JouChaFD3S

Hello, how are you guys, Im new in this so I want to know what is the diference when I use leading or trailing spark plug, more pwer? eficiency which recomennd the experts? thank you

sunburn

your lost... go to howstuffworks.com and check out rotary engine...

each rotor fires twice and needs 2 plugs.. leading and trailing.

96fd3s

hi there, ill give a useful answer

Each housing has two sparks plugs - a leading and a trailing.

Leading = Lower spark plug (L)
Trailing = Top spark plug (T)

just think L and T - lower and top, basically

The difference is, leading and trailing plugs are good for different heat ranges. Different parts of the combustion chamber are subjected to different amounts of heat hence why spark plugs with different heat ranges are used.

off the top of my head the plugs are bur7eq and bur9eq. (i forgot which is leading (lower) and which is trailing (top) though- but the spark plugs have an L or a T on them to let you know if they go in the lower or top spark plug hole anyway.

You dont get more power from using different heat range plugs. I hear using the wrong heat range plugs can make your car hard to start but i have no experience with this.

trochoid

iTrader: (6)

The main difference is the size of the hole in the housing. While the spark plug hole is the same size on the outside, the openings inside the housing are very different. The trailing has a very small hole for the spark to arc through. Since the hole is so much smaller, that plug is subjected to less heat.

kel

I thought this too, but the Haynes manual says the opposite. Anyone know for sure?

misterstyx69

iTrader: (142)

Use that Haynes manual to steady your uneven coffee Table.
Leading is LOWER.
Trailing is TOP.

..by the way,some useless info:
The leading plugs fire at the SAME time,so you can screw up the spark plug wiring on those,with no issues.

BUT you need to have the T1 Plug wire(top front spark plug) to T1 on the trailing coil.
T2(rear top plug) to T2 on the trailing coil.
The coil is marked(says it on the coil,T1,T2) so you can't really screw it up.

Stock N/A plugs:If you order plugs,NGK
Bur7eq (leading) X2(quantity)
Bur9eq (trailing) X2 (quantity)
Platinum plugs have a "P" at the end of the number(like Bur7eqP,Bur9eqP)

MrGoodnight

iTrader: (1)

^Are platinums worth the extra $ for a relatively stock engine, turbo or NA?

j9fd3s

iTrader: (3)

i've never been able to tell a difference, so no. maybe they last a tad longer, but its really hard to tell

misterstyx69

iTrader: (142)

When I started my "rotary infatuation" I went into it thinking that the Best stuff works.
I use Platinums,and I find they are great.But I did foul some out when I Over-premixed in my TII.
I've read they last a bit longer,so if you have the habit of not changing plugs you would be ok,just a bit longer!
But as you know,most Fc owners are thifty..lol.,so using the Regular NGK plugs are just fine.
For N/A the regulars are perfect.
For me personally Platinum.( on my TII..9's)

Tem120

iTrader: (5)

leading plugs tend to be hotter , for emissions ,

trailing a bit colder burnning . to reduce knock , if you have emissions use the stock plugs if not upgrade to all 4 plugs being trailing plugs for reduced knock

misterstyx69

iTrader: (142)

well,I am definitely not stock,or emissions friendly anymore..lol!
I figure the only thing in this car that hasn't been changed is the windshield wiper linkage!