Jefnes

I am a degreed mechanical engineer, so
I feel I have a pretty good grasp on the fundamentals of tuning
a high specific output engine. So there is nothing TOO technical you say
here that would be 'lost.

Background:
Honda B16A
making ~340whp on 18 psi of turbocharged boost.

My specific question relates to combustion and detonation.

I tore down my current engine due to an oil pump failure and took the
opportunity to examine the pistons and the combustion chambers.
Why not since I needed to tear it down anyway.

I noticed that all four piston/combustion chambers are a nice golden
brown with exception of the area near the intake valves...I have
a small 'hot spot' that is evident due to the 'clean' piston appearance
and very slight scuffing of the cylinder walls in this area.
Plugs look good too. (can't tel much from plugs unless you shut off
mid-pull)

This is after 5,000 miles of street driving mixed with long high speed
runs. (i.e. not 1/4 mile, more like 5-6 miles WOT)

This could be evidence of slight detonation but due to the rod bearing
damage from the failed oil pump I cannot use them for discovery.
Usually I see the rod bearings taking a 'pounding' if detonation was
present.


Main question:
What is the cause of the intake side being the 'hot-spot', as this seems to
go against traditional wisdom?
Is the a/f mixture not truly homogeneous at high load/rpm? (fast burn and
little time)

Any 'real' comments/suggestions would be helpful.

I am not looking for things like: what a/f are you running or
how much ignition lead as these are VERY application specific and
I don't want this thread to go into tuning basics... we already know
these things


Thanks,
Jeffrey Atwood