I don't see a problem with 117 unleaded. It shouldn't blow your motor up. I've never heard of anyone blowing a motor up from using too high of an octane. It will cause carbon deposits over time. Give that a shot. IMO, I don't think it is true knock, as long as you're running 93 (98 in Europe), the car isn't over-heating, and you're running 27* of timing. But, it's still best to figure it out for sure.

 

Yes I'm using 98 - 100 octane (equals 93-95 in USA) all the time. Ion sent me another tune and my current timing is 5 degree less. Nothing is changed. I think I will change the tune back to 27* advance. Big cams like more advance right?

 

So, you're running 22* at idle? I think that is less than the stock cam. It won't hurt anything to have it retarded, the car will just not perform like it should. Did the knock retard change at all when you took out the 5*? Try the 117 stuff and see what it does then. What kind of SCR (static compression ratio) are you running?

 

I guess its less than 20* advance in stock cam at idle.
I took out 5* to look if there will be any changes in knock retard, but nothing changed. So I will tune it back to 27* advance.
My SCR is 11:1
So nothing dangerous with using 117 unleaded race fuel?

 

Nope, the 117 unleaded is probably the equivalent 104 unleaded here, should be no issues...if its leaded, then extened use will burn out your O2 sensors and mess up the cat convertors if you have them.
I doubt the header being against the oil pan would be the cause, the header is bolted to the heads, which bolt to the block which the oil pan is bolted to...its a rigid structure/object, so how could the header move independent of the oil pan and bang against it?? They will vibrate together as one piece...now the header hiting the floor pan would be a different story, but thats not the case here.

I had the same problem after my heads/cam swap, swapped PCMs, KM, knock sensors, etc. My mechanic buddy that did the swap suggested that it may be the poly motor and trans mount as there are a ton of vibrations from the car transmitted to the engine and vice versa...so I'm swapping in rubber mounts in a few weeks just to see.....for now I zeroed out all of the knock tables in the PCM as I know its not real knock...I removed 5 and 10 degrees across the board in the tables with no change.
The stock timing at idle, 0% TPS is 20 degrees.

 

I think 117 is 117 in USA. Its unleaded for sure. Yes I have cats. So there is no problem with 117 unleaded. I can use safely without any doubt right??

No there is no "bang" issue. They move together as you say. The only thing maybe the Knock Sensor hears the abnormal sounds because of headers. (You know LTs are way louder)

My motor mounts are Poly, but I checked them. They are tight.

So 27* degree advance is pretty good for kind a big cam (240/246dur.)

 

At idle?? If that's what you mean, then I would say no. You need more like 32-34* to get the maximum amount of vacuum.

 

Yes at idle. I guess it is between 20-40*, so at idle 34* is pretty too much, isn't it?

 

No, 34* is not necessarily too much. Especially with the cam you have. You add timing until you have the most vacuum possible (lowest MAP), and that is your idle timing.

 

I looked at your log and you also have the retard when you accelerate. Mine doesn't like that. When I press accelerate pedal, my KR becomes 0.0
Its possible you got header gasket leak.

BTW today I took off my LT4 KM and replaced the LT1 KM which Ion sent me (desensitisized) I don't know how much desensitisized, but now I have 0 retard. Sometimes it jumps to 1 and than again becomes zero.
I got really tired dealing with this KR issue.

 

There is no "117" unleaded fuel available in the US. The highest value available (R+M)/2 is 104. Anything with a higher octane will be leaded. You can blend toluene for higher unleaded octane, but you aren't going to find it coming out of a pump, nor in drums from the leading racing fuel manufacturers.