Hey guys...

I know that a lot of the Evolution VIII cars that have alcohol injection or those that run high boost upgrade their spark plugs. Ive been searching and there is no real info on upgrading the OEM Evo 9 spark plugs one step colder.

Is it necessary to upgrade the IX spark plugs when running 26-30 psi (high boost) or 365-400 whp (high horsepower)? Do a lot of you IX guys with high boost / horsepower upgrade your plugs or are the OEM plugs fine? Lastly, are the 8 and 9 cars the same coldness or are the IX's colder and thats why no one seems to upgrade them?

Thanks!

 

To my knowledge a friend of mine ended up getting NGK's for his IX because while he was getting his car tuned the engine was knocking to much. After he got NGK's he was able to put down 300whp 280tq at 22psi.

His mods were AMS Exhaust, AMS LICP, Walbro 255, K&N Drop-In.

 

9's use a different spark plug than the 8's

https://www.evolutionm.net/forums/sh...hlight=BPR7EIX

I found some plugs that are 1 step colder on NGK's website that would fit the 9, but they are like 30 bucks plug.

 

Yeah I know theyre different.

Anyone know anythin else?

 

Yes, upgrade them. With that level of modification you need to upgrade your plugs....their not expensive.

 

there is about 4 threads about this, and im sure more than that

I am running the Denso Iridiums, one step colder, with the meth

model number is IKH24

 

I have never heard of raw data that would say what heat range to be at with high boost. I have recently heard that unless you run No2 you should be running one heat range hotter than stock instead of colder. This is the only subject that i have gotten confused with.

 

AMS road tuned me, and they told me the one step colders is what I want. I also spoke to Sean Ivey and he told me the same...

If they didnt tell me what I needed, i would have had no clue lol

 

When i go down to AMS again i'll talk to Martin about it. I would like to see the data that all the tuners use to decifer the heat range.

 

Does anyone know the the one step colder NGK from the stock NGK?

 

How is your car running with them and how did the tune go?

Also, where did you get them from?

 

Bumps.

 

im running stock plugs on my ix, they come gapped tight, no misfires runs good. im running 26 psi and snow 2d kit. i got some denso ikh24s but never needed them.

 

HKS Part number: S40iL
OE NGK number: ILFR7H

Stock Plug= NGK ILFR7H Stock #5245 LINK
Step colder= NGK R7437-8 Stock #4901 LINK
2 Steps colder= NGK R7437-9 Stock #4654 LINK
3 Steps colder= NGK R7437-10 Stock #4655 LINK

NGK ILFR7H (OEM) Iridium
http://www.sparkplugs.com/more_info.asp?AAIA=&pid=20451

NGK LFR7AIX Iridium
http://www.sparkplugs.com/more_info.asp?AAIA=&pid=16602

 

I think I may stick with the Densos because they are much cheaper. IS there a performance/quality difference between the two?