whats the coldest spark plug available.
anything colder the a 9

 

yea the HKS iridium/ Denso iridium spark plug from 9, 10, 10.5, 11

 

thanks i see if i can get some denso's tomorrow

 

are you eating plugs or having detonation issues that you want to go with a colder plug???

Colder plugs will often result in cold fouling leading to cold start flooding on our cars.

 

I have hit some detonation and I am addressing it with tuning but I may want to try a colder plug.
I am aware that fouling may occur

 

i c, u do need colder plugs for the mods u have according to you sig

 

does any one have a part number for thoes densos?

 

I dunno, I know lots of people that hit 400 on 9s. But if you are experiencing misfire, I suppose you could go to a colder plug, but I tend to think its a tuning issue.

 

hey j rat. i leaned it out to about 11. af ratio and it raps out smooth all the way to redline, no misfire. pulls like a raped ape.

i did some research and the denso iridium trailing plugs (ireo1-31) are equivalent to a heat range of 10 and the 32s are a heat range of 10.5
the 31s are used as stock replacement in iridium,

 

hks parts #
For
9 - 5408-R45RE
10 - 5408-R50RE
10.5 - 5408-R525RE
11 - 5408-R55RE

for Denso

i think there
9 and 10.5
9 - IRE01-27
10.5 - IRE01-31

 

The NGK Iridiums might be a good choice as well, the RE10CL would be a step colder than the 9 for the leadings, and about half the price of the Denso IRE01-31.

The RE9BT would be a 9.0 for thr trailings.

Note that the NGK Iridiums for the rotary engines, use the CL and BT designation to reference the surround of the tip. The CL plugs (normally used in the leading position) have slots in the ground plane:


while the AL and AT and BT designated tips
use a flat surround.

The slots in the CL series help prevent low temp fouling.

 

hey icemark
have you used the ngk cl series? and will the iridum electrode help with fouling at all

 

How much boost are you running?
Are you running pump gas or race gas?


-Ted

 

The slots on the CL seems to help fouling (the 7CL is the curent leading plug on the RX-8 which was having cold fouling issues).

I have not had any issues using the 7, but then I am only running 7 lbs of boost.

Remember they need to regap'd to around .032 or .030, to run in a FC as they come gapped at .048, something our coils won't run

 

1 bar of boost on 92 pump gas

 

holy **** thoes ngk iridium plugs are like 25 bux a piece

 

It's not your spark plugs...

Are you running a Haltech?
What kinda ms are you running on the ignition?
Try pushing it up to 5.0 or even as high as 5.5 (don't go over 5.5) on the stock coils for better spark?

I don't worry about running colder spark plugs unless I'm running race gas over 20psi of boost.
Anything under that should not require cold spark plugs.

BTW, the NGK "Racing" 10.5 / 11 / 13 heat range spark plugs are $35 each.


-Ted

 

running a e6x with 4 ms
thanks for the info i will give that a try.
do you run the stock heat range or 9s all the way arround

 

I run all 9's.
They should be good for what you're running.

BTW how much dwell time are you running?



-Ted

 

4 MS