Spark Plug Debate.

[Tiger_kpt]

Will keep it simple... Car in at WGT\'s having a whole load of work and parts fitted to it as described in another thread in this section titled "Estimated Power Output".
In order to save a bit on the labour cost I fit the Magnecor ignition leads and the NGK plugs myself as well as a few other parts.
 
I used 7\'s for the leading and 9\'s for the trailing.
My engine seemed to run alot better using them for the couple of hundred miles that I did with them.
 
Pip asked me today amidst all of the work why I was using 7\'s as leading? Why not 9\'s all round? And that 9\'s all round in the UK is what is recommended.
 
I said that my engine seemed to prefer the 7\'s and ran better as well as potentially a whole load of other advantages. He said that he will have to see how the 7\'s are performing when the car is rolling roaded, dyno\'d and mapped once all of the parts are fitted (Apexi PFC).
 
Just wondering what you thoughts are on leading plugs. Which are best to use. What the advantages and disadvantages are of both the 7\'s and 9\'s in the leading ports and how 7\'s could adversely affect the mapping needing them to be possibly replaced with 9\'s.
 
Basically discipher what Pip meant. lol. :Hammer

[Martiny]

Search on here. There is a thread where Glenn Butcher states that 9\'s all round is a UK Mazda misprint, and it should be 7 and 9 as you have.

[Tiger_kpt]

Yeah that\'s what I thought. Just wondering why Pip wouldn\'t recommend 7\'s and 9\'s also. Although he did used to work for Mazda right? So maybe just used to using 9\'s all round.

[John Yorke]

Yeah that\'s what I thought. Just wondering why Pip wouldn\'t recommend 7\'s and 9\'s also. Although he did used to work for Mazda right? So maybe just used to using 9\'s all round.

Most likely he is suggesting 9\'s all round because of the increased boost causing more heat which requires cooler plugs

[shaunwil]

Also 7\'s arn\'t all that easy to obtain ! 9\'s all round is usually the best choice on a  slightly modded FD

Shaun

[nikp]

I have 7\'s and 9\'s currently and am getting ignition break up problems at higher boost, and it\'s getting worse (Break up occurring at lower boost). I am running single turbo, but applies equally to twins runnign higher boost. I am going to be getting colder plugs (9\'s leading, 10\'s trailing) very soon.

[probedb]

Mine came back from Pip\'s with 9s all round and has been fine. Will be running 9s all round when it\'s finally back on the road.

Shaun, if you go to summit racing in the US they\'re just as easy to get as 9s and also cost about £3 each...

[Ricco_04]

My car was last serviced by Mazda so I wanted to get 7\'s & 9\'s in mine but finially decided with four 9\'s as I could get them easy and am higher than stock boost - I only wanted 7\'s cause I was worried about flooding the engine. Anyway, I was very surprised to see that MAZDA HAD USED 9\'s ALL ROUND!

I have had no problems all this time (thinking I had 7\'s and 9\'s in) and the engine has never flooded (touch wood)

[peterwolds]

run with 9\'s all round for over a year no problems

[Jake]

I\'ve got 10\'s all round without any issues.  9\'s were giving me ignition break-up on the top end.

[nikp]

What boost are you running Jake?

[shaunwil]

The trouble is im running quite high boost on twins and pip reconmended the NGK racing plugs that I think are 11\'s !

Shaun

[Jake]

it\'s running 0.9 bar.  The 9\'s all round started to break up on the secondary turbo although they wern\'t brand new.  The further up the revs you went the worse it got.  10\'s all round sorted it out.

[Jake]

The trouble is im running quite high boost on twins and pip reconmended the NGK racing plugs that I think are 11\'s !

Shaun

The NGK racing plugs are the ones that I\'m running, they come in 9, 10, 10.5 and 11 heat ranges.

[shaunwil]

Im running 0.96-1.05 bar on the twins ! The 9\'s where being blown out at top end. Saw some really good returns swapping the plugs !

Shaun