Hello,
I search on lancershop for the best spark plugs (2 steps colder) and I find out that the part number that they suggest is R7437-9.
6 months before they suggested R7438-9 of NGK RACING series for evo 9.
The main difference of these 2 spark plugs is the ground electrode and the insulator.
R7437-9 has the classic ground electrode and the classic insulator.
R7438-9 has a small straight ground electrode and very small insulator.
So my issue on these plugs is... which one is the best (or proper) for Evo 9 ?
What is the difference of these 2 plugs?
Why the lancershop change the part numbers?

^^^^^??^^^^^^
Bumpy

7437 has a nickel alloy ground electrode material and 7438 has a platinum ground material.

They have a different firing end

http://www.ngk-sparkplugs.jp/english...e.asp?disp=A14

http://www.ngk-sparkplugs.jp/english...e.asp?disp=C14

by the way the stock plug gap is .032" What is the gap of that plug?
You will most likely need a feeler gauge to reset the gap

DimitrisIX the firing end of R7437-9 is made from platinum.

Here is the answer for these spark plugs directly from NGK!!!

Hello,

Both pugs will work for the EVO though the R-7438 series with its low
angle fine wire ground electrode is better suited for racing only and
very high boost levels. The R7437 series will work better for street use
and resist fouling much better.


If you do mostly street driving with the car I would suggest sticking
with the R7437 series it will have much better throttle response at
lower Rpms and will burn a lot cleaner. I have talked to an Evo team
that ran the R7437 series on their 1000whp Evo without issue, so it
should work just fine for your application. Hope this helps, thank you.

Best regards,



Brandon Peeler

Technical Support Representative

Aftermarket Division

NGK Spark Plugs (U.S.A.), INC.

I have this one:

http://www.ngk-sparkplugs.jp/english...e.asp?disp=C14

in 1 step colder. Works good.

i think that running a 2 step colder plug is like asking for trouble

What trouble will you have if you use a 2 step colder plug???

reduced performance obviously unless you have a 1000whp car. you will find 500whp cars using stock plugs with no problems. why change something that works?

The car will be coughing at low rpm, very poor driveability.

People I know who done this regretted it and changed the plugs back to stock or 1 step colder.

2 steps is very extreme.

I only done this so these plugs can last me same time as standard plugs on standard setup, rather then change them out yearly.

so a 1 step colder plug would also be ok for a GT35R powered car running meth???

Just get the Denso IKH24 or IKH27 for 2 step colder. THey are 11.99 each not 40 plus dollars.


PS these cars kill plugs why spend 140 bucks a set for plugs.


S

BPR7ES never let me down.


These cars don;t kill all plugs.
The iridium (expensive) plugs last longer.

11.99$ each x 4 is 43.96$

yea but those are not the right plugs for an evo 9

I got the Denso IKH24 plugs and they look longer than the stock plugs. That normal?

Longer???
The IX has longer sparkplugs than 6-8.
Could you tell me the part number of the stock plugs you had?