Based on some recommendations, I switched from TR6's to BR7EF's, both gapped at 0.028". Now with the BR7EF's it is cutting out in boost. I can feel the power drop for a split second, then it picks back up, kind of like it's surging. It will do this a dozen times or so before redline. Seems like it might be blowing out spark? It is worse with the cutout open. And then in normal light throttle driving it will surge as well. I didn't have these issues with the TR6's. When I pulled the TR6's they looked to be in great shape.

I'm running a Turbonetics 7668 up to 13psi, 0.76-0.78 lambda on 91 octane (8% methanol), and spraying a 50/50 mix of water/meth at 15gph. Current timing is about 10* and IAT's are ~60F. The tune is conservative at the moment but I plan on adding more timing once my progressive injection controller shows up.

Perhaps these plugs are too cold for spraying water/meth, low IAT's, and low timing. Even with added timing at WOT, this won't help the light throttle surging. I tried reading the plugs but didn't come to any conclusion. I'll post some pics soon.

 

 

the plugs wont tell you anything unless you cut it off right after a wot run or during it doing what its doing.


low timing is not conservative its dangerous.


what kind of surge are you getting on light throttle? afr do anything?

 

AFR doesn't seem to change during the surging at light throttle or breaking up at WOT in boost. I think it happens so fast that it doesn't register on the wideband.

How is low timing dangerous?

I was hoping I could read the plug strap and tell if the plug temp was correct. Is this not possible if the plug wasn't pulled out right after a WOT run?

 

low timing make heat on exhaust valve and runner

 

one of those plugs look like coolant is being burned

 

Lower it to .22-.24 and let it eat.

 

The reddish one? I noticed that too. But my coolant level hasn't changed one bit in the ~1500 miles it's been turbo'd. Also no smoke of any kind comes out in boost or vacuum.

 

Tighten up the gap.

And look for the coolant. The level may be staying the same but that's not to say the head isnt lifting somewhere and allowing coolant in. Try monitoring your cooling system pressure while in boost.

 

Maybe you've got one plug with a crack ceramic and it's just arching every once in a while. I'd try some new plugs, and quit driving around with an unfinished tune. Why do so many people think this is OK.