Spark Plug Database - Colder Than Stock ( Stage 1&2 )
 

This is a compiled database for spark plugs who's heat range is 1 and 2 stages colder than stock. Please add your plugs and we will update this thread.


Gap size - 0.26 - 0.32 | Preferred gap is between 0.26 to 0.28

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

Heat Range Conversion Chart
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

• 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

• NGK IX Iridium
• NGK LTR7IX-11 (6510) - 1 Stage Colder Heat Range
• NGK ILTR6A-8G (3787) - Stock 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

NGK Copper Plugs

LZTR4A-11 (5306)
LZTR5A-13 (4306)
BKR7E

Heh, was about to correct you on the gap. Also perhaps we should sort them by Iridium/Platinum/Copper etc and list a link/price? Great idea though. why preferrably between .03 and .032? I jsut gapped mine to .028 dammit!!! lol

Autolite APP5364. Stock heat range as far as I can tell - Platinum - $3.99

AutoZone.com | Shopping | Parts | Product Detail - Spark Plug

We want colder stage plugs please. We can find stock plug applications all day long, but this isn't why this database is being created. You also do NOT want to be running platinum plugs in boosted applications. Big NONO.. Copper or Iridium plugs only please. Thanks!

How is platinum a big no no. WRXs come with them stock

yeah i have always heard the same thing.

They are junk in high boost... the electrode usually falls right off into the cylinder because they cant handle constant heat temps that boosted engines put out. Platinum work great in NA stock applications and can take day to day abuse... until you boost them.

Thanks for the info. Guess I need to change mine again, LOL. At least they were only 16 bucks. Hope we can find some copper ones in the right size.

Im trying to get some copper numbers, but so far, im having no luck. Hopefully when NGK answers my email, i can get some numbers.

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14mm; 5/8 hex; 25mm reach; projected tip; resistor plug.

some useful info: for those looking for a traditional NGK copper core spark plug.....

here are the specs of the NGK LTR7IX-11 (6510)
Iridium IX Plug, 14mm Thread, 25mm (.984") Reach, 5/8" (16mm) Hex Size, Tapered Seat, Resistor, Fine Wire (0.6mm) Iridium Center Electrode, Tapered Cut Ground Electrode, .044" (1.1mm) Gap

not the right heat range, stock is 6 colder is 7

yeah good call. i just quit at this whole spark plug thing, lol

He should have tried the BR7 series as they are resistor plugs... I run BR7EFs in my truck, which are 2 stages colder than stock.

Not trying to jump off topic or anything, but would there be a greater benefit to going 2 stages colder plugs? I was gonna go colder, but haven't heard of the 2 steps colder plugs till now. I am mild to heavily (at least soon to be) modded.

2 stages will make you idle a little more rough but will be fine.. You will lose a bit of power with stage 2 plugs, over stage 1, but your safety margin is greater.

If a plug is too cold, will it foul easier/faster?

2 stages isnt cold enough to cause fouling. Not with 20 psi of boost.

Here is some initial work. IMO, the stock plugs for the STi and EVO9 are excellent and should be used where possible. Although, I do like copper plugs due to them being less expensive. The below picture has (from left to right) the MS3 stock 6 temp range plug, a 7 temp range plug for the EVO9, and a 7 temp range plug for the STi. Unfortunately, the STi and EVO9 plugs do not seat against the head the same! Otherwise, these would be excellent stock MS3 replacements.

http://www.accessecu.com/Christian/B... for Mazda.jpg

The ILTR6A stock MS3 plug is gapped at ~.031" from the factory.
The LFR7AIX Iridium STi (one range colder than stock) plug is gapped at ~.029" from the factory.
The ILFR7H Laser Iridium EVO9 plug is gapped at ~.022" from the factory.

A few things to note, the different plug MFGs use different numbers for temperature ranges. For NGK and Denso, the higher the number the colder the plug (or the more heat the plug pulls from the combustion chamber and transfers to the head/coolant passages). Temperature ranges of 6 and 7 should be fine choices for most cars. You cannot easily adjust the gap on platinum, iridium, or laser iridium plugs without scratching off the special coatings that make these plugs so expensive...so please be careful. We should be able to find a good replacement spark plug soon, and we will have better input once we analyze the stock used plugs that are being shipped to us by customers.

Christian.

I said on US (backwards) the HKS 50003-M40LF is a heat range of 8, so it's 2 step colder not stock need to edit that first post lol.

And don't forget the itv27 3 step colder (or 3.5).

Sorry off topic. I really don't like US (backwards) due to a wholesale account not getting done with them. I buy my stuff from PG now. I had $10,000 to do an initial buy from them, so now I'm spending it at PG. :laugh2: And will be coming to this forum more often also. :friday:

From NGK...

He also adds:

So .036 reduction is the least safest with iridium.
Copper would be best then, as said before lol.

Anyone know what the Denso itv-20/22/24s are gapped at?

itv20 1.1mm or .044 can gap down to .036
itv22 0.8mm or .032 can gap down to .024
itv24 0.8mm or .032 can gap down to .024
itv27 0.8mm or .032 can gap down to .024

Awesome, looks like the ITV 22/24/27 will work great for us

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

* Above information is just for reference

What heat range is the 27? 3 stage colder or 4?

I'm guessing 3.5, since they are increamenting 2 numbers per 1 heat range number.

This still needs to be fixed!!!

M35LF is 7 heat range - 1 step colder
M40LF is 8 heat range - 2 step colder

fixed

Do we have any answers as too which are the best plugs to run when upping the boost?

denso itv22 recommended by me!

Denso hands down.

at what point do you all think 2 steps colder should be used?

Bump

I like my ste2 colder, I had requested 1 step colder but got 2 step does this cost power? Car runs great, but am I losing a tad of power with the 24 vs 22?

sub

any sources on the Denso Iridium itv-24 - 2 stage colder heat range plugs?

haven't had much luck locally

what step colder would i want for this setup

1.Cobb inlet
2.cobb SRI
3.Cobb Turboback exhaust
4.SU TMIC
5.denso ??????????
6.hks bpv
7.cpe HPFP
8.cpe standback