Silvia Club of NSW

when i get 7s they have to order them in for me as well. i dont think they make -8 youll need to get -9 or -11 and regap them.

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M35 Stagea.info @ http://www.m35stagea.info/

i had my car on the dyno at unigroup and my car had irridums in it and it kept breaking down yavuz changed them to copper plugs and now it runs perfect the part number was bkR7es-11 give it a go

Changing Your Spark Plugs?

The following is NOT the definitive guide to spark plugs.

Standard Plugs

For example recommended plugs from NGK for 200sx 2.0L SR20DET From 94 Onwards:

Platinum Plug PFR6B-9 ( Group 9 ) @ about $21 per
Iridium Plug BKR6EIX ( Group 8 ) @ about $19 per

Both will set you back around 20 $ mark per plug, whereas a BKR6E or BKR6E-11 will set you back about $4 each.

So what’s the diff?

Both the Platinum and Iridium plugs are going to last longer (under normal engine operation). So lets be honest here, a large part for many will come down to if you can be bothered changing your plugs on a more regular basis. Standard plugs are more likely to need changing more often. For many, who change your oil every 5000k, this maybe not such a big deal (plugs are fairly accessible on the SR after all). For others paying for servicing or DIY this may not be as appealing an option.

So what do all the Numbers Mean?

Example 1: PFR6B-9

Character Description
P------------Platinum
F------------Refers to thread dimensions (Dia14 X 19mm Hex size 16.0mm)
R-----------Resistor type plug
6-----------Heat rating (4 Hot type 9 Cold type)
B-----------Suffix code
-9----------Spark gap (none indicates standard)

Example 2: BKR6E-11

Character Description
B-----------Thread diameter (B-14mm)
K-----------Notes on physical Plug Variances (Ref * below)
R-----------Resistor type plug (VS Z Inductive type)
6-----------Heat rating (2 Hot – 10 Cold Type)
E-----------Thread length (E 19.0mm)
-11--------Spark gap (1.1mm)

* K or BK notes indicate: - The length of the plug gasket circuit to the terminal contact on parts using ISO dimensions is 2.5mm shorter than JIS (Japan standard) BCP type

Plug Gaping

Gap size has a direct affect on two major parameters, the spark plug's tip temperature and the voltage necessary to ignite the air/fuel mixture. Current day plugs are pre-gapped from the factory (hence the number coding); the fact remains that the gap must be checked/adjusted for the specific vehicle that the spark plug is intended for.

Opening a plugs gap up, to present a larger spark to the air/fuel mixture maximizes burn efficiency. A larger gap requires more voltage is to bridge the gap. This is the reason that many tuners add high power ignition systems (upgraded coil packs). The added power allows you to open the plug gap yet still provide a strong reliable spark.
Modified engines running high boost levels will typically require smaller gap settings to ensure ignition of denser air/fuel mixtures. So as a general rule, the more power you make, the smaller the gap you need.

Spark Plug Heat Range?

With modified engines more heat is a by-product of the added power that normally comes when running increased boost. In short, select one heat range colder for every 55-75 kw you add, or when you raise boost significantly. Other requirements may include retarding the timing a little and increased fuel enrichment (remap/rising reg) and octane (buy better fuel). These items are critical when dealing with turbo motors, and failure to address ALL of these issues may/will result in engine damage.

Simply put, when experienced mechanics and tuners build motors, they select their spark plugs for various reasons form the plugs technical properties to the tuners own personal taste. For more detailed information selecting the right plugs for your motor and level of modification speak to your mechanic or tuner.

>+(:

[touge]

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cheers [touge] found that very informative. great first post mate.

I was against spending big money on plugs, but when i did my last service i bought the top spec ones. Cant remember if they were platinum or iridium but they were $23 each. To my surprise i could actually notice a difference. In high rpm >6000 my car pulled cleaner and slightly harder.
Personally i wouldnt go for the crappy cheap ones....especially if your running big power.