Using someone else's dialed in timing map to "try" is a bad idea.

 

for the record i was talkin about scotts map, not hustlers. and its just to get the engine going and tune from there. u cant tell me all of you guys made all of your maps from scratch.

 

I did.

But yeah most grab someone's. Most maps suck. I'm not surprised Brain had detonation with his tuning. He ran mid 12 AFR's IIRC and his timing was a bit agrressive IMO.

 

I made my fuel table from scratch. Its not that hard. The spark table was a DIY copy that was stupid retarded. lol@people using my spark table.

 

yeah my NA maps were basicly from scratch. i started off with diy's but then ended up re-scaling everything for NA and just said screw it and started from scratch. Its not bad.. but id basically like to start with a drivable map and tune it asap.

 

then use diy's map.

If you don't have det-cans, you will fail.\
/thread

 

I cleaned off the carbon and look at it closer, it really looks like the FOD that matches #4. Without seeing the piston in front of me I'm speculating. But it looks like a piece of something pressed its imprint in the squish area, hopefully not parts of a piston. But I didn't notice anything when looking at them initially.

The last two blocks that let go from detonation had no head damage what-so-ever, in fact this is the head of my first replacement motor whose ringlands failed.

My spark map isn't much more advanced than DIYs (16-17* @ 13-14psi) and I run between 12-12.3:1 in boost. It ran great everyday for 10 months straight as a DD with a couple autoxes and dyno runs for abuse.

 

Scott, can you post your latest datalog?
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To me that looks like damage from a foreign object. Before installing the head though take some 400 grit sand paper on the tip of youre finger and debur the sharp edge of each combustion chamber, a .020" or .040" radius does wonders for reducing detonation.

 

Yeah, I've pretty much sided with that hypothesis. I've already smoothed it down, then hit it with 2000 grit. Will be going back on Monday.

 

sure: