Big Gun Vortex silencer melt down!

[azcannibal]

I just got my engine back together from my engine builder and started to break it in around the neiborhood. I have a complete big gun exhaust race series. I bought their vortex silencer core that simply bolts right on and off. It has 3 holes @ different lengths sort of like organ pipes. It is CNC'd aluminum. I took it out after seeing aluminum powder on my exhaust tip. Quad is not smoking.

I have stock compression piston and sleeve w/ ported head.
Fuel type: 7 month old U-4 oxygenated (92 octane est.) w/ NOS octane booster since they do not sell 93 pump gas here. Only 91.

I do not know what my ECU is programmed for. I can guess it is way to lean. However, I cannot understand how the exhaust temperature got so hot that far back in the silencer to melt the vortex silencer tips.

I think it's time to hook a D&M kit to it and get some U-2 (100 octane)

Any idea guys on the melt down?

[wanablaze]

Keep in mind we have a shorter headpipe than most 4 strokes. Thus, more heat my meet the silencer, espcially with header wrap. My Ti exhaust is bright blue/purple and the packing and rubber band burnt up in only a few hours. I could have richened it up a bit, but it ran best that way...

You could try to richen it up, but I don't know how well it would run afterwards. The above is my experience, I hope it helps...

[azcannibal]

Reason I'm so puzzled is that I ran the vortex w/ my engine on the last rebuild w/ 13:1 comp w/ X440 map (which was the demise of that rebuild) around the neiberhood and never melted like this.

[cannondale27]

Do a plug reading.Make sure you IACV isnt stuck open.

[djmc]

Same thing happened to me. I called Big Gun and they now make a stainless steel one that does not melt and they replaced mine for free. That does not fix your lean condition but it will save you $100.00.