I just want to know which spark plug IS Trailing and Leading.??

HKS 5408-R50RE: HKS Spark Plug-IRIDIUM
HEAT RANGE 10

HKS 5408-R55RE: HKS Spark Plug-IRIDIUM
HEAT RANGE 11

Which is for Trailing and Which is for Leading???

Any answer is much appreciated...

 

well trailing or top plugs are 9s stock and those are the colder plugs

so im guessing the 11 would be the trailing since it is colder than 10. Most guys run the trailing plug for all 4. I use all stock trailing plugs bur9eq I dont think you need a set of plugs like that unless you have a ton of hp like 550

I could be all wrong however.

 

z28_SS,

How modified is your car? Running plugs in that range on a relatively stock car on the street is going to fowl them in a hurry.

 

I'm at 13 to 12 PSI..

But relatively stock though..

 

run stock plugs

bur7eqp for leading (lower
bur9eq for trailing (top

they run about 9 bucks a piece

 

I bought these plugs already.

But still do you guys think I will be aright with this...

 

Get the reciept and return the plugs in exchange for a set of four 9's.

 

So heat range 9 is better...

But really what will happen if I just stick with the Range 10 and 11.??

Thanks

 

Mahjik what do you mean fowl in a hurry.

The plugs will be done in a hurry or the plugs will fowl the engine.??

 

He means that you will be replacing them again very very soon.

 

But how well is the performance??

Will it even improve at all??

 

No.

 

Okay,

They told me that I could exhange for the same plugs only but different Heat Range.

What Heat Range should I go with then???

Appreciate the help..

 

7's on leading, 9's on trailing.

 

thanks Mahjik

 

would 9s leading and trailing also be a bad idea?

again....mostly stock car.

 

Thats what I use, and so do alot of people.

 

I'd do 9's all around