DTMR

So I just got into reading how plugs effect performance. So because I'm N/A right now the hotter the plug the better. I know they have NGKs with a heat range of 7. I put the stock motorcraft SP-509 plugs in (The 2008-2010 plugs). Does anyone know what the heat range of those plugs are?

Diabolical!

This is not true. You need to stick with the correct plug for your tune.

DTMR

What do you mean? If i changed my plugs Id have to change my tune?

DTMR

well I mean that doesnt make sense haha

Diabolical!

What I'm saying is, don't put hotter plugs in your car.

DTMR

Well what about those ngk performance plugs on american muscle w that heat range of 7? What is our stock plug heat range?

JCON

I think most people switch to the Autolite HT-1 for NA and Autolite HT 0 for FI. I have a set of Brisk plugs that were too cold for my car. Unfortunately they have about 100 miles on them and cost a lot and I can't find anyone to buy them lol.

Diabolical!

Randomly bumping up the heat range of your plugs is an old school band-aid for cars with fuel/spark issues. It doesn't increase HP and could actually decrease it. As for what American muscle is selling, you need to look closer. Those are for the GT500 and the heat ranges for one motor are not the same as another. But if you want to give them a shot, please be sure to post back with results.

DTMR

So when doing heat ranges you look at the heat range of the motor? Well my stock plugs were toast at 35k miles i put a pic up in the msd gap increase thread

Diabolical!

The simplest way to remember it is to always use the heat range recommended by the manufacturer unless modifications dictate otherwise.

Those plugs in your other thread don't look all that bad to me. No excessive carbon between the electrode and tip. Normal discoloration. Gap may have stretched a bit over time. All-in-all, fairly normal wear and tear.