Just pulled these plugs out my FD. They have about 2-3k miles on them. Some racing, some highway, some city. All 4 plugs are NGK B11EGV. The rear leading definintely has some of the tip burnt off. I've heard this is caused by too much timing? What is you opinion on them?

For a high res pic click here

 

Can you post a better pic of L2; more from the right side like the others? It seems as though it's rounded by having buildup?

Overall it looks like it's running rich, but that doesn't mean that you have a good map at every spot. Also looking at the high res picture, it looks like you have too much anti-seize on there. That with such cold plugs all around will make it run colder and foul plugs faster.

Too much timing would have eaten up the center electrode but yours looks okay.

 

how much advanced are you runing up top?

 

Zinx it looks to me like l2 is running lean and melted part of the ground strap, probley only doing it at wot which explains the dark color. If it were timing it would effect the front too.

I would expect the rear egt is high at wot, could be the injector not flowing properly.

If you make a wot pull and then shut it down and then pull the plug you will get a better picture if your running lean on the back rotor!

Anyway check it out before something happens. let us know!

 

No matter which AFRS you run under boost; if you run the leanest posible idle AFR, and tune cruise speeds for 16-16.5 AFR, the plugs will never be that filthy.

Dirtyest - most fouled plugs I ever seen. A very poor tune!

 

15 degrees

I'm wondering if i should just pull the injectors and get them flow tested before i continue.

I'm still running the stock LIM, hasn't running lean on the rear rotor always been an issue with it? I wonder if i can increase my injector trims for the rear rotor to compensate.

Also, i have noticed a lean spot around 3k rpm and slight vacuum. It rarely hits it, but it does stumble a little when it does. Do you think this is enough to cause the burnt tip?

The car runs great, but it was idling quite a bit before these plugs were pulled. Mainly just to take care of some issues after it sat all winter. I think i should run a new set and drive it around like i always do, and then post again. I would generally say the tune is good. It runs hard and drives very smooth, doesn't smoke, doesn't do anything abnormal except for the one lean spot in low revs.

 

I dont know about the lim but ive ran the same plugs for 10/11 months and there not burned and you know i run 20 psi all the time on 93.

I would do what i said before: put in new plugs put a few miles on them do a good pull, stop and pull the front and rear plug and see if the rear looks like its running lean! That didnt burn all at one time. If it does show lean on the one plug only its probley injector, or some flow issue.

A duel egt set up would tell you right away if you have an imbalance in flow to a rotor.

And the 3000 rpm lean spot is transition of primary and secoundary i dont thik its a big deal. Im running 14.8/15.1 afr crusing and its fine under no load and 11.1 wot.

Flow testing the injectors is never a bad idea but it takes time! I would just hate to see you have a problem now it just the begining of the fun season!

I dont mean to alarm you but things like this is a warning that something isn't right.

See ya! Let us know!

 

hey so did u ever figure this out? was it the injectors?

 

Are these for a rotary? Am I the only one picknig up that these are not the flat style from the factory?

 

I think they look a little sooty as well... maybe rich? Lean plugs usually look burned and white...

I am with saabguy about the style of plug?

I've heard/read that you run the possibility of that little electrode/arc piece falling/burning/breaking off and going into the engine with those style of plugs and that you should only use the flat ones??... could be a myth?

Your still fast in my book @ 10.73 @ 128.62mph!

This is an old thread... nevermind.

 

I've run the "traditional" style plugs before, no ill affects.