I'm getting ready to change my plugs over the holidays and I just bought some NGK iridiums. Wouldn't it be a waste of time to index the plugs due to the location of the plugs in our engines?

If you're **** about your car then do it. Personally I woudn't waste my time on the minuscule benefit it provides.

PM GeePasta... he's big on indexing and can give you good insight

I just finished changing my plugs to NGK iridiums. My plugs must have been really bad, because for some reason this was the most noticable butt dyno so far. Wow! My car accelerates so much smoother and faster. I also cleaned my MAFS and filter on the pop charger so this could help also. I decided not to index the plugs. Maybe my car is now running like it should have been all along. The plugs had 86K on them.

edit: old plug...



What do you all think?

I would venture to say cleaning the MAF sensor and air filter had more to do with the acceleration... every time I clean my MAF sensor it's like I added a mod!

Yes it is a waist of time with our engines but if you had a high horsepower motor(and i am talking 1000whp or more)it would be worth the extra time.

On my 250HP Outboard on my boat, I have to index the plugs. The only problem with indexing is sometimes a spark plug may not index properly and you can't use it in the engine. Some engines it is highly beneficial.

by indexing, is that aligning the gap a certain way towards intake or exhaust valves?

yes... and there have been threads out here that say it's beneficial on our motors... I guess as with many things it will be debatable.

The plug looks good, but at 86K, they were due for replacement.

i indexed the plugs on my altima and yes, i did feel a difference. and when you index them you want the back of the electrode facing the intake valves. that way at high rpm's the incoming air charge doesnt ''blow out'' the spark. thats mostly for f.i. applications but it does help n/a as well. if you do index your plugs youll either get one of two things, more hp and crisper acceleration at higher rpm's or, your car will be the same. its not like your going to lose any hp. i say just do it. the indexing washers are not expensive ne way.D-O I-T.

What do you guys use to clean the MAF? Also, how exactly do you index the plugs?

MAF Sensor cleaner… you can get it at auto parts stores – Kragen, Pep Boys and I think Auto Zone has it (in CA)… it’s a can, you just spray it on the sensor itself and lit it evaporate. It makes a big difference when I do it! So does cleaning the TB (however don’t bother if not needed).

I'm not an expert at indexing but, you just index the gap to the valves... the problem is that if you torque the plugs, they might not line up right unless you over tighten or don’t tighten enough... so to do it right you need several sets to be sure the threads allow you to tighten properly and have them facing the right direction.

GeePasta is you guy to ask about this stuff, or DaveO (but neither post out here much anymore, which is really a shame)