

[TheOldGuy]

I never heard of that (but then again I'm not a performance engine builder either) - Great info!:smileup:

What kind of gains will you typically see?

1.5 to 2 HP per cylinder for the cylinders that did not end up aligned through the normal installation on the production line, or by just strange coincidence.

I put my car away for the Winter with less than 4K miles on it. When I take it out in the Spring, I'm going to index my stock plugs that are in there. It's a pain in the butt and can take all day but, I like everything pointing in the right direction. So to speak.

-John

 

[jklotz10]

Those are significant gains.

 

[oilslick]

Those are significant gains.

On a stock engine, I highly doubt it.

 

[jklotz10]

I was thinking that - seeing as you barely get those numbers by adding a CAI & cat-back - but since I never heard of indexing plugs and know nothing about it I have no basis for dispute...........

 

[jklotz10]

OK, I had to know so I looked this up...........

http://www.project33.com/article.cfm?ID=199

It seems you can get some good gains by doing this. Good explanation........
The article says you don't need to do it with a HEMI but I'm guessing they're refering to the old school HEMI with one plug. Since we have two plugs per cylinder, I'm thinking we would want them indexed to point towards the center of the combustion chamber.

Wish I could REP ya OldGuy but I need to spread some around first. Thanks for teaching me something new today...Happy Friday!!

 

[TheOldGuy]

Here is a Major manufacturer that DEMANDS that spark plug indexing be done on their engines. You can get out of it whatever you see, but the reason to do it is crystal clear in the example given.

http://www.youtube.com/watch?v=p68apieFgIA

-John

 

[leloup]

Here is a Major manufacturer that DEMANDS that spark plug indexing be done on their engines. You can get out of it whatever you see, but the reason to do it is crystal clear in the example given.

http://www.youtube.com/watch?v=p68apieFgIA

-John

So where could one find the information on the ideal position for the plugs in our modern hemi dual plug setup? Towards the exhaust valve? That would face them towards a smaller part of the chamber due to the slight offset, no?

 

[TheOldGuy]

So where could one find the information on the ideal position for the plugs in our modern hemi dual plug setup? Towards the exhaust valve? That would face them towards a smaller part of the chamber due to the slight offset, no?

My engine guy says point the open side directly at the intake valve stem.

BTW... I just got my indexing washer cones delivered on Friday.

-John

 

[oilslick]

Not to burst your bubble gents but we have 2 plugs per cylinder on the Hemi which pretty much insures a complete burn anyway. I'd say this is a waste of time on a stock engine and I'd bet if you put it on a dyno before and after the indexing you'd see a zero increase in HP.

But if it gives you a warm and fuzzy feeling, what the hay, go for it. :smileup:


:4-wavey:

 

[TheOldGuy]

Not to burst your bubble gents but we have 2 plugs per cylinder on the Hemi which pretty much insures a complete burn anyway. I'd say this is a waste of time on a stock engine and I'd bet if you put it on a dyno before and after the indexing you'd see a zero increase in HP.

But if it gives you a warm and fuzzy feeling, what the hay, go for it. :smileup:


:4-wavey:

I like being Warm AND Fuzzy.

The indexing I'm doing is just an experiment to shut someone up who don't note here. He thinks I'm going to get like 75 HP. At least this will shut him up.

-John

 

[orangepearlrtsteve]

That's all very interesting information! Something I never would have thought of, when you try it, let us know what you find.