Spark Plug Data Base

Awafrican

Moderator
This is a database for spark plugs which have a heat range of stock / 1 / 2 stages colder than stock. If I'm missing anything let me know and I'll update

MSO Spark Plug Database

Gap size: 0.026" - 0.032"| Preferred gap is between 0.026" - 0.028"
for you those who gap in mm: 0.66mm - 0.71mm

Type and Specs on DISI 2.3L Spark Plugs: 14mm; 5/8 hex; 25mm reach; projected tip; resistor plug

Heat Range Conversion Chart
HKS 25 30 35 40 45 50 52.5 55
DENSO 16 20 22 24 27 31 32 34
NGK 5 6 7 8 9 10 10.5 11
Spark Plug Manf & Part Numbers

Denso Iridium
  • itv-20: Stock heat range
  • itv-22: 1 stage colder heat range
  • itv-24: 2 stage colder heat range
  • itv-27: 3.5 stage colder heat range
NGK IX Iridium

  • NGK LTR7IX-11 (6510): 1 Stage Colder Heat Range
  • NGK LTR6IX-11 (6509): Stock Heat Range
  • NGK ILTR6A-8G (3787): Stock Heat Range
HKS
  • 50003-M35LF 'Mazda MZR Engine': Mazda 3, Mazda 6, MX-5 '06 7 $22.97ea. - 1 Stage Colder Heat Range
  • 50003-M40LF 'Mazda MZR Engine': Mazda 3, Mazda 6, MX-5 '06 8 $22.97ea. - 2 Stage Colder Heat Range
Torque Master Spark Plugs
  • SVTP8BR: Stock Heat Range
  • SVTP7YR: 1 Stage Colder Heat Range
Autolite Iridium
  • Autolite Iridiums XP5364: Stock Heatrange
  • Autolite Iridiums XP5263:1 Step Colder
Copper Plugs

NGK Copper Plugs
  • LZTR4A-11 (5306)
  • LZTR5A-13 (4306)
  • BKR7E
 
Last edited:
Just threw in a new set of NGK plugs for the summer. Gapped them to right around .025
 
Anyone in here experience a lot greater plug life with the copper rod coilpack mod? I've heard it also eliminate all spark blowout at high IDCs too.
 
I gap in mm; suggest to add specs to OP

Sent from my XT1095 using Tapatalk
 
I gap in mm; suggest to add specs to OP

Sent from my XT1095 using Tapatalk
Guys in the USA and gaps in mm? The fuck is wrong with you? Hell I'm in Canada where we use real numbers and I gap in inch. Jokes aside I'm finishing up some shift work and when I can get to the comp tomorrow I'll update OP with mm and other edit suggestions
 
Trying out the Autolite Iridiums XP5263:1 Step Colder
Wish me luck.
I bought a ton of those on Amazon during a sale for about 5 bucks each. I've been changing them every 15k miles cuz I'm at pretty high boost and drive hard, but they have been fine so far.

Sent from my XT1575 using Tapatalk
 
Is there still a fight going on between denso and ngk step colder and which one is better.
My tuner told me he'd never do Densos again because apparently he's seen bits fall off into the cylinders (not sure what--ground electrode, ceramic, etc.). He told me step-colder NGKs for me, so that's what I've run.
 
Guys in the USA and gaps in mm? The fuck is wrong with you?
Hahaha. The car is in metric, the spec was developed in metric, I have metric feelers, why not? Plus this is Detroit. The American auto industry has been on metric for decades now, except the occasional old carryover parts. Therefore I've been metric in my day job for decades too. It just seems normal to me to work in metric. Besides, fractions? Pshaw, ain't nobody got time fo dat.
 
OP Updated


do we know for sure that both 6509 and 3787 (NGK stock range) fit?

6509 (LTR6IX-11) is just 1 step warmer (stock heat range) than 6510 (LTR7IX-11). Otherwise they're identical. They both have a 1.1mm gap (.043") out of the box and need the gap tightened.

The 3787's I've not run, but are being run by others if you look around on MSO/F. They have the more ideal 0.8mm gap (.031"), but should still be checked.
 
Picked up and installed a set of Autolite Iridiums XP5364 no issues with installing them, but all of them had to be re-gaped to .027 as they where all .040 out of the box
 
Add the Gen2 OE plugs to the list - NGK laser iridium - SILTR6A7G. Pre-gapped at 0.028" (my newest set measured around 0.026-0.027). I use these instead of the IX's because of the doubled (60k mile) service life. I've never had issues with the gap widening over time with these either.
 
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