FC_mania

Turbo II running premix , pls let me knwo what you think about the condition of the plugs. when i was tuning it , the wideband afr is cruise 13-14.5 and WOT=rich then change to 10.4afr...

thanks

trailing plugs



leading plugs

RETed

Ignore the trailings plugs - the leadings plugs give you a better idea.

What is your premix ratio?
What brand premix?

The plugs look too rich to me or too much premix.
How much boost?
If it's under 15psi, it's way too rich still.
What kind of gas?


-Ted

FC_mania

i oz per gallon , its coastal brand from autozone

boost is only at 8psi
91 octane......

is my engine dying?( i notice some white deposits on one of the leading plugs) i change my engine oil now at an interval of 500 miles..... with 20w50 castrol dino oil

RETed

Isn't Coastal that cheap stuff?
Can you change pre-mix to something more name brand?
Can you get either Valvoline or Castrol stuff?

For 8psi, I think you're running way too rich.
Hmmm...I don't see any white deposits - did I miss that?
What color is the ceramic below the center electrode?
It looks black to me from the pics - this means it's still rich.


-Ted

Syonyk

I noticed the different color on my leading plugs as well (S4 NA, premix, nothing fancy). I have the same white spot around the electrode. I vaguely recall hearing something about the leading coil firing with different potentials (one plug fires positive, the other negative), which would mean the spark is jumping a different direction, which could account for the difference.

Also, why are you running rich at cruise? At low throttle settings, there's no need to be rich. You could probably tune to 15:1 or so at cruise and gain some fuel economy with no ill effects. As long as it richens up before hitting boost, there shouldn't be any problems. You'd probably want to keep it around 14.7:1 if you still have cats.

-=Russ=-

FC_mania

where can i get some good brand pre-mix? i only found castrol and coastal 2 stroke oil.......

the ceramic side is black..

what kind of timing curve should be used on a rotary turbo?

cruising u can go so lean?....so u shouldnt tune for 13.8 cruising?.....

RETed

Try the Castrol and see if it makes a difference.

You can tune to 14.7 or leaner under cruise.
Just lean the bitch out until it starts to hesitate, and then jack in a little more fuel to keep it happy.
I've tuned a Haltech beyond 15.0:1 under relatively high RPM cruise, and it ran okay - damn EGT's got fricken hot though!


-Ted

Syonyk

Actually, it seems that leaning it out till to just before stumble doesn't provide the best fuel economy. There's a diagram floating around somewhere, but I've tried it with my SAFC (O2 sensor disconnected from the ECU) and fuel economy at the lean stumble point wasn't that great.

-=Russ=-

FC_mania

alright , thanks for the info guys. where did you buy your premix at? like which shop in particular so i know where to find em over here .

RETed : what about the timing curve a rotary should be seeing ? from 30" to 14psi and 500rpm to 9000rpm...?

need help severely on that one before i can mess around with my afr