Spark Plug heat ranges

[Jersthecool]

So I'm in need of purchasing some spark plugs and with the rest of my order I'm getting some NGK Iridium's off of enjuku.

They show the different heat ranges for different amounts of boost you're running here's the list if you don't know what I mean.

• Heat Range 6 for stock turbo 8-12psi
• Heat Range 7 for upgraded turbo 13-15psi
• Heat Range 8 for upgraded turbo 16-20psi
• Heat Range 9 for upgraded turbo 21+psi

Now come's my question.. I'm planning to run 12psi for low boost which is what I'll be at most of the time being as it's my dd but I also was planning to run 18 psi for my high boost so really don't have any idea which heat range to get. Any info is appreciated.

[fliprayzin240sx]

A good rule of thumb...for every 100hp you make over stock, you go up one heat range (colder plugs). So the question is, what turbo are you running? For the most part, most folk upping the boost on stock turbo or even upgrading to GT2871Rs, usually run 7s gapped down to .028.

[KiLLeR2001]

I have a stock SR @ 11.5 psi and I always get the 7's. Stock gap is 0.036, but I usually put mine at 0.030.

[jspaeth]

Originally Posted by fliprayzin240sx

A good rule of thumb...for every 100hp you make over stock, you go up one heat range (colder plugs). So the question is, what turbo are you running? For the most part, most folk upping the boost on stock turbo or even upgrading to GT2871Rs, usually run 7s gapped down to .028.

This!

That boost vs. heat range table sounds like a load of shit....you don't NEED heat range 9 plugs for 20 psi.............I use 7s and every time I pull them out, the band on the strap is perfect.

No need for iridiums, literally a complete waste.

Many of us with SRs in the 400hp range with 2871Rs and 20ish psi of boost are running:

NGK BK7RE or BP7RES (or something close to that.....)............basically they are copper plugs that cost about 2-3 bucks apiece, gapped down to 0.028-0.032, depending on how good your ignition system is.....

They are cheap enough to just replace every oil change.

[fliprayzin240sx]

^^^BCPR7ES...set of 10 for about $25, used to change them every other oil change.

[Jersthecool]

Awesome will definitely hold off on ordering and just go with some bkr7e's after doing a little more research they look like the best bet. Thanks for your guys' help. So should I be good with a .28 gap?